Full time clinician scientist at Royal Adelaide Hospital and University of Adelaide affiliate Professor. Director of kidney and islet transplantation at Royal Adelaide Hospital.
BackgroundThe long-term effects of arteriovenous fistula (AVF) ligation on cardiovascular structu... more BackgroundThe long-term effects of arteriovenous fistula (AVF) ligation on cardiovascular structure following kidney transplantation remain uncertain. A prospective randomized, controlled trial (RCT) examined the effect of AVF ligation at 6 months on cardiovascular magnetic resonance imaging (CMR)–derived parameters in 27 kidney transplant recipients compared with 27 controls. A mean decrease in left ventricular mass (LVM) of 22.1 g (95% CI, 15.0 to 29.1) was observed compared with an increase of 1.2 g (95% CI, −4.8 to 7.2) in the control group (P<0.001). We conducted a long-term follow-up observational cohort study in the treated cohort to determine the evolution of CMR-derived parameters compared with those documented at 6 months post-AVF ligation.MethodsWe performed CMR at long-term follow-up in the AVF ligation observational cohort from our original RCT published in 2019. Results were compared with CMR at 6 months postintervention. The coprimary end point was the change in CM...
Human bone marrow (BM) derived mesenchymal stem cells (MSC) have high capacity to propagate ex vi... more Human bone marrow (BM) derived mesenchymal stem cells (MSC) have high capacity to propagate ex vivo with superior reparative, immunosuppressive, and anti-inflammatory properties. Here we describe standardized protocols and culture conditions that enable the isolation, expansion and maintenance of a highly purified and homogenous population of human MSC. These third party-derived off-the-shelf MSC from healthy human bone marrow donors can potently inhibit mitogenically or allogeneically activated human T cells in proliferation assays. The standard operating procedures described in this chapter can be applied to researchers aiming to enhance MSC immunosuppressive properties and defining MSC mechanisms of action. Importantly, these assays can be incorporated into clinical protocols where the safety and efficacy of human BM MSC can be verified in diseases that are modulated by T cell responses.
Chronic pancreatitis is probably an underestimated cause of chronic abdominal pain in children, a... more Chronic pancreatitis is probably an underestimated cause of chronic abdominal pain in children, and its true incidence remains unknown.1 Chronic inflammatory cell infiltration and fibrosis of pancreatic tissue results in exocrine and endocrine insufficiency with malabsorption and ultimately diabetes mellitus. Although obstruction, toxins and other factors can be associated, genetic mutations contribute toward childhood chronic pancreatitis in 65– 75% of cases.2,3
The field of regenerative medicine provides enormous opportunities for generating beta cells from... more The field of regenerative medicine provides enormous opportunities for generating beta cells from different stem cell sources for cellular therapy. Even though insulin-secreting cells can be generated from a variety of stem cell types like pluripotent stem cells and embryonic stem cells, the ideal functional cells should be generated from patients’ own cells and expanded to considerable levels by non-integrative culture techniques. In terms of the ease of isolation, plasticity, and clinical translation to generate autologous cells, mesenchymal stem cell stands superior. Furthermore, small molecules offer a great advantage in terms of generating functional beta cells from stem cells. Research suggests that most of the mesenchymal stem cell-based protocols to generate pancreatic beta cells have small molecules in their cocktail. However, most of the protocols generate cells that mimic the characteristics of human beta cells, thereby generating “beta cell-like cells” as opposed to matu...
