Nao Hasuzawa - Academia.edu (original) (raw)

Papers by Nao Hasuzawa

Internal Medicine, 2014

We herein report two cases involving a mother and daughter who presented with clinical features o... more We herein report two cases involving a mother and daughter who presented with clinical features of Cushing's syndrome (CS) at 50 and 29 years of age, respectively, and were both found to have adrenocorticotropic hormone-independent adrenal adenoma. Furthermore, a new adenoma was detected in the contralateral adrenal gland in the mother 10 years after surgical treatment, when she presented with subclinical CS. The pathogenesis of this disorder, including the presence of unknown genetic abnormalities causing hereditary CS, is currently poorly understood. In this report, we describe our experience with and consider the pathophysiological implications of two rare and very interesting cases of familial CS.

Frontiers in Pharmacology, Dec 7, 2022

Vesicular nucleotide transporter (VNUT), an active transporter for nucleotides in secretory vesic... more Vesicular nucleotide transporter (VNUT), an active transporter for nucleotides in secretory vesicles, is responsible for the vesicular storage of ATP and plays an essential role in purinergic chemical transmission. Inhibition of VNUT decreases the concentration of ATP in the luminal space of secretory vesicles, followed by decreased vesicular ATP release, resulting in the blockade of purinergic chemical transmission. Very recently, Miyaji and colleagues reported that eicosapentaenoic acid (EPA) is a potent VNUT inhibitor and effective in treating neuropathic and inflammatory pain and insulin resistance through inhibition of vesicular storage and release of ATP. However, our validation study indicated that, in bovine adrenal chromaffin granule membrane vesicles, EPA inhibited the formation of an electrochemical gradient of protons across the membrane with the concentration of 50% inhibition (IC50) being 1.0 μM without affecting concanamycin B-sensitive ATPase activity. Essentially, similar results were obtained with proteoliposomes containing purified vacuolar H +-ATPase. Consistent with these observations, EPA inhibited the ATP-dependent uptakes of ATP and dopamine by chromaffin granule membrane vesicles, with ID50 being 1.2 and 1.0 μM, respectively. Furthermore, EPA inhibited ATP-dependent uptake of L-glutamate by mouse brain synaptic vesicles with ID50 being 0.35 μM. These results indicate that EPA at sub-μM acts as a proton conductor and increases proton permeability across the membrane, regardless of the presence or absence of VNUT, thereby inhibiting non-specifically the vesicular storage of neurotransmitters. Thus, EPA may affect a broader range of chemical transmission than proposed.

Clinical Case Reports, Aug 13, 2020

Pasireotide improves hypercortisolemia and induces hyperglycemia via somatostatin receptor type‐5... more Pasireotide improves hypercortisolemia and induces hyperglycemia via somatostatin receptor type‐5 stimulation. GLP‐1RA and SGLT2 inhibitor potentially help regulate hyperglycemia in patients with Cushing's disease, especially after pasireotide administration.

Biochemical and Biophysical Research Communications, Jul 1, 2014

In studies of gene-ablated mice, activin signaling through activin type IIB receptors (ActRIIB) a... more In studies of gene-ablated mice, activin signaling through activin type IIB receptors (ActRIIB) and Smad2 has been shown to regulate not only pancreatic β cell mass but also insulin secretion. However, it still remains unclear whether gain of function of activin signaling is involved in the modulation of pancreatic β cell mass and insulin secretion. To identify distinct roles of activin signaling in pancreatic β cells, the Cre-loxP system was used to activate signaling through activin type IB receptor (ActRIB) in pancreatic β cells. The resultant mice (pancreatic β cell-specific ActRIB transgenic (Tg) mice; ActRIBCAβTg) exhibited a defect in glucose-stimulated insulin secretion (GSIS) and a progressive impairment of glucose tolerance. Patch-clamp techniques revealed that the activity of ATP-sensitive K(+) channels (KATP channels) was decreased in mutant β cells. These results indicate that an appropriate level of activin signaling may be required for GSIS in pancreatic β cells, and that activin signaling involves modulation of KATP channel activity.

Frontiers in Endocrinology, May 31, 2021

resistance. Administration of SGLT2 inhibitor, along with metreleptin supplementation, could be a... more resistance. Administration of SGLT2 inhibitor, along with metreleptin supplementation, could be a good alternative therapy for diabetic lipodystrophy observed in CCSs.

