Molecular and immunohistochemical effects of metformin in a rat model of type 2 diabetes mellitus. Exp Ther Med. 2015;9:1921-1930. [PMID: 26136915 DOI: 10.3892/etm.2015.2354]

Hypoglycemia and anxiolysis mediated by levofloxacin treatment in diabetic rats

Purpose

The present study was designed to determine the effect of levofloxacin (LVX) treatment on the blood glucose level, insulin sensitivity, anxiety level, nitrite and MDA level of STZ induced diabetic rats.

Methods

Wistar rats were used in the present study. The rats were made diabetic by the administration of single dose of STZ (45 mg/kg, i.p.) and NAD (50 mg/kg, i.p.). The rats with the blood glucose level greater than 200 mg/dl were considered as diabetic (confirmed at day-3 of STZ-NAD administration). The non-diabetic rats were considered as control and received saline.Diabetic rats received metformin (50 mg/kg, p.o.) and LVX (20, 25, 30 and 35 mg/kg, i.p.) daily for 14 days (starting from the day at which STZ was injected). Following administration on 14th day,the blood sample was collected and the rats were subjected to behavioral assays for the determination of locomotor activity and anxiety level. Plasma was separated and used for the estimation ofnitrite and malondialdehyde (MDA)level. On 15th day OGTT was performed in the overnight fasted rats for the assessment of insulin sensitivity.

Results

The results obtained suggested that the administration of STZ-NAD induced the hyperglycemia at day-3 of administration. Diabetic rats displayed the significant increase in blood glucose, anxiety related behavior, MDA level while significant decrease in the insulin sensitivity and plasma nitrite level. Daily administration of metformin to the diabetic rats decreased the blood glucose level, increased the time spent at the center of open field, reversed the anxiety related behavior in LDT and EPM, did not affect the plasma nitrite level, decreased the plasma MDA level, decreased the fasting glucose level and AUC in OGTT assay. LVX (30 and 35 mg/kg) treatment significantly decreased the blood glucose level of diabetic rats. LVX (20, 25 and 30 mg/kg) treatment significantly decreased the number of square crossing while LVX (20, 25, 30 and 35) treatment significantly increased the time spent at the center of the field by the diabetic rats. LVX (20 and 35 mg/kg) treatment significantly reversed the STZ induced anxiety in LDT while LVX (20, 30 and 35 mg/kg) treatment significantly reversed the STZ induced anxiety in EPM test. LVX (20, 25 and 35 mg/kg) treatment significantly increased the plasma nitrite level and LVX (20-35 mg/kg) treatment significantly decreased the MDA level of diabetic rats. Further only LVX (35 mg/kg) treatment significantly decreased the fasting glucose level and increased the AUC of diabetic rats.

Conclusion

In conclusion, STZ-NAD administration increased the blood glucose level, anxiety related behavior, decreased the plasma nitrite and increased the MDA level. LVX administration potentiated the diabetogenic effects of STZ-NAD in rats. Daily administration of LVX decreased the blood glucose level of diabetic rats. LVX administration alleviated the STZ induced anxiety in OFT, LDT and EPM test. LVX administration increased the plasma nitrite level and decreased the lipid peroxidation in diabetic rats.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01234-0.

Green Coffee Bean Extract Potentially Ameliorates Liver Injury due to HFD/STZ-Induced Diabetes in Rats

The goal of the current study was to examine the therapeutic potential of green coffee bean extract (GCBE) in the treatment of diabetic hepatic damage induced by high-fat diet (HFD) and streptozotocin (STZ) administration. The novelty of this study lies in constructing a newly stabilized in vivo obese diabetic animal model in rats using HFD/STZ for investigating the dose-dependent effect of two commonly used doses of GCBE in hepatoprotection against oxidative stress-induced hepatic damage by measuring many parameters that have not been carried out previously in other studies. GCBE that was used in this study was a hot water extract of green coffee beans with a concentration of 0.1 g ml−1. Male albino rats were given a single dose of STZ (35 mg kg−1), and HFD to induce diabetes mellitus (DM). For 28 days, two separate doses of GCBE 50 mg kg−1 and 100 mg kg−1 were administered orally to diabetic animals. Leptin, liver enzymes, oxidative stress parameters, inflammatory parameters, fasting plasma glucose (FPG), fasting plasma insulin (FPI), and lipid profile levels were examined. Real-time PCR and ELISA were used to quantitatively detect the mRNAs of the genes involved in the insulin signaling pathway, the genes involved in glucose metabolism, and the amounts of proteins. The levels of FPG, lipid profile, liver enzymes, inflammatory markers, and leptin in the HFD/STZ diabetic group revealed a considerable spike, while they considerably decreased after GCBE treatment in a dose-dependent manner. After GCBE treatment, the diabetic group showed a significant rise in the antioxidant markers glutathione, superoxide dismutase, and catalase, as well as a decrease in malondialdehyde and nitric oxide levels. The liver changes caused by HFD/STZ were entirely reversed by GCBE, and most intriguingly, in a dose-dependent manner. We concluded that GCBE can repair the hepatic oxidative damage caused by HFD and STZ by reversing all the previously measured parameters and improving the insulin signaling pathways. GCBE demonstrated strong antifree radical activity and significantly protected cells from oxidative damage caused by HFD/STZ.

