Philip O'Connell - Academia.edu (original) (raw)

Papers by Philip O'Connell

JCI Insight

Regulatory T cells (Treg) have potential for the treatment of autoimmune diseases and graft rejec... more Regulatory T cells (Treg) have potential for the treatment of autoimmune diseases and graft rejection. Antigen-specificity and functional stability are considered to be critical for their therapeutic efficacy. In this study, expansion of human Treg in the presence of porcine PBMC (Xn-Treg) allowed the selection of a distinct Treg subset, co-expressing the activation/memory surface markers HLA-DR and CD27 with enhanced proportion of FOXP3+Helios+ Tregs. Compared to their unsorted and HLA-DA+CD27+ double positive (DP) cell depleted Xn-Treg counterparts, HLA-DR+CD27+ DP-Enriched Xn-Treg expressed upregulated Treg function markers CD95 and ICOS with enhanced suppression of xenogeneic but not polyclonal MLR. They also had less methylated Treg-specific demethylated region (TSDR) of FOXP3 and were more resistant to conversion to effector cells under inflammatory conditions. Adoptive transfer of porcine islet recipient NOD-SCID IL2 receptor -/-(NSG) mice with HLA-DR+CD27+ DP-Enriched Xn-Treg in a humanized mouse model inhibited porcine islet graft rejection mediated by 25-fold more human effector cells. The prolonged graft survival was associated with enhanced accumulation of FOXP3+ Treg and upregulated expression of Treg functional genes, IL10 and CTLA4, but downregulated expression of effector Th1, Th2 and Th17 cytokine genes, within surviving grafts. Collectively, human HLA-DR+CD27+ DP-Enriched Xn-Treg expressed a specific regulatory signature that enabled identification and isolation of antigen-specific and functionally stable Treg with potential as a Treg-based therapy.

ABSTRACTDiabetes is a global public health burden and is characterized clinically by a relative o... more ABSTRACTDiabetes is a global public health burden and is characterized clinically by a relative or absolute insulin deficiency. Therapeutic agents that stimulate and improve insulin secretion and insulin sensitivity are in high demand as diabetic treatment. CD47 is a cell surface glycoprotein implicated in multiple cellular functions, including recognition of self, angiogenesis, and nitric oxide signaling, however its role in the regulation of insulin secretion remains unknown. For the first time we demonstrate that CD47 receptor signaling inhibits insulin release from β-cells and that it can be pharmacologically exploited to boost insulin secretion. CD47 depletion stimulates insulin granule exocytosis via activation of the Rho GTPase Cdc42. CD47 deficiency improved glucose clearance and insulin sensitivity in mice. CD47 blockade enhanced islet transplantation efficiency and improved outcomes. Further, anti-CD47 antibody treatment delayed the onset of diabetes in non-obese diabetic ...

Frontiers in Immunology

Porcine islets surviving the acute injury caused by humoral rejection and IBMIR will be subjected... more Porcine islets surviving the acute injury caused by humoral rejection and IBMIR will be subjected to cellular xenograft rejection, which is predominately mediated by CD4+T cells and is characterised by significant infiltration of macrophages, B cells and T cells (CD4+and CD8+). Overall, the response is different compared to the alloimmune response and more difficult to suppress. Activation of CD4+T cells is both by direct and indirect antigen presentation. After activation they recruit macrophages and direct B cell responses. Although they are less important than CD4+T cells in islet xenograft rejection, macrophages are believed to be a major effector cell in this response. Rodent studies have shown that xenoantigen-primed and CD4+T cell-activated macrophages were capable of recognition and rejection of pancreatic islet xenografts, and they destroyed a graftviathe secretion of various proinflammatory mediators, including TNF-α, reactive oxygen and nitrogen species, and complement fa...

Frontiers in Immunology

Xenotransplantation using porcine donors is rapidly approaching clinical applicability as an alte... more Xenotransplantation using porcine donors is rapidly approaching clinical applicability as an alternative therapy for treatment of many end-stage diseases including type 1 diabetes. Porcine neonatal islet cell clusters (NICC) have normalised blood sugar levels for relatively short periods in the preclinical diabetic rhesus model but have met with limited success in the stringent baboon model. Here we report that NICC from genetically modified (GM) pigs deleted for αGal and expressing the human complement regulators CD55 and CD59 can cure diabetes long-term in immunosuppressed baboons, with maximum graft survival exceeding 22 months. Five diabetic baboons were transplanted intraportally with 9,673 – 56,913 islet equivalents (IEQ) per kg recipient weight. Immunosuppression consisted of T cell depletion with an anti-CD2 mAb, tacrolimus for the first 4 months, and maintenance with belatacept and anti-CD154; no anti-inflammatory treatment or cytomegalovirus (CMV) prophylaxis/treatment was...

