M Reza Mirbolooki, MD, PhD | University of California, Irvine (original) (raw)
Books by M Reza Mirbolooki, MD, PhD
"Over the past decade, significant improvements in both pancreas and islet transplantation proced... more "Over the past decade, significant improvements in both pancreas and islet transplantation procedures have led to an increase in the numbers of whole pancreas transplants and the growth of new islet transplantation programs in the US. According to The Organ Procurement and Transplantation Network (OPTN) from Jan-1988 to Oct-2008, there were 21,656 (4.6% of all transplants) pancreas transplants from a total of 30,329 (5.8% of all recoveries) recoveries in the US. However, the number of islet transplants is much smaller and stops around 1.0% of the total pancreas transplants. The reason could be that the number of pancreata processed to get enough islet numbers for transplantation is currently imbalanced to that of potential recipients, with a success rate for islet isolation of about 50%. The other reason could be the costs of islet transplantation are much higher than those of pancreas transplantation generally due to the islet isolation failures. It is estimated that islet transplantation costs for achieving insulin independence in one recipient is between 50−90K.Consideringtheisletisolationfailurerate,thiscostwouldbedoubledat50-90K. Considering the islet isolation failure rate, this cost would be doubled at 50−90K.Consideringtheisletisolationfailurerate,thiscostwouldbedoubledat100-180K. Despite advancements in manufacturing highly purified enzymes, islet purification procedure, and cell culture methods, recovering sufficient islet mass for single donor islet transplantation is rare mostly due to donor-related factors, procurement techniques, and preservation methods affecting islet isolation outcome.
Data from multicenter trials have shown that the experience of the center in human islet isolation greatly decreases the failure rate of islet isolations. However, there are many factors prior to islet isolation process that could limit obtaining sufficient functional islets from a single pancreas regardless of islet isolation laboratory staffs’ experience. These factors include donor’s background variables (age, sex, and body mass index [BMI]); past social and medical history (alcohol abuse, hypertension, diabetes, and pancreatitis); current medical situation (cause of death, hospital stay, prolonged hypotensive episodes, hyperglycemia, and cardiac arrest); pancreas procurement (warm ischemia time, damaged capsule, pancreas flush); pancreas quality (hematoma, bruise, edema, and fat infiltration); and pancreas preservation (cold ischemia time, preservation solutions, and quality of packaging). In order to make islet transplantation available for all diabetics there is an urgent need for establishing more efficient ways of selecting the donors, pancreas procurement, and preservation. In this chapter, all pre-isolation factors affecting islet isolation outcomes will be reviewed."
In the past several decades, cell transplantation has been growing widespread as one of the most ... more In the past several decades, cell transplantation has been growing widespread as one of the most promising treatments for different diseases. However, the methods of cell isolation are not optimized at the current time. Therefore, the choice of one technique over another has been often arbitrary and based more on individual experiences rather than on an understanding of why a certain method works and what modifications could lead it to even a better outcome. The goal of a cell isolation procedure is to optimize the yield of functionally viable, isolated cells. Since cell isolation is a complex procedure, many factors affect its outcome. Type of tissue, donor’s body main index and age, cold ischemia during organ preservation, dissociation medium, dissociation enzyme(s), Impurities in any crude enzyme preparation, concentration(s) of enzyme(s), temperature, and digestion times are among the factors that affect the cell isolation outcome. Researchers searching the scientific literature for information on the ideal enzymes and optimal conditions for tissue dissociation are often confronted with conflicting data. Much of the variation stems from the complex and dynamic nature of the extracellular matrix and from the historical use of relatively crude, undefined enzyme preparations for cell isolation applications. This chapter summarizes our knowledge of how these enzymes accomplish the "routine" operations of tissue dissociation and cell harvesting; describes standard lab procedures; offers a logical experimental approach for establishing a cell isolation protocol; and lists many tissue specific references.
Pancreas transplants are performed for the amelioration of insulin-requiring diabetes. Initially,... more Pancreas transplants are performed for the amelioration of insulin-requiring diabetes. Initially, pancreas transplants were performed only in those diabetic patients with chronic kidney disease who needed kidney transplants; these patients underwent simultaneous pancreas-kidney transplantation (SPK). Today, pancreas transplantation alone (PTA) or pancreas transplantation after living related or unrelated kidney transplantation (PAK) is increasingly common. SPK accounted for 67% of all pancreas transplants in 2006 (Fig. 106.1). The 2007 Annual Report of the Organ Procurement and Transplantation Network (OPTN) and the Scientific Registry of Transplant Recipients (SRTR) reveals that the number of pancreata recovered in the United States for 2006 increased by 53% compared with 1997, and there were approximately 4000 people in the United States waiting for pancreas transplants at the end of 2006.1 Interestingly, there have been recent downward trends in numbers of patients registered for pancreas transplants. New SPK registrations rose from 1412 in 1997 to a high of 2007 in 2000 and declined to 1671 in 2006. Some of this reduction may be due to an increase in the number of patients receiving islet cell transplants. The relative roles of pancreas and islet cell transplantation remain controversial.
