Metformin attenuates diabetic renal injury via the AMPK-autophagy axis

Targeting Epigenetic Plasticity to Reduce Periodontitis-Related Inflammation in Diabetes: CBD, Metformin, and Other Natural Products as Potential Synergistic Candidates for Regulation? A Narrative Review

Periodontitis is unanimously accepted to be the sixth complication of diabetes mellitus (DM), while the inverse relationship of causality is still to be deciphered. Among the proposed mechanisms is gut dysbiosis, which is responsible for the systemic release of proinflammatory mediators. In this process, Gram-negative bacteria from the oral cavity enter the general circulation, leading to the emergence of bi-hormonal beta-pancreatic cells that lack the ability to secrete insulin. Additionally, epigenetic and adaptive mechanisms in affected cells may play a role in reducing inflammation. The release of reactive oxygen species, proinflammatory cytokines, and adipokines, such as interleukins, tumor necrosis factor alpha, leptin, prostaglandin E2, C-reactive protein, or matrix metalloproteinases, determine epigenetic changes, such as the methylation of DNA nucleotides or changes in the activity of histone acetylases/deacetylases. The management of periodontitis involves targeting inflammation, and its potential connection to epigenetic modulation observed in other chronic conditions may help to explain its role in preventing DM in affected patients. This review focuses on the key epigenetic changes in periodontitis that might contribute to DM development, and explores the mechanisms and novel multi-drug therapies that could help to prevent these effects.

Changes in Urinary NGAL, FN, and LN Excretion in Type 2 Diabetic Patients Following Anti-Diabetic Therapy with Metformin

Background: Excessive accumulation of glomerular extracellular matrix (ECM) is a key factor in the development and progression of diabetic nephropathy (DN). As kidney dysfunction has been reported in normoalbuminuric patients, identifying novel diagnostic and prognostic markers is essential for the prevention and treatment of DN. Methods: Urinary excretion of neutrophil gelatinase-associated lipocalin (NGAL) and ECM-related glycoproteins, i.e., fibronectin (FN) and laminin (LN), was measured in obese patients with newly diagnosed type 2 diabetes mellitus (T2DM) before and after 6 months of metformin therapy. Results: Baseline NGAL (1.27 (0.80-2.36) ng/mg Cr), FN (11.19 (5.31-21.56) ng/mg Cr) and LN (123.17 (54.56-419.28) pg/mg Cr) levels did not significantly differ between T2DM patients and controls (1.95 (1.09-2.97) ng/mg Cr, 11.94 (7.78-18.01) ng/mg Cr and 157.85 (83.75-326.40) pg/mg Cr, respectively). In multivariate regression analysis, the body mass index was identified as the only significant predictor influencing urinary NGAL and FN levels at baseline, with β = 0.249, p = 0.005 and β = 1.068, p = 0.010, respectively. Metformin treatment significantly increased urinary levels of both ECM proteins, i.e., FN (18.48 (11.64-32.46) ng/mg Cr) and LN (179.51 (106.22-414.68) pg/mg Cr), without any effect on NGAL levels (1.44 (0.81-2.72) ng/mg Cr). FN and LN were positively associated with NGAL both before (r = 0.709 and r = 0.646, both p < 0.001, respectively) and after (r = 0.594 and r = 0.479, both p < 0.001, respectively) therapy. No correlations were found between NGAL, FN, LN, and albuminuria. However, NGAL was positively correlated with the albumin/creatinine ratio (ACR) both before (r = 0.323, p < 0.05) and after (r = 0.287, p < 0.05) therapy, and negatively with estimated glomerular filtration rate (eGFR) in pre-treatment diabetics (r = -0.290, p < 0.05). FN and LN were also correlated with ACR (r = 0.384, p < 0.01 and r = 0.470, p < 0.001), although the association for LN was limited to untreated patients (r = 0.422, p < 0.01). Conclusions: Our results suggest that metformin has a beneficial effect on ECM turnover with a significant increase in urinary excretion of non-collagenous markers of glomerular injury, i.e., FN and LN. Additionally, ECM-related markers may serve as useful tools for monitoring early renal injury in obese diabetic patients.

