Metformin Use and Long-term Clinical Outcomes in Kidney Transplant Recipients

Metformin and vitamin D combination therapy ameliorates type 2 diabetes mellitus-induced renal injury in male Wistar rats

Diabetic kidney disease is a major microvascular diabetes mellitus (DM) complication clinically associated with a gradual renal function decline. Although metformin is a common drug for managing DM, however, monotherapy treatment with any antidiabetic drug will necessitate dosage increment since type 2 DM (T2DM) deteriorates over time due to the increasing pancreatic β-cell dysfunction and will eventually require a combination therapy approach with another antidiabetic medication. Vitamin D is a food supplement that has been proven to have antidiabetic and reno-protective activities. Hence, we explore the combination of vitamin D and metformin on T2DM-induced renal dysfunction. Thirty male Wistar rats were randomized into five (5) groups: control, diabetes untreated, diabetics treated with metformin, vitamin D, and vitamin D + metformin. Vitamin D and metformin significantly reversed DM-induced hyperglycemia, electrolyte imbalance, and dyslipidemia. Also, vitamin D and metformin reversed T2DM-induced increase in serum creatinine and urea and renal lactate, LDH, and oxido-inflammatory response. These observed alterations were accompanied by an increase in proton pump activities and modulation of Nrf2/Nf-κB and XO/UA signaling. This study revealed that vitamin D and/or metformin ameliorated T2DM-induced renal injury.

New Onset Diabetes After Organ Transplantation: Risk Factors, Treatment, and Consequences

New onset diabetes mellitus after organ transplantation (NODAT) is a frequent and serious complication of solid organ transplantation. It significantly impacts graft function, patient survival, and quality of life. NODAT is diagnosed based on the criteria for type 2 diabetes, with the oral glucose tolerance test (OGTT) serving as the gold standard for diagnosis. The development of NODAT is influenced by a range of risk factors, which are classified into modifiable and non-modifiable categories. Post-transplant, regular glycemic monitoring at specific intervals is essential for timely diagnosis and initiation of therapy. Early intervention can help prevent or delay the onset of diabetes-related complications. The treatment strategy for NODAT involves lifestyle modifications and pharmacological interventions. These include medications such as metformin, sulfonylureas, glinides, thiazolidinediones, DPP-4 inhibitors, GLP-1 agonists, SGLT-2 inhibitors, and insulin. Adjusting immunosuppressive therapy-either by reducing dosages or substituting drugs with lower diabetogenic potential-is a common preventative and therapeutic measure. However, this must be performed cautiously to avoid acute graft rejection, which poses a greater risk to the patient compared to NODAT itself. In addition to managing diabetes, addressing comorbidities such as hypertension and dyslipidemia is crucial, as they elevate the risk of cardiovascular events and mortality. Patients with NODAT are also prone to developing common diabetes-related complications, including diabetic nephropathy, neuropathy, retinopathy, and peripheral vascular disease. Therefore, regular follow-ups and appropriate treatment are vital to maintaining quality of life and improving long-term outcomes.

Association between HOMA2 based beta-cell function or insulin resistance and long-term outcomes in kidney transplant recipients with type 2 diabetes

Type 2 diabetes (T2D) is a common comorbidity in kidney transplant recipients, representing a significant proportion of the candidate pool. Post-kidney transplantation management of T2D remains challenging, leading to inferior long-term outcomes compared to non-diabetic recipients. This study aimed to assess the association between Homeostatic Model Assessment 2 (HOMA2) derived insulin resistance and beta-cell function on kidney graft outcomes in T2D kidney transplant recipients. We conducted a monocentric retrospective study at the University Hospital of Lille, including all consecutive adult T2D patients who underwent kidney transplantation between January 2007 and December 2018. HOMA2 indexes (HOMA2 IR for insulin resistance and HOMA2 B for beta-cell function) were calculated at one-year post-transplantation. Primary endpoint was graft survival and secondary endpoints were death-censored graft survival, patient survival and post-transplant metabolic control. Among 1620 kidney transplant recipients, 138 patients with T2D were included, with a median follow-up of 1837 days [1283-2726]. HOMA2 IR was significantly associated with an increased risk of kidney graft failure or death (HR per unit = 1.11 (1.02-1.21). Beta-cell function was not associated with graft prognosis, but decreased beta-cell function was associated with poorer metabolic control over time. This study highlights the significance of insulin resistance as a potential determinant of long-term outcomes in T2D kidney transplant recipients.

