Pancreas transplant as treatment to arrest renal function decline in patients with type 1 diabetes and proteinuria

Management of hypertension and renin-angiotensin-aldosterone system blockade in adults with diabetic kidney disease: Association of British Clinical Diabetologists and the Renal Association UK guideline update 2021

People with type 1 and type 2 diabetes are at risk of developing progressive chronic kidney disease (CKD) and end-stage kidney failure. Hypertension is a major, reversible risk factor in people with diabetes for development of albuminuria, impaired kidney function, end-stage kidney disease and cardiovascular disease. Blood pressure control has been shown to be beneficial in people with diabetes in slowing progression of kidney disease and reducing cardiovascular events. However, randomised controlled trial evidence differs in type 1 and type 2 diabetes and different stages of CKD in terms of target blood pressure. Activation of the renin-angiotensin-aldosterone system (RAAS) is an important mechanism for the development and progression of CKD and cardiovascular disease. Randomised trials demonstrate that RAAS blockade is effective in preventing/ slowing progression of CKD and reducing cardiovascular events in people with type 1 and type 2 diabetes, albeit differently according to the stage of CKD. Emerging therapy with sodium glucose cotransporter-2 (SGLT-2) inhibitors, non-steroidal selective mineralocorticoid antagonists and endothelin-A receptor antagonists have been shown in randomised trials to lower blood pressure and further reduce the risk of progression of CKD and cardiovascular disease in people with type 2 diabetes. This guideline reviews the current evidence and makes recommendations about blood pressure control and the use of RAAS-blocking agents in different stages of CKD in people with both type 1 and type 2 diabetes.

C-peptide as a Therapy for Kidney Disease: A Systematic Review and Meta-Analysis

C-peptide has intrinsic biological activity and may be renoprotective. We conducted a systematic review to determine whether C-peptide had a beneficial effect on renal outcomes. MEDLINE, EMBASE, and the Cochrane Central Databases were searched for human and animal studies in which C-peptide was administered and renal endpoints were subsequently measured. We identified 4 human trials involving 74 patients as well as 18 animal studies involving 35 separate experiments with a total of 641 animals. In humans, the renal effects of exogenously delivered C-peptide were only studied in type 1 diabetics with either normal renal function or incipient nephropathy. Pooled analysis showed no difference in GFR (mean difference, -1.36 mL/min/1.73 m2, p = 0.72) in patients receiving C-peptide compared to a control group, but two studies reported a reduction in glomerular hyperfiltration (p<0.05). Reduction in albuminuria was also reported in the C-peptide group (p<0.05). In diabetic rodent models, C-peptide led to a reduction in GFR (mean difference, -0.62 mL/min, p<0.00001) reflecting a partial reduction in glomerular hyperfiltration. C-peptide also reduced proteinuria (mean difference, -186.25 mg/day, p = 0.05), glomerular volume (p<0.00001), and mesangial matrix area (p<0.00001) in diabetic animals without affecting blood pressure or plasma glucose. Most studies were relatively short-term in duration, ranging from 1 hour to 3 months. Human studies of sufficient sample size and duration are needed to determine if the beneficial effects of C-peptide seen in animal models translate into improved long-term clinical outcomes for patients with chronic kidney disease. (PROSPERO CRD42014007472)

Progressive renal decline as the major feature of diabetic nephropathy in type 1 diabetes

Despite almost universal implementation of renoprotective therapies over the past 25 years, the risk of end-stage renal disease (ESRD) in type 1 diabetes (T1D) is not decreasing, and ESRD remains the major cause of excess morbidity and premature mortality [1]. Such a state of affairs prompts a call to action. In this review we re-evaluated the proteinuria-centric model of diabetic nephropathy and showed its deficiencies. On the basis of extensive studies that we have been conducting on the patients attending the Joslin Clinic, we propose that progressive renal decline, not abnormalities in urinary albumin excretion, should be considered as the major feature of disease processes leading to ESRD in T1D. The etiology of diabetic nephropathy should be reconsidered in light of our new findings so our perspective can be broadened regarding new therapeutic targets available for interrupting the progressive renal decline in T1D. Reduction in the loss of glomerular filtration rate, not reduction of albumin excretion rate, should become the measure for evaluating the effectiveness of new therapeutic interventions. We need new accurate methods for early diagnosis of patients at risk of progressive renal decline or, better still, for detecting in advance which patients will have rapid, moderate or minimal rate of progression to ESRD.