PLOS ONE, 2019

Understanding the immunological phenotype of transplant recipients is important to improve outcom... more Understanding the immunological phenotype of transplant recipients is important to improve outcomes and develop new therapies. Immunophenotyping of whole peripheral blood (WPB) by flow cytometry is a rapid method to obtain large amounts of data relating to the outcomes of different transplant treatments with limited patient impact. Healthy individuals and patients with type 1 diabetes (T1D) enrolled in islet transplantation were recruited and WPB was collected. 46 fluorochrome-conjugated mouse-anti-human antibodies were used (43 of 46 antibodies were titrated). BD cytometer setup and tracking beads were used to characterize and adjust for cytometer performance. Antibody cocktails were pre-mixed <60 minutes before staining. Multicolour panels were designed based on fluorochrome brightness, antigen density, co-expression, and fluorochrome spillover into non-primary detectors in each panel on a 5 laser flow cytometer. WPB sample staining used 50-300 μl WPB for each panel and was performed within 2 hours of blood sample collection. Samples were acquired on a BD-LSRFortessa. The operating procedures, including specimen collection, antibody cocktails, staining protocol, flow-cytometer setup and data analysis, were standardized. The staining index of 43 antibodies and the spillover spreading matrix for each panel was calculated. The final concentrations for the 46 antibodies used was determined for staining of WPB samples. Absolute cell-count and 7 leukocyte profiling panels consisting of subsets and/or status of granulocytes, monocytes, dendritic, B, NK, and T cells including regulatory T cells (Tregs) and NKT were designed and established on a 5 laser BD-LSR Fortessa. 13 T1D patients, including 4 islet transplant recipients and 8 healthy controls, were evaluated. The ability to reproducibly measure immune subsets and immune-profiles of islet transplant patients up to 18 months post transplantation has been established as a tool to measure immune cell reconstitution after transplantation.

Cell Transplantation, 2013

Islet cell transplantation as a therapy for type 1 diabetes has been limited by progressive graft... more Islet cell transplantation as a therapy for type 1 diabetes has been limited by progressive graft loss. Significant immunosuppression including T-cell ablation has been used in an attempt to limit islet rejection. Here, we show that CD3+lymphocytes depleted of alloreactive T cells selected from a mixed lymphocyte reaction (MLR), where responder BALB/c splenocytes stained with carboxyfluorescein succinimidyl ester (CFSE) were stimulated with irradiated C57BL/6 splenocytes for 5 days, infused into diabetic immunodeficient mice are capable of restoring a broad T-cell repertoire and specifically do not reject islet transplants from the strain (C57BL/6) used in the original depletion. These mice demonstrate reconstitution with CD4+and CD8+T cells, the capacity to reject third-party grafts (CBA), and restoration of interferon-γ (IFN-γ) responses to third-party alloantigens. Over time, both forkhead box P3-positive (Foxp3+) T regulatory cells (Tregs) and γδ T cells expand, suggesting a rol...

JCI insight, Feb 13, 2024

Medical Journal of Australia, 2006

Objective: To determine whether pancreatic islet transplantation can control diabetes and prevent... more Objective: To determine whether pancreatic islet transplantation can control diabetes and prevent severe life-threatening hypoglycaemia. Design, setting and participants: A single-arm observation study of six patients undergoing islet transplantation. All patients had had type 1 diabetes mellitus for over 5 years and documented episodes of repeated severe hypoglycaemia. Islets were isolated from donor pancreases digested by Liberase. Separated islets were infused into the recipient's liver via the portal vein. Patients were immunosuppressed with daclizumab, sirolimus and tacrolimus. The transplants were performed at Westmead Hospital, NSW, between October 2002 and February 2005. Main outcome measures: Normal blood glucose control without administration of exogenous insulin; demonstration of islet function and abolition of hypoglycaemia. Results: Five of the patients received two islet infusions, and the sixth was withdrawn after one infusion following a portal vein thrombosis. Three patients became insulinindependent, with excellent glycaemic control. Two had islet function with circulating C-peptide, improved glycaemic control, reduced insulin requirement and abolition of severe hypoglycaemia. However, over a 2-year period, graft function deteriorated. Recipients who were initially insulin free remained C-peptide positive but required supplemental insulin. Complications included one postoperative bleed, two portal vein thromboses (which resolved completely), presumed recurrence of tuberculosis in one patient, and deterioration in renal function in one patient. Conclusions: Islet transplantation is effective at improving glycaemic control and hypoglycaemia unawareness in the short to medium term. However, problems with longterm safety of immunosuppression, islet-induced thrombosis and early detection of loss MJA 2006; 184: 221-225 of islet function remain to be addressed.

