Comparative evaluation of metformin and liraglutide cardioprotective effect in rats with impaired glucose tolerance

Pharmacological correction of experimentally induced osteoporosis complicated by type 2 diabetes mellitus

BACKGROUND: Osteoporosis remains one of the most important medical problems worldwide with significant economic consequences. The development of new drugs based on unique biologically active compounds can contribute significantly to osteoporosis management. AIM: To evaluate the osteogenesis processes by evaluating bone-remodeling markers in the blood serum during the treatment of experimental osteoporosis complicated by type 2 diabetes mellitus. MATERIALS AND METHODS: The study was performed on an experimental model of osteoporosis, followed by the induction of type 2 diabetes mellitus, using biochemical methods to analyze markers of osteoporosis in the blood serum. RESULTS: The results of the analysis of bone remodeling markers revealed that the antiosteoporotic activity of a composite preparation based on succinic acid salts is dependent on glucose metabolism disorders such as diabetes mellitus. The high efficacy of the new drug in monotherapy and combination with vitamin D3 in the activation of osteogenesis in experimental osteoporosis was balanced by impaired metabolic processes in type 2 diabetes mellitus. CONCLUSIONS: The results indicate the dependence of the pharmacological effectiveness of the antiosteoporosis agent on metabolic disorders, such as type 2 diabetes mellitus, in female rats with experimental osteoporosis.

Bone remodeling in experimental diabetes mellitus and surgical menopause in Wistar rats

BACKGROUND: Osteoporosis is metabolic skeletal disease characterized with low bone mass, bone microarchitecture disturbance that together lead to high prevalence of fragility fractures. Postmenopausal osteoporosis accounts for about 80% of the osteoporosis structure in women over 50 years. Diabetes mellitus (DM) is an independent risk factor for low-traumatic fractures. The incidence of both type 2 DM and osteoporosis increases during menopause. Therefore, the study of bone metabolism in experimental diabetes and surgical menopause seems important.

THE AIM of the study was to investigate bone metabolism parameters during menopause and experimental type 2 DM.

MATERIALS AND METHODS: The half of female Wistar rats had been subjected to bilateral ovariectomy at the beginning of the experiment. Diabetes mellitus (DM) was modelled using a high-fat diet and streptozotocin+nicotinamide. Four weeks after the following groups were formed: «Сontrol» (females without any interventions receiving standard chew, n=5) «OE» (females after ovariectomy n=5), «DM» (females with DM, n=4), «OE+DM» (females after ovariectomy with DM, n=4). The observation period lasted 8 weeks. Bone turnover and calcium-phosphorus metabolism markers (osteocalcin, osteoprotegerin (OPG), nuclear factor-kappa-beta receptor activator ligand (RANKL), sclerostin, fibroblast growth factor-23 (FGF-23), calcium, phosphorus) were measured in the end of experiment. Bone histomorphometry was performed after euthanasia.

RESULTS: Phosphorus level was significantly lower both in the «OE» group (1.63 [1.58; 1.65] mmol/L) and in the «DM» group (2.81 [2.57; 2.83] mmol /l) compared to the «Control» group (3.12 [2.55; 3.24] mmol/l) (p<0.001). This marker was significantly higher in the «OE+DM» group (2.79 [2.46; 2.81] mmol/l) in comparison to the «OE» group (2.79 [2.46; 2.81] mmol /l), p=0.025. Osteocalcin level was significantly lower in the «DM» group (8.1 [7.8; 9.2] ng/ml) compared to the «Control» group (16.97 [14.07; 17.07] ng/ml ), p=0.005. A weak negative correlation (r= -0.5, p<0,05) was found between glucose and osteocalcin levels (p=0.03). RANKL level was significantly lower in the «OE+DM» group (278,1 [273.1; 289.7] pg/mL) compared to the «OE» group (400.6 [394.5; 415.1] pg/mL), besides the OPG/RANKL ratio was higher in this group (0.03 [0.02; 0.035] and 0.01 [0.004; 0.014], respectively), p=0.05. In the «OE» group lower OPG level (5.1 [1.5; 5.6] pmol/L) and OPG/RANKL ratio (0.01 [0.003; 0.014]) were obtained in comparison to the «Control» group (12.3 [8.8; 14.2] pmol/l and (0.34[0.33; 0.4], p=0.025 and p=0.07, respectively. The area of bone trabeculae in the epiphyseal zone was the largest in the «Control» group (42 [39; 45]) %; the difference was significant compared to the «OE» group (29 [25; 33] %, p=0.011) and the «OE+DM» group (30 [23; 25] %, p=0.016). The area of bone trabeculae in the metaepiphyseal zone was also the largest in the «Control» group (49 [46; 52] %) compared to the «OE» (35 [25; 39] %), «DM» (31 [26; 34] %), «OE+DM» (35 [33; 38] %), p<0.001. There was no difference in the thickness of the bone trabeculae among the groups.

