Metformin affects macrophages' phenotype and improves the activity of glutathione peroxidase, superoxide dismutase, catalase and decreases malondialdehyde concentration in a partially AMPK-independent manner in LPS-stimulated human monocytes/macrophages

Progress of polysaccharide-based tissue adhesives

Recently, polymer-based tissue adhesives (TAs) have gained the attention of scientists and industries as alternatives to sutures for sealing and closing wounds or incisions because of their ease of use, low cost, minimal tissue damage, and short application time. However, poor mechanical properties and weak adhesion strength limit the application of TAs, although numerous studies have attempted to develop new TAs with enhanced performance. Therefore, next-generation TAs with improved multifunctional properties are required. In this review, we address the requirements of polymeric TAs, adhesive characteristics, adhesion strength assessment methods, adhesion mechanisms, applications, advantages and disadvantages, and commercial products of polysaccharide (PS)-based TAs, including chitosan (CS), alginate (AL), dextran (DE), and hyaluronic acid (HA). Additionally, future perspectives are discussed.

Effect of Metformin on Oxidative Stress and Left Ventricular Geometry in Nondiabetic Heart Failure Patients: A Randomized Controlled Trial

Introduction: There is an increasing interest in using metformin in cardiovascular diseases and its potential new roles. Only two randomized controlled trials investigated the effect of metformin in nondiabetic heart failure (HF) patients. However, none of these studies assess the role of metformin in reducing oxidative stress. We hypothesized that metformin might improve oxidative stress and left ventricular remodeling in nondiabetic HF patients with reduced ejection fraction (HFrEF). Methods and Methods: Seventy HFrEF patients (EF 37% ± 8%; median age 66 years) were randomized to metformin (n = 35) or standard of care (SOC) for HF (n = 35) for 6 months in addition to standard therapy. Outcomes included the difference in the change (Δ) in total antioxidant capacity (TAC) and malondialdehyde (MDA), both assessed colorimetrically and left ventricular mass index (LVMI) assessed through transthoracic echocardiography. Results: Compared with the SOC, metformin treatment increased TAC [Δ = 0.12 mmol/L, confidence intervals (95% CIs): 0.03-0.21; P = 0.007]. TAC increased significantly only in the metformin group (0.90 ± 0.08 mmol/L at baseline vs. 1.04 ± 0.99 mmol/L at 6 months, P < 0.05). Metformin therapy preserved LVMI (Δ = -23 g/m2, 95% CI: -42.91 to -4.92; P = 0.014) and reduced fasting plasma glucose (Δ = -6.16, 95% CI: -12.31 to -0.02, P = 0.047) compared with the SOC. Results did not change after adjusting for baseline values. Changes in MDA left ventricular ejection fraction (LVEF) and blood pressure were not significantly different between groups. Conclusion: Metformin treatment in HF patients with reduced LVEF improved TAC and prevented the increase in LVMI compared with the SOC. These effects of metformin warrant further research in HF patients without diabetes to explore the potential benefits of metformin. Trial Registration Number: This protocol was registered in ClinicalTrials.gov under the number NCT05177588.

Promising drug candidates for the treatment of polycystic ovary syndrome (PCOS) as alternatives to the classical medication metformin

Polycystic ovary syndrome (PCOS) is a prevalent hormonal disorder that affects women of reproductive age. It is characterized by abnormal production of androgens, typically present in small quantities in females. This study aimed to investigate the therapeutic potential of Irosustat (STX64), STX140, and compound 1G as new drug candidates for the treatment of letrozole-induced PCOS in female Wistar rats. 36 rats were divided into six groups of equal size. PCOS was induced in all groups, except the normal control group, by administering letrozole orally (1 mg/kg/day for 35 days). The onset of abnormal estrous cycle was confirmed by examining daily vaginal smears under a microscope. Subsequently, each rat group was assigned to a different treatment regimen, including one control group, one letrozole group, one metformin group (500 mg/kg/day) as a reference drug, and the other groups received a different drug candidate orally for 30 days. After treatment, blood collection was performed for biochemical measurements and determination of oxidative stress markers. The rats were dissected to separate ovaries and uterus for morphological, histological, and western blotting studies. Treatment with the drug candidates improved the ovaries and uterus weight measurements compared to the untreated PCOS group. The three tested drug candidates demonstrated promising improvements in lipid profile, blood glucose level, testosterone, progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol levels. In addition, western blotting confirmed their promising effects on Akt, mTOR, and AMPK-α pathways. This study led to the discovery of three promising drug candidates for the management of PCOS as alternatives to metformin.

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.

Does the addition of metformin to carboplatin treatment decreases ovarian reserve damage associated with carboplatin usage?

BACKGROUND

We aimed to determine whether adding metformin to carboplatin treatment would reduce the damage to ovarian reserve associated with carboplatin use.

METHODS

We included 35 adult female non-pregnant albino Wistar rats approximately three months old, weighing 220-310 g. The rats were divided into five groups of seven rats according to the treatment they received. Carboplatin and salin was given to Group 2, and carboplatin plus metformin was given to Group 3. Group 4 was administered only metformin. Group 5 was administered only salin. Carboplatin was given to Groups 2 and 3 as a single dose on the 15th day, while metformin was given to Groups 3 and 4 during the 28-day experiment. After oophorectomy, histopathologic analyses of primordial, primary, secondary, and tertiary Graff follicles according to the epithelial cells surrounding the oocyte and total follicular number were conducted per section. Serum Anti-Mullerian Hormone (AMH), tissue catalase, and malonyl dialdehyde levels were measured and compared within each group.

RESULTS

The baseline and 15th-day serum AMH values of the menstrual cycle were compared among the groups, and no statistically significant differences were observed (p > 0.05). Group 3, which was given both carboplatin and metformin, had statistically significantly higher 28th-day AMH levels than Group 2, which was given only carboplatin and saline (p < 0.001). The number of primordial follicles in Group 3 was found to be statistically significantly higher than in Group 2 (p < 0.001). Tissue catalase enzyme levels in Group 3 were statistically significantly higher than in Group 2 (p < 0.001). Tissue malondialdehyde levels in Group 2 were statistically significantly higher than tissue malondialdehyde levels in Groups 3 and 4 (p < 0.001).

CONCLUSIONS

Metformin may attenuate carboplatin-induced ovarian damage, possibly through its antioxidative effects.