American Journal of Case Reports, Nov 20, 2019

Rare co-existance of disease or pathology Background: Patients with type 1 diabetes mellitus, mya... more Rare co-existance of disease or pathology Background: Patients with type 1 diabetes mellitus, myasthenia gravis (MG), and Hashimoto disease are diagnosed as having autoimmune polyendocrine syndrome type 3 (APS3). APS3 is rare, and its pathogenesis is unclear. We describe a female patient with APS3 whose human leukocyte antigen (HLA) type could provide a clue to the pathogenesis of APS3. Case Report: A 40-year-old Japanese female patient who had been diagnosed with MG at 5 years of age, and which had been treated with cholinesterase inhibitors, was referred to our hospital with thirst, polydipsia, polyuria, weight loss, and hyperglycemia. She was found to have type 1 diabetes mellitus based on laboratory tests. She was also positive for anti-thyroid peroxidase antibody and was thus diagnosed with Hashimoto disease. This combination of type 1 diabetes mellitus, myasthenia gravis, and Hashimoto disease led to a diagnosis of APS3. Her HLA serotype was A24; B46/54; DR4/9; DQ8/9, and genotype was A*24: 02; B

Scientific Reports, Mar 4, 2021

The vesicular nucleotide transporter (VNUT) is responsible for the vesicular storage and release ... more The vesicular nucleotide transporter (VNUT) is responsible for the vesicular storage and release of ATP from various ATP-secreting cells, and it plays an essential role in purinergic signaling. Although extracellular ATP and its degradation products are known to mediate various inflammatory responses via purinoceptors, whether vesicular ATP release affects steatohepatitis and acute liver injury is far less understood. In the present study, we investigated the effects of clodronate, a potent and selective VNUT inhibitor, on acute and chronic liver inflammation in mice. In a model of methionine/ choline-deficient diet-induced non-alcoholic steatohepatitis (NASH), the administration of clodronate reduced hepatic inflammation, fibrosis, and triglyceride accumulation. Clodronate also protected mice against high-fat/high-cholesterol diet-induced steatohepatitis. Moreover, prophylactic administration of clodronate prevented d-galactosamine and lipopolysaccharide-induced acute liver injury by reducing inflammatory cytokines and hepatocellular apoptosis. In vitro, clodronate inhibited glucose-induced vesicular ATP release mediated by VNUT and reduced the intracellular level and secretion of triglycerides in isolated hepatocytes. These results suggest that VNUT-dependent vesicular ATP release plays a crucial role in the recruitment of immune cells, cytokine production, and the aggravation of steatosis in the liver. Pharmacological inhibition of VNUT may provide therapeutic benefits in liver inflammatory disorders, including NASH and acute toxin-induced injury.

Endocrine connections, Jul 1, 2020

Background and Aims: It is currently unclear whether sodium-glucose co-transporter 2 (SGLT2) inhi... more Background and Aims: It is currently unclear whether sodium-glucose co-transporter 2 (SGLT2) inhibitor administration can improve the insulin sensitivity as well as rapidly reduce plasma glucose concentrations in humans during the early phase of treatment initiation. This study aimed to investigate the effect of SGLT2 inhibitor on insulin sensitivity in the early phase of treatment initiation. Methods and Results: This single-center, open label, and single-arm prospective study recruited 20 patients (14 men) with type 2 diabetes mellitus (T2DM). We examined the patients' metabolic parameters before and 1 week after SGLT2 inhibitor (10 mg/day of empagliflozin) administration. The glucose infusion rate (GIR) was evaluated using the euglycemic hyperinsulinemic glucose clamp technique. Changes in laboratory and anthropometric parameters before and after SGLT2 inhibitor administration were analyzed according to the change in the GIR. The BMI, body fat amount, skeletal muscle amount, systolic blood pressure, and triglyceride level significantly decreased along with the treatment, while urinary glucose level and log GIR value significantly increased. Notably, changes in the GIR after SGLT2 inhibitor administration, which indicated improvement in peripheral insulin sensitivity, were negatively correlated with T2DM duration and positively with reduction in fluctuation of daily plasma glucose profiles before and after treatment. Conclusion: SGLT2 inhibitor improved insulin sensitivity in the skeletal muscle independent of anthropometric changes. Patients with short duration of T2DM and insulin resistance can be good candidates for short-term SGLT2 inhibitor administration to improve insulin sensitivity in the skeletal muscle.

