1.
COVID-19 and comorbidities: A role for dipeptidyl peptidase 4 (DPP4) in disease severity?
Bassendine, MF, Bridge, SH, McCaughan, GW, Gorrell, MD
Journal of diabetes. 2020;(9):649-658
Abstract
The coronavirus disease 2019 (COVID-19) pandemic is caused by a novel betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), similar to SARS-CoV and Middle East respiratory syndrome (MERS-CoV), which cause acute respiratory distress syndrome and case fatalities. COVID-19 disease severity is worse in older obese patients with comorbidities such as diabetes, hypertension, cardiovascular disease, and chronic lung disease. Cell binding and entry of betacoronaviruses is via their surface spike glycoprotein; SARS-CoV binds to the metalloprotease angiotensin-converting enzyme 2 (ACE2), MERS-CoV utilizes dipeptidyl peptidase 4 (DPP4), and recent modeling of the structure of SARS-CoV-2 spike glycoprotein predicts that it can interact with human DPP4 in addition to ACE2. DPP4 is a ubiquitous membrane-bound aminopeptidase that circulates in plasma; it is multifunctional with roles in nutrition, metabolism, and immune and endocrine systems. DPP4 activity differentially regulates glucose homeostasis and inflammation via its enzymatic activity and nonenzymatic immunomodulatory effects. The importance of DPP4 for the medical community has been highlighted by the approval of DPP4 inhibitors, or gliptins, for the treatment of type 2 diabetes mellitus. This review discusses the dysregulation of DPP4 in COVID-19 comorbid conditions; DPP4 activity is higher in older individuals and increased plasma DPP4 is a predictor of the onset of metabolic syndrome. DPP4 upregulation may be a determinant of COVID-19 disease severity, which creates interest regarding the use of gliptins in management of COVID-19. Also, knowledge of the chemistry and biology of DPP4 could be utilized to develop novel therapies to block viral entry of some betacoronaviruses, potentially including SARS-CoV-2.
2.
Current treatment options for nonalcoholic fatty liver disease.
Shetty, A, Syn, WK
Current opinion in gastroenterology. 2019;(3):168-176
Abstract
PURPOSE OF REVIEW Nonalcoholic fatty liver disease (NAFLD) is the leading cause of liver disease in the United States and is strongly associated to the metabolic syndrome. In this review, we will discuss the evidence behind the current recommendations on lifestyle modifications and available treatment options for NAFLD. RECENT FINDINGS The unrelenting rise in obesity and diabetes epidemic has led to a large healthcare burden from NAFLD and it is projected to continue to grow over the next two decades. Lifestyle modification that leads to weight loss is effective at treating NAFLD, but these modifications require a multidisciplinary approach for success in the real world. Multiple pharmacologic treatment options have been studied with promising results, but none have been approved for treatment in the United States. Clinical trials are on-going to study further pharmacologic treatment alternatives. SUMMARY NAFLD is the most common chronic liver disease in United States, and an independent risk factor for mortality. Implementation of lifestyle modifications through a multidisciplinary approach and careful selection of patients for pharmacologic interventions will be essential for successful management of NAFLD.
3.
Does dipeptidyl peptidase-4 inhibition prevent the diabetogenic effects of glucocorticoids in men with the metabolic syndrome? A randomized controlled trial.
van Genugten, RE, van Raalte, DH, Muskiet, MH, Heymans, MW, Pouwels, PJ, Ouwens, DM, Mari, A, Diamant, M
European journal of endocrinology. 2014;(3):429-39
Abstract
OBJECTIVE Anti-inflammatory glucocorticoid (GC) therapy often induces hyperglycemia due to insulin resistance and islet-cell dysfunction. Incretin-based therapies may preserve glucose tolerance and pancreatic islet-cell function. In this study, we hypothesized that concomitant administration of the dipeptidyl peptidase-4 inhibitor sitagliptin and prednisolone in men at high risk to develop type 2 diabetes could protect against the GC-induced diabetogenic effects. DESIGN AND METHODS Men with the metabolic syndrome but without diabetes received prednisolone 30 mg once daily plus sitagliptin 100 mg once daily (n=14), prednisolone (n=12) or sitagliptin alone (n=14) or placebo (n=12) for 14 days in a double-blind 2 × 2 randomized-controlled study. Glucose, insulin, C-peptide, and glucagon were measured in the fasted state and following a standardized mixed-meal test. β-cell function parameters were assessed both from a hyperglycemic-arginine clamp procedure and from the meal test. Insulin sensitivity (M-value) was measured by euglycemic clamp. RESULTS Prednisolone increased postprandial area under the curve (AUC)-glucose by 17% (P<0.001 vs placebo) and postprandial AUC-glucagon by 50% (P<0.001). Prednisolone reduced 1st and 2nd phase glucose-stimulated- and combined hyperglycemia-arginine-stimulated C-peptide secretion (all P ≤ 0.001). When sitagliptin was added, both clamp-measured β-cell function (P=NS for 1st and 2nd phase vs placebo) and postprandial hyperglucagonemia (P=NS vs placebo) remained unaffected. However, administration of sitagliptin could not prevent prednisolone-induced increment in postprandial glucose concentrations (P<0.001 vs placebo). M-value was not altered by any treatment. CONCLUSION Fourteen-day treatment with high-dose prednisolone impaired postprandial glucose metabolism in subjects with the metabolic syndrome. Concomitant treatment with sitagliptin improved various aspects of pancreatic islet-cell function, but did not prevent deterioration of glucose tolerance by GC treatment.