Novel mechanistic insights of the potential role of gasotransmitters and autophagy in the protective effect of metformin against hepatic ischemia/reperfusion injury in rats

Metformin exerts antidiabetic and pleiotropic effects. This study investigated the function and mechanisms of gasotransmitters and autophagy in the metformin-induced protection against ischemia/reperfusion injury (I/RI). According to measurements of serum hepatic function indicators and histopathological evaluation, metformin protected against hepatic I/RI-induced impairment of liver function and structure. In addition, metformin inhibited hepatic I/RI-induced hepatic oxidative stress, nitrosative stress, inflammation, and apoptosis. Also, it suppressed hepatic I/RI-induced decrease in hepatic heme oxygenase-1 (HO-1) and hydrogen sulfide (H2S) levels and increase in nitric oxide (NO) production. Furthermore, metformin inhibited hepatic I/RI-induced decrease in protein expressions of endothelial NO synthase (eNOS), HO-1, cystathionine γ-lyase (CSE), and Beclin-1 and increase in the protein expression of inducible NO synthase (iNOS) in the liver tissue. Co-administration of the NO biosynthesis inhibitor, L-NAME, carbon monoxide(CO)-releasing molecule-A1 (CORM-A1), the H2S donor, NaHS, or the autophagy stimulator, rapamycin (RAPA), enhanced all effects of metformin. The NO donor, L-arginine, the CO biosynthesis inhibitor, zinc protoporphyrin, the H2S biosynthesis inhibitor, DL-propargylglycine, or the autophagy inhibitor, chloroquine (CQ), antagonized the effects of metformin. These findings reveal, for the first time, that increasing CO, H2S, and autophagy levels with subsequent decreasing NO level play a critical role in metformin's protective action against hepatic I/RI. The ability of L-NAME, CORM-A1, NaHS, and RAPA to boost metformin's protective effect in hepatic I/RI may positively be attributed to their ability to lower hepatic oxidative stress, nitrosative stress, inflammation, and apoptosis.

Saracatinib, a Src kinase inhibitor, enhances the renoprotective effect of metformin and losartan in diabetic nephropathy

OBJECTIVE

This research assesses renoprotective effects of saracatinib (Src) in diabetic nephropathy (DN) and the potential underlying processes.

MATERIALS AND METHODS

Rats were divided into: control, DN, DN + Met + Los, DN + Met + Src, and DN + Met + Los + Src. Rats' ABP, urinary albumin, urinary nephrin, and creatinine clearance were assessed. Blood samples were collected for measuring glycaemic state parameters, renal functions, oxidative stress markers, inflammatory mediators, aldosterone, and lipid profile. Kidneys were extracted for KIM-1 and nephrin gene expression, H&E, Masson's trichrome staining, and immunohistochemical assessment.

RESULTS

Significant increases in ABP, urinary albumin and nephrin, glycaemic measurements, urea, creatinine, aldosterone, inflammatory cytokines, MDA, lipids, renal fibrosis, H scores of VEGF and TGF-β, and renal KIM-1 expression were related to DN. However, there was a significant decrease in creatinine clearance, GSH, and nephrin expression in DN group compared with control group.

DISCUSSION AND CONCLUSION

The combination of metformin (Met), losartan (Los), and Src repaired DN alterations. Adding Src to Met and Los is superior to using them alone.

Dapagliflozin restores autophagy and attenuates apoptosis via the AMPK/mTOR pathway in diabetic nephropathy rats and high glucose-induced HK-2 cells

PURPOSE

Diabetic nephropathy (DN) is a serious microvascular complication of diabetes mellitus. Significantly reduced levels of autophagy in diabetic kidneys play an important role in the development of DN. The present study investigated the effects of dapagliflozin (DAP) on renal autophagy and AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway in vivo and in vitro.