CONCLUSION: DM induction can significantly inhibit bone remodeling in animals without menopause, which is reflected in a lower osteocalcin level. Bone turnover during DM and surgical menopause is characterized by lower RANKL levels and higher OPG/RANKL ratio. The effect of ovariectomy on bone metabolism was manifested in more extensive decrease in bone trabeculae area than in DM.

Effect of liraglutide on atherosclerosis in patients with impaired glucose tolerance: A double‑blind, randomized controlled clinical trial

Glucagon-like peptide-1 receptor agonist liraglutide may have beneficial effects on atherosclerosis development in impaired glucose tolerance (IGT). To the best of our knowledge, however, little conclusive evidence from clinical trials has been presented. The present study aimed to investigate the effect of liraglutide on atherosclerosis progression in patients with IGT. The present study was a double-blind, randomized controlled clinical trial. A total of 39 of patients aged 20-75 years who were overweight or obese (BMI, 27-40 kg/m²) and presented IGT were randomized to receive liraglutide (n=17) or lifestyle interventions (n=22) for 6 months. Serum glucose and insulin (INS) levels, lipid profile, inflammatory biomarkers and carotid intima-media thickness (CIMT) were assessed at the start and end of each treatment. Side effects were also recorded. Liraglutide treatment was found to significantly improve glycaemia, including glycosylated hemoglobin, fasting and postprandial glucose as well as INS levels (all P<0.001). Liraglutide also significantly decreased serum total cholesterol and low-density lipoprotein levels (all P<0.001). Furthermore, serum levels of inflammatory biomarkers, as well as CIMT, were decreased following liraglutide treatment compared with those in the lifestyle intervention group (all P<0.001). Kaplan-Meier analysis showed that the risk of vasculopathy in the liraglutide group was lower than that in the lifestyle intervention group (log-rank test; P=0.041). The monitoring of drug-associated side effects indicated that the dose of liraglutide (0.6 to 1.2 mg/QD via subcutaneous injection) was safe and well-tolerated. The present study suggested that liraglutide may slow atherosclerosis development and improve inflammatory status as well as intimal function in patients with IGT with few side effects. The trial was registered through the Chinese Clinical Trial Registry (ChiCTR; trial registration no. ChiCTR2200063693; retrospectively registered) on Sep 14, 2022.

Modern glucose-lowering treatment effect on bone remodeling in experimental diabetes mellitus and surgical menopause

BACKGROUND: Diabetes mellitus (DM) is an independent risk factor for low-traumatic fractures. On the other hand, hypoglycemic drugs can have both positive and negative effects on bone remodeling.

THE AIM: Тo investigate bone metabolism parameters during surgical menopause and experimental DM under the treatment with glucagon-like peptide receptor agonist type 1 (arGLP-1) liraglutide (LIRA) and sodium-glucose cotransporter type 2 inhibitor (iSGLT-2) canagliflozin (CANA).