T art and science of kidney transplantation has evolved since Ronald Lee Herrick donated a kidney... more T art and science of kidney transplantation has evolved since Ronald Lee Herrick donated a kidney to his twin brother in 1954 and the boundaries of transplant achievement continue to be challenged including the acceptance of older, more marginal grafts. We describe the case of a woman diagnosed with medullary cystic kidney disease at 17 years of age. She progressed to end-stage kidney disease, treated with an uncomplicated preemptive transplant at 19 years from her grandfather, aged 70 years, in our transplant center. The choice of donor was based on good donor kidney function notwithstanding donor age, reasonable HLA antigen match (4 of 6 tested loci), future transplant needs, and lack of other live-donor options. Surgery was uncomplicated, she received standard immunosuppression with tacrolimus, mycophenolate, and prednisolone. An early episode of biopsy-proven cellular rejection was steroid responsive and graft function stabilized with a serum creatinine of 1.35 mg/dL at 1 year. Her first pregnancy occurred 8 years posttransplant, after a transition to a prednisolone, azathioprine, and tacrolimus regimen. At this time, she was medically well, with a normal-range BMI and stable graft function. Pregnancy was complicated at 35-week gestation by accelerated hypertension and proteinuria. She was induced at 36 weeks and delivered a male baby (birthweight 2767 g) by emergency lower uterine segment cesarean section (LUSCS). A second pregnancy occurred 2 years later, complicated by earlier onset hypertension and worsening graft function necessitating delivery via elective LUSCS at 35 weeks of a healthy baby girl (birthweight 3175 g). She subsequently underwent tubal ligation. Fourteen years posttransplant, the patient returned to our jurisdiction with a serum creatinine of 1.58 mg/dL and diet-controlled diabetes, but no hypertension and minimal proteinuria. She desired a further pregnancy with a new partner, surrogacy was not acceptable to the patient. Following extensive prepregnancy counseling, she achieved pregnancy via in vitro fertilization. Medical management included optimization of immunosuppression, low-dose aspirin, and calcium for preeclampsia prophylaxis, insulin therapy for worsening diabetes, and close fetal monitoring within a multidisciplinary obstetric nephrology and maternal-fetal medicine expert team. She remained normotensive with stable allograft function and no significant proteinuria. At 35 weeks she had an antepartum hemorrhage and proceeded to LUSCS, birthing a healthy baby girl (birthweight 2050 g). Breastfeeding was successfully established. Six months postpartum, serum creatinine is 1.8 mg/dL, with normal blood pressure and diet-controlled diabetes. Her grandfather remains well with a creatinine of 1.42 mg/dL. The historical adage that ‘children of woman with renal disease are born dangerously or not at all, if their doctors had their way’ has been superseded by evidence-based shared decision-making that prioritizes the patient’s perspective, goals, and perception of risk when considering family planning. For many women, there are complex emotional, social, and ethical challenges faced when considering motherhood with advanced renal disease and successful transplantation facilitates parenthood. We recognize pregnancy in transplanted women has higher risk and adverse events for mother and baby occur more frequently. Over time, outcomes of pregnancy posttransplant have improved. Yet, the risk of preeclampsia and perinatal complications remain significant and linked to preconception allograft function. Woman having multiple pregnancies posttransplant is not common, but is well-reported with potentially better outcomes in subsequent pregnancies. In this case, postpartum graft function was slightly worse than preconception. This was expected, based on our past experience where preconception kidney function determines whether a “stage-shift” in graft function will occur in pregnancy. Importantly, this was considered carefully in the preconception pregnancy counseling. Prepregnancy counseling of risk, as relevant to each patient allows for shared decision-making. For patients ISSN: 0041-1337/19/10312-e397
Kidney transplantation restores fertility in patients with end-stage renal disease, with many suc... more Kidney transplantation restores fertility in patients with end-stage renal disease, with many successful pregnancies after kidney transplantation being reported. However, there are little data regarding pregnancy in women transplanted under modern-era desensitisation protocols that utilise rituximab, plasma exchange and intravenous immunoglobulin, including ABO-incompatible transplants. Pregnancies in ABO-incompatible recipients can pose new challenges from an immunological perspective. Here, we report a case of successful pregnancy using in vitro fertilisation, in a renal transplant recipient who underwent desensitisation two years prior, that included use of rituximab and plasma exchange to receive an ABO-incompatible transplant from her husband and subsequent father of the baby. We believe this was the first case of successful pregnancy after ABO-incompatible kidney transplantation in Australia and New Zealand. This case also highlights the difficulties faced in conception follow...
Islet transplantation is currently the only minimally invasive therapy available for patients wit... more Islet transplantation is currently the only minimally invasive therapy available for patients with type 1 diabetes that can lead to insulin independence; however, it is limited to only a small number of patients. Although clinical procedures have improved in the isolation and culture of islets, a large number of islets are still lost in the pre-transplant period, limiting the success of this treatment. Moreover, current practice includes islets being prepared at specialized centers, which are sometimes remote to the transplant location. Thus, a critical point of intervention to maintain the quality and quantity of isolated islets is during transportation between isolation centers and the transplanting hospitals, during which 20-40% of functional islets can be lost. The current study investigated the use of an oxygen-permeable PDMS microwell device for long-distance transportation of isolated islets. We demonstrate that the microwell device protected islets from aggregation during tr...