A new form of therapy based on biological rather than pharmacological intervention has grown dram... more A new form of therapy based on biological rather than pharmacological intervention has grown dramatically in power and scope in the past decade. This novel therapeutic option, cell therapy, utilizes living cells to rebuild or replace damaged organs and tissues. Hematopoietic stem cell transplantation in cancer therapy, mesenchymal stem cell transplantation in orthopedic repair, and pancreatic islet cell transplantation in diabetes are some examples of cell therapy currently being used or currently under development. Preparing cellular based products often requires complex procedures.
For example, harvested human cells are sometimes implanted onto a scaffold material, which enhances the cells’ structural properties, delivers biochemical factors or cell nutrients, or exerts mechanical or biological influences to modify the behavior of the cells or tissue. Regardless of the complexity in process, it must be recognized that consistency, potency, and purity are characteristics of optimal cellular-based products.
To manufacture these products, cell-processing facilities require highly controlled process environments that must not only protect the products from biological and environmental contamination but protect their personnel. This chapter discusses several issues related to the design and construction of a cell-processing facility, the implementation of cell manipulation process, quality control of the final products, and regulation.
The evolution of clinical islet transplantation has made islet allografting a practical treatment... more The evolution of clinical islet transplantation has made islet allografting a practical treatment for patients with Type 1 diabetes. However, in its present form, it can benefit less than 0.5% of all affected patients. Offsetting this success is the increasing discrepancy between the availability of, and demand for, transplantable islets. Pancreas preservation method has been reported as a major factor affecting the quality of islets for transplantation. Suppression of cellular metabolism by hypothermia is the main method being used to preserve pancreas. During organ removal, blood supply is necessarily interrupted and should be replaced with an appropriate hypothermic preservation solution. The composition of this solution is critical to make the hypothermic storage tolerable maintaining pancreatic viability. During the last three decades, several solutions have been used for hypothermic preservation of pancreas. These solutions have been designed to address biological and physiological requirements for survival in a lowtemperature environment. They differ in basic ionic composition, which can reflect either intracellular (rich in K), including standard University of Wisconsin (UW), Bretschneider, Los Angeles preservation solution (LAP-1), and EuroCollins® solution; or extracellular environment (rich in Na) including Celsior® solution. Some of these solutions have been modified by adding nutrients, antioxidants, and anti-apoptotic agents to improve the current outcomes of islet isolation. In this chapter, we firstdiscuss the principles of pancreas preservation and then review the advantages and disadvantages of different solutions.
The discovery of insulin by Banting and Best in 1922 transformed diabetes from a fatal disease in... more The discovery of insulin by Banting and Best in 1922 transformed diabetes from a fatal disease into a chronic incurable illness with major comorbidities and premature death. It is well established that tight control of blood glucose is essential to the prevention of microvascular complications. However, even aggressive insulin therapy is unable to control transient variations in blood glucose. Chronic hyperglycemia and peripheral hyperinsulinemia are believed to accelerate diabetic microangiopathy. Hence, b-cell replacement has been believed to be the only treatment that reestablishes and maintains long-term glucose homeostasis with near-perfect feedback controls.
Pancreas transplantation has been the standard therapy for Type 1 diabetes with established or imminent end-stage renal disease for several years. The procedure is technically demanding and continues to have significant perioperative mortality and morbidity despite refined surgical techniques, effective immunosuppression modalities, antiviral prophylaxis, and post-transplant monitoring. In contrast, islet transplantation, with its reduced antigen load, technical simplicity, and low morbidity, has the potential to prevent chronic transplantation complications, while providing
physiologic glucose control.
Transplanting pieces or extracts of pancreas in patients with diabetes was performed over 100 years ago; however, accelerated developments and improved understanding of the issues that face clinical islet transplantation during the last 30 years have led this simple concept to a successful treatment for diabetes. After implantation in patients with Type 1 diabetes, the treatment can provide near perfect, moment-to-moment control of blood glucose, far more effectively than injected insulin. The hope is that, with tighter glucose control, the long-term complications of diabetes may be avoided. Since cells are injected percutaneously into the liver via the portal vein under radiographic guidance, and the transplant procedure avoids major surgery, islet transplantation offers the benefits of whole pancreas transplantation but with less risk. Achieving good islet isolation is one of the most important factors in achieving successful islet transplantation. Islet isolation involves the extraction of islets of Langerhans from organ donors through complex digestion and purification processes. In the following sections, the challenges of the extraction of islets, arguably the most complicated and difficult procedure involved in islet transplantation, are reviewed.
Clinical outcomes of pancreas transplantation were superior to that of islet transplantation unti... more Clinical outcomes of pancreas transplantation were superior to that of islet transplantation until the introduction of the Edmonton protocol. Significant advances in islet isolation
and purification technology, novel immunosuppression and tolerance strategies, and effective antiviral prophylaxis have renewed interest in clinical islet transplantation for the treatment of diabetes mellitus. The introduction of a steroid-free antirejection protocol and islets prepared from two donors led to high rates of insulin independence. The Edmonton protocol has been successfully replicated by other centers in an international multicenter trial. A number of key refinements in pancreas transportation, islet preparation, and newer immunological conditioning and induction therapies have led to continued advancement through extensive collaboration between key centers. This chapter provides an overview of the history of islet transplantation followed by a discussion of the state of the art of clinical islet transplantation. The challenges facing the clinician–scientist in the 21st century are also presented in this review.