MATERIALS AND METHODS: Female Wistar rats have been subjected to bilateral ovariectomy at the beginning of the experiment. Diabetes mellitus (DM) was modelled using a high-fat diet and streptozotocin+nicotinamide. Four weeks after the following groups were formed: “OE+DM” (females after ovariectomy with DM and without any therapy, n=4) «OE+DM+CANA» (females after ovariectomy with DM under treatment with CANA, n=4), «OE+DM+LIRA» (females after ovariectomy with DM under treatment LIRA, n=5). The treatment or observation period were continuing for 8 weeks. Calcium, phosphorus and bone turnover markers (fibroblast growth factor-23 (FGF-23), osteocalcin, sclerostin, osteoprotegerin (OPG), nuclear factor-kappa-B receptor activator ligand (RANKL), were measured in the end of experiment. Bone histomorphometry was performed after euthanasia.

RESULTS: Treatment with both CANA and LIRA did not significantly affect the phosphorus-calcium metabolism, sclerostin and osteocalcin concentrations. At the same time, the level of OPG was the highest in «OE+DM ‘’ group (9.1 [7.81; 10.045] pmol/l). The differences were significant compared with «OE+DM+CANA’’ (2, 33 [1.84; 5.84] pmol/l, p = 0.003) and «OE+DM+LIRA» (1.7 [1; 2] pmol/l, p = 0.003) groups. There were no differences in OPG levels between animals treated with different drugs. Similarly, the OPG/RANKL ratio was similarly reduced with both types of treatment. In “OE+DM+CANA’’ group the bone trabeculae number of   the femur epiphysis (p=0.042) were decreased in comparison to «OE+DM» group. LIRA did not change the histoarchitectonic parameters.

CONCLUSION: Bone metabolism markers did not differ when using as canagliflozin as liraglutide. Besides, canagliflosin can lead to the activation of bone resorption, which is expressed in the femur epiphyseal trabeculae number decreasing.

Combination of Empagliflozin and Liraglutide protects heart against isoproterenol-induced myocardial infarction in rats

Cardiovascular benefit of new anti-hyperglycemic agent such as glucagon like peptide-1 receptor agonist (GLP-1RA) or sodium glucose co-transporter-2 inhibitor (SGLT2i) has been proven, with the proposed-mechanism that might be complementary. We investigated the effects of its combination on blood glucose profile and cardiac biomarkers. The rats were given lipid emulsion for 2 weeks, followed by a single dose of streptozotocin (STZ) 35 mg/kg BW, then treated with empagliflozin and/ liraglutide for 30 days while receiving isoproterenol (ISO) 85 mg/kg on day 29 and 30. The results showed no superior improvement on fasting blood glucose (FBG) and insulin sensitivity (KITT) in the combination group compared to empagliflozin/liraglutide group. However, the combination group showed a higher inhibition in almost all biomarkers, specifically against the elevation of CK-MB compared to one of these agents alone. The histopathological examination using H&E staining even showed a minimal inflammation and gap between cardiomyocytes. These findings may indicate the combination of empagliflozin and liraglutide has a better cardiac protection effect.

Scientific Basics of Personalized Medicine: Realities and Opportunities

Modern trends in the development of health care suggest its focus on the interests of the patient and its holistic nature, as well as deep penetration into all parts of health care information technology. The driving force behind the ongoing changes, of course, are scientific achievements, the importance of which in the development of new medical technologies and the creation of innovative diagnostic devices, as well as medicines, has grown significantly in recent years. These processes provide conditions for the introduction into clinical practice of a new model of medical care-personalized medicine, based on the choice of methods of diagnosis and treatment with account for the individual characteristics of the course of the disease, as well as the patient's lifestyle. Personalized medicine technologies, which involve the creation of an appropriate, often expensive, infrastructure of omics technologies, should ultimately lead to an increase in the efficiency, quality, and, most importantly, safety of medical care. In the Russian Federation, this area is actively developing in four world-class research centers, including the Almazov National Medical Research Center. The current state and prospects of research in the field of personalized medicine are discussed in this article, prepared by the author on the basis of his scientific report at a meeting of the Presidium of the Russian Academy of Sciences.