Islet transplantation can restore lost glycemic control in type 1 diabetes subjects, but is restr... more Islet transplantation can restore lost glycemic control in type 1 diabetes subjects, but is restricted in its clinical application by limiting supplies of islets and the need for heavy immune suppression to prevent rejection.TNFAIP3, encoding the ubiquitin editing enzyme A20, regulates the activation of immune cells by raising NF-κB signalling thresholds. Here we show that increasing A20 expression in allogeneic islet grafts resulted in permanent survival for ~45 % of recipients, and >80% survival when combined with subtherapeutic rapamycin. Allograft survival was dependent upon regulatory T cells, was antigen-specific and grafts showed reduced expression of inflammatory factors, but increased TGFβ and IL-10. By analysing islets expressing an A20 coding mutation (I325N) that cripples A20’s OTU ubiquitin editing domain, we found that A20 regulates intra-graft RIPK1 levels to modulate NF-κB signalling. Transplantation of I325N islets resulted in increased NF-κB signalling, graft hy...

Journal of the American Society of Nephrology, 2019

Significance Statement Biomarkers for noninvasive diagnosis of subclinical acute rejection are ne... more Significance Statement Biomarkers for noninvasive diagnosis of subclinical acute rejection are needed to enable risk-stratification and tailoring of immunosuppression for kidney transplant recipients. Using RNA sequencing analyses of whole blood collected from a cohort of transplant recipients at the time of surveillance biopsy, the authors identified a transcriptional signature on the basis of a set of 17 genes that accurately detects ongoing subclinical rejection. After extensive validation, they developed a sequencing-based targeted expression assay on the basis of this gene set that was able to identify subclinical rejection at 3 months post-transplant and increased risk of graft loss in an independent cohort of 110 patients. This assay represents a potentially useful tool to monitor kidney transplant recipients and optimize immunosuppressive therapy, although larger studies are needed to validate the assay’s clinical utility. Background In kidney transplant recipients, surveill...

Cell Transplantation, 2000

The long-term goal of this study is to assess the feasibility of using fetal pig pancreas fragmen... more The long-term goal of this study is to assess the feasibility of using fetal pig pancreas fragment (FPPF) transplantation to treat patients with type I diabetes. Using the highly inbred Westran Pigs, our initial aim was to establish a rejection-free transplant model of FPPF grafted into sibling recipient pigs without immunosuppression. FPPFs were isolated from 80–100-day-old fetuses of either Westran Pigs or outbred pigs and transplanted into the thymus, spleen, liver, or kidney of the recipient Westran pig. Biopsies were taken from each transplant site at set time points and assessed histologically for islet viability, rejection, and endocrine function. Fifty-eight fetal donors were used to transplant 16 recipient pigs. A nonspecific inflammation was seen for both outbred and inbred FPPF donor tissue at day 3 and was considered a response to ischemic necrosis. However, all the transplanted outbred FPPF donor tissue was acutely rejected and lost by day 10–14. In contrast, inbred FPP...

Journal of the American Society of Nephrology, 2005

The major causes of renal transplant loss are death from vascular, malignant or infectious diseas... more The major causes of renal transplant loss are death from vascular, malignant or infectious disease, and loss of the allograft from chronic renal dysfunction associated with the development of graft fibrosis and glomerulosclerosis. Chronic allograft nephropathy (CAN) is the histologic description of the fibrosis, vascular and glomerular damage occurring in renal allografts. Clinical programs rely on monitoring change in serum creatinine for identification of patients at risk of CAN, but this change occurs late in the course of the disease, and underestimates the severity of pathologic change. CAN has several causes: ischemia-reperfusion injury, ineffectively or untreated clinical and subclinical rejection, and superimposed calcineurin inhibitor nephrotoxicity, exacerbating pre-existing donor disease. Once established, interstitial fibrosis and arteriolar hyalinosis lead to progressive glomerulosclerosis over the subsequent years. There have been a number of approaches to treatment aimed at reducing the impact of CAN, mostly centered around avoidance of calcineurin inhibitors through their elimination in all, or just selected, patients. These immunosuppression strategies combine corticosteroids with azathioprine or mycophenolate mofetil, and/or sirolimus and everolimus. Late identification of CAN in individual patients has meant that strategies for intervening to prevent chronic renal allograft dysfunction and subsequent graft loss tend to be "too little and far too late."