Arteriosclerosis, Thrombosis, and Vascular Biology, Jul 1, 2020

Objective: Mitochondria consistently change their morphology in a process regulated by proteins, ... more Objective: Mitochondria consistently change their morphology in a process regulated by proteins, including Drp1 (dynamin-related protein 1), a protein promoting mitochondrial fission. Drp1 is involved in the mechanisms underlying various cardiovascular diseases, such as myocardial ischemia/reperfusion injury, heart failure, and pulmonary arterial hypertension. However, its role in macrophages, which promote various vascular diseases, is poorly understood. We therefore tested our hypothesis that macrophage Drp1 promotes vascular remodeling after injury. Method and Results: To explore the selective role of macrophage Drp1, we created macrophage-selective Drp1-deficient mice and performed femoral arterial wire injury. In these mice, intimal thickening and negative remodeling were attenuated at 4 weeks after injury when compared with control mice. Deletion of macrophage Drp1 also attenuated the macrophage accumulation and cell proliferation in the injured arteries. Gain- and loss-of-function experiments using cultured macrophages indicated that Drp1 induces the expression of molecules associated with inflammatory macrophages. Morphologically, mitochondrial fission was induced in inflammatory macrophages, whereas mitochondrial fusion was induced in less inflammatory/reparative macrophages. Pharmacological inhibition or knockdown of Drp1 decreased the mitochondrial reactive oxygen species and chemotactic activity in cultured macrophages. Co-culture experiments of macrophages with vascular smooth muscle cells indicated that deletion of macrophage Drp1 suppresses growth and migration of vascular smooth muscle cells induced by macrophage-derived soluble factors. Conclusions: Macrophage Drp1 accelerates intimal thickening after vascular injury by promoting macrophage-mediated inflammation. Macrophage Drp1 may be a potential therapeutic target of vascular diseases.

Proceedings of the National Academy of Sciences of the United States of America, Jul 18, 2017

Clinical Case Reports, Apr 1, 2022

Eruptive xanthomas are skin manifestations associated with hypertriglyceridemia. Accordingly, the... more Eruptive xanthomas are skin manifestations associated with hypertriglyceridemia. Accordingly, the improvement of hypertriglyceridemia can ameliorate this condition. We report a case of a patient with type 2 diabetes mellitus who was diagnosed with this skin lesion. Clinicians should be aware that eruptive xanthomas could indicate metabolic disorders associated with atherosclerosis.

American Journal of Case Reports, Feb 10, 2020

Diabetology international, Feb 15, 2014

The patient presented in this case was an 83-year-old female who was referred to our department f... more The patient presented in this case was an 83-year-old female who was referred to our department for a detailed examination and treatment of a diabetic foot. She had history of treatment with continuous oral steroid therapy (8 mg/day) for polymyalgia rheumatica (PMR), insulin therapy (NovoRapid 30 Mix: 8 units in the morning and 2 units in the evening), and oral treatment with acarbose (100 mg, 3T) for diabetes. Although she did not complain of abdominal fullness or pain, a routine abdominal X-ray revealed free air below the diaphragm and noticeable gaseous distention in the ascending and transverse colon. Abdominal CT demonstrated dilatation, mesenteric edema, and diffuse pneumatosis intestinalis throughout the ascending and transverse colon. A diagnosis of pneumatosis cystoides intestinalis (PCI) was made based on these findings. As the α-glucosidase inhibitor (α-GI) was suspected to be the cause of the PCI, we administered conservative treatment, discontinuing acarbose with fasting and fluid supplementation. The patient progressed well, and 3 weeks later, an abdominal X-ray and CT scan confirmed the disappearance of the pneumocystis lesions in the colon. With the recent rise in the number of elderly individuals and increased awareness of PMR, the number of reported patients with PMR receiving steroid therapy in Japan has increased. Therefore, the incidence of PMR among elderly patients with diabetes mellitus receiving α-GI and steroid therapy is anticipated to increase in the future. Hence, PCI should be carefully assessed as a possible complication and the gastrointestinal tract should be investigated in such patients.

Biochimica Et Biophysica Acta: Molecular Basis Of Disease, Mar 1, 2021

Non-alcoholic steatohepatitis (NASH) is becoming a growing public health problem along with the i... more Non-alcoholic steatohepatitis (NASH) is becoming a growing public health problem along with the increase of metabolic syndrome worldwide. Extracellular nucleotides are known to serve as a danger signal by initiating purinergic signaling in many inflammatory disorders, although the role of purinergic signaling in the progression of NASH remains to be clarified. Vesicular nucleotide transporter (VNUT) is a key molecule responsible for vesicular ATP release to initiate purinergic signaling. Here, we studied the role of VNUT in the progression of nonalcoholic steatohepatitis. VNUT was expressed in mouse hepatocytes and associated, at least in part, with apolipoprotein B (apoB)-containing vesicles. High glucose stimulation evoked release of appreciable amount of ATP from hepatocytes, which disappeared in hepatocytes of Vnut knockout (Vnut − /−) mice. Glucose treatment also stimulated triglyceride secretion from hepatocytes, which was inhibited by PPADS and MRS211, antagonists of P2Y receptors, and clodronate, a VNUT inhibitor, and was significantly reduced in Vnut − /− mice. In vivo, postprandial secretion of triglyceride from hepatocytes was observed, while the serum triglyceride level was significantly reduced in Vnut − /− mice. On a high-fat diet, the liver of wild type mice exhibited severe inflammation, fibrosis, and macrophage infiltration, which is similar to NASH in humans, while this NASH pathology was not observed in Vnut − /− mice. These results suggest that VNUT-mediated vesicular ATP release regulates triglyceride secretion and involves in chronic inflammation in hepatocytes. Since blockade of vesicular ATP release protects against progression of steatohepatitis, VNUT may be a pharmacological target for NASH.

