Coronary artery calcium may stabilize following islet cell transplantation in patients with type 1 diabetes

Impact of Islet Transplantation on Diabetes Complications and Mortality in Patients Living With Type 1 Diabetes

OBJECTIVE

This study aimed to evaluate the impact of islet transplantation (IT) on diabetes complications, death, and cancer incidence.

RESEARCH DESIGN AND METHODS

This retrospective, multicenter, cohort study included patients from three IT clinical trials (intervention group) and from the French health insurance claims database Système National des Données de Santé (SNDS) (control group). Two cohorts of IT recipients were analyzed: IT recipients after kidney transplantation (IAK) and IT recipients alone (ITA). They were matched with patients living with type 1 diabetes (T1D) from the SNDS using a propensity score. The primary outcome was a composite criterion including death, dialysis, amputation, nonfatal stroke, nonfatal myocardial infarction, and transient ischemic attack. The secondary outcome was cancer. Hazard ratio (HRs) and P values were obtained using Cox proportional hazards analysis and log-rank test, respectively.

RESULTS

The study included 61 ITA recipients matched to 610 T1D control patients and 45 IAK recipients matched to 45 T1D control patients over a median follow-up period >10 years. Compared with T1D control patients, ITA and IAK recipients had a lower composite outcome risk (HR 0.39 [95% CI 0.21-0.71; P = 0.002] and 0.52 [0.30-0.88; P = 0.014], respectively) that seemed driven by reduced mortality (0.22 [0.09-0.54]; P < 0.001) for ITA and reduced dialysis (0.19 [0.07-0.50]; P < 0.001) for IAK. Both groups showed no significant changes in cancer risk.

CONCLUSIONS

This study suggests long-term benefits of IT on diabetes-related outcomes. Furthermore, despite the use of immunosuppressive drugs following IT, we observed no significant increase in the risk of cancer. Altogether, these findings highlight a favorable risk-benefit ratio of IT in treating patients with unstable T1D.

Subclinical macroangiopathic target organ damage in type 1 diabetes mellitus patients

PURPOSE

We have summarized key studies regarding the assessment of subclinical macroangiopathic target organ damage (TOD) in type 1 diabetes mellitus (T1DM).

RESULTS

Although chronic complications resulting from hyperglycemia, in particular macroangiopathies, are still the first cause of death in T1DM, there has been growing recognition of the role of hypoglycemia in cardiovascular morbidity and mortality. Subclinical TOD diagnosis ensures early implementation of the complex management aiming at either partial reversal of these complications or at least its downturn. To better identify patients with early TODs, several non-invasive diagnostic techniques are employed, including the ultrasonographic assessment of the intima-media thickness (IMT), computed tomography (CT) for coronary artery calcium (CAC) scores, and pulse wave velocity (PWV) measurement for arterial stiffness evaluation. Various studies reported that T1DM patients present an increased IMT. An increasing IMT fairly correlates with the cardiovascular (CV) events risk even after the adjustment to age, diabetes duration, quality of glucose control as well as the presence of hypertension, and chronic complications. Another, well established marker of the organ damage - CAC score is recommended by ACC/AHA guidelines to assess the overall CV risk in T1DM. Also, the arterial stiffness evaluation with PWV may further improve CV risk prediction, which has been reported in multiple studies including the Framingham Heart Study.

CONCLUSIONS

There is shortage of data from prospective studies which could confirm the benefits of early treatment initiation based on the presence of the subclinical organ damage in T1DM. Most evidence comes from T2DM trials, where effective preventive measures were identified i.e.: smoking cessation, reasonable blood glucose control, efficacious hypertension treatment, and dyslipidemia management, as well as renoprotection. There is still a field for further research to see if routine assessment of asymptomatic vascular damage and early implementation of aggressive treatment would reduce mortality excess from CVD in T1DM.

Ten-Year Outcome of Islet Alone or Islet After Kidney Transplantation in Type 1 Diabetes: A Prospective Parallel-Arm Cohort Study

OBJECTIVE

The long-term outcome of allogenic islet transplantation is unknown. The aim of this study was to evaluate the 10-year outcome of islet transplantation in patients with type 1 diabetes and hypoglycemia unawareness and/or a functioning kidney graft.

RESEARCH DESIGN AND METHODS

We enrolled in this prospective parallel-arm cohort study 28 subjects with type 1 diabetes who received islet transplantation either alone (ITA) or after a kidney graft (IAK). Islet transplantation consisted of two or three intraportal infusions of allogenic islets administered within (median [interquartile range]) 68 days (43-92). Immunosuppression was induced with interleukin-2 receptor antibodies and maintained with sirolimus and tacrolimus. The primary outcome was insulin independence with A1C ≤6.5% (48 mmol/mol). Secondary outcomes were patient and graft survival, severe hypoglycemic events (SHEs), metabolic control, and renal function.

RESULTS

The primary outcome was met by (Kaplan-Meier estimates [95% CI]) 39% (22-57) and 28% (13-45) of patients 5 and 10 years after islet transplantation, respectively. Graft function persisted in 82% (62-92) and 78% (57-89) of case subjects after 5 and 10 years, respectively, and was associated with improved glucose control, reduced need for exogenous insulin, and a marked decrease of SHEs. ITA and IAK had similar outcomes. Primary graft function, evaluated 1 month after the last islet infusion, was significantly associated with the duration of graft function and insulin independence.

CONCLUSIONS

Islet transplantation with the Edmonton protocol can provide 10-year markedly improved metabolic control without SHEs in three-quarters of patients with type 1 diabetes, kidney transplanted or not.

Advances in β-cell replacement therapy for the treatment of type 1 diabetes

The main goal of treatment for type 1 diabetes is to control glycaemia with insulin therapy to reduce disease complications. For some patients, technological approaches to insulin delivery are inadequate, and allogeneic islet transplantation is a safe alternative for those patients who have had severe hypoglycaemia complicated by impaired hypoglycaemia awareness or glycaemic lability, or who already receive immunosuppressive drugs for a kidney transplant. Since 2000, intrahepatic islet transplantation has proven efficacious in alleviating the burden of labile diabetes and preventing complications related to diabetes, whether or not a previous kidney transplant is present. Age, body-mass index, renal status, and cardiopulmonary status affect the choice between pancreas or islet transplantation. Access to transplantation is limited by the number of deceased donors and the necessity of immunosuppression. Future approaches might include alternative sources of islets (eg, xenogeneic tissue or human stem cells), extrahepatic sites of implantation (eg, omental, subcutaneous, or intramuscular), and induction of immune tolerance or encapsulation of islets.