Journal of Clinical Investigation, 2021

Authorship note: ZZ and ZS contributed equally to this work. BM is deceased. Conflict of interest... more Authorship note: ZZ and ZS contributed equally to this work. BM is deceased. Conflict of interest: BM reports personal fees from ITBMed Biopharmaceuticals and holds stock in RenalytixAI. WZ reports personal fees from RenalytixAI. In addition, BM and WZ are inventors on the following patents: "Method for identifying kidney allograft recipients at risk for chronic injury" (US Provisional Patent Application no. 27527-0134P01, serial number 61/951,651); "Methods for diagnosing risk of renal allograft fibrosis and rejection (miRNA)" (US Provisional Patent Application no. 20190345556); "Method for diagnosing subclinical acute rejection by RNA-Seq analysis of a predictive gene set" (US Provisional Patent Application no. WO2015200887A2); and "Pretransplant prediction of post-transplant acute rejection" (US Provisional Patent Application no. WO2017100259). RBC reports personal fees from Shire/Takeda, CSL Behring, Alexion, and eGenesis; in addition, RBC reports royalties from Takeda Pharmaceuticals for Entyvio (for inflammatory bowel disease). KH receives financial compensation from Sema4 (an Icahn School of Medicine at Mount Sinai spin-off company). Sema4 is currently majority owned by the Icahn School of Medicine at Mount Sinai.

Kidney International, 2020

Strategic plan for integrated care of patients with kidney failure. Kidney International, 98(5 (s... more Strategic plan for integrated care of patients with kidney failure. Kidney International, 98(5 (supplement)), S117-S134.

Kidney International, 2021

Interstitial fibrosis, tubular atrophy, and inflammation are major contributors to kidney allogra... more Interstitial fibrosis, tubular atrophy, and inflammation are major contributors to kidney allograft failure. Here we sought an objective, quantitative pathological assessment of these lesions to improve predictive utility and constructed a deep-learning-based pipeline recognizing normal vs. abnormal kidney tissue compartments and mononuclear leukocyte infiltrates. Periodic acid- Schiff stained slides of transplant biopsies (60 training and 33 testing) were used to quantify pathological lesions specific for interstitium, tubules and mononuclear leukocyte infiltration. The pipeline was applied to 789 whole slide images from baseline (478 pre-transplant and 311 post-transplant 12-month protocol biopsies) in two independent cohorts (GoCAR: 404 patients, AUSCAD: 212 patients) of transplant recipients to correlate composite lesion features with graft loss. Our model accurately recognized kidney tissue compartments and mononuclear leukocytes. The digital features significantly correlated with revised Banff 2007 scores, but were more sensitive to subtle pathological changes below the thresholds in the Banff scores. The Interstitial and Tubular Abnormality Score (ITAS) in baseline samples was highly predictive of one-year graft loss, while a Composite Damage Score in 12-month post-transplant protocol biopsies predicted later graft loss. ITASs and Composite Damage Scores outperformed Banff scores or clinical predictors with superior graft loss prediction accuracy. High/intermediate risk groups stratified by ITASs or Composite Damage Scores also demonstrated significantly higher incidence of estimated glomerular filtration rate decline and subsequent graft damage. Thus, our deep-learning approach accurately detected and quantified pathological lesions from baseline or post-transplant biopsies, and demonstrated superior ability for prediction of post-transplant graft loss with potential application as a prevention, risk stratification or monitoring tool.

iScience, 2021

Unbiased machine learning workflow ranks miRNAs associated with insulin transcription Forced expr... more Unbiased machine learning workflow ranks miRNAs associated with insulin transcription Forced expression of topranked miRNAs drives pro-endocrine program in progenitor cells Knockdown of top-ranked miRNAs retards insulin gene transcription in human islets Insulin transcriptassociated miRNAs are reduced in islets of donors with type 2 diabetes

Kidney International, 2019

The views expressed in this commentary are solely the responsibility of the authors and they do n... more The views expressed in this commentary are solely the responsibility of the authors and they do not necessarily reflect the views, decisions, or policies of the institutions with which they are affiliated.

Transplantation Direct, 2018

no competing financial interests. P.J.O. consults for CSL, Vitaeris and eGenesis; and has receive... more no competing financial interests. P.J.O. consults for CSL, Vitaeris and eGenesis; and has received research grants from CSL. M.H.L. contributed to the literature review, data interpretation and wrote the article. D.G. conceived the study, analyzed the data and reviewed and edited the article. K.H., P.A., T.R. were involved in data collection and interpretation. G.