The Effects of Metformin Treatment on Diabetic Albino Rats' Pancreas, Liver, and Kidney Histology

Metformin, an oral hypoglycemic drug, has traditionally been considered the standard therapy for hyperglycemia. Metformin's several modes of action include inhibition of hepatic gluconeogenesis, anti-glucagon activity, and insulin-sensitizing effect. This study aims to assess the effectiveness of Metformin on the liver, pancreatic, and kidney tissues of alloxan-induced diabetic albino rats. Twenty mature albino white male rats were allocated at random into two groups. Intraperitoneal injections of alloxan monohydrate were utilised to induce diabetic Mellitus type II in the first ten rats. The second group of rats were injected intraperitoneally with normal saline. Both groups were then separated into four subgroups: Group 1 consisted of non-diabetic rats that were only administered distilled water (control), Group 2 consisted of non-diabetic rats that were administered metformin at a dose of 1000 mg/kg/day, and Group 3 consisted of diabetic control animals that were administered alloxan intravenously and distilled water orally, but were not given any medications. After seven days of DM induction, diabetic rats were administered Metformin at a dose of 1000 mg/kg/day orally. After one month of therapy, the animals were slaughtered and their organs were harvested. Compared to the control group, the histological results of pancreatic tissue were normal in the treatment groups. In contrast, liver and kidney sections from non-diabetic control, non-diabetic, and diabetic animals given 1000 mg/kg/day of Metformin had normal histology. Still, both tissues of untreated diabetic control mice exhibited lymphocyte infiltration. Metformin has been found to have significant blood glucose lowering properties and the capacity to protect several organs from the negative consequences of diabetes.

Huang-Lian-Jie-Du decoction attenuates cognitive dysfunction of rats with type 2 diabetes by regulating autophagy and NLRP3 inflammasome activation

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Lian-Jie-Du decoction (HLJDD) is a traditional Chinese formula that is efficacious in treating diabetes mellitus, Alzheimer's disease, and diabetic encephalopathy; the underlying mechanisms of HLJDD in diabetes-associated cognitive dysfunction remain unclear.

AIM OF THE STUDY

This study investigated the neuroprotective effects of HLJDD on cognitive function, and the possible underlying mechanisms in type 2 diabetes mellitus (T2DM) in a rat model of cognitive impairment.

MATERIALS AND METHODS

Twelve active ingredients in HLJDD were detected using high-performance liquid chromatography analysis. An animal model of cognitive dysfunction in T2DM was induced via a high-sugar and high-fat diet combined with a low dose of streptozotocin. Sprague-Dawley rats were randomly divided into six groups: control, T2DM, metformin (0.34 g/kg/day), and HLJDD groups (3, 1.5, and 0.75 g/kg/day). All treatments were intragastrically administrated for nine continuous weeks after the development of T2DM. Body weight, food and water intake, fasting blood glucose, insulin sensitivity, and blood lipid levels were measured. Spatial learning and memory of the rats were assessed using the Morris water maze test. Hematoxylin and eosin and Nissl staining were performed to evaluate neuronal morphology and vitality. Glutathione, malondialdehyde, and superoxide dismutase levels were measured to determine the level of oxidative stress in the hippocampus. Transmission electron microscopy was performed to observe the synaptic morphology and structure of hippocampal neurons. IL-1β levels in the hippocampus and cerebrospinal fluid were determined. The protein expression of NLRP3, cleaved caspase-1, mature IL-1β, ATG7, P62, LC3, and brain-derived neurotrophic factor (BDNF) was determined using western blotting and immunofluorescence analysis.

RESULTS

HLJDD attenuated cognitive dysfunction in rats with T2DM as shown by the decreased escape latency, increased times crossing the platform and time spent in the target quadrant in the Morris water maze test (P < 0.05), improvement in hippocampal histopathological changes, and an elevated level of cell vitality. HLJDD treatment also reduced blood glucose and lipid levels, ameliorated oxidative stress, and downregulated IL-1β expression in the hippocampus and cerebrospinal fluid (P < 0.05). Moreover, HLJDD enhanced BDNF, ATG7, and LC3 protein expression and significantly inhibited the expression of P62, NLRP3, cleaved caspase-1, and mature IL-1β in the hippocampal CA1 region (P < 0.05). Immunofluorescence results further confirmed that the fluorescence intensity of NLRP3 and P62 in the hippocampus decreased after HLJDD intervention (P < 0.05).

CONCLUSIONS

HLJDD ameliorated cognitive dysfunction in T2DM rats. The neuroprotective effect is exerted via the modulation of glucose and lipid metabolism, upregulation of autophagy, and inhibition of NLRP3 inflammasome signaling pathway.