Papers by M Reza Mirbolooki, MD, PhD
Molecular imaging, Jan 5, 2015
AbstractMetabolic activity of brown adipose tissue (BAT) is activated by β3-adrenoceptor agonists... more AbstractMetabolic activity of brown adipose tissue (BAT) is activated by β3-adrenoceptor agonists and norepinephrine transporter (NET) blockers and is measurable using [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) in rats. Using the streptozotocin (STZ)-treated rat model of type 1 diabetes mellitus (T1DM), we investigated BAT activity in this rat model under fasting and nonfasting conditions using [18F]FDG PET/CT. Drugs that enhance BAT activity may have a potential for therapeutic development in lowering blood sugar in insulin-resistant diabetes. Rats were rendered diabetic by administration of STZand confirmed by glucose measures. [18F]FDG was injected in the rats (fasted or nonfasted) pretreated with either saline or β3-adrenoceptor agonist CL316,243 or the NET blocker atomoxetine for PET/CT scans. [18F]FDG metabolic activity was computed as standard uptake values (SUVs) in interscapular brown adipose tissue (IBAT) and compared acros...
Synapse, 2016
Alzheimer's disease (AD) is a neurodegenerative d... more Alzheimer's disease (AD) is a neurodegenerative disease characterized by Aβ plaques in the brain. The aim of this study was to evaluate the effectiveness of a novel radiotracer, 4-[(11) C]methylamino-4'-N,N-dimethylaminoazobenzene ([(11) C]TAZA), for binding to Aβ plaques in postmortem human brain (AD and normal control (NC)). Radiosyntheses of [(11) C]TAZA, related [(11) C]Dalene ((11) C-methylamino-4'-dimethylaminostyrylbenzene) and reference [(11) C]PIB were carried out by using [(11) C]methyltriflate prepared from [(11) C]CO2 and purified using HPLC. In vitro binding affinities were carried out in human AD brain homogenate with Aβ plaques labeled with [(3) H]PIB. In vitro autoradiography studies with the three radiotracers were performed on of hippocampus of AD and NC brains. PET/CT studies were carried out in normal rats to study brain and whole body distribution. The 3 radiotracers were produced in high radiochemical yields (>40%) and had specific activities >37 GBq/μmol. TAZA had an affinity, Ki= 0.84 nM and was to be 5 times more potent than PIB. [(11) C]TAZA bound specifically to Aβ plaques present in AD brains with grey matter to white matter ratios >20. [(11) C]TAZA was displaced by PIB (>90%), suggesting similar binding site for [(11) C]TAZA and [(11) C]PIB. [(11) C]TAZA exhibited slow kinetics of uptake in the rat brain and whole body images showed uptake in interscapular brown adipose tissue (IBAT). Binding in brain and IBAT were affected by pre-injection of atomoxetine, a norepinephrine transporter blocker. [(11) C]TAZA exhibited high binding to Aβ plaques in human AD hippocampus. Rat brain kinetics were slow and peripheral binding to IBAT needs to be further evaluated. This article is protected by copyright. All rights reserved.
Objectives: Dopamine D3 receptors have been associated with a number of neurological and psychiat... more Objectives: Dopamine D3 receptors have been associated with a number of neurological and psychiatric disorders. Development of agonist-based imaging methodologies of this receptor is important for studies of normal and abnormal brain function and dopamine competition studies. Our goal is to streamline radiosynthesis and evaluate 18F-7-OH-FHXPAT as a tracer for D3 receptors in rats using PET imaging.Methods: Radiolabeling of precursor molecule, 2-(N-propyl-N-6'-bromohexyl)amino-7-tetrahydroxypyranyltetralin was carried out using 18F-fluoride, Kryptofix/K2CO3 in acetonitrile at 95oC for 30 min. Product mixture was purified on RP-HPLC (CH3CN:H2O 0.25%Et3N,68%:32%; flow rate 2.5ml/min. Male Sprague-Dawley rats (2% isoflurane) were used for PET imaging using Inveon PET/CT. Rats were injected 18F-7-OH-FHXPAT iv and imaged for 90 mins. Blocking/displacement studies were carried out using 7-OH-DPAT. Reconstructed brain images were coregistered with MR template and were analyzed using PM...
Objectives Our previous work has shown significant brown adipose tissue (BAT) 18F-FDG metabolic a... more Objectives Our previous work has shown significant brown adipose tissue (BAT) 18F-FDG metabolic activation using β3-adrenoceptor agonists such as CL316,243 in normal rats. This is of value in efforts to reduce obesity by enhancing thermogenic capabilities of BAT. We have now investigated the Zucker lean (Fa/Fa) and obese (fa/fa) rat model with and without activation by β3-adrenoceptor agonist using 18F-FDG PET/CT. Methods 18F-FDG (0.4-0.6 mCi) was injected after 30 minutes into 24 hour fasted male lean and fat Zucker rats pre-treated with saline or CL316,243 (2mg/Kg) for PET/CT study. The rats were awake for 60 minutes with injected 18F-FDG after which, 2% isoflurane was used for anesthesia. The rats were placed within the field of view of the PET scanner and data was acquired for 30 minutes. A CT scan was followed for attenuation correction. From the obtained images, regions of interest were drawn on interscapular, cervical, and periaortic BAT using ASIPRO and 18F-FDG metabolic act...