METHODS

We explored the effect of DAP in streptozotocin (STZ)-induced DN rats. The anti-DN effect of DAP was assessed by body weight, kidney weight/body weight ratio, blood and urine biochemical parameters, and pathological changes of kidney tissue. Number of autophagosomes in the kidney was investigated through Transmission electron microscopy. Besides, cell viability and apoptosis of DAP alone or combined with Compound C (CC, a selective AMPK inhibitor)-treated high glucose (HG)-induced HK-2 cells were detected by Cell Counting Kit-8 (CCK-8) and flow cytometry assays. Immunohistochemistry, Western blot, Enzyme-linked immunosorbent assay (ELISA), and immunofluorescence were employed to detect the expression levels of extracellular matrix (ECM) deposition, autophagy, apoptosis, and AMPK/mTOR pathway-associated targets in vivo and in vitro.

RESULTS

The results showed that DAP ameliorated the body weight and decreased kidney weight, fasting blood glucose, and serum/urine biochemical parameters of renal damage, as well as renal pathological changes. Moreover, DAP significantly ameliorated HG-induced cell apoptosis and ECM deposition in HK-2 cells. However, these favorable effects of DAP could be abolished by co-treatment with CC in HG-induced HK-2 cells. Mechanistically, DAP can enhance autophagy in DN including increased LC3-II/I ratio, Beclin-1, p-AMPK protein levels, and decreased p62 and p-mTOR protein expressions, as well as inhibited renal fibrosis and apoptosis.

CONCLUSION

In summary, DAP alleviated fibrosis, apoptosis, and autophagy in DN rats and HG-induced HK-2 cells by regulating the AMPK/mTOR pathway.

Prevalent Metformin Use in Adults With Diabetes and the Incidence of Long COVID: An EHR-Based Cohort Study From the RECOVER Program

OBJECTIVE

Studies show metformin use before and during SARS-CoV-2 infection reduces severe COVID-19 and postacute sequelae of SARS-CoV-2 (PASC) in adults. Our objective was to describe the incidence of PASC and possible associations with prevalent metformin use in adults with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

This is a retrospective cohort analysis using the National COVID Cohort Collaborative (N3C) and Patient-Centered Clinical Research Network (PCORnet) electronic health record (EHR) databases with an active comparator design that examined metformin-exposed individuals versus nonmetformin-exposed individuals who were taking other diabetes medications. T2DM was defined by HbA1c ≥6.5 or T2DM EHR diagnosis code. The outcome was death or PASC within 6 months, defined by EHR code or computable phenotype.

RESULTS

In the N3C, the hazard ratio (HR) for death or PASC with a U09.9 diagnosis code (PASC-U09.0) was 0.79 (95% CI 0.71-0.88; P < 0.001), and for death or N3C computable phenotype PASC (PASC-N3C) was 0.85 (95% CI 0.78-0.92; P < 0.001). In PCORnet, the HR for death or PASC-U09.9 was 0.87 (95% CI 0.66-1.14; P = 0.08), and for death or PCORnet computable phenotype PASC (PASC-PCORnet) was 1.04 (95% CI 0.97-1.11; P = 0.58). Incident PASC by diagnosis code was 1.6% metformin vs. 2.0% comparator in the N3C, and 2.1% metformin vs. 2.5% comparator in PCORnet. By computable phenotype, incidence was 4.8% metformin and 5.2% comparator in the N3C and 24.7% metformin vs. 26.1% comparator in PCORnet.

CONCLUSIONS

Prevalent metformin use is associated with a slightly lower incidence of death or PASC after SARS-CoV-2 infection. PASC incidence by computable phenotype is higher than by EHR code, especially in PCORnet. These data are consistent with other observational analyses showing prevalent metformin is associated with favorable outcomes after SARS-CoV-2 infection in adults with T2DM.