The effect of Madhumeha Kusumakar Rasa - an Ayurved medicine - in insulin resistance

OBJECTIVES

Madhumeha Kusumakar Rasa (MKR) is an Ayurved formulation having a strong pharmacological base for diabetes management. This study aimed to validate MKR's efficacy in dexamethasone-induced insulin resistance (IR).

METHODS

Albino Wistar rats were divided into four groups. Group 1 served as the normal control, Group 2 received dexamethasone 1.5 mg/kg (i.p.), Group 3 received dexamethasone and metformin 200 mg/kg (p.o.), and Group 4 received dexamethasone and MKR 236 mg/kg (p.o.). Animals were evaluated for serum glucose levels and glucose tolerance, serum insulin, Homeostatic model assessment of insulin resistance (HOMA-IR), Homeostatic model assessment of insulin sensitivity (HOMA-IS), fasting glucose to insulin ratio (FGIR), and lipid parameters. Pancreas, liver, and kidneys were evaluated for reduced Glutathione (GSH) and Malondialdehyde (MDA) levels. These tissues were also evaluated for histopathological changes.

RESULTS

MKR showed significant improvement in serum glucose and glucose tolerance, serum insulin and HOMA-IR, HOMA-IS, and FGIR. It also showed a significant improvement in lipid parameters as compared to the dexamethasone-treated group. It prevented depletion of GSH levels and elevation in MDA levels. These effects were supported by histopathological analysis.

CONCLUSIONS

MKR treatment significantly attenuated dexamethasone-induced IR. This study validates the mechanism of the anti-diabetic potential of MKR.

Hepatic PTEN Signaling Regulates Systemic Metabolic Homeostasis through Hepatokines-Mediated Liver-to-Peripheral Organs Crosstalk

Liver-derived circulating factors deeply affect the metabolism of distal organs. Herein, we took advantage of the hepatocyte-specific PTEN knockout mice (LPTENKO), a model of hepatic steatosis associated with increased muscle insulin sensitivity and decreased adiposity, to identify potential secreted hepatic factors improving metabolic homeostasis. Our results indicated that protein factors, rather than specific metabolites, released by PTEN-deficient hepatocytes trigger an improved muscle insulin sensitivity and a decreased adiposity in LPTENKO. In this regard, a proteomic analysis of conditioned media from PTEN-deficient primary hepatocytes identified seven hepatokines whose expression/secretion was deregulated. Distinct expression patterns of these hepatokines were observed in hepatic tissues from human/mouse with NAFLD. The expression of specific factors was regulated by the PTEN/PI3K, PPAR or AMPK signaling pathways and/or modulated by classical antidiabetic drugs. Finally, loss-of-function studies identified FGF21 and the triad AHSG, ANGPTL4 and LECT2 as key regulators of insulin sensitivity in muscle cells and in adipocytes biogenesis, respectively. These data indicate that hepatic PTEN deficiency and steatosis alter the expression/secretion of hepatokines regulating insulin sensitivity in muscles and the lipid metabolism in adipose tissue. These hepatokines could represent potential therapeutic targets to treat obesity and insulin resistance.

Therapeutic Effect of P-Cymene on Lipid Profile, Liver Enzyme, and Akt/Mtor Pathway in Streptozotocin-Induced Diabetes Mellitus in Wistar Rats

Diabetes is a serious public health problem in low- and middle-income countries. There is a strong link between hyperglycemia, oxidative stress, inflammation, and the development of diabetes mellitus. PI3K/Akt/mTOR is the main signaling pathway of insulin for controlling lipid and glucose metabolism. P-cymene is an aromatic monoterpene with a widespread range of therapeutic properties including antioxidant and anti-inflammatory activity. In the present study, the antidiabetic effects of p-cymene were investigated. Diabetes was induced using streptozotocin in male Wistar rats. The effects of p-cymene and metformin were studied on levels of glucose (Glu), lipid profile, liver enzymes, oxidative stress, and the expression of Akt, phospho-Akt, and mTOR (mammalian target of rapamycin) proteins, using biochemical, histological, and immunohistochemical analysis. Data have shown that p-cymene can improve serum levels of Glu, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), and the expression of mTOR, Akt, and phospho-Akt protein in diabetic animals. These results suggest that p-cymene has hypoglycemia, hypolipidemia, and antioxidant properties. It can regulate Akt/mTOR pathway and reduce hepatic and pancreas injury. It can be suggested for diabetes management alone or simultaneously with metformin.

