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.
Dipeptidyl peptidase-4 inhibitors (DPP-4i) combined with vitamin D3: An exploration to treat new-onset type 1 diabetes mellitus and latent autoimmune diabetes in adults in the future.
Pinheiro, MM, Pinheiro, FMM, Trabachin, ML
International immunopharmacology. 2018;:11-17
Abstract
Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease characterized by destruction of pancreatic beta cells through cell injury caused primarily by cytotoxic T lymphocytes (CD8+). The pathophysiological basis of T1DM seems to be an imbalance between a reduced function of T regulatory lymphocytes and an increased inflammatory activity of Th17 lymphocytes caused by increased production of inflammatory cytokines, as IL-1β, IL-6, IL-17 and IFN-gamma due to environmental factors and genetic predisposition. The preservation of the reserve of beta cells in new-onset T1DM and latent autoimmune diabetes in adults (LADA) by immunomodulation in addition to the incretin effect seems to be possible with an association of DPP-4 inhibitors and vitamin D3. In this review, we discuss the effects of both drugs on the immune system and on beta cell function and their eventual additive effects in preserving the residual function of beta cells in new-onset T1DM and LADA.