Microenvironment responsive nanocomposite hydrogel with NIR photothermal therapy, vascularization and anti-inflammation for diabetic infected wound healing

Bacterial infection, excessive inflammation and damaging blood vessels network are the major factors to delay the healing of diabetic ulcer. At present, most of wound repair materials are passive and can't response to the wound microenvironment, resulting in a low utilization of bioactive substances and hence a poor therapeutic effect. Therefore, it's essential to design an intelligent wound dressing responsive to the wound microenvironment to achieve the release of drugs on-demand on the basis of multifunctionality. In this work, metformin-laden CuPDA NPs composite hydrogel (Met@ CuPDA NPs/HG) was fabricated by dynamic phenylborate bonding of gelatin modified by dopamine (Gel-DA), Cu-loaded polydopamine nanoparticles (CuPDA NPs) with hyaluronic acid modified by phenyl boronate acid (HA-PBA), which possessed good injectability, self-healing, adhesive and DPPH scavenging performance. The slow release of metformin was achieved by the interaction with CuPDA NPs, boric groups (B-N coordination) and the constraint of hydrogel network. Metformin had a pH and glucose responsive release behavior to treat different wound microenvironment intelligently. Moreover, CuPDA NPs endowed the hydrogel excellent photothermal responsiveness to kill bacteria of >95% within 10 min and also the slow release of Cu²⁺ to protect wound from infection for a long time. Met@ CuPDA NPs/HG also recruited cells to a certain direction and promoted vascularization by releasing Cu²⁺. More importantly, Met@CuPDA NPs/HG effectively decreased the inflammation by eliminating ROS and inhibiting the activation of NF-κB pathway. Animal experiments demonstrated that Met@CuPDA NPs/HG significantly promoted wound healing of diabetic SD rats by killing bacteria, inhibiting inflammation, improving angiogenesis and accelerating the deposition of ECM and collagen. Therefore, Met@CuPDA NPs/HG had a great application potential for diabetic wound healing.

Identification of stable reference genes for quantitative gene expression analysis in the duodenum of meat-type ducks

Quantitative polymerase chain reaction (qPCR) is an important method to detect gene expression at the molecular level. The selection of appropriate housekeeping genes is the key to accurately calculating the expression level of target genes and conducting gene function studies. In this study, the expression of eight candidate reference genes, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta-actin (β-actin), 18S ribosomal RNA (18S rRNA), hydroxymethylbilane synthase (HMBS), hypoxanthine phosphoribosyltransferase 1 (HPRT1), TATA box binding protein (TBP), ribosomal protein L13 (RPL13), and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein (YWHAZ), in the duodenal epithelial tissue of 42-day-old meat-type ducks were detected using qPCR. Furthermore, their expression stability was analyzed using the geNorm, NormFinder, and BestKeeper programs. The results indicated that HMBS and YWHAZ were the most stably expressed genes. All three programs indicated that the expression of 18S rRNA was the least stable, making it unsuitable for the study of gene expression in meat-type duck tissues. This study provides stable reference genes for gene expression analysis and contributes to further studies on the gene function of meat-type ducks.

Anti-oxidant effect of metformin through AMPK/SIRT1/PGC-1α/SIRT3- independent GPx1 expression in the heart of mice with endometriosis

OBJECTIVES

Endometriosis is a gynecological disease associated with an imbalance between oxidative species production and anti-oxidative defenses. In women, endometriosis has been reported to associate with increased incidence of cardiovascular events. As such, this study aimed to analyze the oxidation-responsive AMPK/SIRT1/PGC-1α/SIRT3 pathway in the heart of a mouse model of endometriosis. The effect of metformin, an insulin-sensitizing and anti-oxidative drug with already shown positive results in endometriotic tissue was studied.

METHODS

Thirty-six female B6CBA/F1 mice were divided into 4 groups (Control-C, Surgery-induced Endometriosis and Metformin-EM (50 mg/kg/day orally administrated for 3 months), Endometriosis-E and Metformin-M). Immunofluorescent labelling of SIRT1 and SIRT3 was performed in the heart tissue. Assessment of expression of AMPKα, SIRT1, PGC-1α, SIRT3, SOD2, and GPx1 was performed by Western Blotting. The quantification of microRNA(miR)-34a, miR-195, miR-217, miR-155 and miR-421, involved in the regulation of expression of SIRT1 and SIRT3, was performed by Real-Time PCR.

RESULTS

Data showed an increase in phospho-AMPKα and in GPx1 expression in the EM group when compared to the C group, but not in the total AMPK, SIRT1, PGC-1α, SIRT3 and SOD2, suggesting a GPx1 expression increase independently of the AMPK/SIRT1/PGC-1α/SIRT3 pathway. MicroRNAs, excepting miR-217, showed a consistent trend of increase in the M group.

CONCLUSIONS

Our study showed that endometriosis does not significantly affect the expression of the components of the AMPK/SIRT1/PGC-1α/SIRT3 pathway in the heart. However, it indicates that an oxidative condition underlying endometriosis is required for metformin to evidence an increment in the expression of the anti-oxidative enzyme GPx1.

Effects and Progress of Photo-Crosslinking Hydrogels in Wound Healing Improvement

Wound healing is a dynamic physiological process, including three stages: inflammation, tissue formation, and remodeling. The quality of wound healing is affected by many topical and systemic factors, while any small factor may affect the process. Therefore, improving the quality of wound healing is a complex and arduous challenge. Photo-crosslinking reaction using visible light irradiation is a novel method for hydrogel preparation. Photo-crosslinking hydrogels can be controlled in time and space, and are not interfered by temperature conditions, which have been widely used in the fields of medicine and engineering. This review aims to summarize the application of photo-crosslinking hydrogels in improving the quality of wound healing, mainly including the material design, application mechanism, and effect of photo-crosslinking hydrogels applied in wound healing, followed by the applicable animal models for experimental research. Finally, this review analyzes the clinical application prospects of photo-crosslinking hydrogels in the field of wound healing.

Dose-dependent immunomodulatory effects of metformin on human neonatal monocyte-derived macrophages

While the association of inflammation with bronchopulmonary dysplasia (BPD) has long been appreciated, M1 proinflammatory macrophage population is emerging as the key element in driving the BPD inflammatory environment. Previous study suggests that low-dose metformin elicits an anti-inflammatory response, possibly through modulating macrophages, to improve disease outcome in a rat BPD model. To investigate this concept further, we examined the dose-dependent immunomodulatory function of metformin directly on human macrophages derived from cord blood (CB) monocytes. We demonstrate that low-dose metformin promotes expansion of M2 anti-inflammatory macrophages, contrasted with high-dose treatment, which exacerbates inflammation by favoring M1 polarization and restricting M2 phenotype. These findings highlight that metformin hold immunomodulatory ability by regulating macrophage polarization in a dose-dependent manner, and only when applied at low dose, exhibiting potential for beneficial anti-inflammatory adjuvant in BPD setting.