Journal of Clinical Investigation, 2014

JCI Insight

Regulatory T cells (Treg) have potential for the treatment of autoimmune diseases and graft rejec... more Regulatory T cells (Treg) have potential for the treatment of autoimmune diseases and graft rejection. Antigen-specificity and functional stability are considered to be critical for their therapeutic efficacy. In this study, expansion of human Treg in the presence of porcine PBMC (Xn-Treg) allowed the selection of a distinct Treg subset, co-expressing the activation/memory surface markers HLA-DR and CD27 with enhanced proportion of FOXP3+Helios+ Tregs. Compared to their unsorted and HLA-DA+CD27+ double positive (DP) cell depleted Xn-Treg counterparts, HLA-DR+CD27+ DP-Enriched Xn-Treg expressed upregulated Treg function markers CD95 and ICOS with enhanced suppression of xenogeneic but not polyclonal MLR. They also had less methylated Treg-specific demethylated region (TSDR) of FOXP3 and were more resistant to conversion to effector cells under inflammatory conditions. Adoptive transfer of porcine islet recipient NOD-SCID IL2 receptor -/-(NSG) mice with HLA-DR+CD27+ DP-Enriched Xn-Treg in a humanized mouse model inhibited porcine islet graft rejection mediated by 25-fold more human effector cells. The prolonged graft survival was associated with enhanced accumulation of FOXP3+ Treg and upregulated expression of Treg functional genes, IL10 and CTLA4, but downregulated expression of effector Th1, Th2 and Th17 cytokine genes, within surviving grafts. Collectively, human HLA-DR+CD27+ DP-Enriched Xn-Treg expressed a specific regulatory signature that enabled identification and isolation of antigen-specific and functionally stable Treg with potential as a Treg-based therapy.

ABSTRACTDiabetes is a global public health burden and is characterized clinically by a relative o... more ABSTRACTDiabetes is a global public health burden and is characterized clinically by a relative or absolute insulin deficiency. Therapeutic agents that stimulate and improve insulin secretion and insulin sensitivity are in high demand as diabetic treatment. CD47 is a cell surface glycoprotein implicated in multiple cellular functions, including recognition of self, angiogenesis, and nitric oxide signaling, however its role in the regulation of insulin secretion remains unknown. For the first time we demonstrate that CD47 receptor signaling inhibits insulin release from β-cells and that it can be pharmacologically exploited to boost insulin secretion. CD47 depletion stimulates insulin granule exocytosis via activation of the Rho GTPase Cdc42. CD47 deficiency improved glucose clearance and insulin sensitivity in mice. CD47 blockade enhanced islet transplantation efficiency and improved outcomes. Further, anti-CD47 antibody treatment delayed the onset of diabetes in non-obese diabetic ...

Frontiers in Immunology

Porcine islets surviving the acute injury caused by humoral rejection and IBMIR will be subjected... more Porcine islets surviving the acute injury caused by humoral rejection and IBMIR will be subjected to cellular xenograft rejection, which is predominately mediated by CD4+T cells and is characterised by significant infiltration of macrophages, B cells and T cells (CD4+and CD8+). Overall, the response is different compared to the alloimmune response and more difficult to suppress. Activation of CD4+T cells is both by direct and indirect antigen presentation. After activation they recruit macrophages and direct B cell responses. Although they are less important than CD4+T cells in islet xenograft rejection, macrophages are believed to be a major effector cell in this response. Rodent studies have shown that xenoantigen-primed and CD4+T cell-activated macrophages were capable of recognition and rejection of pancreatic islet xenografts, and they destroyed a graftviathe secretion of various proinflammatory mediators, including TNF-α, reactive oxygen and nitrogen species, and complement fa...

Frontiers in Immunology

Xenotransplantation using porcine donors is rapidly approaching clinical applicability as an alte... more Xenotransplantation using porcine donors is rapidly approaching clinical applicability as an alternative therapy for treatment of many end-stage diseases including type 1 diabetes. Porcine neonatal islet cell clusters (NICC) have normalised blood sugar levels for relatively short periods in the preclinical diabetic rhesus model but have met with limited success in the stringent baboon model. Here we report that NICC from genetically modified (GM) pigs deleted for αGal and expressing the human complement regulators CD55 and CD59 can cure diabetes long-term in immunosuppressed baboons, with maximum graft survival exceeding 22 months. Five diabetic baboons were transplanted intraportally with 9,673 – 56,913 islet equivalents (IEQ) per kg recipient weight. Immunosuppression consisted of T cell depletion with an anti-CD2 mAb, tacrolimus for the first 4 months, and maintenance with belatacept and anti-CD154; no anti-inflammatory treatment or cytomegalovirus (CMV) prophylaxis/treatment was...