"Over the past decade, significant improvements in both pancreas and islet transplantation proced... more "Over the past decade, significant improvements in both pancreas and islet transplantation procedures have led to an increase in the numbers of whole pancreas transplants and the growth of new islet transplantation programs in the US. According to The Organ Procurement and Transplantation Network (OPTN) from Jan-1988 to Oct-2008, there were 21,656 (4.6% of all transplants) pancreas transplants from a total of 30,329 (5.8% of all recoveries) recoveries in the US. However, the number of islet transplants is much smaller and stops around 1.0% of the total pancreas transplants. The reason could be that the number of pancreata processed to get enough islet numbers for transplantation is currently imbalanced to that of potential recipients, with a success rate for islet isolation of about 50%. The other reason could be the costs of islet transplantation are much higher than those of pancreas transplantation generally due to the islet isolation failures. It is estimated that islet transplantation costs for achieving insulin independence in one recipient is between 50−90K.Consideringtheisletisolationfailurerate,thiscostwouldbedoubledat50-90K. Considering the islet isolation failure rate, this cost would be doubled at 50−90K.Consideringtheisletisolationfailurerate,thiscostwouldbedoubledat100-180K. Despite advancements in manufacturing highly purified enzymes, islet purification procedure, and cell culture methods, recovering sufficient islet mass for single donor islet transplantation is rare mostly due to donor-related factors, procurement techniques, and preservation methods affecting islet isolation outcome.
Data from multicenter trials have shown that the experience of the center in human islet isolation greatly decreases the failure rate of islet isolations. However, there are many factors prior to islet isolation process that could limit obtaining sufficient functional islets from a single pancreas regardless of islet isolation laboratory staffs’ experience. These factors include donor’s background variables (age, sex, and body mass index [BMI]); past social and medical history (alcohol abuse, hypertension, diabetes, and pancreatitis); current medical situation (cause of death, hospital stay, prolonged hypotensive episodes, hyperglycemia, and cardiac arrest); pancreas procurement (warm ischemia time, damaged capsule, pancreas flush); pancreas quality (hematoma, bruise, edema, and fat infiltration); and pancreas preservation (cold ischemia time, preservation solutions, and quality of packaging). In order to make islet transplantation available for all diabetics there is an urgent need for establishing more efficient ways of selecting the donors, pancreas procurement, and preservation. In this chapter, all pre-isolation factors affecting islet isolation outcomes will be reviewed."
In the past several decades, cell transplantation has been growing widespread as one of the most ... more In the past several decades, cell transplantation has been growing widespread as one of the most promising treatments for different diseases. However, the methods of cell isolation are not optimized at the current time. Therefore, the choice of one technique over another has been often arbitrary and based more on individual experiences rather than on an understanding of why a certain method works and what modifications could lead it to even a better outcome. The goal of a cell isolation procedure is to optimize the yield of functionally viable, isolated cells. Since cell isolation is a complex procedure, many factors affect its outcome. Type of tissue, donor’s body main index and age, cold ischemia during organ preservation, dissociation medium, dissociation enzyme(s), Impurities in any crude enzyme preparation, concentration(s) of enzyme(s), temperature, and digestion times are among the factors that affect the cell isolation outcome. Researchers searching the scientific literature for information on the ideal enzymes and optimal conditions for tissue dissociation are often confronted with conflicting data. Much of the variation stems from the complex and dynamic nature of the extracellular matrix and from the historical use of relatively crude, undefined enzyme preparations for cell isolation applications. This chapter summarizes our knowledge of how these enzymes accomplish the "routine" operations of tissue dissociation and cell harvesting; describes standard lab procedures; offers a logical experimental approach for establishing a cell isolation protocol; and lists many tissue specific references.
Pancreas transplants are performed for the amelioration of insulin-requiring diabetes. Initially,... more Pancreas transplants are performed for the amelioration of insulin-requiring diabetes. Initially, pancreas transplants were performed only in those diabetic patients with chronic kidney disease who needed kidney transplants; these patients underwent simultaneous pancreas-kidney transplantation (SPK). Today, pancreas transplantation alone (PTA) or pancreas transplantation after living related or unrelated kidney transplantation (PAK) is increasingly common. SPK accounted for 67% of all pancreas transplants in 2006 (Fig. 106.1). The 2007 Annual Report of the Organ Procurement and Transplantation Network (OPTN) and the Scientific Registry of Transplant Recipients (SRTR) reveals that the number of pancreata recovered in the United States for 2006 increased by 53% compared with 1997, and there were approximately 4000 people in the United States waiting for pancreas transplants at the end of 2006.1 Interestingly, there have been recent downward trends in numbers of patients registered for pancreas transplants. New SPK registrations rose from 1412 in 1997 to a high of 2007 in 2000 and declined to 1671 in 2006. Some of this reduction may be due to an increase in the number of patients receiving islet cell transplants. The relative roles of pancreas and islet cell transplantation remain controversial.