Modulation of Reactive Oxygen Species Homeostasis as a Pleiotropic Effect of Commonly Used Drugs

Age-associated diseases represent a growing burden for global health systems in our aging society. Consequently, we urgently need innovative strategies to counteract these pathological disturbances. Overwhelming generation of reactive oxygen species (ROS) is associated with age-related damage, leading to cellular dysfunction and, ultimately, diseases. However, low-dose ROS act as crucial signaling molecules and inducers of a vaccination-like response to boost antioxidant defense mechanisms, known as mitohormesis. Consequently, modulation of ROS homeostasis by nutrition, exercise, or pharmacological interventions is critical in aging. Numerous nutrients and approved drugs exhibit pleiotropic effects on ROS homeostasis. In the current review, we provide an overview of drugs affecting ROS generation and ROS detoxification and evaluate the potential of these effects to counteract the development and progression of age-related diseases. In case of inflammation-related dysfunctions, cardiovascular- and neurodegenerative diseases, it might be essential to strengthen antioxidant defense mechanisms in advance by low ROS level rises to boost the individual ROS defense mechanisms. In contrast, induction of overwhelming ROS production might be helpful to fight pathogens and kill cancer cells. While we outline the potential of ROS manipulation to counteract age-related dysfunction and diseases, we also raise the question about the proper intervention time and dosage.

An injectable photo-cross-linking silk hydrogel system augments diabetic wound healing in orthopaedic surgery through spatiotemporal immunomodulation

BACKGROUND

The complicated hyperglycaemic and chronic inflammation of diabetic wounds in orthopaedic surgery leads to dysregulated immune cell function and potential infection risk. Immune interventions in diabetic wounds face a possible contradiction between simultaneous establishment of the pro-inflammatory microenvironment in response to potential bacterial invasion and the anti-inflammatory microenvironment required for tissue repair. To study this contradiction and accelerate diabetic-wound healing, we developed a photocurable methacryloxylated silk fibroin hydrogel (Sil-MA) system, co-encapsulated with metformin-loaded mesoporous silica microspheres (MET@MSNs) and silver nanoparticles (Ag NPs).

RESULTS

The hydrogel system (M@M-Ag-Sil-MA) enhanced diabetic-wound healing via spatiotemporal immunomodulation. Sil-MA imparts a hydrogel system with rapid in situ Ultra-Violet-photocurable capability and allows preliminary controlled release of Ag NPs, which can inhibit bacterial aggregation and create a stable, sterile microenvironment. The results confirmed the involvement of Met in the immunomodulatory effects following spatiotemporal dual-controlled release via the mesoporous silica and Sil-MA. Hysteresis-released from Met shifts the M1 phenotype of macrophages in regions of diabetic trauma to an anti-inflammatory M2 phenotype. Simultaneously, the M@M-Ag-Sil-MA system inhibited the formation of neutrophil extracellular traps (NETs) and decreased the release of neutrophil elastase, myeloperoxidase, and NETs-induced pro-inflammatory factors. As a result of modulating the immune microenvironmental, the M@M-Ag-Sil-MA system promoted fibroblast migration and endothelial cell angiogenesis in vivo, with verification of enhanced diabetic-wound healing accompanied with the spatiotemporal immunoregulation of macrophages and NETs in a diabetic mouse model.

CONCLUSIONS

Our findings demonstrated that the M@M-Ag-Sil-MA hydrogel system resolved the immune contradiction in diabetic wounds through spatiotemporal immunomodulation of macrophages and NETs, suggesting its potential as a promising engineered nano-dressing for the treatment of diabetic wounds in orthopaedic surgery.

Redox Homeostasis Involvement in the Pharmacological Effects of Metformin in Systemic Lupus Erythematosus

Significance: Metformin has been proposed as a treatment for systemic lupus erythematosus (SLE). The primary target of metformin, the electron transport chain complex I in the mitochondria, is associated with redox homeostasis in immune cells, which plays a critical role in the pathogenesis of autoimmune diseases. This review addresses the evidence and knowledge gaps on whether a beneficial effect of metformin in lupus may be due to a restoration of a balanced redox state. Recent Advances: Clinical trials in SLE patients with mild-to-moderate disease activity and preclinical studies in mice have provided encouraging results for metformin. The mechanism by which this therapeutic effect was achieved is largely unknown. Metformin regulates redox homeostasis in a context-specific manner. Multiple cell types contribute to SLE, with evidence of increased mitochondrial oxidative stress in T cells and neutrophils. Critical Issues: The major knowledge gaps are whether the efficacy of metformin is linked to a restored redox homeostasis in the immune system, and if it does, in which cell types it occurs? We also need to know which patients may have a better response to metformin, and whether it corresponds to a specific mechanism? Finally, the identification of biomarkers to predict treatment outcomes would be of great value. Future Directions: Mechanistic studies must address the context-dependent pharmacological effects of metformin. Multiple cell types as well as a complex disease etiology should be considered. These studies must integrate the rapid advances made in understanding how metabolic programs direct the effector functions of immune cells. Antioxid. Redox Signal. 36, 462-479.

Growth Differentiation Factor-15 in Immunity and Aging

Aging increases susceptibility to and severity of a variety of chronic and infectious diseases. Underlying this is dysfunction of the immune system, including chronic increases in low-grade inflammation (inflammaging) and age-related immunosuppression (immunosenescence). Growth differentiation factor-15 (GDF-15) is a stress-, infection-, and inflammation-induced cytokine which is increased in aging and suppresses immune responses. This mini review briefly covers existing knowledge on the immunoregulatory and anti-inflammatory roles of GDF-15, as well as its potential importance in aging and immune function.

Multistability in Macrophage Activation Pathways and Metabolic Implications

Macrophages are innate immune cells with a dynamic range of reversible activation states including the classical pro-inflammatory (M1) and alternative anti-inflammatory (M2) states. Deciphering how macrophages regulate their transition from one state to the other is key for a deeper understanding of inflammatory diseases and relevant therapies. Common regulatory motifs reported for macrophage transitions, such as positive or double-negative feedback loops, exhibit a switchlike behavior, suggesting the bistability of the system. In this review, we explore the evidence for multistability (including bistability) in macrophage activation pathways at four molecular levels. First, a decision-making module in signal transduction includes mutual inhibitory interactions between M1 (STAT1, NF-KB/p50-p65) and M2 (STAT3, NF-KB/p50-p50) signaling pathways. Second, a switchlike behavior at the gene expression level includes complex network motifs of transcription factors and miRNAs. Third, these changes impact metabolic gene expression, leading to switches in energy production, NADPH and ROS production, TCA cycle functionality, biosynthesis, and nitrogen metabolism. Fourth, metabolic changes are monitored by metabolic sensors coupled to AMPK and mTOR activity to provide stability by maintaining signals promoting M1 or M2 activation. In conclusion, we identify bistability hubs as promising therapeutic targets for reverting or blocking macrophage transitions through modulation of the metabolic environment.