Inflammatory pathways in patients with post-acute sequelae of COVID-19: The role of the clinical immunologist

As the SARS-CoV-2 pandemic progressed, some survivors noted prolonged symptoms after acute infection, termed post-acute sequelae of COVID-19 (PASC) or "long COVID." PASC is a significant clinical and public health concern that adversely affects patients' quality of life, income, and health care expenses. Moreover, PASC symptoms are highly heterogeneous, the most common being fatigue and cognitive impairment, and they likely reflect a spectrum of clinical phenotypes. The proposed role of persistent inflammation is one of leading pathophysiological theories. This review article addresses these proposed mechanisms of persistent and aberrant inflammation, their clinical evaluation, and theoretical approaches to management. A review of public databases was used to collect literature for the review. The literature supports a prominent role of persistent and aberrant inflammation as a major contributor to the symptoms of PASC. Proposed mechanisms for persistent inflammation include reactivation of latent viruses, viral persistence, loss of immunoregulatory pathways, autoimmune mechanisms, and/or mast cell dysregulation. Persistent inflammation may result in constitutional symptoms such as fatigue, brain fog, body aches, and/or organ-specific dysfunction, such as gastrointestinal dysregulation and myocardial inflammation. There are no approved or even proven therapies for PASC at this time, but some studies have identified therapeutic options that may either reduce the risk for progression to PASC or decrease symptom burden. Laboratory evaluation and therapeutic options are limited and require further investigation to establish their clinical value. A more refined definition of PASC is needed to address the wide variety of clinical presentations, pathophysiology, and therapeutic options.

Metformin modulates mitochondrial autophagy in renal tubular epithelial injury induced by high glucose via the Keap1/Nrf2 pathway

The current study aimed to explore the role and underpinning molecular mechanisms of metformin in renal cellular injury induced by high glucose levels. Male C57BL/KsJ (db/db) and (db/m +) mice were utilized in this study. The experimental group was administered 1 mg/mL of metformin through drinking water. Renal tissues were harvested for hematoxylin and eosin (HE) staining, superoxide dismutase (SOD) activity detection, biochemical indices analysis, Western blotting, and qRT-PCR. HK-2 cells were utilized for Nrf2 siRNA transfection and to establish a high level of glucose-induced cell models. Metformin was administered at a concentration of 1 mmol/L in the experimental group. Cellular viability was assessed using CCK-8, whereas acridine orange (AO) staining and LC3-mitotracker co-localization staining were employed to evaluate autophagy. The expression of Nrf2, P21, LC3, PTEN-induced putative kinase 1 (PINK1), translocase of outer mitochondrial membrane 20 (TOMM20), and Kelch-like ECH-associated protein 1 (Keap1) were determined through Western blotting and qRT-PCR. Metformin mitigated renal tissue inflammatory damage in diabetic mice, as indicated by upregulated expression of Nrf2, PINK1, LC3, and TOMM20, and downregulated expression of Keap1 and P21. High level of glucose treatment in HK-2 cells resulted in decreased autophagy, and reduced expression of Nrf2, PINK1, LC3, and TOMM20 alongside elevated the expression of Keap1 and P21. Notably, metformin treatment partially counteracted these effects. Nrf2 knockdown intensified these phenomena in the high level of glucose-induced model. Protein-protein interaction network analysis indicated that Nrf2 could regulate the majority autophagy-related proteins via Keap1. Metformin modulates mitochondrial autophagy in high glucose-induced renal tubular epithelial senescence via the Keap1/Nrf2 pathway.

Metformin modulates autophagic pathway in renal fibrosis induced by carbon tetrachloride in adult male albino rats

BACKGROUNDS

Chronic kidney disease (CKD) is a global public health problem. All progressive chronic kidney disease (CKD) is characterized by tubulointerstitial fibrosis. Exposure to high concentrations of carbon tetrachloride (including vapor) can destroy the kidneys. Autophagy played an important role in maintaining the homeostasis of organs. Impaired autophagy was frequently associated with renal damage and fibrosis. Recent data suggests that metformin protects against a variety of kidney disorders.

