Effect of Sitagliptin on Serum Irisin Levels in Patients with Newly Diagnosed Type 2 Diabetes Mellitus

Diabetes Mellitus Should Be Considered While Analysing Sarcopenia-Related Biomarkers

Sarcopenia is a chronic, progressive skeletal muscle disease characterised by low muscle strength and quantity or quality, leading to low physical performance. Patients with type 2 diabetes mellitus (T2DM) are more at risk of sarcopenia than euglycemic individuals. Because of several shared pathways between the two diseases, sarcopenia is also a risk factor for developing T2DM in older patients. Various biomarkers are under investigation as potentially valuable for sarcopenia diagnosis and treatment monitoring. Biomarkers related to sarcopenia can be divided into markers evaluating musculoskeletal status (biomarkers specific to muscle mass, markers of the neuromuscular junction, or myokines) and markers assuming causal factors (adipokines, hormones, and inflammatory markers). This paper reviews the current knowledge about how diabetes and T2DM complications affect potential sarcopenia biomarker concentrations. This review includes markers recently proposed by the expert group of the European Society for the Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) as those that may currently be useful in phase II and III clinical trials of sarcopenia: myostatin (MSTN); follistatin (FST); irisin; brain-derived neurotrophic factor (BDNF); procollagen type III N-terminal peptide (PIIINP; P3NP); sarcopenia index (serum creatinine to serum cystatin C ratio); adiponectin; leptin; insulin-like growth factor-1 (IGF-1); dehydroepiandrosterone sulphate (DHEAS); C-reactive protein (CRP); interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). A better understanding of factors influencing these biomarkers' levels, including diabetes and diabetic complications, may lead to designing future studies and implementing results in clinical practice.

Microbial gatekeepers: unraveling the role of the gut microbiota enzyme DPP4 in diabetes management

Wang et al. identified dipeptidyl peptidase 4 (DPP4) as a gut microbe-derived enzyme that impacts on host glucose metabolism. They further introduced a novel therapeutic, daurisoline-d4 (Dau-d4), a selective microbial DPP4 (mDPP4) inhibitor that shows promise in improving glucose tolerance, highlighting the potential of therapies that target both host enzymes and gut microbial enzymes.

Move Your Body toward Healthy Aging: Potential Neuroprotective Mechanisms of Irisin in Alzheimer's Disease

Alzheimer's disease (AD) is the leading cause of dementia in older adults, having a significant global burden and increasing prevalence. Current treatments for AD only provide symptomatic relief and do not cure the disease. Physical activity has been extensively studied as a potential preventive measure against cognitive decline and AD. Recent research has identified a hormone called irisin, which is produced during exercise, that has shown promising effects on cognitive function. Irisin acts on the brain by promoting neuroprotection by enhancing the growth and survival of neurons. It also plays a role in metabolism, energy regulation, and glucose homeostasis. Furthermore, irisin has been found to modulate autophagy, which is a cellular process involved in the clearance of protein aggregates, which are a hallmark of AD. Additionally, irisin has been shown to protect against cell death, apoptosis, oxidative stress, and neuroinflammation, all of which are implicated in AD pathogenesis. However, further research is needed to fully understand the mechanisms and therapeutic potential of irisin in AD. Despite the current gaps in knowledge, irisin holds promise as a potential therapeutic target for slowing cognitive decline and improving quality of life in AD patients.

Regulation of Adropin by Sitagliptin monotherapy in participants with newly diagnosed type 2 Diabetes

BACKGROUND

Adropin is a potent metabolic regulator of insulin sensitivity and glycolipid metabolism. The present study investigated the effects of sitagliptin on adropin and metabolic parameters in participants with newly diagnosed type 2 diabetes (T2D).

METHODS

Thirty-five participants newly-diagnosed with T2D were prescribed sitagliptin 100 mg once daily for 17 weeks. Twenty-eight age-, sex-, and BMI-matched healthy subjects were included as the control group. Adropin and clinical parameters were assessed at baseline and after treatment.

RESULTS

At baseline, serum adropin levels were lower in T2D participants than in the healthy individuals (3.12 ± 0.73 vs. 5.90 ± 1.22 ng/ml, P <  0.01). Serum adropin levels were significantly higher in T2D patients after sitagliptin treatment (4.97 ± 1.01 vs. 3.12 ± 0.73 ng/ml, P <  0.01). The changes in serum adropin levels after sitagliptin treatment were associated with the improvements of fasting blood glucose (FBG) (β = - 0.71, P <  0.01), glycosylated hemoglobin (HbA1c) (β = - 0.44, P <  0.01) and homeostatic model assessment of β-cell function (HOMA-β) (β = 9.02, P <  0.01).

CONCLUSIONS

Sitagliptin treatment could significantly increase serum adropin levels in participants with newly diagnosed T2D. The increase in serum adropin levels could be associated with the amelioration of glucose metabolism, which might be involved in beneficial glucose-lowering mechanisms of sitagliptin.

TRIAL REGISTRATION

Clinicaltrials.gov , NCT04495881 . Retrospectively registered on 03/08/2020.

Irisin alleviates high glucose-induced hypertrophy in H9c2 cardiomyoblasts by inhibiting endoplasmic reticulum stress

BACKGROUND

Endoplasmic reticulum stress (ERS) plays an important role in the process of myocardial hypertrophy in diabetic cardiomyopathy (DCM). Irisin, a novel cytokine, has been found to protect against cardiac diastolic dysfunction in DCM. We aimed to investigate the role of irisin in cardiac hypertrophy and to elucidate the underlying mechanisms.