PLOS ONE, 2019

Understanding the immunological phenotype of transplant recipients is important to improve outcom... more Understanding the immunological phenotype of transplant recipients is important to improve outcomes and develop new therapies. Immunophenotyping of whole peripheral blood (WPB) by flow cytometry is a rapid method to obtain large amounts of data relating to the outcomes of different transplant treatments with limited patient impact. Healthy individuals and patients with type 1 diabetes (T1D) enrolled in islet transplantation were recruited and WPB was collected. 46 fluorochrome-conjugated mouse-anti-human antibodies were used (43 of 46 antibodies were titrated). BD cytometer setup and tracking beads were used to characterize and adjust for cytometer performance. Antibody cocktails were pre-mixed <60 minutes before staining. Multicolour panels were designed based on fluorochrome brightness, antigen density, co-expression, and fluorochrome spillover into non-primary detectors in each panel on a 5 laser flow cytometer. WPB sample staining used 50-300 μl WPB for each panel and was performed within 2 hours of blood sample collection. Samples were acquired on a BD-LSRFortessa. The operating procedures, including specimen collection, antibody cocktails, staining protocol, flow-cytometer setup and data analysis, were standardized. The staining index of 43 antibodies and the spillover spreading matrix for each panel was calculated. The final concentrations for the 46 antibodies used was determined for staining of WPB samples. Absolute cell-count and 7 leukocyte profiling panels consisting of subsets and/or status of granulocytes, monocytes, dendritic, B, NK, and T cells including regulatory T cells (Tregs) and NKT were designed and established on a 5 laser BD-LSR Fortessa. 13 T1D patients, including 4 islet transplant recipients and 8 healthy controls, were evaluated. The ability to reproducibly measure immune subsets and immune-profiles of islet transplant patients up to 18 months post transplantation has been established as a tool to measure immune cell reconstitution after transplantation.

Cell Transplantation, 2013

Islet cell transplantation as a therapy for type 1 diabetes has been limited by progressive graft... more Islet cell transplantation as a therapy for type 1 diabetes has been limited by progressive graft loss. Significant immunosuppression including T-cell ablation has been used in an attempt to limit islet rejection. Here, we show that CD3+lymphocytes depleted of alloreactive T cells selected from a mixed lymphocyte reaction (MLR), where responder BALB/c splenocytes stained with carboxyfluorescein succinimidyl ester (CFSE) were stimulated with irradiated C57BL/6 splenocytes for 5 days, infused into diabetic immunodeficient mice are capable of restoring a broad T-cell repertoire and specifically do not reject islet transplants from the strain (C57BL/6) used in the original depletion. These mice demonstrate reconstitution with CD4+and CD8+T cells, the capacity to reject third-party grafts (CBA), and restoration of interferon-γ (IFN-γ) responses to third-party alloantigens. Over time, both forkhead box P3-positive (Foxp3+) T regulatory cells (Tregs) and γδ T cells expand, suggesting a rol...

JCI insight, Feb 13, 2024

Medical Journal of Australia, 2006

Objective: To determine whether pancreatic islet transplantation can control diabetes and prevent... more Objective: To determine whether pancreatic islet transplantation can control diabetes and prevent severe life-threatening hypoglycaemia. Design, setting and participants: A single-arm observation study of six patients undergoing islet transplantation. All patients had had type 1 diabetes mellitus for over 5 years and documented episodes of repeated severe hypoglycaemia. Islets were isolated from donor pancreases digested by Liberase. Separated islets were infused into the recipient's liver via the portal vein. Patients were immunosuppressed with daclizumab, sirolimus and tacrolimus. The transplants were performed at Westmead Hospital, NSW, between October 2002 and February 2005. Main outcome measures: Normal blood glucose control without administration of exogenous insulin; demonstration of islet function and abolition of hypoglycaemia. Results: Five of the patients received two islet infusions, and the sixth was withdrawn after one infusion following a portal vein thrombosis. Three patients became insulinindependent, with excellent glycaemic control. Two had islet function with circulating C-peptide, improved glycaemic control, reduced insulin requirement and abolition of severe hypoglycaemia. However, over a 2-year period, graft function deteriorated. Recipients who were initially insulin free remained C-peptide positive but required supplemental insulin. Complications included one postoperative bleed, two portal vein thromboses (which resolved completely), presumed recurrence of tuberculosis in one patient, and deterioration in renal function in one patient. Conclusions: Islet transplantation is effective at improving glycaemic control and hypoglycaemia unawareness in the short to medium term. However, problems with longterm safety of immunosuppression, islet-induced thrombosis and early detection of loss MJA 2006; 184: 221-225 of islet function remain to be addressed.