AIM

To investigate the protective role of metformin on carbon tetrachloride induced renal damage via autophagy pathway.

MATERIALS AND METHODS

Forty adult male albino rats were divided into four equal groups (10 rats, each); Group 1: control group. Group 2: olive oil group received olive oil 1.5 mg/kg twice weekly S.C for 12 weeks. Group 3: The ccl4 group, the rats were received ccl4 1.5 mg/kg twice weekly S.C for 12 weeks. Group 4: CCL4 and Metformin group received concomitant treatment of CCL4, 1.5 mg/kg twice weekly S.C and 100 mg/kg/day Metformin orally for 12 weeks. After sacrifice, kidneys were taken from all animal groups and processed for light and electron microscopy, immunological studies and biochemical tests. Statistical analysis was done.

RESULTS

Administration of ccl4 resulted in histopathological changes in the kidney tissue in the form of areas of tissue destruction, inflammatory cell infiltration, congestion and fibrosis. Ultrastructurally, irregular thickening of GBM was observed. Improvement was noticed with concomitant treatment of ccl4 with metformin.

CONCLUSION

Metformin administration can modulate histological and biochemical effects in the renal tissue induced by of ccl4.

The Role and Mechanism of Metformin in Inflammatory Diseases

Metformin is a classical drug used to treat type 2 diabetes. With the development of research on metformin, it has been found that metformin also has several advantages aside from its hypoglycemic effect, such as anti-inflammatory, anti-aging, anti-cancer, improving intestinal flora, and other effects. The prevention of inflammation is critical because chronic inflammation is associated with numerous diseases of considerable public health. Therefore, there has been growing interest in the role of metformin in treating various inflammatory conditions. However, the precise anti-inflammatory mechanisms of metformin were inconsistent in the reported studies. Thus, this review aims to summarize various currently known possible mechanisms of metformin involved in inflammatory diseases and provide references for the clinical application of metformin.

The Role of Autophagy in Type 2 Diabetic Kidney Disease Management

Diabetic kidney disease (DKD), or diabetic nephropathy (DN), is one of the most prevalent complications of type 2 diabetes mellitus (T2DM) and causes severe burden on the general welfare of T2DM patients around the world. While several new agents have shown promise in treating this condition and potentially halting the progression of the disease, more work is needed to understand the complex regulatory network involved in the disorder. Recent studies have provided new insights into the connection between autophagy, a physiological metabolic process known to maintain cellular homeostasis, and the pathophysiological pathways of DKD. Typically, autophagic activity plays a role in DKD progression mainly by promoting an inflammatory response to tissue damage, while both overactivated and downregulated autophagy worsen disease outcomes in different stages of DKD. This correlation demonstrates the potential of autophagy as a novel therapeutic target for the disease, and also highlights new possibilities for utilizing already available DN-related medications. In this review, we summarize findings on the relationship between autophagy and DKD, and the impact of these results on clinical management strategies.

Mechanisms and effects of metformin on skeletal muscle disorders

Skeletal muscle disorders are mostly genetic and include several rare diseases. With disease progression, muscle fibrosis and adiposis occur, resulting in limited mobility. The long course of these diseases combined with limited treatment options affect patients both psychologically and economically, hence the development of novel treatments for neuromuscular diseases is crucial to obtain a better quality of life. As a widely used hypoglycemic drug in clinical practice, metformin not only has anti-inflammatory, autophagy-regulating, and mitochondrial biogenesis-regulating effects, but it has also been reported to improve the symptoms of neuromuscular diseases, delay hypokinesia, and regulate skeletal muscle mass. However, metformin's specific mechanism of action in neuromuscular diseases requires further elucidation. This review summarizes the evidence showing that metformin can regulate inflammation, autophagy, and mitochondrial biogenesis through different pathways, and further explores its mechanism of action in Duchenne muscular dystrophy, statin-associated muscle disorders, and age-related sarcopenia. This review clarifies the directions of future research on therapy for neuromuscular diseases.