Rola autoimmunizacji w rozwoju powikłań cukrzycowych – przegląd badań

Przewlekłe powikłania cukrzycy są główną przyczyną obniżenia jakości życia, niepełnosprawności, a nawet przedwczesnej śmierci pacjentów cierpiących na tę chorobę. Mimo istotnego postępu w dziedzinie farmakoterapii, ich leczenie pozostaje nadal wyzwaniem w codziennej praktyce klinicznej. Brak terapii przyczynowej wynika z niewystarczającego zrozumienia molekularnych mechanizmów uszkadzających poszczególne narządy w cukrzycy. Uważa się, że etiopatogeneza tych powikłań jest złożona i zależy od czynników genetycznych i środowiskowych. W ich rozwoju, oprócz zaburzeń metabolicznych związanych z hiperglikemią, nasilenia stresu oksydacyjnego, dysfunkcji śródbłonka, indukcji stanu zapalnego, coraz częściej wskazuje się też na znaczącą rolę zaburzeń immunologicznych.

Wyniki badań doświadczalnych przeprowadzonych na zwierzętach, jak również na hodowlach tkankowych, oraz obserwacje kliniczne potwierdzają udział układu odpornościowego obejmujący aktywność autoreaktywnych limfocytów oraz cytotoksyczne działanie autoprzeciwciał w rozwoju poszczególnych powikłań w obu typach cukrzycy. Wydaje się zatem, że zachwianie równowagi immunologicznej wyzwalające autoagresję jest ważnym czynnikiem przyczyniającym się do dysfunkcji poszczególnych organów w typach cukrzycy 1 i 2.

Dokładne zrozumienie immunopatogenezy tych zaburzeń może zmienić dotychczasowe podejście w leczeniu powikłań cukrzycy oraz umożliwić opracowanie skutecznej terapii przyczynowej ukierunkowanej na układ odpornościowy. Identyfikacja swoistych autoprzeciwciał mogłaby usprawnić ich wczesną diagnostykę i prewencję. W artykule podjęto próbę analizy czynników ryzyka najczęstszych schorzeń o podłożu autoimmunizacyjnym, ich związku z typem 1 i 2 cukrzycy oraz podsumowano potencjalne znaczenie autoagresji w rozwoju jej powikłań w oparciu o wyniki dotychczasowych badań doświadczalnych i klinicznych.

Evaluation of the immunomodulatory effects of C9-13-CPs in macrophages

Short-chain chlorinated paraffins (SCCPs) have been listed as a new class of persistent organic pollutants by the Stockholm Convention. SCCPs exhibit carcinogenic-, endocrine-, and metabolism-disrupting effects. However, the knowledge of the immunomodulatory effects of SCCPs and their underlying mechanisms, especially in specific immune cells, remains limited. In addition to SCCPs, C9-13-CPs have also been detected in humans. In this study, murine RAW264.7 macrophages were exposed to C9-13-CPs at environmentally relevant concentrations to investigate whether or how C9-13-CPs exhibit immunomodulatory effects. The results showed that the exposure of RAW264.7 cells to C9-13-CPs increased cell viability, as assayed by MTT analysis at 490 nm, and also promoted cell proliferation, as indicated by EdU uptake assay, which was measured at excitation and emission wavelengths of 488 and 512 nm, respectively. In addition, exposure to C9-13-CPs not only led to elevated ATP level and intracellular Ca2+ level but also caused AMPK signaling activation and NF-κB signaling inhibition. Moreover, molecular docking showed that the β2-AR receptor could bind to C9-13-CPs. Taken together, these results suggest that the immune dysfunction of RAW264.7 cells caused by C9-13-CPs is closely related to the β2-AR/AMPK/NF-κB signaling axis.

Metformin intervention ameliorates AS in ApoE-/- mice through restoring gut dysbiosis and anti-inflammation

Atherosclerosis (AS) is closely associated with chronic low-grade inflammation and gut dysbiosis. Metformin (MET) presents pleiotropic benefits in the control of chronic metabolic diseases, but the impacts of MET intervention on gut microbiota and inflammation in AS remain largely unclear. In this study, ApoE^-/- mice with a high-fat diet (HFD) were adopted to assess the MET treatment. After 12 weeks of MET intervention (100mg·kg^-1·d^-1), relevant indications were investigated. As indicated by the pathological measurements, the atherosclerotic lesion was alleviated with MET intervention. Moreover, parameters in AS including body weights (BWs), low-density lipoprotein (LDL), triglyceride (TG), total cholesterol (TC) and malondialdehyde (MDA) were elevated; whereas high-density lipoprotein (HDL) and total superoxide dismutase (T-SOD) levels were decreased, which could be reversed by MET intervention. Elevated pro-inflammatory interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and lipopolysaccaride (LPS) in AS were decreased after MET administration. However, anti-inflammatory IL-10 showed no significant difference between AS group and AS+MET group. Consistently, accumulated macrophages in the aorta of AS were conversely lowered with MET treatment. The results of 16S rRNA sequencing and analysis displayed that the overall community of gut microbiota in AS was notably changed with MET treatment mainly through decreasing Firmicutes, Proteobacteria, Romboutsia, Firmicutes/Bacteroidetes, as well as increasing Akkermansia, Bacteroidetes, Bifidobacterium. Additionally, we found that microbiota-derived short-chain fatty acids (SCFAs) including acetic acid, propionic acid, butyric acid and valeric acid in AS were decreased, which were significantly up-regulated with MET intervention. Consistent with the attenuation of MET on gut dysbiosis, decreased intestinal tight junction protein zonula occludens-1 (ZO)-1 in AS was restored after MET supplementation. Correlation analysis showed close relationships among gut bacteria, microbial metabolites SCFAs and inflammation. Collectively, MET intervention ameliorates AS in ApoE^-/- mice through restoring gut dysbiosis and anti-inflammation, thus can potentially serve as an inexpensive and effective intervention for the control of the atherosclerotic cardiovascular disease.

Metformin, Macrophage Dysfunction and Atherosclerosis

Metformin is one of the most widely prescribed hypoglycemic drugs and has the potential to treat many diseases. More and more evidence shows that metformin can regulate the function of macrophages in atherosclerosis, including reducing the differentiation of monocytes and inhibiting the inflammation, oxidative stress, polarization, foam cell formation and apoptosis of macrophages. The mechanisms by which metformin regulates the function of macrophages include AMPK, AMPK independent targets, NF-κB, ABCG5/8, Sirt1, FOXO1/FABP4 and HMGB1. On the basis of summarizing these studies, we further discussed the future research directions of metformin: single-cell RNA sequencing, neutrophil extracellular traps (NETs), epigenetic modification, and metformin-based combination drugs. In short, macrophages play an important role in a variety of diseases, and improving macrophage dysfunction may be an important mechanism for metformin to expand its pleiotropic pharmacological profile. In addition, the combination of metformin with other drugs that improve the function of macrophages (such as SGLT2 inhibitors, statins and IL-1β inhibitors/monoclonal antibodies) may further enhance the pleiotropic therapeutic potential of metformin in conditions such as atherosclerosis, obesity, cancer, dementia and aging.