Cardioprotective Effects of 1-(3,6-Dibromo-carbazol-9-yl)-3-Phenylamino-Propan-2-Ol in Diabetic Hearts via Nicotinamide Phosphoribosyltransferase Activation

Diabetes is associated with increased cardiac injury and sudden death. Nicotinamide phosphoribosyltransferase (Nampt) is an essential enzyme for the NAD+ salvage pathway and is dysregulated in diabetes. Nampt activation results in rescued NADH/NAD+ ratios and provides pharmacological changes necessary for diabetic cardioprotection. Computer docking shows that 1-(3,6-Dibromo-carbazol-9-yl)-3-phenylamino-propan-2-ol (P7C3) allows for enhanced Nampt dimerization and association. To test the pharmacological application, we used male leptin receptor-deficient (db/db) mice and treated them with Nampt activator P7C3. The effects of 4-week P7C3 treatment on cardiac function were evaluated along with molecular signaling changes for phosphorylated protein kinase B (p-AKT), phosphorylated endothelial nitric oxide synthase (p-eNOS), and sirtuin 1 (SIRT1). The cardiac function evaluated by ECG and echocardiography were significantly improved after 4 weeks of P7C3 treatment. Biochemically, higher NADH/NAD+ ratios in diabetic hearts were rescued by P7C3 treatment. Moreover, activities of Nampt and SIRT1 were significantly increased in P7C3-treated diabetic hearts. P7C3 treatment significantly decreased the blood glucose in diabetic mice with 4-week treatment as noted by glucose tolerance test and fasting blood glucose measurements compared with vehicle-treated mice. P7C3 activated Nampt enzymatic activity both in vitro and in the 4-week diabetic mouse hearts, demonstrating the specificity of the small molecule. P7C3 treatment significantly enhanced the expression of cardioprotective signaling of p-AKT, p-eNOS, and Beclin 1 in diabetic hearts. Nampt activator P7C3 allows for decreased infarct size with decreased Troponin I and lactose dehydrogenase (LDH) release, which is beneficial to the heart. Overall, the present study shows that P7C3 activates Nampt and SIRT1 activity and decreases NADH/NAD+ ratio, resulting in improved biochemical signaling providing cardioprotection. SIGNIFICANCE STATEMENT: This study shows that 1-(3,6-Dibromo-carbazol-9-yl)-3-phenylamino-propan-2-ol (P7C3) is effective in treating diabetes and cardiovascular diseases. The novel small molecule is antiarrhythmic and improves the ejection fraction in diabetic hearts. The study successfully demonstrated that P7C3 decreases the infarct size in hearts during myocardial infarction and ischemia-reperfusion injury. Biochemical and cellular signaling show increased NAD+ levels, along with Nampt activity involved in upregulating protective signaling in the diabetic heart. P7C3 has high therapeutic potential for rescuing heart disease.

Metformin Influence on the Intestinal Microbiota and Organism of Rats with Metabolic Syndrome

Metformin is a first-line drug for DM2 treatment and prevention, but its complex effect on impaired glucose tolerance (IGT), including its influence on myocardial resistance to ischemia-reperfusion injury, is not completely studied. We aimed to evaluate the influence of metformin on the intestinal microbiota (IM), metabolism, and functional and morphological characteristics of myocardium in rats with IGT. IGT was modelled in SPF Wistar rats with a high-fat diet and streptozotocin and nicotinamide injection. Rats were divided into three groups: IGT (without treatment), IGT MET (metformin therapy), and CRL (without IGT induction and treatment). IGT group was characterized by: higher body weight, increased serum glucose and total cholesterol levels, atherogenic coefficient, impairment in the functional parameters of the isolated heart during perfusion, and larger myocardium infarction (MI) size in comparison with the CRL group. IM of IGT rats differed from that of CRL: an increase of Bacteroides, Acinetobacter, Akkermansia, Roseburia, and a decrease of Lactobacillus genera representation. Metformin therapy led to the diminishing of metabolic syndrome (MS) symptoms, which correlated with IM restoration, especially with the growth of Akkermansia spp. and decline of Roseburia populations and their influence on other members of IM. The obtained results allow us to consider from a new point of view the expediency of probiotic A. muciniphila use for MS treatment.