Kolaviron attenuates cardiovascular injury in fructose-streptozotocin induced type-2 diabetic male rats by reducing oxidative stress, inflammation, and improving cardiovascular risk markers

The prevalence of cardiovascular disease among type-2 diabetic patients has become a source of major concern world over. This study explored the protective effect of kolaviron, a bioflavonoid, against oxidative cardiovascular injury in fructose- streptozotocin-induced type 2 diabetic male Sprague Dawley rats. After acclimatization, induction, and confirmation of type-2 diabetes, kolaviron was administered for 28days, after which the animals were anesthetized with Isofor and euthanized. Blood from each rat were collected, and blood samples were then centrifuged for serum and plasma. Cardiac troponin I (cTnI), creatine kinase myocardial band (CK-MB), Creatine phosphokinase (CK), and insulin levels were immediately determined in serum, while remaining samples (serum, plasma, and organs) were stored in the bio-freezer at - 80 °C and 10% formalin for enzyme-link immunosorbent assay (ELISA), biochemical, molecular, and histopathological studies. The results show that type-2 diabetes induction with fructose and streptozotocin led to increased blood glucose levels, decreased insulin levels and cardiac antioxidant enzyme activities, increased malondialdehyde levels, cardiac biomarkers and pro-inflammatory cytokines levels, resulted in abnormal lipid profile, increased blood pressure and angiotensin-converting enzyme (ACE) activity, and decreased plasma endothelial nitric oxide synthase (eNOS) concentration. The histopathological examination of the cardiac tissue revealed severe lesion, hypertrophy, and myofibrils degeneration. However, administration of kolaviron for 28days remarkably improved these conditions. Hence the result from the study validates the potency of kolaviron, and suggests it could serve as an alternative to existing remedy in ameliorating or protecting against cardiovascular injury in type-2 diabetes.

Low Levels of Serum Fetuin-A and Retinol-Binding Protein 4 Correlate with Lipoprotein Subfractions in Morbid Obese and Lean Non-Diabetic Subjects

Background: Fetuin-A and retinol-binding protein 4 (RBP4) are secreted as both hepatokine and adipokine. These are involved in insulin resistance, obesity-related dyslipidemia, and atherosclerosis. To date, correlations of circulating fetuin-A and RBP4 with lipoprotein subfractions as well as high-density lipoprotein (HDL)-linked proteins have not been entirely investigated in morbid obese and lean non-diabetic subjects. Methods: One-hundred obese non-diabetic patients (body mass index, BMI: 42.5 ± 8.1 kg/m²) along with 32 gender and age-matched normal weight controls (BMI: 24.5 ± 2.5 kg/m²) were enrolled in our study. Serum fetuin-A and RBP4 were measured by ELISA. Lipoprotein subfractions were distributed by Lipoprint gelelectrophoresis. Results: Serum fetuin-A and RBP4 were unexpectedly lower in obese patients (p < 0.01 and p < 0.01, respectively) compared to controls and correlated with each other (r = 0.37; p < 0.001). Fetuin-A had positive correlations with HDL-C (r = 0.22; p = 0.02), apolipoprotein AI (apoAI) (r = 0.33; p < 0.001), very-low density lipoprotein (VLDL) subfraction (r = 0.18; p = 0.05), and large HDL subfraction levels (r = 0.3; p = 0.001) but did not show correlation with carbohydrate parameters in all subjects. RBP4 correlated positively with HDL-C (r = 0.2; p = 0.025), apoAI (r = 0.23; p = 0.01), VLDL subfraction (r = 0.37; p < 0.001), intermediate HDL subfraction (r = 0.23; p = 0.01), and small HDL subfraction (r = 0.21; p = 0.02) concentrations, as well as C-peptide levels in overall participants. Backward stepwise multiple regression analysis showed that serum fetuin-A concentration is best predicted by RBP4 and large HDL subfraction. In model 2, VLDL subfraction was the independent predictor of serum RBP4 level. Conclusions: Our data may indicate a potential role of fetuin-A and RBP4 in impaired lipoprotein metabolism associated with obesity.

Sustained In Vitro and In Vivo Delivery of Metformin from Plant Pollen-Derived Composite Microcapsules

We developed a dual microencapsulation platform for the type 2 diabetes drug metformin (MTF), which is aimed to increase its bioavailability. We report the use of Lycopodium clavatum sporopollenin (LCS), derived from their natural spores, and raw Phoenix dactylifera L. (date palm) pollens (DPP) for MTF microencapsulation. MTF was loaded into LCS and DPP via a vacuum and a novel method of hydration-induced swelling. The loading capacity (LC) and encapsulation efficiency (EE) percentages for MTF-loaded LCS and MTF-loaded DPP microcapsules were 14.9% ± 0.7, 29.8 ± 0.8, and 15.2% ± 0.7, 30.3 ± 1.0, respectively. The release of MTF from MTF-loaded LCS microcapsules was additionally controlled by re-encapsulating the loaded microcapsules into calcium alginate (ALG) microbeads via ionotropic gelation, where the release of MTF was found to be significantly slower and pH-dependent. The pharmacokinetic parameters, obtained from the in vivo study, revealed that the relative bioavailability of the MTF-loaded LCS-ALG beads was 1.215 times higher compared to pure MTF, following oral administration of a single dose equivalent to 25 mg/kg body weight MTF to streptozotocin (STZ)-induced diabetic male Sprague-Dawley rats. Significant hypoglycemic effect was obtained for STZ-induced diabetic rats orally treated with MTF-loaded LCS-ALG beads compared to control diabetic rats. Over a period of 29 days, the STZ-induced diabetic rats treated with MTF-loaded LCS-ALG beads showed a decrease in the aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglycerides, cholesterol, and low-density lipoprotein-cholesterol (LDL-C) levels, as well as an increase in glutathione peroxidase (GPx) and a recovery in the oxidative stress biomarker, lipid peroxidation (LPx). In addition, histopathological studies of liver, pancreas, kidney, and testes suggested that MTF-loaded LCS-ALG beads improved the degenerative changes in organs of diabetic rats. The LCS-ALG platform for dual encapsulation of MTF achieved sustained MTF delivery and enhancement of bioavailability, as well as the improved biochemical and histopathological characteristics in in vivo studies, opening many other intriguing applications in sustained drug delivery.