A new form of therapy based on biological rather than pharmacological intervention has grown dram... more A new form of therapy based on biological rather than pharmacological intervention has grown dramatically in power and scope in the past decade. This novel therapeutic option, cell therapy, utilizes living cells to rebuild or replace damaged organs and tissues. Hematopoietic stem cell transplantation in cancer therapy, mesenchymal stem cell transplantation in orthopedic repair, and pancreatic islet cell transplantation in diabetes are some examples of cell therapy currently being used or currently under development. Preparing cellular based products often requires complex procedures.
For example, harvested human cells are sometimes implanted onto a scaffold material, which enhances the cells’ structural properties, delivers biochemical factors or cell nutrients, or exerts mechanical or biological influences to modify the behavior of the cells or tissue. Regardless of the complexity in process, it must be recognized that consistency, potency, and purity are characteristics of optimal cellular-based products.
To manufacture these products, cell-processing facilities require highly controlled process environments that must not only protect the products from biological and environmental contamination but protect their personnel. This chapter discusses several issues related to the design and construction of a cell-processing facility, the implementation of cell manipulation process, quality control of the final products, and regulation.
The evolution of clinical islet transplantation has made islet allografting a practical treatment... more The evolution of clinical islet transplantation has made islet allografting a practical treatment for patients with Type 1 diabetes. However, in its present form, it can benefit less than 0.5% of all affected patients. Offsetting this success is the increasing discrepancy between the availability of, and demand for, transplantable islets. Pancreas preservation method has been reported as a major factor affecting the quality of islets for transplantation. Suppression of cellular metabolism by hypothermia is the main method being used to preserve pancreas. During organ removal, blood supply is necessarily interrupted and should be replaced with an appropriate hypothermic preservation solution. The composition of this solution is critical to make the hypothermic storage tolerable maintaining pancreatic viability. During the last three decades, several solutions have been used for hypothermic preservation of pancreas. These solutions have been designed to address biological and physiological requirements for survival in a lowtemperature environment. They differ in basic ionic composition, which can reflect either intracellular (rich in K), including standard University of Wisconsin (UW), Bretschneider, Los Angeles preservation solution (LAP-1), and EuroCollins® solution; or extracellular environment (rich in Na) including Celsior® solution. Some of these solutions have been modified by adding nutrients, antioxidants, and anti-apoptotic agents to improve the current outcomes of islet isolation. In this chapter, we firstdiscuss the principles of pancreas preservation and then review the advantages and disadvantages of different solutions.
The discovery of insulin by Banting and Best in 1922 transformed diabetes from a fatal disease in... more The discovery of insulin by Banting and Best in 1922 transformed diabetes from a fatal disease into a chronic incurable illness with major comorbidities and premature death. It is well established that tight control of blood glucose is essential to the prevention of microvascular complications. However, even aggressive insulin therapy is unable to control transient variations in blood glucose. Chronic hyperglycemia and peripheral hyperinsulinemia are believed to accelerate diabetic microangiopathy. Hence, b-cell replacement has been believed to be the only treatment that reestablishes and maintains long-term glucose homeostasis with near-perfect feedback controls.
Pancreas transplantation has been the standard therapy for Type 1 diabetes with established or imminent end-stage renal disease for several years. The procedure is technically demanding and continues to have significant perioperative mortality and morbidity despite refined surgical techniques, effective immunosuppression modalities, antiviral prophylaxis, and post-transplant monitoring. In contrast, islet transplantation, with its reduced antigen load, technical simplicity, and low morbidity, has the potential to prevent chronic transplantation complications, while providing
physiologic glucose control.
Transplanting pieces or extracts of pancreas in patients with diabetes was performed over 100 years ago; however, accelerated developments and improved understanding of the issues that face clinical islet transplantation during the last 30 years have led this simple concept to a successful treatment for diabetes. After implantation in patients with Type 1 diabetes, the treatment can provide near perfect, moment-to-moment control of blood glucose, far more effectively than injected insulin. The hope is that, with tighter glucose control, the long-term complications of diabetes may be avoided. Since cells are injected percutaneously into the liver via the portal vein under radiographic guidance, and the transplant procedure avoids major surgery, islet transplantation offers the benefits of whole pancreas transplantation but with less risk. Achieving good islet isolation is one of the most important factors in achieving successful islet transplantation. Islet isolation involves the extraction of islets of Langerhans from organ donors through complex digestion and purification processes. In the following sections, the challenges of the extraction of islets, arguably the most complicated and difficult procedure involved in islet transplantation, are reviewed.
Clinical outcomes of pancreas transplantation were superior to that of islet transplantation unti... more Clinical outcomes of pancreas transplantation were superior to that of islet transplantation until the introduction of the Edmonton protocol. Significant advances in islet isolation
and purification technology, novel immunosuppression and tolerance strategies, and effective antiviral prophylaxis have renewed interest in clinical islet transplantation for the treatment of diabetes mellitus. The introduction of a steroid-free antirejection protocol and islets prepared from two donors led to high rates of insulin independence. The Edmonton protocol has been successfully replicated by other centers in an international multicenter trial. A number of key refinements in pancreas transportation, islet preparation, and newer immunological conditioning and induction therapies have led to continued advancement through extensive collaboration between key centers. This chapter provides an overview of the history of islet transplantation followed by a discussion of the state of the art of clinical islet transplantation. The challenges facing the clinician–scientist in the 21st century are also presented in this review.