The therapeutic potential of C-peptide in kidney disease: a protocol for a systematic review and meta-analysis

BACKGROUND

Kidney disease remains a major cause of morbidity and mortality in Canada and worldwide. New medical treatments are needed to reduce the progression of kidney disease to improve patient outcomes. C-peptide is normally released by pancreatic beta-cells along with insulin in healthy individuals, and has been shown to have intrinsic biological activity and to potentially be renoprotective. The effect of exogenous C-peptide on kidney structure and function, and the role of C-peptide in the treatment of kidney disease have not yet been fully elucidated.

METHODS/DESIGN

We will conduct a systematic review of the literature in human clinical trials and mammalian experimental models to ascertain the current evidence for the role of C-peptide as a potential therapeutic agent for the treatment of kidney disease. We aim to identify whether exogenously delivered C-peptide has an effect on clinically relevant outcomes such as glomerular filtration rate, proteinuria, kidney histology, requirement of renal replacement therapy, and mortality. We will search MEDLINE, EMBASE, and the Cochrane Central Databases for human or animal studies in which C-peptide was administered and renal endpoints were subsequently measured. Study quality will be assessed using the Cochrane Collaboration's tool for assessing risk of bias. If appropriate, a meta-analysis will be performed as per standard techniques.

DISCUSSION

The results of this study will determine the potential role of C-peptide as a therapeutic intervention for patients with kidney disease and will help guide subsequent clinical trials. The study may also provide insight into which patients or disease states are likely to benefit the most from C-peptide.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014007472.

Can improved glycemic control slow renal function decline at all stages of diabetic nephropathy?

Observational studies have shown the strong association between level of glycemic control and the key outcome measure, risk of glomerular filtration rate (GFR) loss rather than subsequent course of albumin excretion, in type 1 diabetes patients at all stages of nephropathy. However, it has not been clear if clinical interventions designed to normalize glycemic control are equally effective at all stages, such as primary prevention in normoalbuminuric patients, secondary prevention in microalbuminuria and macroalbuminuria, or tertiary prevention aimed at slowing or reversing further loss of GFR once impaired. Substantial randomized controlled trial data from the Diabetes Control and Complications Trial and Epidemiology of Diabetes Interventions and Complications exists to support postponement, but not outright prevention, of GFR loss in normoalbuminuric patients. Although secondary and tertiary prevention systematic studies are limited to methodologically insufficient insulin pump and transplantation trials, the reversal of advanced glomerular lesions observed in whole-pancreas transplant recipients who experienced long-term glycemic normalization offers convincing support for further research into glycemic interventions specifically for GFR preservation. In light of existing literature, we encourage the design of secondary and tertiary prevention trials that incorporate biomarker methods for identifying patients at highest risk of GFR loss because interventions to normalize hyperglycemia are resource-intensive and may be applied unnecessarily to clinical populations at low long-term GFR loss risk.

High risk of ESRD in type 1 diabetes: new strategies are needed to retard progressive renal function decline

Care of patients with type 1 diabetes (T1D) has changed during the past 30 years. Tools to control hyperglycemia have improved and it was shown that improvement in glycemic control diminished the risk of late diabetic complications, including nephropathy. Moreover, in patients with impaired renal function, aggressive treatment of hypertension and renoprotective blockade of the renin-angiotensin system were shown to postpone end-stage renal disease (ESRD), albeit for a short while. Despite these achievements, the incidence of ESRD caused by T1D in the US population has not decreased but rather has increased over the past 20 years, although it now occurs at slightly older ages. This state of affairs is a call to action. This should begin with adopting a new model of diabetic nephropathy in human beings. In that model, instead of microalbuminuria or proteinuria, the focus should be on diagnosis and treatment of progressive renal function decline that leads to ESRD. Such a model has received significant support in clinical and epidemiologic studies. Investigation of mechanisms of such progressive renal function decline should help in the identification of new therapeutic targets and the development of new interventions. To evaluate these interventions, accurate diagnostic algorithms are needed so T1D patients will be stratified according to time to onset to ESRD. Consistent with concepts of personalized medicine, the new interventions should be tailored to and evaluated in patients predicted to have rapid, moderate, or even slow progression to ESRD.