Metformin slows liver cyst formation and fibrosis in experimental model of polycystic liver disease

Polycystic liver disease (PLD) is a hereditary liver disease in which the number of cysts increases over time, causing various abdominal symptoms and poor quality of life. Although effective treatment for PLD has not been established, we recently reported that long-term exercise ameliorated liver cyst formation and fibrosis with the activation of AMP-activated protein kinase (AMPK) in polycystic kidney (PCK) rats, a PLD model. Therefore, the aim of this study was to investigate whether metformin, an indirect AMPK activator, was effective in PCK rats. PCK rats were randomly divided into a control (Con) group and a metformin-treated (Met) group. The Met group was treated orally with metformin in drinking water. After 12 wk, liver function, histology, and signaling cascades of PLD were examined in the groups. Metformin did not affect the body weight or liver weight, but it reduced liver cyst formation, cholangiocyte proliferation, and fibrosis around the cyst. Metformin increased the phosphorylation of AMPK and tuberous sclerosis complex 2 and decreased the phosphorylation of mammalian target of rapamycin, S6, and extracellular signal-regulated kinase and the expression of cystic fibrosis transmembrane conductance regulator, aquaporin I, transforming growth factor-β, and type 1 collagen without changes in apoptosis or collagen degradation factors in the liver. Metformin slows the development of cyst formation and fibrosis with the activation of AMPK and inhibition of signaling cascades responsible for cellular proliferation and fibrosis in the liver of PCK rats.NEW & NOTEWORTHY This study indicates that metformin, an indirect AMPK activator slows liver cyst formation and fibrosis in PLD rat model. Metformin attenuates excessive cell proliferation in the liver with the inactivation of mTOR and ERK pathways. Metformin also reduces the expression of proteins responsible for cystic fluid secretion and liver fibrosis. Metformin and AMPK activators may be potent drugs for polycystic liver disease.

Pilosocereus gounellei (Cactaceae) stem extract decreases insulin resistance, inflammation, oxidative stress, and cardio-metabolic risk in diet-induced obese mice

ETHNOPHARMACOLOGICAL RELEVANCE

Pilosocereus gounellei (xique-xique) is a popular cactus from Caatinga, traditionally used to counter inflammatory processes and indicated as a hypoglycemic agent. Previous studies have shown that mice treated orally with saline extract of P. gounellei stem (containing flavonoids and sugars) showed decreased serum lipid levels.

AIM OF THE STUDY

In this work, we evaluated whether this extract would have beneficial effects against hyperglycemia and inflammatory status related to obesity in mice fed a high-fat diet (HFD).

METHODS

Obese animals were treated daily per os with the extract (EXT; 125, 250, and 500 mg/kg), metformin (MET; 400 mg/kg), or saline solution (diet-induced obese, DIO) for 21 days. A group of non-obese animals served as the control. We evaluated lipid profile, glucose and insulin tolerance, atherogenic indices, histological alterations, cytokine levels, and oxidative stress in liver, muscle, and adipose tissue.

RESULTS

At the end of the experiment, mice from EXT groups showed lower body weight and total cholesterol, LDL-cholesterol, and triglycerides compared with the DIO group; in addition, HDL-cholesterol levels and glucose and insulin tolerance were similar to those of the control group. When compared with the DIO group, the extract-treated mice showed reduction in cardiac risk ratio, atherogenic coefficient, atherogenic index of plasma, and Castelli's Risk Index II; decrease in epididymal fat; reduction in steatosis, collagen deposition, and liver inflammation; lower serum levels of pro-inflammatory cytokines (tumor necrosis factor α, interleukin 6, and monocyte chemoattractant protein-1); inhibited lipid peroxidation; and increased superoxide dismutase levels in liver, muscle, and adipose tissue.

CONCLUSION

The P. gounellei saline extract was able to improve physiological parameters of obese mice, which highlight the potential of this plant as source of compounds with biotechnological relevance for pharmaceutical industry.

Effects of different doses of metformin on bone mineral density and bone metabolism in elderly male patients with type 2 diabetes mellitus

BACKGROUND

Diabetes is a chronic disease, which may cause various complications. Patients with diabetes are at high risk of bone and joint disorders, such as osteoporosis and bone fractures. In addition, it became widely accepted that diabetes has an important impact on bone metabolism. Metformin is a commonly used and effective first-line treatment for type 2 diabetes. Some glucose-lowering agents have been found to have an effect on bone metabolism. The present study explored if different doses of metformin have an effect on bone mineral density (BMD) and bone metabolism in type 2 diabetes.