Molecular imaging, Jan 5, 2015
AbstractMetabolic activity of brown adipose tissue (BAT) is activated by β3-adrenoceptor agonists... more AbstractMetabolic activity of brown adipose tissue (BAT) is activated by β3-adrenoceptor agonists and norepinephrine transporter (NET) blockers and is measurable using [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) in rats. Using the streptozotocin (STZ)-treated rat model of type 1 diabetes mellitus (T1DM), we investigated BAT activity in this rat model under fasting and nonfasting conditions using [18F]FDG PET/CT. Drugs that enhance BAT activity may have a potential for therapeutic development in lowering blood sugar in insulin-resistant diabetes. Rats were rendered diabetic by administration of STZand confirmed by glucose measures. [18F]FDG was injected in the rats (fasted or nonfasted) pretreated with either saline or β3-adrenoceptor agonist CL316,243 or the NET blocker atomoxetine for PET/CT scans. [18F]FDG metabolic activity was computed as standard uptake values (SUVs) in interscapular brown adipose tissue (IBAT) and compared acros...
Synapse, 2016
Alzheimer's disease (AD) is a neurodegenerative d... more Alzheimer's disease (AD) is a neurodegenerative disease characterized by Aβ plaques in the brain. The aim of this study was to evaluate the effectiveness of a novel radiotracer, 4-[(11) C]methylamino-4'-N,N-dimethylaminoazobenzene ([(11) C]TAZA), for binding to Aβ plaques in postmortem human brain (AD and normal control (NC)). Radiosyntheses of [(11) C]TAZA, related [(11) C]Dalene ((11) C-methylamino-4'-dimethylaminostyrylbenzene) and reference [(11) C]PIB were carried out by using [(11) C]methyltriflate prepared from [(11) C]CO2 and purified using HPLC. In vitro binding affinities were carried out in human AD brain homogenate with Aβ plaques labeled with [(3) H]PIB. In vitro autoradiography studies with the three radiotracers were performed on of hippocampus of AD and NC brains. PET/CT studies were carried out in normal rats to study brain and whole body distribution. The 3 radiotracers were produced in high radiochemical yields (>40%) and had specific activities >37 GBq/μmol. TAZA had an affinity, Ki= 0.84 nM and was to be 5 times more potent than PIB. [(11) C]TAZA bound specifically to Aβ plaques present in AD brains with grey matter to white matter ratios >20. [(11) C]TAZA was displaced by PIB (>90%), suggesting similar binding site for [(11) C]TAZA and [(11) C]PIB. [(11) C]TAZA exhibited slow kinetics of uptake in the rat brain and whole body images showed uptake in interscapular brown adipose tissue (IBAT). Binding in brain and IBAT were affected by pre-injection of atomoxetine, a norepinephrine transporter blocker. [(11) C]TAZA exhibited high binding to Aβ plaques in human AD hippocampus. Rat brain kinetics were slow and peripheral binding to IBAT needs to be further evaluated. This article is protected by copyright. All rights reserved.
Objectives: Dopamine D3 receptors have been associated with a number of neurological and psychiat... more Objectives: Dopamine D3 receptors have been associated with a number of neurological and psychiatric disorders. Development of agonist-based imaging methodologies of this receptor is important for studies of normal and abnormal brain function and dopamine competition studies. Our goal is to streamline radiosynthesis and evaluate 18F-7-OH-FHXPAT as a tracer for D3 receptors in rats using PET imaging.Methods: Radiolabeling of precursor molecule, 2-(N-propyl-N-6'-bromohexyl)amino-7-tetrahydroxypyranyltetralin was carried out using 18F-fluoride, Kryptofix/K2CO3 in acetonitrile at 95oC for 30 min. Product mixture was purified on RP-HPLC (CH3CN:H2O 0.25%Et3N,68%:32%; flow rate 2.5ml/min. Male Sprague-Dawley rats (2% isoflurane) were used for PET imaging using Inveon PET/CT. Rats were injected 18F-7-OH-FHXPAT iv and imaged for 90 mins. Blocking/displacement studies were carried out using 7-OH-DPAT. Reconstructed brain images were coregistered with MR template and were analyzed using PM...
Objectives Our previous work has shown significant brown adipose tissue (BAT) 18F-FDG metabolic a... more Objectives Our previous work has shown significant brown adipose tissue (BAT) 18F-FDG metabolic activation using β3-adrenoceptor agonists such as CL316,243 in normal rats. This is of value in efforts to reduce obesity by enhancing thermogenic capabilities of BAT. We have now investigated the Zucker lean (Fa/Fa) and obese (fa/fa) rat model with and without activation by β3-adrenoceptor agonist using 18F-FDG PET/CT. Methods 18F-FDG (0.4-0.6 mCi) was injected after 30 minutes into 24 hour fasted male lean and fat Zucker rats pre-treated with saline or CL316,243 (2mg/Kg) for PET/CT study. The rats were awake for 60 minutes with injected 18F-FDG after which, 2% isoflurane was used for anesthesia. The rats were placed within the field of view of the PET scanner and data was acquired for 30 minutes. A CT scan was followed for attenuation correction. From the obtained images, regions of interest were drawn on interscapular, cervical, and periaortic BAT using ASIPRO and 18F-FDG metabolic act...