Histological and biochemical investigation of the renoprotective effects of metformin in diabetic and prostate cancer model

BACKGROUND

Diabetes and cancer have common physiological and biochemical mechanisms. Metformin is the preferred drug of choice for the treatment of diabetes. Prostate cancer can be modeled in by injection of MAT-Lylu cells. A model of diabetes in rats is induced by streptozotocin injectıon. In the current study, we explored the mechanisms by which diabetes accelerates cancer, and evaluated the effects of metformin to know whether it has any impact against the damage caused by cancer and diabetic + cancer via histopathological and biochemical parameters of kidney tissue.

METHODS

The experiment was carried out in rats. Groups 1-Control, 2- Diabetic, 3-Cancer, 4-Diabetic + cancer, 5-Diabetic + cancer + metformin, 6-Cancer + metformin. Metformin treatment was applied by gavage every day. The research ended on the 14th day. The collected kidney tissue sections were stained with Hematoxylin-Eosin.

RESULTS

Histological evaluation showed moderate to severe damage to the kidney tissue following diabetic and cancer processess. In diabetic, cancer and diabetic + cancer groups, reduced glutathione levels, total antioxidant status, sodium/potassium-ATPase and paraoxonase1 activities were found to be significantly abated. While advanced oxidized protein products, lipid peroxidation, nitric oxide, tumor necrosis factor-alpha, reactive oxygen species levels, total oxidant status, catalase, superoxide dismutase, glutathione-related antioxidant enzymes, myeloperoxidase, and arginase activities were significantly raised. The administration of metformin reversed these defects. The outcome of the reveals that histopathological and biochemical damage in cancer and diabetes + cancer groups decreased in the groups that received metformin.

CONCLUSION

In conclusion, metformin treatment can be considered an adjuvant candidate for kidney tissue in diabetes, prostate cancer and cancer therapy related damage.

Metformin Attenuates ROS via FOXO3 Activation in Immune Cells

Forkhead box O 3 (FOXO3) is a transcription factor involved in cell metabolism, inflammation and longevity. Here, we investigated if metformin can activate FOXO3 in human immune cells and affects the subsequent level of reactive oxygen/nitrogen species (ROS/RNS) in immune cells. AMP-activated protein kinase (AMPK) and FOXO3 activation were investigated by immunoblot or flow cytometry (FC) analysis, respectively. FOXO3 target gene expression was quantified by real-time PCR. ROS/RNS measurement using dichlorodihydrofluorescein diacetate (DCFH-DA) dye was investigated by FC. The role of the FOXO3 single nucleotide polymorphisms (SNPs) rs12212067, rs2802292 and rs12206094 on ROS/RNS production was studied using allelic discrimination PCR. Metformin induced activation of AMPK (pT172) and FOXO3 (pS413). ROS/RNS level was reduced in immune cells after metformin stimulation accompanied by induction of the FOXO3 targets mitochondrial superoxide dismutase and cytochrome c. Studies in Foxo3 deficient (Foxo3-/- ) mouse splenocytes confirmed that metformin mediates its effects via Foxo3 as it attenuates ROS/RNS in myeloid cells of wildtype (WT) but not of Foxo3-/- mice. Our results suggest that FOXO3 can be activated by metformin leading to reduced ROS/RNS level in immune cells. This may add to the beneficial clinical effects of metformin observed in large cohort studies on longevity, cardiovascular and cancer risk.

Ion Transport Modulators Differentially Modulate Inflammatory Responses in THP-1-Derived Macrophages

Ion transport modulators are most commonly used to treat various noncommunicable diseases including diabetes and hypertension. They are also known to bind to receptors on various immune cells, but the immunomodulatory properties of most ion transport modulators have not been fully elucidated. We assessed the effects of thirteen FDA-approved ion transport modulators, namely, ambroxol HCl, amiloride HCl, diazoxide, digoxin, furosemide, hydrochlorothiazide, metformin, omeprazole, pantoprazole, phenytoin, verapamil, drug X, and drug Y on superoxide production, nitric oxide production, and cytokine expression by THP-1-derived macrophages that had been stimulated with ethanol-inactivated Mycobacterium bovis BCG. Ambroxol HCl, diazoxide, digoxin, furosemide, hydrochlorothiazide, metformin, pantoprazole, phenytoin, verapamil, and drug Y had an inhibitory effect on nitric oxide production, while all the test drugs had an inhibitory effect on superoxide production. Amiloride HCl, diazoxide, digoxin, furosemide, phenytoin, verapamil, drug X, and drug Y enhanced the expression of IL-1β and TNF-α. Unlike most immunomodulatory compounds currently in clinical use, most of the test drugs inhibited some inflammatory processes while promoting others. Ion pumps and ion channels could therefore serve as targets for more selective immunomodulatory agents which do not cause overt immunosuppression.

Oxidative Imbalance as a Crucial Factor in Inflammatory Lung Diseases: Could Antioxidant Treatment Constitute a New Therapeutic Strategy?

Inflammatory lung disease results in a high global burden of death and disability. There are no effective treatments for the most severe forms of many inflammatory lung diseases, such as chronic obstructive pulmonary disease, emphysema, corticosteroid-resistant asthma, and coronavirus disease 2019; hence, new treatment options are required. Here, we review the role of oxidative imbalance in the development of difficult-to-treat inflammatory lung diseases. The inflammation-induced overproduction of reactive oxygen species (ROS) means that endogenous antioxidants may not be sufficient to prevent oxidative damage, resulting in an oxidative imbalance in the lung. In turn, intracellular signaling events trigger the production of proinflammatory mediators that perpetuate and aggravate the inflammatory response and may lead to tissue damage. The production of high levels of ROS in inflammatory lung diseases can induce the phosphorylation of mitogen-activated protein kinases, the inactivation of phosphoinositide 3-kinase (PI3K) signaling and histone deacetylase 2, a decrease in glucocorticoid binding to its receptor, and thus resistance to glucocorticoid treatment. Hence, antioxidant treatment might be a therapeutic option for inflammatory lung diseases. Preclinical studies have shown that antioxidants (alone or combined with anti-inflammatory drugs) are effective in the treatment of inflammatory lung diseases, although the clinical evidence of efficacy is weaker. Despite the high level of evidence for the efficacy of antioxidants in the treatment of inflammatory lung diseases, the discovery and clinical investigation of safer, more efficacious compounds are now a priority.