AIM

To investigate the effects of different doses of metformin on BMD and bone metabolism in elderly male patients with type 2 diabetes mellitus.

METHODS

A total of 120 elderly male outpatients with type 2 diabetes mellitus who were admitted to our hospital were included in the study from July 2018 to June 2019. They were randomly assigned to an experimental group and a control group with 60 patients in each group. Patients in the experimental group were given high dose metformin four times a day 0.5 g each time for 12 wk. Patients in the control group were given low dose metformin orally twice a day 0.5 g each time for 12 wk. The changes in bone mineral density and bone metabolism before and after treatment and the efficacy rate of the treatment were compared between the two groups.

RESULTS

There was no significant difference in the efficacy rate between the two groups (P > 0.05). Before the treatment, there was no significant difference in BMD and bone metabolism between the two groups (P > 0.05). However, after the treatment, BMD and bone metabolism were improved in the two groups. Moreover, BMD and 25-hydroxyvitamin D were significantly higher in the experimental group than in the control group, and N-terminal/midregion and β-isomerized C-terminal telopeptides were significantly lower in the experimental group than in the control group (all P < 0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P > 0.05).

CONCLUSION

Both high and low dose metformin can effectively control the blood glucose levels in elderly male patients with type 2 diabetes mellitus. However, the benefits of high dose metformin in improving BMD and bone metabolism level was more obvious in patients with type 2 diabetes mellitus.

Icariin treatment reduces blood glucose levels in type 2 diabetic rats and protects pancreatic function

Icariin, a flavonoid isolated from traditional oriental herbal medicines, has been demonstrated to exhibit several health benefits in animal models and in humans. The aim of the present study was to investigate the effect of Icariin on hyperglycemia in type 2 diabetes mellitus (T2DM) in rats. A model of diabetes was established in 50 Sprague Dawley rats using a high-sugar and high-fat diet and peritoneal injection of streptozotocin. Diabetic rats were divided into five groups: Diabetic control; metformin; and rats treated with three different doses of Icariin, 5, 10 and 20 mg/kg. Body weight and blood glucose levels were measured, and serum adiponectin levels, expression of phospho-AMP mediated protein kinase (p-AMPK) and glucose transporter isoform 4 (GLUT-4) were measured using ELISA, Realtime PCR and western blotting, respectively. Diabetic rats without drug treatment exhibited reduced body weight, increased blood glucose levels and decreased the number of islets. In T2DM rats treated with 10 or 20 mg/kg Icariin, the blood glucose levels were reduced, whereas serum adiponectin levels were not affected. Additionally, the mRNA and protein expression levels of p-AMPK and GLUT-4 protein were increased in the T2DM rats treated with Icariin. In conclusion, in the diabetes rat model, Icariin alleviated the severity of diabetes, and the effects may be associated with reduction of hyperglycemia by activating an AMPK/GLUT-4 pathway.

Effect of olive leaves extract on the antidiabetic effect of glyburide for possible herb-drug interaction

The concomitant use of olive leaves (OL) and glyburide (GLB) is a possible therapy for diabetic patients. However, there is no report about the effect of OL on the antidiabetic effect of GLB till now. In the current study, the possible interaction of olive leaves extract (OLE) with GLB was assessed to determine if there was any pharmacological benefit over GLB alone. Seven groups of male Sprague Dawley rats were used. Normal rats of the 1st group treated with 2 mL/kg of 3% Tween 80 (vehicle). The 2nd–5th groups were diabetic rats received vehicle, GLB (5 mg/kg), OLE low dose and OLE high dose respectively, while the 6th–7th groups administered combinations of GLB plus OLE low dose and GLB plus OLE high dose, respectively. All treatments were administered orally once daily for 8 weeks.

The use of GLB+OLE-500 obviously improved fasting blood glucose (FBG), insulin and glycated hemoglobin (HbA1c) in diabetic rats (95.5 ± 5.55 mg/dL, 6.8 ± 0.16 mg/dL and 6.1 ± 0.29%, respectively) compared to those treated with GLB monotherapy (140.0 ± 6.36 mg/dL, 5.4 ± 0.19 mg/dL and 7.0 ± 0.20%, respectively). The lipid profile [triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C)] was significantly improved in diabetic rats exposed to GLB+OLE-500 (35.6 ± 1.51 mg/dL, 48.5 ± 2.74 mg/dL, 25.1 ± 1.21 mg/dL and 17.0 ± 0.82 mg/dL, respectively) in comparison with diabetic group exposed to GLB alone (43.2 ± 2.15 mg/dL, 56.8 ± 2.14 mg/dL, 18.6 ± 0.96 mg/dL, 23.0 ± 1.26 mg/dL, respectively). Additionally, the benefit impacts of GLB+OLE-500GLB+OLE-500 therapy on the antioxidant and lipid peroxidation parameters in the pancreatic tissues of diabetic rats were higher than those of GLB monotherapy. Moreover, GLB plus OLE-500 combination had the greatest effect on restoration of the insulin content of Beta (β) cells and reduction of the glucagon and somatostatin of Alpha (α) and Delta (δ) endocrine cells in the pancreatic islets among the different treatment. The current study suggests that OL and GLB combination could cause herb-drug interactions through modulation of insulin receptor (INR), glucose transporter 2 (Slc2a2) and peroxisome proliferator-activated receptor α (PPAR-α) genes expression in the liver of diabetic rats.