Tandem mass tag-based proteomic profiling revealed potential therapeutic targets and mechanisms of liraglutide for the treatment of impaired glucose tolerance

OBJECTIVE

Based on the tandem mass tag (TMT) technique, our study investigated the potential therapeutic targets of Liraglutide (LIRA) on streptozotocin (STZ) induced impaired glucose tolerance (IGT) in rats and discuss the biological mechanism of the drug against IGT.

METHODS

10 rats were randomly selected from 31 male wistar rats of specific pathogen free (SPF) grade as control group and fed with conventional chow, offered the remaining rats a high fat and high sugar (HFSD) diet combined with an intraperitoneal injection of STZ to establish the IGT model, and excluded 2 non-model rats. Specifically, the model rats were randomly divided into Model group (n=10) and LIRA group (n=9). In addition, the LIRA group was subcutaneously injected with 0.06 mg/kg LIRA, during which the metabolic parameters including body weight and fasting blood glucose were recorded. After 8 weeks, samples were taken under anesthesia. Then, the cell morphology was observed using HE staining, and immunofluorescence was performed on the pancreatic tissues of the three groups of rats. Besides, the expression of differential proteins in pancreatic tissues of the three groups of rats was determined by the TMT proteomic labeling. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) biological function analysis were performed on the intersection of Model and LIRA differential proteins.

RESULTS

LIRA could not only significantly reduce blood glucose levels but also improve islet cell morphology and function in IGT rats. Among the differential proteins between the model group and the blank group, 44 were reversed after LIRA treatment, of which 14 were up-regulated, while 30 were down-regulated, including PPIF, MPRIP, CYP51, TXNL1, BCL-2, etc. (FC>1.1 or<0.909, P<0.05). According to the GO and KEGG analysis results, it was related to biological processes such as fatty acid metabolism and adipocyte generation, which involved multiple signaling pathways regulating the function of islet cells, such as MAPK, PI, Ras, FcγR, and unsaturated fatty acids, and pyruvate metabolism.

CONCLUSION

To sum up, LIRA participated in anti-IGT therapy through regulation of multiple target proteins and biological functions. This study is of great reference for further exploring the mechanism of action of LIRA at the protein level of IGT.

Interference With the AMPKα/mTOR/NLRP3 Signaling and the IL-23/IL-17 Axis Effectively Protects Against the Dextran Sulfate Sodium Intoxication in Rats: A New Paradigm in Empagliflozin and Metformin Reprofiling for the Management of Ulcerative Colitis

Empagliflozin and metformin are widely used for the treatment of type 2 diabetes. These drugs showed marked anti-inflammatory effects in different animal models via enhancing AMPK activity. Yet, the protective anti-inflammatory effects of their combination against ulcerative colitis have not been previously investigated. The current study aimed to explore the potential of empagliflozin/metformin combination to mitigate the DSS-induced rat colitis model. The modulating effects of empagliflozin and metformin on the AMPK/mTOR/NLRP3 axis and T cell polarization were delineated. In this study, distal colons were examined for macroscopic and microscopic pathological alterations. ELISA, qRT-PCR, and immunohistochemistry techniques were applied to detect proteins and cytokines involved in AMPK/mTOR/NLRP3 axis and T Cell polarization. Oral administration of empagliflozin (10 mg/kg/day) and metformin (200 mg/kg/day) combination alleviated colitis as revealed by the reduced disease activity index, macroscopic damage index, colon weight/length ratio, and histopathologic scoring values. Interestingly, empagliflozin/metformin combination significantly enhanced AMPK phosphorylation and depressed mTOR and NLRP3 expression leading to a subsequent reduction in caspase-1 cleavage and inhibition of several inflammatory cytokines, including IL-1β, and IL-18. Reduced mTOR expression and reduced IL-6 levels led to a reduction in Th17 cell polarization and maintenance. Together, the current study reveals that the protective effects of empagliflozin and metformin against DSS-induced colitis are fundamentally mediated via enhancing AMPK phosphorylation. Since adult humans with diabetes mellitus are at greater risk for developing inflammatory bowel diseases, clinical application of empagliflozin/metformin combination represents a novel therapeutic approach for treating diabetic patients with ulcerative colitis.