Islet transplantation can restore lost glycemic control in type 1 diabetes subjects, but is restr... more Islet transplantation can restore lost glycemic control in type 1 diabetes subjects, but is restricted in its clinical application by limiting supplies of islets and the need for heavy immune suppression to prevent rejection.TNFAIP3, encoding the ubiquitin editing enzyme A20, regulates the activation of immune cells by raising NF-κB signalling thresholds. Here we show that increasing A20 expression in allogeneic islet grafts resulted in permanent survival for ~45 % of recipients, and >80% survival when combined with subtherapeutic rapamycin. Allograft survival was dependent upon regulatory T cells, was antigen-specific and grafts showed reduced expression of inflammatory factors, but increased TGFβ and IL-10. By analysing islets expressing an A20 coding mutation (I325N) that cripples A20’s OTU ubiquitin editing domain, we found that A20 regulates intra-graft RIPK1 levels to modulate NF-κB signalling. Transplantation of I325N islets resulted in increased NF-κB signalling, graft hy...

Journal of the American Society of Nephrology, 2019

Significance Statement Biomarkers for noninvasive diagnosis of subclinical acute rejection are ne... more Significance Statement Biomarkers for noninvasive diagnosis of subclinical acute rejection are needed to enable risk-stratification and tailoring of immunosuppression for kidney transplant recipients. Using RNA sequencing analyses of whole blood collected from a cohort of transplant recipients at the time of surveillance biopsy, the authors identified a transcriptional signature on the basis of a set of 17 genes that accurately detects ongoing subclinical rejection. After extensive validation, they developed a sequencing-based targeted expression assay on the basis of this gene set that was able to identify subclinical rejection at 3 months post-transplant and increased risk of graft loss in an independent cohort of 110 patients. This assay represents a potentially useful tool to monitor kidney transplant recipients and optimize immunosuppressive therapy, although larger studies are needed to validate the assay’s clinical utility. Background In kidney transplant recipients, surveill...

Cell Transplantation, 2000

The long-term goal of this study is to assess the feasibility of using fetal pig pancreas fragmen... more The long-term goal of this study is to assess the feasibility of using fetal pig pancreas fragment (FPPF) transplantation to treat patients with type I diabetes. Using the highly inbred Westran Pigs, our initial aim was to establish a rejection-free transplant model of FPPF grafted into sibling recipient pigs without immunosuppression. FPPFs were isolated from 80–100-day-old fetuses of either Westran Pigs or outbred pigs and transplanted into the thymus, spleen, liver, or kidney of the recipient Westran pig. Biopsies were taken from each transplant site at set time points and assessed histologically for islet viability, rejection, and endocrine function. Fifty-eight fetal donors were used to transplant 16 recipient pigs. A nonspecific inflammation was seen for both outbred and inbred FPPF donor tissue at day 3 and was considered a response to ischemic necrosis. However, all the transplanted outbred FPPF donor tissue was acutely rejected and lost by day 10–14. In contrast, inbred FPP...

Journal of the American Society of Nephrology, 2005

The major causes of renal transplant loss are death from vascular, malignant or infectious diseas... more The major causes of renal transplant loss are death from vascular, malignant or infectious disease, and loss of the allograft from chronic renal dysfunction associated with the development of graft fibrosis and glomerulosclerosis. Chronic allograft nephropathy (CAN) is the histologic description of the fibrosis, vascular and glomerular damage occurring in renal allografts. Clinical programs rely on monitoring change in serum creatinine for identification of patients at risk of CAN, but this change occurs late in the course of the disease, and underestimates the severity of pathologic change. CAN has several causes: ischemia-reperfusion injury, ineffectively or untreated clinical and subclinical rejection, and superimposed calcineurin inhibitor nephrotoxicity, exacerbating pre-existing donor disease. Once established, interstitial fibrosis and arteriolar hyalinosis lead to progressive glomerulosclerosis over the subsequent years. There have been a number of approaches to treatment aimed at reducing the impact of CAN, mostly centered around avoidance of calcineurin inhibitors through their elimination in all, or just selected, patients. These immunosuppression strategies combine corticosteroids with azathioprine or mycophenolate mofetil, and/or sirolimus and everolimus. Late identification of CAN in individual patients has meant that strategies for intervening to prevent chronic renal allograft dysfunction and subsequent graft loss tend to be "too little and far too late."