Outpatient treatment of COVID-19 and incidence of post-COVID-19 condition over 10 months (COVID-OUT): a multicentre, randomised, quadruple-blind, parallel-group, phase 3 trial

BACKGROUND

Post-COVID-19 condition (also known as long COVID) is an emerging chronic illness potentially affecting millions of people. We aimed to evaluate whether outpatient COVID-19 treatment with metformin, ivermectin, or fluvoxamine soon after SARS-CoV-2 infection could reduce the risk of long COVID.

METHODS

We conducted a decentralised, randomised, quadruple-blind, parallel-group, phase 3 trial (COVID-OUT) at six sites in the USA. We included adults aged 30-85 years with overweight or obesity who had COVID-19 symptoms for fewer than 7 days and a documented SARS-CoV-2 positive PCR or antigen test within 3 days before enrolment. Participants were randomly assigned via 2 × 3 parallel factorial randomisation (1:1:1:1:1:1) to receive metformin plus ivermectin, metformin plus fluvoxamine, metformin plus placebo, ivermectin plus placebo, fluvoxamine plus placebo, or placebo plus placebo. Participants, investigators, care providers, and outcomes assessors were masked to study group assignment. The primary outcome was severe COVID-19 by day 14, and those data have been published previously. Because the trial was delivered remotely nationwide, the a priori primary sample was a modified intention-to-treat sample, meaning that participants who did not receive any dose of study treatment were excluded. Long COVID diagnosis by a medical provider was a prespecified, long-term secondary outcome. This trial is complete and is registered with ClinicalTrials.gov, NCT04510194.

FINDINGS

Between Dec 30, 2020, and Jan 28, 2022, 6602 people were assessed for eligibility and 1431 were enrolled and randomly assigned. Of 1323 participants who received a dose of study treatment and were included in the modified intention-to-treat population, 1126 consented for long-term follow-up and completed at least one survey after the assessment for long COVID at day 180 (564 received metformin and 562 received matched placebo; a subset of participants in the metformin vs placebo trial were also randomly assigned to receive ivermectin or fluvoxamine). 1074 (95%) of 1126 participants completed at least 9 months of follow-up. 632 (56·1%) of 1126 participants were female and 494 (43·9%) were male; 44 (7·0%) of 632 women were pregnant. The median age was 45 years (IQR 37-54) and median BMI was 29·8 kg/m2 (IQR 27·0-34·2). Overall, 93 (8·3%) of 1126 participants reported receipt of a long COVID diagnosis by day 300. The cumulative incidence of long COVID by day 300 was 6·3% (95% CI 4·2-8·2) in participants who received metformin and 10·4% (7·8-12·9) in those who received identical metformin placebo (hazard ratio [HR] 0·59, 95% CI 0·39-0·89; p=0·012). The metformin beneficial effect was consistent across prespecified subgroups. When metformin was started within 3 days of symptom onset, the HR was 0·37 (95% CI 0·15-0·95). There was no effect on cumulative incidence of long COVID with ivermectin (HR 0·99, 95% CI 0·59-1·64) or fluvoxamine (1·36, 0·78-2·34) compared with placebo.

INTERPRETATION

Outpatient treatment with metformin reduced long COVID incidence by about 41%, with an absolute reduction of 4·1%, compared with placebo. Metformin has clinical benefits when used as outpatient treatment for COVID-19 and is globally available, low-cost, and safe.

FUNDING

Parsemus Foundation; Rainwater Charitable Foundation; Fast Grants; UnitedHealth Group Foundation; National Institute of Diabetes, Digestive and Kidney Diseases; National Institutes of Health; and National Center for Advancing Translational Sciences.