A new platform for the culture of pancreatic islets that improves the cell viability and quality.... more A new platform for the culture of pancreatic islets that improves the cell viability and quality. Paving the way for a highly efficient islet clinical transport.
Pancreatic islet transplantation is a promising clinical treatment for type 1 diabetes, but succe... more Pancreatic islet transplantation is a promising clinical treatment for type 1 diabetes, but success is limited by extensive β-cell death in the immediate posttransplant period and impaired islet function in the longer term. Following transplantation, appropriate vascular remodeling is crucial to ensure the survival and function of engrafted islets. The sphingosine kinase (SK) pathway is an important regulator of vascular beds, but its role in the survival and function of transplanted islets is unknown. We observed that donor islets from mice deficient in SK1 (Sphk1 knockout) contain a reduced number of resident intraislet vascular endothelial cells. Furthermore, we demonstrate that the main product of SK1, sphingosine-1-phosphate, controls the migration of intraislet endothelial cells in vitro. We reveal in vivo that Sphk1 knockout islets have an impaired ability to cure diabetes compared with wild-type controls. Thus, SK1-deficient islets not only contain fewer resident vascular ce...
Islet-specific memory T cells arise early in type 1 diabetes (T1D), persist for long periods, per... more Islet-specific memory T cells arise early in type 1 diabetes (T1D), persist for long periods, perpetuate disease, and are rapidly reactivated by islet transplantation. As memory T cells are poorly controlled by “conventional” therapies, memory T cell–mediated attack is a substantial challenge in islet transplantation, and this will extend to application of personalized approaches using stem cell–derived replacement β-cells. New approaches are required to limit memory autoimmune attack of transplanted islets or replacement β-cells. Here, we show that transfer of bone marrow encoding cognate antigen directed to dendritic cells, under mild, immune-preserving conditions, inactivates established memory CD8+ T-cell populations and generates a long-lived, antigen-specific tolerogenic environment. Consequently, CD8+ memory T cell–mediated targeting of islet-expressed antigens is prevented and islet graft rejection alleviated. The immunological mechanisms of protection are mediated through d...
BackgroundThe long-term effects of arteriovenous fistula (AVF) ligation on cardiovascular structu... more BackgroundThe long-term effects of arteriovenous fistula (AVF) ligation on cardiovascular structure following kidney transplantation remain uncertain. A prospective randomized, controlled trial (RCT) examined the effect of AVF ligation at 6 months on cardiovascular magnetic resonance imaging (CMR)–derived parameters in 27 kidney transplant recipients compared with 27 controls. A mean decrease in left ventricular mass (LVM) of 22.1 g (95% CI, 15.0 to 29.1) was observed compared with an increase of 1.2 g (95% CI, −4.8 to 7.2) in the control group (P<0.001). We conducted a long-term follow-up observational cohort study in the treated cohort to determine the evolution of CMR-derived parameters compared with those documented at 6 months post-AVF ligation.MethodsWe performed CMR at long-term follow-up in the AVF ligation observational cohort from our original RCT published in 2019. Results were compared with CMR at 6 months postintervention. The coprimary end point was the change in CM...
Human bone marrow (BM) derived mesenchymal stem cells (MSC) have high capacity to propagate ex vi... more Human bone marrow (BM) derived mesenchymal stem cells (MSC) have high capacity to propagate ex vivo with superior reparative, immunosuppressive, and anti-inflammatory properties. Here we describe standardized protocols and culture conditions that enable the isolation, expansion and maintenance of a highly purified and homogenous population of human MSC. These third party-derived off-the-shelf MSC from healthy human bone marrow donors can potently inhibit mitogenically or allogeneically activated human T cells in proliferation assays. The standard operating procedures described in this chapter can be applied to researchers aiming to enhance MSC immunosuppressive properties and defining MSC mechanisms of action. Importantly, these assays can be incorporated into clinical protocols where the safety and efficacy of human BM MSC can be verified in diseases that are modulated by T cell responses.