Nuclear Medicine and Biology, 2015
We have investigated β3-adrenoceptor agonist mediated brown adipose tissue (BAT) activation using... more We have investigated β3-adrenoceptor agonist mediated brown adipose tissue (BAT) activation using (18)F-FDG PET/CT in Zucker lean (ZL) and obese (ZF) rats. (18)F-FDG was injected into ZL and ZF rats pretreated with saline or agonist CL316,243 for scans. (18)F-FDG metabolic activity was computed as standard uptake values. CL316,243 in ZL activated BAT up to 4-fold compared to saline, while ZF BAT was only up by 2 fold. The decreased activation was consistent with lower β3-adrenoceptor levels in ZF rats. The genetically modified ZL and ZF rats may provide a useful rat model to evaluate the significance of β3-adrenoceptor agonist-induced BAT activation in obesity.
Synapse, 2014
We report the use of b3 adrenergic receptor mediated activation of rat brain frontal cortex using... more We report the use of b3 adrenergic receptor mediated activation of rat brain frontal cortex using mirabegron (a selective b3 adrenoceptor agonist), measured by 18 F-FDG PET/CT. Another b3 agonist, CL 316,243, did not have this effect due to impermeability through the blood brain barrier (BBB), while atomoxetine, a norepinephrine transporter blocker, did increase 18 F-FDG uptake in the frontal cortex. Mirabegron exhibited a dose-dependent increase in frontal cortex 18 F-FDG uptake. These findings suggest a possible use of selective b3 adrenoceptor agonists in reversing regional glucose hypometabolism in the brain. Synapse 69:96-98,
Biophysical Journal, 2012
Synapse, 2013
Brown adipose tissue (BAT) plays a significant role in metabolism. In this study, we report the u... more Brown adipose tissue (BAT) plays a significant role in metabolism. In this study, we report the use of atomoxetine (a clinically applicable norepinephrine reuptake inhibitor) for 18 F-FDG PET imaging of BAT and its effects on heat production and blood glucose concentration. Fasted-male Sprague-Dawley rats were administered with intravenous 18 F-FDG. The same rats were treated with atomoxetine (0.1 mg/kg, i.v.) 30 min before 18 F-FDG administration. To confirm theadrenergic effects, propranolol ( -adrenergic inhibitor) 5 mg/kg was given intraperitoneally 30 min prior to atomoxetine administration. The effect of atomoxetine on BAT metabolism was assessed in fasted and non-fasted rats and on BAT temperature and blood glucose in fasted rats. In 18 F-FDG PET/CT images, interscapular BAT (IBAT) and other areas of BAT were clearly visualized. When rats were fasted, atomoxetine (0.1 mg/kg) increased the 18 F-FDG uptake of IBAT by factor of 24 within 30 min. Propranolol reduced the average 18 F-FDG uptake of IBAT significantly. Autoradiography of IBAT and white adipose tissue confirmed the data obtained by PET. When rats were not fasted, atomoxetine-induced increase of 18 F-FDG uptake in IBAT was delayed and occurred in 120 min. For comparison, direct stimulation of 3 -adrenreceptors in nonfasted rats with CL-316, 243 occurred within 30 min. Atomoxetine-induced IBAT activation was associated with higher IBAT temperature and lower blood glucose. This was mediated by inhibition of norepinephrine reuptake transporters in IBAT leading to increased norepinephrine concentration in the synapse. Increased synaptic norepinephrine activates 3-adrenreceptors resulting in BAT hypermetabolism that is visible and quantifiable by 18 F-FDG PET/CT.
OBJECTIVE: Pharmacologic approaches to study brown adipocyte activation in vivo with a potential... more OBJECTIVE:
Pharmacologic approaches to study brown adipocyte activation in vivo with a potential of being translational to humans are desired. The aim of this study was to examine pre- and postsynaptic targeting of adrenergic system for enhancing brown adipose tissue (BAT) metabolism quantifiable by [18F]fluoro-2-deoxyglucose ([18F]FDG) positron emission tomography (PET)/computed tomography (CT) in mice.
METHODS:
A β3-adrenoreceptor selective agonist (CL 316243), an adenylyl cyclase enzyme activator (forskolin) and a potent blocker of presynaptic norepinephrine transporter (atomoxetine), were injected through the tail vein of Swiss Webster mice 30minutes before intravenous (iv) administration of [18F]FDG. The mice were placed on the PET/CT bed for 30min PET acquisition followed by 10min CT acquisition for attenuation correction and anatomical delineation of PET images.
RESULTS:
Activated interscapular (IBAT), cervical, periaortic and intercostal BAT were observed in 3-dimentional analysis of [18F]FDG PET images. CL 316243 increased the total [18F]FDG standard uptake value (SUV) of IBAT 5-fold greater compared to that in placebo-treated mice. It also increased the [18F]FDG SUV of white adipose tissue (2.4-fold), and muscle (2.7-fold), as compared to the control. There was no significant difference in heart, brain, spleen and liver uptakes between groups. Forskolin increased [18F]FDG SUV of IBAT 1.9-fold greater than that in placebo-treated mice. It also increased the [18F]FDG SUV of white adipose tissue (2.2-fold) and heart (5.4-fold) compared to control. There was no significant difference in muscle, brain, spleen, and liver uptakes between groups. Atomoxetine increased [18F]FDG SUV of IBAT 1.7-fold greater than that in placebo-treated mice. There were no significant differences in all other organs compared to placebo-treated mice except liver (1.6 fold increase). A positive correlation between SUV levels of IBAT and CT Hounsfield unit (HU) (R2=0.55, p<0.001) and between CT HU levels of IBAT and liver (R2=0.69, p<0.006) was observed.