METHODS

H9c2 cells were induced with 33 mM glucose to construct a cardiac hypertrophy cell model, which was then treated with irisin in the presence or absence of the ERS inducer tunicamycin (TM). The cell surface area was measured by FITC-phalloidin staining. The atrial natriuretic peptide levels were detected by an enzyme-linked immunosorbent assay. Furthermore, the expression of the ERS-related proteins, P-PERK, PERK, IRE1α and GRP78, was detected by western blotting.

RESULTS

Irisin significantly reduced myocardial hypertrophy and suppressed high glucose (HG)-induced oxidative stress. Meanwhile, the protective effect of irisin on cardiomyoblasts was reversed by the ERS inducer, TM. Additionally, we detected ERS-associated signaling pathway proteins and found that irisin significantly reduced the protein expression levels of GRP78 and p-PERK/PERK.

CONCLUSION

These results suggest that irisin ameliorates HG-induced cardiac hypertrophy by inhibiting ERS.

Sitagliptin Attenuates the Cognitive Deficits in L-Methionine-Induced Vascular Dementia in Rats

Vascular dementia (VaD) is the second most prevalent type of dementia characterized by progressive cognitive deficits and is a major risk factor for the development of Alzheimer's disease and other neurodegenerative disorders. This study is aimed at determining the potential neuroprotective effect of sitagliptin (STG) on cognitive deficits in L-methionine-induced VaD in rats and the possible underlying mechanisms. 30 adult male Wistar albino rats were divided equally (n = 10) into three groups: control, VaD, and VaD + STG groups. The cognitive performance of the animals was conducted by open field, elevated plus maze, Y-maze, novel object recognition, and Morris water maze tests. Serum homocysteine, TNF-α, IL-6, IL-10, total cholesterol, and triglycerides levels were assessed together with hippocampal MDA, SOD, and BDNF. Histopathological and immunohistochemical assessments of the thoracic aorta and hippocampus (CA1 region) were also performed. Chronic L-methionine administration impaired memory and learning and induced anxiety. On the other hand, STG protected against cognitive deficits through improving oxidative stress biomarkers, inflammatory mediators, lipid profiles, and hippocampus level of BDNF as well as decreasing caspase-3 and GFAP and increasing Ki-67 immunoreactions in the hippocampus. Also, STG improved the endothelial dysfunction via upregulation of aortic eNOS immunoreaction. STG improved the cognitive deficits of L-methionine-induced VaD by its antioxidant, anti-inflammatory, antiapoptotic, and neurotrophic effects. These findings suggest that STG may be a promising future agent for protection against VaD.

One hundred years since insulin discovery: An update on current and future perspectives for pharmacotherapy of diabetes mellitus

Diabetes mellitus was considered a fatal malady until the discovery, extraction and commercial availability of insulins. Numerous other classes of drugs ranging from sulfonylureas to sodium-glucose co-transporter-2 inhibitors were then marketed. However, with the prevalence of diabetes mellitus increasing every year, many more drugs and therapies are under investigation. This review article aimed to summarize the significant developments in the pharmacotherapy of diabetes mellitus and outline the progress made by the recent advances, 100 years since insulins were first extracted successfully. Insulin analogues and insulin delivery pumps have further improved glycaemic control in diabetes mellitus. Cardiovascular and renal outcome trials have changed the landscape of diabetology, with some of these drugs also efficacious in nondiabetics. Newer drug delivery systems are being evaluated to improve the efficacy and reduce the dosing frequency and adverse effects of antidiabetics. Some newer drugs with novel mechanisms of action targeting type 1 and type 2 diabetes have also shown promise in recent clinical trials. These drugs include dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1-agonists, glucokinase activators, anti-CD3 monoclonal antibodies and glimins. Their efficacy needs to be evaluated in larger studies.

Glucosamine Ameliorates Symptoms of High-Fat Diet-Fed Mice by Reversing Imbalanced Gut Microbiota

Glucosamine (GlcN) is used as a supplement for arthritis and joint pain and has been proved to have effects on inflammation, cancer, and cardiovascular diseases. However, there are limited studies on the regulatory mechanism of GlcN against glucose and lipid metabolism disorder. In this study, we treated high-fat diet (HFD)-induced diabetic mice with GlcN (1 mg/ml, in drinking water) for five months. The results show that GlcN significantly reduced the fasting blood glucose of HFD-fed mice and improved glucose tolerance. The feces of intestinal contents in mice were analyzed using 16s rDNA sequencing. It was indicated that GlcN reversed the imbalanced gut microbiota in HFD-fed mice. Based on the PICRUSt assay, the signaling pathways of glucolipid metabolism and biosynthesis were changed in mice with HFD feeding. By quantitative real-time PCR (qPCR) and hematoxylin and eosin (H&E) staining, it was demonstrated that GlcN not only inhibited the inflammatory responses of colon and white adipose tissues, but also improved the intestinal barrier damage of HFD-fed mice. Finally, the correlation analysis suggests the most significantly changed intestinal bacteria were positively or negatively related to the occurrence of inflammation in the colon and fat tissues of HFD-fed mice. In summary, our studies provide a theoretical basis for the potential application of GlcN to glucolipid metabolism disorder through the regulation of gut microbiota.