Synergy Effects of Metformin and Berberine on Glyoxal-induced Carbonyl Stress in Isolated Rat Liver Mitochondria

Objective:

Carbonyl stress, resulting from toxic effects of alpha-dicarbonyls such as glyoxal (GO), plays an important role in mitochondrial dysfunction and subsequent development of diabetic complications. This study evaluated the ability of metformin (MET), berberine (BBR), and their combination to prevent GO-induced carbonyl stress in isolated rat liver mitochondria.

Methods:

Mitochondria (0.5 mg protein/mL) were isolated from the Wistar rat liver and incubated with various concentrations of GO (1, 2.5, 5, 7.5, and 10 mM) for 30 minutes and IC50 for GO was calculated. The suspensions of mitochondria were incubated with various concentrations of MET (2.5, 5, 10, and 20 mM) or BBR (2.5, 5, 10, and 20 μM) for 30 min and then GO in a dose of IC50 at 37 ºC for 30 min. Mitochondrial complex II activity, mitochondrial membrane potential (MMP), MDA level, reactive oxygen species (ROS) formation, reduced glutathione (GSH) content, and protein carbonylation were assessed. The combination index and isobologram of MET and BBR on GO toxicity were calculated.

Results:

IC50 of GO was assigned approximately 3 mM. GO disrupted the electron transfer chain and significantly increased mitochondrial ROS formation, protein carbonylation, and MDA level. GO decreased mitochondrial viability, MMP, and GSH content. Pre-treatment with MET and BBR could potentially reverse GO-induced deleterious effects in a concentration-dependent manner. Results of the drug combination indicated that CI for Fa 0.5 (Effect 50 %) was 0.83.

Conclusion:

These results suggest that BBR in combination with MET has a moderate synergistic effect on GO-induced carbonyl stress in isolated rat liver mitochondria.

Resveratrol: Change of SIRT 1 and AMPK signaling pattern during the aging process

One of the causes for aging is free radical damage. Resveratrol (RSV), a polyphenolic compound has been shown to act as an antioxidant and anti-inflammatory. The objective this study was to verify in an oxidative stress environment in Human Mononuclear cells from Middle aged and Elderly donors, the existence of a change in the SIRT1 and AMPK signaling pattern by RSV. In both age groups there was a reduction in reactive oxygen species (ROS) in cells stimulated with RSV. It was observed that in the Elderly group there was a higher production of ROS and that the reduction from RSV was smaller compared to the other group. There was an increased activity of Superoxide Dismutase in cells exposed to RSV in the elderly group. It was observed that for the Middle Aged group, SIRT 1 and AMPK are antioxidant pathways and RSV acts via SIRT1. In the elderly, the SIRT1 remains antioxidant and RSV ceases its operation via SIRT1. RSV has an antioxidant action in both age groups, and that in aging there was a change in the cellular context characterized by the silencing of the AMPK pathway antioxidant character.

A versatile EPR toolbox for the simultaneous measurement of oxygen consumption and superoxide production

In this paper, we describe an assay to analyze simultaneously the oxygen consumption rate (OCR) and superoxide production in a biological system. The analytical set-up uses electron paramagnetic resonance (EPR) spectroscopy with two different isotopically-labelled sensors: ¹⁵N-PDT (4-oxo-2,2,6,6-tetramethylpiperidine-d₁₆-¹⁵N-1-oxyl) as oxygen-sensing probe and ¹⁴N-CMH (1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine, a cyclic hydroxylamine, as sensor of reactive oxygen species (ROS). The superoxide contribution to CMH oxidation is assessed using SOD or PEGSOD as controls. Because the EPR spectra are not superimposable, the variation of EPR linewidth of ¹⁵N-PDT (linked to OCR) and the formation of the nitroxide from ¹⁴N-CMH (linked to superoxide production) can be recorded simultaneously over time on a single preparation. The EPR toolbox was qualified in biological systems of increasing complexity. First, we used an enzymatic assay based on the hypoxanthine (HX)/xanthine oxidase (XO) which is a well described model of oxygen consumption and superoxide production. Second, we used a cellular model of superoxide production using macrophages exposed to phorbol 12-myristate 13-acetate (PMA) which stimulates the NADPH oxidase (NOX) to consume oxygen and produce superoxide. Finally, we exposed isolated mitochondria to established inhibitors of the electron transport chain (rotenone and metformin) in order to assess their impact on OCR and superoxide production. This EPR toolbox has the potential to screen the effect of intoxicants or drugs targeting the mitochondrial function.

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OCR and superoxide production are crucial to assess mitochondrial (dys)function.

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The EPR toolbox analyzes simultaneously the OCR and superoxide production.

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The EPR toolbox was validated in enzymatic system, cells and isolated mitochondria.

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The EPR toolbox has the potential to screen compounds altering mitochondrial function.

Metformin partially reverses the inhibitory effect of co-culture with ER-/PR-/HER2+ breast cancer cells on biomarkers of monocyte antitumor activity

BACKGROUND

Immune activities of monocytes (MOs) can be altered within the microenvironment of solid malignancies, including breast cancer. Metformin (1,1-dimethylbiguanide hydrochloride, MET), has been shown to decrease tumor cell proliferation, but its effects have yet to be explored with respect to MOs (monocytes) activity during their crosstalk with breast cancer cells. Here, we investigated the effects of MET on overall phenotypic functional activities, including cellular immunometabolism and protective redox signaling based-biomarkers, intracellular free calcium ions (ifCa2+), phagocytosis and co-operative cytokines (IFN-γ and IL-10) of autologous MOs before and during their interplay with primary ER-/PR-/HER2+ breast cancer cells.

METHODS

Human primary breast cancer cells were either cultured alone or co-cultured with autologous MOs before treatment with MET.

RESULTS

MET downregulated breast cancer cell proliferation and phagocytosis, while having no significant effect on the ratio of phosphorylated Akt (p-Akt) to total Akt. Additionally, we observed that, in the absence of MET treatment, the levels of lactate dehydrogenase (LDH)-based cytotoxicity, catalase, ifCa2+, IL-10 and arginase activity were significantly reduced in co-cultures compared to levels in MOs cultured alone whereas levels of inducible nitric oxide synthase (iNOS) activity were significantly increased. In contrast, MET treatment reduced the effects measured in co-culture on the levels of LDH-based cytotoxicity, arginase activity, catalase, ifCa2+, and IFN-γ. MET also induced upregulation of both iNOS and arginase in MO cells, although the increase did not reach significant difference for iNOS activity. Moreover, MET induced a robust increase of superoxide dismutase (SOD) activity in MOs, but not in MOs co-cultured with breast cancer cells. Furthermore, MET markedly upregulated the levels of IFN-γ production and downregulated those of IL-10 in isolated MOs, while inducing a slight opposing up-regulation of IL-10 production in co-cultures.