Metformin and Canagliflozin Are Equally Renoprotective in Diabetic Kidney Disease but Have No Synergistic Effect

Diabetic Kidney Disease (DKD) is a major microvascular complication for diabetic patients and is the most common cause of chronic kidney disease (CKD) and end-stage renal disease. Antidiabetic drugs, such as metformin and canagliflozin, have been shown to exert renoprotective effects. Additionally, quercetin recently showed promising results for the treatment of DKD. However, the molecular pathways through which these drugs exert their renoprotective effects remain partly unknown. The current study compares the renoprotective potential of metformin, canagliflozin, metformin + canagliflozin, and quercetin in a preclinical rat model of DKD. By combining streptozotocin (STZ) and nicotinamide (NAD) with daily oral N(ω)-Nitro-L-Arginine Methyl Ester (L-NAME) administration, DKD was induced in male Wistar Rats. After two weeks, rats were assigned to five treatment groups, receiving vehicle, metformin, canagliflozin, metformin + canagliflozin, or quercetin for a period of 12 weeks by daily oral gavage. Non-diabetic vehicle-treated control rats were also included in this study. All rats in which diabetes was induced developed hyperglycemia, hyperfiltration, proteinuria, hypertension, renal tubular injury and interstitial fibrosis, confirming DKD. Metformin and canagliflozin, alone or together, exerted similar renoprotective actions and similar reductions in tubular injury and collagen accumulation. Renoprotective actions of canagliflozin correlated with reduced hyperglycemia, while metformin was able to exert these effects even in the absence of proper glycemic control. Gene expression revealed that the renoprotective pathways may be traced back to the NF-κB pathway. No protective effect was seen with quercetin. In this experimental model of DKD, metformin and canagliflozin were able to protect the kidney against DKD progression, albeit in a non-synergistic way. These renoprotective effects may be attributable to the inhibition of the NF-κB pathway.

Comparison of the anti-diabetic and nephroprotective activities of vitamin E, metformin, and Nigella sativa oil on kidney in experimental diabetic rats

Objectives

In this study, we aimed to evaluate and compare the nephroprotective and possible anti-diabetic effects of vitamin E, metformin, and Nigella sativa.

Materials and Methods

Thirty male Wistar Albino rats were randomly divided into control, experimental diabetes (DM), vitamin E + DM, Metformin + DM, and N. sativa + DM. For experimental diabetes induction, IP 45 mg/kg streptozotocin was administered. Rats in vitamin E + DM, Metformin + DM, and N. sativa + DM received 100 mg/kg vitamin E, 100 mg/kg metformin, and 2.5 ml/kg N. sativa oil for 56 days. After the experiment, all animals were sacrificed, and blood and kidney samples were collected.

Results

The blood urea level of the DM group was significantly higher (P<0.01) than the control group. Urea levels in vitamin E, metformin, and N. sativa groups were similar to the control group (P>0.05) but significantly different from the DM group (P<0.01). Bax, caspase-3, and caspase-9 immunopositivity intensity were quite low in the control group, and similar to the N. sativa group (P>0.05). Bcl-2 immunopositivity density was highest in the N. sativa group, similar to the control group in terms of percentile area (P>0.05).

Conclusion

When all three treatment methods were compared in terms of their effectiveness in alleviating DM and DN, it was determined that the most successful result was obtained with N. sativa oil.

A cross-talk between sestrins, chronic inflammation and cellular senescence governs the development of age-associated sarcopenia and obesity