Emerging Topics in Cardiometabolic and Psychologic Sequelae, Pathogenesis, and Treatment of Polycystic Ovarian Syndrome: A Review

Polycystic ovarian syndrome (PCOS) is a common endocrine disorder, affecting 6–10% of reproductive age women and influences the reproductive, metabolic, dermatologic, and psychiatric health of affected girls and women. Despite its prevalence, the pathogenesis of the disease is largely unknown, and treatment options are limited. Thus, PCOS has been a ripe area for research in recent years, and novel etiologic pathways, diagnostic parameters, and treatment options are being explored. This review focuses on recent data suggesting pathogenic and therapeutic considerations, as well as the psychiatric and metabolic sequelae of PCOS.

[Cerebroprotective activity of metformin, gosogliptin, citicoline and a novel GPR119 agonist in cerebral ischemia under experimental diabetes mellitus]

Hypoglycemic agents of some groups: sodium-glucose cotransporter type 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists reduce the risk and/or severity of cardiovascular diseases. Studies of such properties are currently focused on metformin and dipeptidyl peptidase-4 (DPP-4) inhibitors. Agonists of GPR119 receptor, increasing the secretion of GLP-1 and insulin, are also actively studied as hypoglycemic drugs with endothelial and cerebroprotective potential.

AIM

To evaluate the cerebroprotective activity of metformin, gosogliptin, citicoline and an agonist of GPR119 (ZB-16) in middle cerebral artery occlusion (MCAO) in animals with 4-week streptozotocin-nicotinamide-induced diabetes.

MATERIAL AND METHODS

A study included 73 male rats. Hypoglycemic agents and ZB-16 were administered on the first day of diabetes and citicoline was administered after MCAO. Cerebroprotective effect was evaluated using Garcia, Combs and D'Alecy score test, 'Rotarod' and 'open field' test, as well as the infarct volume and severity of brain edema measurement.

RESULTS AND CONCLUSION

Preventive administration of metformin resulted in the pronounced hypoglycemic activity without a significant cerebroprotective effect in subsequent brain ischemia modelling. Administration of substances with incretin activity (gosogliptin and, in particular, ZB-16) in addition to the hypoglycemic action promoted a significant reduction of infarct volume, brain edema and severity of neurologic deficit of the surviving animals. At the same time, the introduction of citicoline without proper glycemic control didn't reduce the brain ischemia severity.

Metformin improves ovarian follicle dynamics by reducing theca cell proliferation and CYP-17 expression in an androgenized rat model

Background

Metformin influences insulin receptor signaling, which might interfere with the proliferation of ovarian follicular structures and steroidogenesis. We hypothesize that reductions in glucose and insulin levels might interfere with CYP-17 expression and histomorphological changes in an androgenized rat model. The aim of this study was to analyze the effect of metformin on CYP-17 expression, follicular dynamics, and proliferative parameters in neonatally androgenized female rats.

Methods

Thirty-six newborn rats were randomly allocated to the following three groups on the third day of life: control (CG, n = 12), androgenized (GA, n = 12), and androgenized + metformin (GAmet, n = 12). The GA and GAmet animals were administered 0.1 mL of testosterone propionate (1.25 mg/animal) diluted in castor oil (vehicle) in a single dose; the CG rats received a subcutaneous injection of the vehicle in the dorsum. After 90 days, gavage treatment was initiated, distilled water was administered to the CG and GA rats, and metformin (150 mg/kg) was administered to the GAmet animals. The treatment was administered daily for six weeks. Following anesthesia, blood was drawn for biochemical measurements, and the ovaries were removed for histological and immunohistochemical analyses of Ki67, VEGFA and CYP17 expression. The glucose and insulin levels were also measured.

Results

The comparison of the GA and GAmet animals revealed that metformin decreased the weight as well as the glucose and insulin levels, slowed the proliferation of the theca interna and interstitial cells, as evidenced by Ki-67 and VEGF-A expression, and diminished CYP17 expression in the analyzed ovarian structures. In addition, metformin reduced the number of degenerating follicles and interstitial cells and improved angiogenesis.

Conclusion

Metformin improves the carbohydrate metabolism, reduces proliferation, and decreases CYP-17 expression in the follicular structures of androgenized rats.