Journal of Clinical Investigation, 2021

Authorship note: ZZ and ZS contributed equally to this work. BM is deceased. Conflict of interest... more Authorship note: ZZ and ZS contributed equally to this work. BM is deceased. Conflict of interest: BM reports personal fees from ITBMed Biopharmaceuticals and holds stock in RenalytixAI. WZ reports personal fees from RenalytixAI. In addition, BM and WZ are inventors on the following patents: "Method for identifying kidney allograft recipients at risk for chronic injury" (US Provisional Patent Application no. 27527-0134P01, serial number 61/951,651); "Methods for diagnosing risk of renal allograft fibrosis and rejection (miRNA)" (US Provisional Patent Application no. 20190345556); "Method for diagnosing subclinical acute rejection by RNA-Seq analysis of a predictive gene set" (US Provisional Patent Application no. WO2015200887A2); and "Pretransplant prediction of post-transplant acute rejection" (US Provisional Patent Application no. WO2017100259). RBC reports personal fees from Shire/Takeda, CSL Behring, Alexion, and eGenesis; in addition, RBC reports royalties from Takeda Pharmaceuticals for Entyvio (for inflammatory bowel disease). KH receives financial compensation from Sema4 (an Icahn School of Medicine at Mount Sinai spin-off company). Sema4 is currently majority owned by the Icahn School of Medicine at Mount Sinai.

Kidney International, 2020

Strategic plan for integrated care of patients with kidney failure. Kidney International, 98(5 (s... more Strategic plan for integrated care of patients with kidney failure. Kidney International, 98(5 (supplement)), S117-S134.

Kidney International, 2021

Interstitial fibrosis, tubular atrophy, and inflammation are major contributors to kidney allogra... more Interstitial fibrosis, tubular atrophy, and inflammation are major contributors to kidney allograft failure. Here we sought an objective, quantitative pathological assessment of these lesions to improve predictive utility and constructed a deep-learning-based pipeline recognizing normal vs. abnormal kidney tissue compartments and mononuclear leukocyte infiltrates. Periodic acid- Schiff stained slides of transplant biopsies (60 training and 33 testing) were used to quantify pathological lesions specific for interstitium, tubules and mononuclear leukocyte infiltration. The pipeline was applied to 789 whole slide images from baseline (478 pre-transplant and 311 post-transplant 12-month protocol biopsies) in two independent cohorts (GoCAR: 404 patients, AUSCAD: 212 patients) of transplant recipients to correlate composite lesion features with graft loss. Our model accurately recognized kidney tissue compartments and mononuclear leukocytes. The digital features significantly correlated with revised Banff 2007 scores, but were more sensitive to subtle pathological changes below the thresholds in the Banff scores. The Interstitial and Tubular Abnormality Score (ITAS) in baseline samples was highly predictive of one-year graft loss, while a Composite Damage Score in 12-month post-transplant protocol biopsies predicted later graft loss. ITASs and Composite Damage Scores outperformed Banff scores or clinical predictors with superior graft loss prediction accuracy. High/intermediate risk groups stratified by ITASs or Composite Damage Scores also demonstrated significantly higher incidence of estimated glomerular filtration rate decline and subsequent graft damage. Thus, our deep-learning approach accurately detected and quantified pathological lesions from baseline or post-transplant biopsies, and demonstrated superior ability for prediction of post-transplant graft loss with potential application as a prevention, risk stratification or monitoring tool.

iScience, 2021

Unbiased machine learning workflow ranks miRNAs associated with insulin transcription Forced expr... more Unbiased machine learning workflow ranks miRNAs associated with insulin transcription Forced expression of topranked miRNAs drives pro-endocrine program in progenitor cells Knockdown of top-ranked miRNAs retards insulin gene transcription in human islets Insulin transcriptassociated miRNAs are reduced in islets of donors with type 2 diabetes

Kidney International, 2019

The views expressed in this commentary are solely the responsibility of the authors and they do n... more The views expressed in this commentary are solely the responsibility of the authors and they do not necessarily reflect the views, decisions, or policies of the institutions with which they are affiliated.

Transplantation Direct, 2018

no competing financial interests. P.J.O. consults for CSL, Vitaeris and eGenesis; and has receive... more no competing financial interests. P.J.O. consults for CSL, Vitaeris and eGenesis; and has received research grants from CSL. M.H.L. contributed to the literature review, data interpretation and wrote the article. D.G. conceived the study, analyzed the data and reviewed and edited the article. K.H., P.A., T.R. were involved in data collection and interpretation. G.

Journal of Clinical Investigation, 2014