Chronic pancreatitis is probably an underestimated cause of chronic abdominal pain in children, a... more Chronic pancreatitis is probably an underestimated cause of chronic abdominal pain in children, and its true incidence remains unknown.1 Chronic inflammatory cell infiltration and fibrosis of pancreatic tissue results in exocrine and endocrine insufficiency with malabsorption and ultimately diabetes mellitus. Although obstruction, toxins and other factors can be associated, genetic mutations contribute toward childhood chronic pancreatitis in 65– 75% of cases.2,3
The field of regenerative medicine provides enormous opportunities for generating beta cells from... more The field of regenerative medicine provides enormous opportunities for generating beta cells from different stem cell sources for cellular therapy. Even though insulin-secreting cells can be generated from a variety of stem cell types like pluripotent stem cells and embryonic stem cells, the ideal functional cells should be generated from patients’ own cells and expanded to considerable levels by non-integrative culture techniques. In terms of the ease of isolation, plasticity, and clinical translation to generate autologous cells, mesenchymal stem cell stands superior. Furthermore, small molecules offer a great advantage in terms of generating functional beta cells from stem cells. Research suggests that most of the mesenchymal stem cell-based protocols to generate pancreatic beta cells have small molecules in their cocktail. However, most of the protocols generate cells that mimic the characteristics of human beta cells, thereby generating “beta cell-like cells” as opposed to matu...
T art and science of kidney transplantation has evolved since Ronald Lee Herrick donated a kidney... more T art and science of kidney transplantation has evolved since Ronald Lee Herrick donated a kidney to his twin brother in 1954 and the boundaries of transplant achievement continue to be challenged including the acceptance of older, more marginal grafts. We describe the case of a woman diagnosed with medullary cystic kidney disease at 17 years of age. She progressed to end-stage kidney disease, treated with an uncomplicated preemptive transplant at 19 years from her grandfather, aged 70 years, in our transplant center. The choice of donor was based on good donor kidney function notwithstanding donor age, reasonable HLA antigen match (4 of 6 tested loci), future transplant needs, and lack of other live-donor options. Surgery was uncomplicated, she received standard immunosuppression with tacrolimus, mycophenolate, and prednisolone. An early episode of biopsy-proven cellular rejection was steroid responsive and graft function stabilized with a serum creatinine of 1.35 mg/dL at 1 year. Her first pregnancy occurred 8 years posttransplant, after a transition to a prednisolone, azathioprine, and tacrolimus regimen. At this time, she was medically well, with a normal-range BMI and stable graft function. Pregnancy was complicated at 35-week gestation by accelerated hypertension and proteinuria. She was induced at 36 weeks and delivered a male baby (birthweight 2767 g) by emergency lower uterine segment cesarean section (LUSCS). A second pregnancy occurred 2 years later, complicated by earlier onset hypertension and worsening graft function necessitating delivery via elective LUSCS at 35 weeks of a healthy baby girl (birthweight 3175 g). She subsequently underwent tubal ligation. Fourteen years posttransplant, the patient returned to our jurisdiction with a serum creatinine of 1.58 mg/dL and diet-controlled diabetes, but no hypertension and minimal proteinuria. She desired a further pregnancy with a new partner, surrogacy was not acceptable to the patient. Following extensive prepregnancy counseling, she achieved pregnancy via in vitro fertilization. Medical management included optimization of immunosuppression, low-dose aspirin, and calcium for preeclampsia prophylaxis, insulin therapy for worsening diabetes, and close fetal monitoring within a multidisciplinary obstetric nephrology and maternal-fetal medicine expert team. She remained normotensive with stable allograft function and no significant proteinuria. At 35 weeks she had an antepartum hemorrhage and proceeded to LUSCS, birthing a healthy baby girl (birthweight 2050 g). Breastfeeding was successfully established. Six months postpartum, serum creatinine is 1.8 mg/dL, with normal blood pressure and diet-controlled diabetes. Her grandfather remains well with a creatinine of 1.42 mg/dL. The historical adage that ‘children of woman with renal disease are born dangerously or not at all, if their doctors had their way’ has been superseded by evidence-based shared decision-making that prioritizes the patient’s perspective, goals, and perception of risk when considering family planning. For many women, there are complex emotional, social, and ethical challenges faced when considering motherhood with advanced renal disease and successful transplantation facilitates parenthood. We recognize pregnancy in transplanted women has higher risk and adverse events for mother and baby occur more frequently. Over time, outcomes of pregnancy posttransplant have improved. Yet, the risk of preeclampsia and perinatal complications remain significant and linked to preconception allograft function. Woman having multiple pregnancies posttransplant is not common, but is well-reported with potentially better outcomes in subsequent pregnancies. In this case, postpartum graft function was slightly worse than preconception. This was expected, based on our past experience where preconception kidney function determines whether a “stage-shift” in graft function will occur in pregnancy. Importantly, this was considered carefully in the preconception pregnancy counseling. Prepregnancy counseling of risk, as relevant to each patient allows for shared decision-making. For patients ISSN: 0041-1337/19/10312-e397