Modulation of the rod outer segment aerobic metabolism diminishes the production of radicals due to light absorption

Oxidative stress is a primary risk factor for both inflammatory and degenerative retinopathies. Our previous data on blue light-irradiated retinas demonstrated an oxidative stress higher in the rod outer segment (OS) than in the inner limb, leading to impairment of the rod OS extra-mitochondrial aerobic metabolism. Here the oxidative metabolism and Reactive Oxygen Intermediates (ROI) production was evaluated in purified bovine rod OS in function of exposure to different illumination conditions. A dose response was observed to varying light intensities and duration in terms of both ROI production and ATP synthesis. Pretreatment with resveratrol, inhibitor of F₁F_o-ATP synthase, or metformin, inhibitor of the respiratory complex I, significantly diminished the ROI production. Metformin also diminished the rod OS Complex I activity and reduced the maximal OS response to light in ATP production. Data show for the first time the relationship existing in the rod OS between its -aerobic- metabolism, light absorption, and ROI production. A beneficial effect was exerted by metformin and resveratrol, in modulating the ROI production in the illuminated rod OS, suggestive of their beneficial action also in vivo. Data shed new light on preventative interventions for cone loss secondary to rod damage due to oxidative stress.

MANAGEMENT OF ENDOCRINE DISEASE: Polycystic ovary syndrome and nonalcoholic fatty liver disease

Polycystic ovary syndrome (PCOS) is a frequent endocrine disease in women, with a number of metabolic and reproductive consequences. Obesity, insulin resistance (IR) and type 2 diabetes are prominent metabolic characteristics of PCOS and common factors affecting liver function and generating nonalcoholic fatty liver disease (NAFLD). Multiple genes involved in the synthesis of androgens, cytokines and IR, as well as acquired factors, such as endocrine disruptors, could associate the etiopathogenesis of PCOS and NAFLD. Besides the high prevalence of PCOS in general population, NAFLD was shown to be a frequent condition in transition periods, such as adolescence and menopause. Although liver biopsy is considered to be the gold standard for diagnosing liver damage, its routine use in such a prevalent condition as PCOS can be related to a higher rate of complications. Therefore, it is necessary to be able to diagnose NAFLD using simple and reliable surrogate markers. Recently, fatty liver index and NAFLD fatty liver score analyzed in large cohorts of PCOS women have been shown as accurate markers of liver damage in this metabolically vulnerable population. Lifestyle changes are still the mainstay of the management of NAFLD in PCOS, although prospective randomized controlled clinical studies remain a priority in the field. With regard to medications, metformin may be the drug of choice for treating PCOS patients with NAFLD when pharmacologic therapy is considered. Liraglutide use in obese PCOS has shown favorable effects on the predictors of liver fibrosis. In this review, we aim to summarize the influence of the common risk factors and to discuss the diagnostic approaches and management options for NAFLD in patients with PCOS.

Plasma fetuin-A/α2-HS-glycoprotein correlates negatively with inflammatory cytokines, chemokines and activation biomarkers in individuals with type-2 diabetes

Background

Fetuin-A/AHSH is a novel hepatokine that acts as a vascular calcification inhibitor and as an endogenous TLR-4 ligand. Fetuin-A may act as a positive or negative acute phase protein (APP) in disease conditions. The relationship between circulatory fetuin-A and inflammatory biomarkers in type-2 diabetes (T2D) remains controversial. Therefore, the purpose of this study was to determine the plasma fetuin-A levels in 53 T2D (BMI = 29.7 ± 4.5 kg/m²) and 72 non-diabetic individuals (BMI = 28.2 ± 5.8 kg/m²) using premixed 38-plex MAP human cytokine/chemokine magnetic bead immunoassays and the data (mean ± SEM) were statistically analyzed to determine Pearson’s correlation (r) between fetuin-A and detected analytes; P-values ≤0.05 were considered significant.

Results

The data show that plasma fetuin-A levels were comparable in both groups (P = 0.27) and in T2D individuals, fetuin-A associated negatively (P ≤ 0.05) with a large number of proinflammatory cytokines/chemokines and activation biomarkers including TNF-α, IFN-α2, IFN-γ, IL-1α, IL-1β, IL-1RA, IL-3, IL-4, IL-7, IL-9, IL-12p40/p70, IL-15, CCL-2, CCL-4, CCL-11, CCL-22, CXCL-8, CX3CL-1, EFF-2, EGF, G-CSF, GM-CSF, GRO, sCD40L, and VEGF. In non-diabetics, fetuin-A also correlated positively with certain T_H2 cytokines (IL-5, IL-13) and chemokines (CCL-3, CCL-5, CCL-7). Notably, in vitro fetuin-A production was significantly suppressed in HepG2 cells treated with TNF-α, IL-1β, and IFN-γ which supported the clinical findings of a negative association between fetuin A and inflammatory mediators.

Conclusions

The negative association between circulatory fetuin-A and systemic inflammatory mediators in T2D patients suggests that plasma fetuin-A may have predictive significance as a negative APP in metabolic disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-016-0171-y) contains supplementary material, which is available to authorized users.