CONCLUSIONS

Our results show that the biomarkers of phenotypic functional activities of MOs are modified after co-culturing with primary human breast cancer cells. Treatment of co-cultures with MET resulted in increased release of antitumor cytokine IFN-γ and ifCa2+, and increased cell necrosis during breast cancer cells-MOs crosstalk.

Systemic Oxidative Stress and Visceral Adipose Tissue Mediators of NLRP3 Inflammasome and Autophagy Are Reduced in Obese Type 2 Diabetic Patients Treated with Metformin

Obesity is a low-grade inflammatory condition affecting a range of individuals, from metabolically healthy obese (MHO) subjects to type 2 diabetes (T2D) patients. Metformin has been shown to display anti-inflammatory properties, though the underlying molecular mechanisms are unclear. To study whether the effects of metformin are mediated by changes in the inflammasome complex and autophagy in visceral adipose tissue (VAT) of obese patients, a biopsy of VAT was obtained from a total of 68 obese patients undergoing gastric bypass surgery. The patients were clustered into two groups: MHO patients and T2D patients treated with metformin. Patients treated with metformin showed decreased levels of all analyzed serum pro-inflammatory markers (TNFα, IL6, IL1β and MCP1) and a downwards trend in IL18 levels associated with a lower production of oxidative stress markers in leukocytes (mitochondrial ROS and myeloperoxidase (MPO)). A reduction in protein levels of MCP1, NFκB, NLRP3, ASC, ATG5, Beclin1 and CHOP and an increase in p62 were also observed in the VAT of the diabetic group. This downregulation of both the NLRP3 inflammasome and autophagy in VAT may be associated with the improved inflammatory profile and leukocyte homeostasis seen in obese T2D patients treated with metformin with respect to MHO subjects and endorses the cardiometabolic protective effect of this drug.

Metformin protects against diabetes-induced heart injury and dunning prostate cancer model

In this study, both diabetes and Dunning prostate cancer were induced for the first time in Copenhagen rats in vivo. Thus, the effects of metformin against heart tissue damage of these rats were investigated by biochemical methods. Dunning prostate cancer was induced in Copenhagen rats using high metastatic MAT-LyLu cells. The rats were divided as follows: Control group: only injected with 0.9% NaCl for 14 days; Diabetic group: only injected single dose of streptozotocin (STZ) (65 mg/kg); Cancer group: subcutaneously (s.c) inoculated with 2 x 10⁴ MAT-LyLu cells only; Diabetic + cancer (DC) group: inoculated with 2 x 10⁴ MAT-LyLu cells and STZ injection, Cancer + metformin (CM) group: injected with metformin for 14 days after Mat-LyLu cells application; Diabetic + cancer + metformin (DCM) group: metformin administered for 14 days together with STZ and Mat-LyLu cells. At the end of the experimental period, heart tissues were taken. Reduced glutathione and total antioxidant status levels in heart tissues were decreased, whereas lipid peroxidation, advanced oxidized protein products, nitric oxide, homocysteine, and reactive oxygen species levels, total oxidant status and catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and xanthine oxidase activities increased in the diabetic, cancer and DC groups. Treatment with metformin reversed these effects. In conclusion, the present study shows that metformin has a protective effect against heart tissue damage in STZ-induced diabetic rats with Dunning prostate cancer.

Metformin Ameliorates Oxidative Stress Induced by Diabetes Mellitus and Hepatocellular Carcinoma in Rats

Background

Several studies have found an association between Diabetes mellitus (DM) and an increased risk for hepatocellular carcinoma (HCC). Evidence suggests that Metformin (Met) may have a therapeutic and protective effect against both DM and HCC. Therefore, the aim of this study was to evaluate the antioxidant effect of Met against DM and HCC-induced oxidative stress in rat model.

Methods

Forty-two male albino rats were randomly divided into six groups. Group 1 (Gp1) was the control group, Gp2 received an intraperitoneal (i.p.) injection with streptozotocin (STZ), Gp3 was injected i.p. with diethyl nitrosamine (DEN), Gp4 received an oral administration of Met, Gp5 and Gp6 received the same injections as Gp2 and Gp3, respectively, then received an additional injection of Met. Oxidative stress biomarkers, including superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and malondialdehyde (MDA), were examined. Furthermore, biochemical parameters including liver function tests were assessed. Histopathological and immunohistochemical alterations of the liver were also examined.

Results

Our results demonstrate that Gp2 and Gp3 had significant signs of liver dysfunction and had elevated levels of MDA and reduced levels of SOD, CAT, and GSH. Additionally, Gp2 and Gp3 showed significant alterations in the liver architecture shown by high PCNA and caspase-3 expression. In the Gp5 and Gp6, treatment with Met showed an improvement in liver function, oxidative stress biomarkers, and reduced histopathological changes in hepatocytes.

Conclusion

This study offers insight into the potential for Metformin as a novel therapeutic against the oxidative stress induced by DM or HCC.

Exenatide ameliorates experimental non-alcoholic fatty liver in rats via suppression of toll-like receptor 4/NFκB signaling: Comparison to metformin

AIMS

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease. This study aimed to evaluate the role of exenatide compared with metformin in halting the progression of fatty liver stimulated by a high-fat diet (HiFD) in rats.

MAIN METHODS

Thirty male Wistar rats were allocated into 6 groups, 5 rats per each group. Group I: maintained on normal diet (normal group) for fourteen weeks. The other five groups were kept on HiFD throughout the experiment, HiFD was administered beside pharmacological treatments/or vehicle. Group II: (NAFLD control group), group III: received metformin (60 mg/kg/day, P.O.), group IV-VI: received exenatide (10, 20, and 40 μg/kg/day, S.C.) respectively for 7 weeks. At the end of the therapeutic period, fasting blood glucose was determined, and body weight was registered. Rats were sacrificed, and blood samples were taken to measure serum insulin, lipids, and liver enzymes. The liver index and homeostasis model of insulin resistance (HOMA-IR) index were calculated. Further, livers were dissected for histopathological examination and Western blot analysis.

KEY FINDINGS

NAFLD control group showed hyperglycemia, hyperinsulinemia, increased liver enzymes, hypertriglyceridemia, elevated hepatic lipid peroxides, and inflammatory mediators (interlukin 6, nuclear factor-κB, tumor necrosis factor-α and Toll-like receptor4) in addition to hepatic fatty degeneration. In a dose-dependent manner, exenatide significantly improved most of the above mentioned markers in comparsion with NAFLD at P≤0.05.