Current Oncology, Feb 1, 2019

Purinergic Signalling, Dec 16, 2022

Journal of Oncology Practice, Jul 1, 2018

The Japanese Biochemical Society/The Molecular Biology Society of Japan, Oct 31, 2017

Purinergic Signalling, Oct 28, 2021

Quinacrine, a fluorescent amphipathic amine, has been used as a vital fluorescent probe to visual... more Quinacrine, a fluorescent amphipathic amine, has been used as a vital fluorescent probe to visualize vesicular storage of ATP in the field of purinergic signaling. However, the mechanism(s) by which quinacrine represents vesicular ATP storage remains to be clarified. The present study investigated the validity of the use of quinacrine as a vial fluorescent probe for ATP-storing organelles. Vesicular nucleotide transporter (VNUT), an essential component for vesicular storage and ATP release, is present in very low density lipoprotein (VLDL)-containing secretory vesicles in hepatocytes. VNUT gene knockout (Vnut−/−) or clodronate treatment, a VNUT inhibitor, disappeared vesicular ATP release (Tatsushima et al., Biochim Biophys Acta Molecular Basis of Disease 2021, e166013). Upon incubation of mice’s primary hepatocytes, quinacrine accumulates in a granular pattern into the cytoplasm, sensitive to 0.1-μM bafilomycin A1, a vacuolar ATPase (V-ATPase) inhibitor. Neither Vnut−/− nor treatment of clodronate affected quinacrine granular accumulation. In vitro, quinacrine is accumulated into liposomes upon imposing inside acidic transmembranous pH gradient (∆pH) irrespective of the presence or absence of ATP. Neither ATP binding on VNUT nor VNUT-mediated uptake of ATP was affected by quinacrine. Consistently, VNUT-mediated uptake of quinacrine was negligible or under the detection limit. From these results, it is concluded that vesicular quinacrine accumulation is not due to a consequence of its interaction with ATP but due to ∆pH-driven concentration across the membranes as an amphipathic amine. Thus, quinacrine is not a vital fluorescent probe for vesicular ATP storage.

Internal Medicine, Apr 1, 2023

Objective This study assessed the relationships between oral health (number of remaining and heal... more Objective This study assessed the relationships between oral health (number of remaining and healthy teeth and periodontal disease) and type 2 diabetes mellitus (T2DM) to contribute to improved patient care. Patients We conducted a cross-sectional cohort study of consecutive patients being regularly treated for chronic diseases (T2DM, hypertension, and dyslipidemia). A dentist or dental hygienist accurately evaluated the oral environment. Patients with fewer than 20 teeth were classified as having reduced remaining teeth (RRT). Results A total of 267 patients were enrolled, including 153 patients (57%) with T2DM and 114 without (43%). Patients with T2DM had 3 fewer remaining teeth on average than those without DM [median: 22 (interquartile range (IQR): 11-27) vs. median: 25 (IQR: 17.3-28), p=0.02]. In addition, patients with T2DM had 4 fewer healthy teeth on average than those without DM [median: 8 (IQR: 2.8-15) vs. median: 12 (IQR: 6-16), p=0.02]. The frequency of RRT was higher in the T2DM group (n=63; 41%) than in the non-DM group (n=31; 27%, p=0.02). Multivariable logistic regression for the presence of RRT in the T2DM group found that age [odds ratio (OR), 1.08; 95% confidence interval (CI), 1.03-1.13; p<0.01] and regular dental consultations (OR, 0.28; 95% CI, 0.10-0.76; p=0.01) were independently and significantly associated. Conclusion The number of remaining or healthy teeth was significantly lower in patients with T2DM than in those without T2DM in current Japanese clinical practice. Regular dental consultation is recommended to preserve remaining teeth in patients with T2DM.