CONCLUSIONS:
The three pharmacologic approaches reported here enhanced BAT metabolism by targeting different sites in adrenergic system as measured by [18F]FDG PET/CT.
Obesity is an epidemic, calling for innovative and reliable pharmacological strategies. Here, we ... more Obesity is an epidemic, calling for innovative and reliable pharmacological strategies. Here, we show that ShK-186, a selective and potent blocker of the voltage-gated Kv1.3 channel, counteracts the negative effects of increased caloric intake in mice fed a diet rich in fat and fructose. ShK-186 reduced weight gain, adiposity, and fatty liver; decreased blood levels of cholesterol, sugar, HbA1c, insulin, and leptin; and enhanced peripheral insulin sensitivity. These changes mimic the effects of Kv1.3 gene deletion. ShK-186 did not alter weight gain in mice on a chow diet, suggesting that the obesity-inducing diet enhances sensitivity to Kv1.3 blockade. Several mechanisms may contribute to the therapeutic benefits of ShK-186. ShK-186 therapy activated brown adipose tissue as evidenced by a doubling of glucose uptake, and increased β-oxidation of fatty acids, glycolysis, fatty acid synthesis, and uncoupling protein 1 expression. Activation of brown adipose tissue manifested as augmented oxygen consumption and energy expenditure, with no change in caloric intake, locomotor activity, or thyroid hormone levels. The obesity diet induced Kv1.3 expression in the liver, and ShK-186 caused profound alterations in energy and lipid metabolism in the liver. This action on the liver may underlie the differential effectiveness of ShK-186 in mice fed a chow vs. an obesity diet. Our results highlight the potential use of Kv1.3 blockers for the treatment of obesity and insulin resistance.
Brown adipose tissue (BAT) plays a significant role in metabolism. In this study, we report the u... more Brown adipose tissue (BAT) plays a significant role in metabolism. In this study, we report the use of atomoxetine (a clinically applicable norepinephrine reuptake inhibitor) for (18)F-FDG PET imaging of BAT and its effects on heat production and blood glucose concentration. Fasted-male Sprague-Dawley rats were administered with intravenous (18)F-FDG. The same rats were treated with atomoxetine (0.1 mg/kg, i.v.) 30 min before (18)F-FDG administration. To confirm the β-adrenergic effects, propranolol (β-adrenergic inhibitor) 5 mg/kg was given intraperitoneally 30 min prior to atomoxetine administration. The effect of atomoxetine on BAT metabolism was assessed in fasted and non-fasted rats and on BAT temperature and blood glucose in fasted rats. In (18)F-FDG PET/CT images, interscapular BAT (IBAT) and other areas of BAT were clearly visualized. When rats were fasted, atomoxetine (0.1 mg/kg) increased the (18)F-FDG uptake of IBAT by factor of 24 within 30 min. Propranolol reduced the average (18)F-FDG uptake of IBAT significantly. Autoradiography of IBAT and white adipose tissue confirmed the data obtained by PET. When rats were not fasted, atomoxetine-induced increase of (18)F-FDG uptake in IBAT was delayed and occurred in 120 min. For comparison, direct stimulation of β(3)-adrenreceptors in non-fasted rats with CL-316, 243 occurred within 30 min. Atomoxetine-induced IBAT activation was associated with higher IBAT temperature and lower blood glucose. This was mediated by inhibition of norepinephrine reuptake transporters in IBAT leading to increased norepinephrine concentration in the synapse. Increased synaptic norepinephrine activates β(3)-adrenreceptors resulting in BAT hypermetabolism that is visible and quantifiable by (18)F-FDG PET/CT.
Essential Cell Biology provides an accessible introduction to the fundamental concepts of cell bi... more Essential Cell Biology provides an accessible introduction to the fundamental concepts of cell biology. Its lively writing and exceptional illustrations make it the ideal textbook for a first course in cell and molecular biology. The text and figures are easy-to-follow, accurate, clear, and engaging for the introductory student. Molecular detail has been kept to a minimum in order to provide the reader with a cohesive, conceptual framework of the basic science that underlies our current understanding of biology.
1. Introduction to Cells
2. Chemical Components of Cells
3. Energy, Catalysis, and Biosynthesis
4. Protein Structure and Function
5. DNA and Chromosomes
6. DNA Replication, Repair, and Recombination
7. From DNA to Protein: How Cells Read the Genome
8. Control of Gene Expression
9. How Genes and Genomes Evolve
10. Manipulating Genes and Cells
11. Membrane Structure
12. Membrane Transport
13. How Cells Obtain Energy from Food
14. Energy Generation in Mitochondria and Chloroplasts
15. Intracellular Compartments and Transport
16. Cell Communication
17. Cytoskeleton
18. The Cell Division Cycle
19. Sex and Genetics
20. Tissues and Cancer