Posttransplant complications: molecular mechanisms and therapeutic interventions

Posttransplantation complications pose a major challenge to the long-term survival and quality of life of organ transplant recipients. These complications encompass immune-mediated complications, infectious complications, metabolic complications, and malignancies, with each type influenced by various risk factors and pathological mechanisms. The molecular mechanisms underlying posttransplantation complications involve a complex interplay of immunological, metabolic, and oncogenic processes, including innate and adaptive immune activation, immunosuppressant side effects, and viral reactivation. Here, we provide a comprehensive overview of the clinical features, risk factors, and molecular mechanisms of major posttransplantation complications. We systematically summarize the current understanding of the immunological basis of allograft rejection and graft-versus-host disease, the metabolic dysregulation associated with immunosuppressive agents, and the role of oncogenic viruses in posttransplantation malignancies. Furthermore, we discuss potential prevention and intervention strategies based on these mechanistic insights, highlighting the importance of optimizing immunosuppressive regimens, enhancing infection prophylaxis, and implementing targeted therapies. We also emphasize the need for future research to develop individualized complication control strategies under the guidance of precision medicine, ultimately improving the prognosis and quality of life of transplant recipients.

An update review of post-transplant diabetes mellitus: Concept, risk factors, clinical implications and management

OBJECTIVE

Kidney transplantation is the gold standard therapeutic alternative for patients with end-stage renal disease; nevertheless, it is not without potential complications leading to considerable morbidity and mortality such as post-transplant diabetes mellitus (PTDM). This narrative review aims to comprehensively evaluate PTDM in terms of its diagnostic approach, underlying pathophysiological pathways, epidemiological data, and management strategies.

METHODS

Articles were retrieved from electronic databases using predefined search terms. Inclusion criteria encompassed studies investigating PTDM diagnosis, pathophysiology, epidemiology, and management strategies.

RESULTS

PTDM emerges as a significant complication following kidney transplantation, influenced by various pathophysiological factors including peripheral insulin resistance, immunosuppressive medications, infections, and proinflammatory pathways. Despite discrepancies in prevalence estimates, PTDM poses substantial challenges to transplant. Diagnostic approaches, including traditional criteria such as fasting plasma glucose (FPG) and HbA1c, are limited in their ability to capture early PTDM manifestations. Oral glucose tolerance test (OGTT) emerges as a valuable tool, particularly in the early post-transplant period. Management strategies for PTDM remain unclear, within sufficient evidence from large-scale randomized clinical trials to guide optimal interventions. Nevertheless, glucose-lowering agents and life style modifications constitute primary modalities for managing hyperglycemia in transplant recipients.

DISCUSSION

The complex interplay between PTDM and the transplant process necessitates individualized diagnostic and management approaches. While early recognition and intervention are paramount, modifications to maintenance immunosuppressive regimens based solely on PTDM risk are not warranted, given the potential adverse consequences such as increased rejection risk. Further research is essential to refine management strategies and enhance outcomes for transplant recipients.

Delaying Renal Aging: Metformin Holds Promise as a Potential Treatment

Given the rapid aging of the population, age-related diseases have become an excessive burden on global health care. The kidney, a crucial metabolic organ, ages relatively quickly. While the aging process itself does not directly cause kidney damage, the physiological changes that accompany it can impair the kidney's capacity for self-repair. This makes aging kidneys more susceptible to diseases, including increased risks of chronic kidney disease and end-stage renal disease. Therefore, delaying the progression of renal aging and preserving the youthful vitality of the kidney are crucial for preventing kidney diseases. However, effective strategies against renal aging are still lacking due to the underlying mechanisms of renal aging, which have not been fully elucidated. Accumulating evidence suggests that metformin has beneficial effects in mitigating renal aging. Metformin has shown promising anti-aging results in animal models but has not been tested for this purpose yet in clinical trials. These findings indicate the potential of metformin as an anti-renal aging drug. In this review, we primarily discuss the characteristics and mechanisms of kidney aging and the potential effects of metformin against renal aging.

International consensus on post-transplantation diabetes mellitus

Post-transplantation diabetes mellitus (PTDM) remains a leading complication after solid organ transplantation. Previous international PTDM consensus meetings in 2003 and 2013 provided standardized frameworks to reduce heterogeneity in diagnosis, risk stratification and management. However, the last decade has seen significant advancements in our PTDM knowledge complemented by rapidly changing treatment algorithms for management of diabetes in the general population. In view of these developments, and to ensure reduced variation in clinical practice, a 3rd international PTDM Consensus Meeting was planned and held from 6-8 May 2022 in Vienna, Austria involving global delegates with PTDM expertise to update the previous reports. This update includes opinion statements concerning optimal diagnostic tools, recognition of prediabetes (impaired fasting glucose and/or impaired glucose tolerance), new mechanistic insights, immunosuppression modification, evidence-based strategies to prevent PTDM, treatment hierarchy for incorporating novel glucose-lowering agents and suggestions for the future direction of PTDM research to address unmet needs. Due to the paucity of good quality evidence, consensus meeting participants agreed that making GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) recommendations would be flawed. Although kidney-allograft centric, we suggest that these opinion statements can be appraised by the transplantation community for implementation across different solid organ transplant cohorts. Acknowledging the paucity of published literature, this report reflects consensus expert opinion. Attaining evidence is desirable to ensure establishment of optimized care for any solid organ transplant recipient at risk of, or who develops, PTDM as we strive to improve long-term outcomes.