Phenotype and predictors of insulin independence in adults presenting with diabetic ketoacidosis: a prospective cohort study

AIMS/HYPOTHESIS

The aim of this work was to describe the phenotype of adults presenting with a first episode of diabetic ketoacidosis (DKA) in Cape Town, South Africa, and identify predictors of insulin independence at 12 and 60 months after presentation.

METHODS

A prospective, descriptive cohort study of all individuals, 18 years or older, presenting for the first time with DKA to four public-sector hospitals of the Groote Schuur Academic Health Complex was performed. Clinical, biochemical and laboratory data including GAD antibody and C-peptide status were collected at baseline. Insulin was systematically weaned and stopped in individuals who achieved normoglycaemia within the months after DKA. Individuals were followed for 12 months and then annually until 5 years after initial presentation with ketoacidosis.

RESULTS

Eighty-eight individuals newly diagnosed with diabetes when presenting with DKA were included and followed for 5 years. The mean ± SD age was 35±10 years and the median (IQR) BMI at diagnosis was 28.5 (23.3-33.4) kg/m2. Overall, 46% were insulin independent 12 months after diagnosis and 26% remained insulin independent 5 years after presentation. Forty-one participants (47%) tested negative for anti-GAD and anti-IA-2 antibodies and had C-peptide levels >0.3 nmol/l; in this group, 68% were insulin independent at 12 months and 37% at 5 years after diagnosis. The presence of acanthosis nigricans was strongly associated with insulin independence (OR 27.1 [95% CI 7.2, 102.2]; p<0.001); a positive antibody status was associated with a lower likelihood of insulin independence at 12 months (OR 0.10 [95% CI 0.03, 0.36]; p<0.001). On multivariable analysis only acanthosis (OR 11.5 [95% CI 2.5, 53.2]; p=0.004) was predictive of insulin independence 5 years after diagnosis.

CONCLUSIONS/INTERPRETATION

The predominant phenotype of adults presenting with a first episode of DKA in Cape Town, South Africa, was that of ketosis-prone type 2 diabetes. These individuals presented with obesity, acanthosis nigricans, negative antibodies and normal C-peptide and could potentially be weaned off insulin at follow-up. Classic type 1 diabetes (lower weight, antibody positivity, low or unrecordable C-peptide levels and long-term insulin dependence) was less common. The simple clinical sign of acanthosis nigricans is a strong predictor of insulin independence at 12 months and 5 years after initial presentation.

Adjudin improves beta cell maturation, hepatic glucose uptake and glucose homeostasis

AIMS/HYPOTHESIS

Recovering functional beta cell mass is a promising approach for future diabetes therapies. The aim of the present study is to investigate the effects of adjudin, a small molecule identified in a beta cell screen using zebrafish, on pancreatic beta cells and diabetes conditions in mice and human spheroids.

METHODS

In zebrafish, insulin expression was examined by bioluminescence and quantitative real-time PCR (qPCR), glucose levels were examined by direct measurements and distribution using a fluorescent glucose analogue, and calcium activity in beta cells was analysed by in vivo live imaging. Pancreatic islets of wild-type postnatal day 0 (P0) and 3-month-old (adult) mice, as well as adult db/db mice (i.e. BKS(D)-Leprdb/JOrlRj), were cultured in vitro and analysed by qPCR, glucose stimulated insulin secretion and whole mount staining. RNA-seq was performed for islets of P0 and db/db mice. For in vivo assessment, db/db mice were treated with adjudin and subjected to analysis of metabolic variables and islet cells. Glucose consumption was examined in primary human hepatocyte spheroids.

RESULTS

Adjudin treatment increased insulin expression and calcium response to glucose in beta cells and decreased glucose levels after beta cell ablation in zebrafish. Adjudin led to improved beta cell function, decreased beta cell proliferation and glucose responsive insulin secretion by decreasing basal insulin secretion in in vitro cultured newborn mouse islets. RNA-seq of P0 islets indicated that adjudin treatment resulted in increased glucose metabolism and mitochondrial function, as well as downstream signalling pathways involved in insulin secretion. In islets from db/db mice cultured in vitro, adjudin treatment strengthened beta cell identity and insulin secretion. RNA-seq of db/db islets indicated adjudin-upregulated genes associated with insulin secretion, membrane ion channel activity and exocytosis. Moreover, adjudin promoted glucose uptake in the liver of zebrafish in an insulin-independent manner, and similarly promoted glucose consumption in primary human hepatocyte spheroids with insulin resistance. In vivo studies using db/db mice revealed reduced nonfasting blood glucose, improved glucose tolerance and strengthened beta cell identity after adjudin treatment.

CONCLUSIONS/INTERPRETATION

Adjudin promoted functional maturation of immature islets, improved function of dysfunctional islets, stimulated glucose uptake in liver and improved glucose homeostasis in db/db mice. Thus, the multifunctional drug adjudin, previously studied in various contexts and conditions, also shows promise in the management of diabetic states.