Kidney transplantation restores fertility in patients with end-stage renal disease, with many suc... more Kidney transplantation restores fertility in patients with end-stage renal disease, with many successful pregnancies after kidney transplantation being reported. However, there are little data regarding pregnancy in women transplanted under modern-era desensitisation protocols that utilise rituximab, plasma exchange and intravenous immunoglobulin, including ABO-incompatible transplants. Pregnancies in ABO-incompatible recipients can pose new challenges from an immunological perspective. Here, we report a case of successful pregnancy using in vitro fertilisation, in a renal transplant recipient who underwent desensitisation two years prior, that included use of rituximab and plasma exchange to receive an ABO-incompatible transplant from her husband and subsequent father of the baby. We believe this was the first case of successful pregnancy after ABO-incompatible kidney transplantation in Australia and New Zealand. This case also highlights the difficulties faced in conception follow...
Islet transplantation is currently the only minimally invasive therapy available for patients wit... more Islet transplantation is currently the only minimally invasive therapy available for patients with type 1 diabetes that can lead to insulin independence; however, it is limited to only a small number of patients. Although clinical procedures have improved in the isolation and culture of islets, a large number of islets are still lost in the pre-transplant period, limiting the success of this treatment. Moreover, current practice includes islets being prepared at specialized centers, which are sometimes remote to the transplant location. Thus, a critical point of intervention to maintain the quality and quantity of isolated islets is during transportation between isolation centers and the transplanting hospitals, during which 20-40% of functional islets can be lost. The current study investigated the use of an oxygen-permeable PDMS microwell device for long-distance transportation of isolated islets. We demonstrate that the microwell device protected islets from aggregation during tr...
A new platform for the culture of pancreatic islets that improves the cell viability and quality.... more A new platform for the culture of pancreatic islets that improves the cell viability and quality. Paving the way for a highly efficient islet clinical transport.
Pancreatic islet transplantation is a promising clinical treatment for type 1 diabetes, but succe... more Pancreatic islet transplantation is a promising clinical treatment for type 1 diabetes, but success is limited by extensive β-cell death in the immediate posttransplant period and impaired islet function in the longer term. Following transplantation, appropriate vascular remodeling is crucial to ensure the survival and function of engrafted islets. The sphingosine kinase (SK) pathway is an important regulator of vascular beds, but its role in the survival and function of transplanted islets is unknown. We observed that donor islets from mice deficient in SK1 (Sphk1 knockout) contain a reduced number of resident intraislet vascular endothelial cells. Furthermore, we demonstrate that the main product of SK1, sphingosine-1-phosphate, controls the migration of intraislet endothelial cells in vitro. We reveal in vivo that Sphk1 knockout islets have an impaired ability to cure diabetes compared with wild-type controls. Thus, SK1-deficient islets not only contain fewer resident vascular ce...
Islet-specific memory T cells arise early in type 1 diabetes (T1D), persist for long periods, per... more Islet-specific memory T cells arise early in type 1 diabetes (T1D), persist for long periods, perpetuate disease, and are rapidly reactivated by islet transplantation. As memory T cells are poorly controlled by “conventional” therapies, memory T cell–mediated attack is a substantial challenge in islet transplantation, and this will extend to application of personalized approaches using stem cell–derived replacement β-cells. New approaches are required to limit memory autoimmune attack of transplanted islets or replacement β-cells. Here, we show that transfer of bone marrow encoding cognate antigen directed to dendritic cells, under mild, immune-preserving conditions, inactivates established memory CD8+ T-cell populations and generates a long-lived, antigen-specific tolerogenic environment. Consequently, CD8+ memory T cell–mediated targeting of islet-expressed antigens is prevented and islet graft rejection alleviated. The immunological mechanisms of protection are mediated through d...
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