The rapid increase in both the lifespan and proportion of older adults is accompanied by the unprecedented rise in age-associated chronic diseases, including sarcopenia and obesity. Aging is also manifested by increased susceptibility to multiple endogenous and exogenous stresses enabling such chronic conditions to develop. Among the main physiological regulators of cellular adaption to various stress stimuli, such as DNA damage, hypoxia, and oxidative stress, are sestrins (Sesns), a family of three evolutionarily conserved proteins, Sesn1, 2, and 3. Age-associated sarcopenia and obesity are characterized by two key processes: (i) accumulation of senescent cells in the skeletal muscle and adipose tissue and (ii) creation of a systemic, chronic, low-grade inflammation (SCLGI). Presumably, failed SCLGI resolution governs the development of these chronic conditions. Noteworthy, Sesns activate senolytics, which are agents that selectively eliminate senescent cells, as well as specialized pro-resolving mediators, which are factors that physiologically provide inflammation resolution. Sesns reveal clear beneficial effects in pre-clinical models of sarcopenia and obesity. Based on these observations, we propose a novel treatment strategy for age-associated sarcopenia and obesity, complementary to the conventional therapeutic modalities: Sesn activation, SCLGI resolution, and senescent cell elimination.

Intestinal microbiome diversity of diabetic and non-diabetic kidney disease: Current status and future perspective

A significant portion of the health burden of diabetic kidney disease (DKD) is caused by both type 1 and type 2 diabetes which leads to morbidity and mortality globally. It is one of the most common diabetic complications characterized by loss of renal function with high prevalence, often leading to acute kidney disease (AKD). Inflammation triggered by gut microbiota is commonly associated with the development of DKD. Interactions between the gut microbiota and the host are correlated in maintaining metabolic and inflammatory homeostasis. However, the fundamental processes through which the gut microbiota affects the onset and progression of DKD are mainly unknown. In this narrative review, we summarised the potential role of the gut microbiome, their pathogenicity between diabetic and non-diabetic kidney disease (NDKD), and their impact on host immunity. A well-established association has already been seen between gut microbiota, diabetes and kidney disease. The gut-kidney interrelationship is confirmed by mounting evidence linking gut dysbiosis to DKD, however, it is still unclear what is the real cause of gut dysbiosis, the development of DKD, and its progression. In addition, we also try to distinguish novel biomarkers for early detection of DKD and the possible therapies that can be used to regulate the gut microbiota and improve the host immune response. This early detection and new therapies will help clinicians for better management of the disease and help improve patient outcomes.

Dioscin relieves diabetic nephropathy via suppressing oxidative stress and apoptosis, and improving mitochondrial quality and quantity control

Dioscin is a steroidal saponin isolated from various kinds of vegetables and herbs and possesses various biological activities. In this study, the protective effect of dioscin on diabetic nephropathy (DN) was explored. Dioscin and metformin (positive control) were administered orally to diabetic rats daily for 8 weeks. The biochemistry parameters, pancreas and kidney histological changes, oxidative stress, inflammation, apoptosis, autophagy, and mitochondrial quality and quantity control (mitophagy and mitochondrial fission/fusion) were measured. Our results showed that dioscin effectively reduced blood glucose, pancreatic injury, renal function markers and renal pathological changes in DN rat kidneys. Dioscin reduced O^2- and H₂O₂ levels, decreased MDA levels, enhanced antioxidant enzyme (SOD, CAT) activities, and reduced inflammatory factor expressions. Moreover, NOX4 expression and the disorder of the mitochondrial respiratory chain were reversed by dioscin. Furthermore, apoptosis mediated by the mitochondria and ER stress was inhibited by dioscin through downregulating the expressions of Bax, CytC, Apaf-1, caspase 9, p-PERK, p-EIF2α, IRE1, p-IRE1, XBP1s, ATF4, p-CHOP and caspase 12. In addition, autophagy was enhanced by dioscin via an AMPK-mTOR pathway. Mitophagy and mitochondrial fission/fusion belong to the mitochondrial quality and quantity control process, which was improved by dioscin via regulating Parkin, PINK1, DRP1, p-DRP1 and MFN2 expressions. Collectively, these results suggested that dioscin protected against DN through inhibiting oxidative stress, inflammation, and apoptosis mediated by the mitochondria and ER stress. Autophagy and mitochondrial quality and quantity control (mitophagy and mitochondrial fission/fusion) were also improved by dioscin.