DATA AVAILABILITY

Raw and processed RNA-seq data for this study have been deposited in the Gene Expression Omnibus under accession number GSE235398 ( https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE235398 ).

Ketosis-Prone Diabetes (Flatbush Diabetes): an Emerging Worldwide Clinically Important Entity

PURPOSE OF REVIEW

Ketosis-prone diabetes or Flatbush diabetes has been widely recognized as a clinical entity since 1984. Most of the early clinical studies focused on African American or Afro-Caribbean individuals. It is now being recognized as an important clinical entity in sub-Saharan Africans, Asian and Indian populations, and Hispanic populations. Major questions remain as to its pathogenesis and whether it is a unique type of diabetes or a subset of more severe type 2 diabetes with greater loss of insulin action in target tissues. This review summarizes the main clinical and mechanistic studies to improve the understanding of ketosis-prone (Flatbush) diabetes.

RECENT FINDINGS

Little data are available on the magnitude of KPD in the different susceptible populations. It is relatively common in black populations. KPD is defined as a syndrome in which diabetes commences with ketoacidosis in individuals who are GAD and anti-islet cell antibody negative and have no known precipitating causes. The patients present during middle age, are overweight or mildly obese, and in many reports are more likely to be male. After intensive initial insulin therapy, many patients become insulin independent and can be well controlled on diet alone or diet plus oral medications. The clinical course of KPD is like that of patients with type 2 diabetes rather than that of type 1 diabetes. Little differences are found in the clinical characteristics and clinical outcomes between patients presenting with KPD and those presenting with severe hyperglycemia with no ketoacidosis. The mechanisms responsible for the development of ketosis-prone diabetes as well its remission remain unknown.

Glycemic Outcomes of Islet Autotransplantation

PURPOSE OF REVIEW

While there has been a growing utilization of total pancreatectomy with islet autotransplantation (TPIAT) for patients with medically refractory chronic pancreatitis over the past few decades, there remains a lack of consensus clinical guidelines to inform the counseling and management of patients undergoing TPIAT. In this article, we review the current clinical practice and published experience of several TPIAT centers, outline key aspects in managing patients undergoing TPIAT, and discuss the glycemic outcomes of this procedure.

RECENT FINDINGS

Aiming for lower inpatient glucose targets immediately after surgery (usually 100-120 mg/dl), maintaining all patients on subcutaneous insulin for at least 3 months to "rest" islets before an attempt is made to wean insulin, and close outpatient endocrinology follow-up after TPIAT particularly in the first year is common and related to better outcomes. Although TPIAT procedures and glycemic outcomes may differ across surgical centers, overall, approximately one third of patients are insulin independent at 1 year after TPIAT. Higher islet yield and lower preoperative glucose levels are among the strongest predictors of short-term post-operative insulin independence. Beyond 1 year post-operatively, the clinical management and long-term glycemic outcomes of patients after TPIAT are more variable. A multidisciplinary approach is essential in optimizing the preoperative, inpatient, and post-operative management and counseling of patients about the expected glycemic outcomes after surgery. Consensus guidelines for the clinical management of diabetes after TPIAT and harmonization of data collection protocols among TPIAT centers are needed to address the current knowledge gaps in clinical care and research and to optimize glycemic outcomes after TPIAT.

Clinical results of islet transplantation

Islet transplantation is considered an advanced therapy in the treatment of type-1 diabetes, with a progressive improvement of clinical results as seen in the Collaborative Islet Transplant Registry (CITR) report. It is an accepted method for the stabilization of frequent hypoglycemia, or severe glycemic lability, in patients with hypoglycemic unawareness, poor diabetic control, or a resistance to intensive insulin-based therapies. Worldwide data confirm a positive trend in this field, with the integrated management of pivotal factors: adequate islet mass, immunosuppressive protocols, additional anti-inflammatory therapy, and pre-transplant allo-immunity assessment. Insulin independence has been observed in several clinical trials with different rate, ranging 100-65% of patients; the maintenance of this condition during the follow-up progressively decreased, actually arranged on 44% 3 years after the last infusion, according to data reported from the CITR. Successful duration is progressively increasing, with ≥13 years being the longest reported insulin-free condition on record. The immediate results of functioning islet transplantation are an improvement in hypoglycemic awareness and a reduction in the glycated hemoglobin level. Furthermore, many studies have shown its influence on the chronic complications of diabetes, such as peripheral neuropathy, retinopathy, and macroangiopathy. Pre-transplant nephropathy remains an exclusion criterion as immunosuppressive therapy can exacerbate kidney-function deterioration. The problems linked to immunosuppression following islet transplantation for the treatment of type-1 diabetes need to be considered in order to achieve the correct risk/benefit ratio for each patient.