SIGNIFICANCE

The current results suggest that exenatide is equivalent to metformin in controlling insulin resistance, body weight gain, improving liver function, suppressing inflammation, and attenuating NAFLD progression in male rats.

Gamma-hexalactone flavoring causes DNA lesion and modulates cytokines secretion at non-cytotoxic concentrations

BACKGROUND

The γ-hexalactone is a flavoring agent for alcoholic beverages, teas, breads, dairy products, coffees, buttery products among others. It presents low molecular weight and exhibits sweet fruity aroma with nuances of nuts. As far as we know, both literature and government regulations have gaps regarding the safe use of the γ-hexalactone. In this context, the main objective of this work was to evaluate the effects of γ-hexalactone through in silico and in vitro approaches.

METHODS

The in silico analysis was performed through four free online platforms (admetSAR, Osiris Property Explorer^®, pkCSM platform and PreADMET) and consisted of comparative structural analysis with substances present in databases. The computational prediction was performed in the sense of complement and guide the in vitro tests. Regarding in vitro investigations, screening of cytotoxicity (assessed by cell proliferation and viability parameters) in lymphocytes exposed to γ-hexalactone for 72 h were carried out previously to determine non-cytotoxic concentrations. Following this screening, concentrations of 5.15, 0.515, and 0.0515 μM were selected for the study of the respective potentials: genotoxic (assessed by DNA comet assay), chromosomal mutation (analysis of micronucleus frequency) and immunomodulatory (cytokine quantification using ELISA immunoassay). The results of in vitro assays were compared by one-way analysis of variance (ANOVA), followed by Bonferroni's post hoc test, conducted by statistic software.

RESULTS

The platform PreADMET pointed out that γ-hexalactone is potentially mutagenic and carcinogenic. The comet assay data corroborate with these results demonstrating that γ-hexalactone at 5.15 μM caused lymphocytes DNA damage. In relation to cytokine secretion, the results indicate that lymphocytes were activated by γ-hexalactone at non-cytotoxic concentrations, involving an increase in the IL-1 levels in all tested concentrations, ranging from approximately 56 to 93%. The γ-hexalactone only at 5.15 μM induced increase in the levels of IL-6 (~ 60%), TNF-α (~ 68%) and IFN-γ (~ 29%), but decreased IL-10 (~ 46%) in comparison with the negative control (p < 0.05). No change was observed in total lymphocytes or in cell viability at the concentrations tested.

CONCLUSIONS

In summary, the γ-hexalactone demonstrated immunomodulatory and genotoxic effects at non-cytotoxic concentrations in healthy lymphocytes.

Understanding the glucoregulatory mechanisms of metformin in type 2 diabetes mellitus

Despite its position as the first-line drug for treatment of type 2 diabetes mellitus, the mechanisms underlying the plasma glucose level-lowering effects of metformin (1,1-dimethylbiguanide) still remain incompletely understood. Metformin is thought to exert its primary antidiabetic action through the suppression of hepatic glucose production. In addition, the discovery that metformin inhibits the mitochondrial respiratory chain complex 1 has placed energy metabolism and activation of AMP-activated protein kinase (AMPK) at the centre of its proposed mechanism of action. However, the role of AMPK has been challenged and might only account for indirect changes in hepatic insulin sensitivity. Various mechanisms involving alterations in cellular energy charge, AMP-mediated inhibition of adenylate cyclase or fructose-1,6-bisphosphatase 1 and modulation of the cellular redox state through direct inhibition of mitochondrial glycerol-3-phosphate dehydrogenase have been proposed for the acute inhibition of gluconeogenesis by metformin. Emerging evidence suggests that metformin could improve obesity-induced meta-inflammation via direct and indirect effects on tissue-resident immune cells in metabolic organs (that is, adipose tissue, the gastrointestinal tract and the liver). Furthermore, the gastrointestinal tract also has a major role in metformin action through modulation of glucose-lowering hormone glucagon-like peptide 1 and the intestinal bile acid pool and alterations in gut microbiota composition.

Resveratrol Improves Boar Sperm Quality via 5'AMP-Activated Protein Kinase Activation during Cryopreservation

Mammalian sperm is highly susceptible to the reactive oxygen species (ROS) stress caused by biochemical and physical modifications during the cryopreservation process. 5′AMP-activated protein kinase (AMPK) is involved in regulating both cell metabolism and cellular redox status. The aim of the present study was to investigate whether the resveratrol protects boar sperm against ROS stress via activation of AMPK during cryopreservation. Boar sperm was diluted with the freezing medium supplemented with resveratrol at different concentrations (0, 25, 50, 75, 100, and 125 μM). It was observed that the addition of 50 μM resveratrol significantly improved the postthaw sperm progressive motility, membrane integrity, acrosome integrity, mitochondrial activity, glutathione (GSH) level, activities of enzymatic antioxidants (glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase), and the phosphorylation of AMPK. Meanwhile, the lipid peroxidation, ROS levels, and apoptosis of postthaw sperm were reduced in the presence of 50 μM resveratrol. Furthermore, when fresh boar sperm was incubated with the medium in the presence of 50 μM resveratrol and 30 μM Compound C (an AMPK inhibitor), the effects of the resveratrol were partly counteracted by the Compound C. These observations suggest that the resveratrol protects boar sperm via promoting AMPK phosphorylation. In conclusion, the addition of resveratrol to the freezing extenders protects boar sperm against ROS damage via promoting AMPK phosphorylation for decreasing the ROS production and improving the antioxidative defense system of postthaw sperm. These findings provide novel insights into understanding the mechanisms of resveratrol on how to protect boar sperm quality contrary to the ROS production during cryopreservation.

Metformin ameliorates acetaminophen-induced sub-acute toxicity via antioxidant property

Acetaminophen or N-acetyl-p-amino-phenol (APAP) is a drug which is available over-the-counter for fever and pain. Its overdosing causes oxidative stress and subsequent acute liver damage. In the present study, we scrutinized the protective effect of metformin co-treatment in APAP induced blood and liver sub-acute toxicity. This is a pre-clinical study in which male Wistar Rats (BW: 300 ± 20 g) were orally co-treated with APAP (1 g/kg/day) and metformin (300 mg/kg/day) for 28-days. Pro- and anti-oxidant markers viz reactive oxygen species, protein carbonyl, malondialdehyde (MDA), the ferric reducing ability of plasma (FRAP), plasma membrane redox system(PMRS) and reduced glutathione (GSH) were evaluated in blood. Additionally, in liver tissue, catalase (CAT), superoxide dismutase (SOD), MDA and GST level were also evaluated. Histological study and estimation of alanine aminotransferase (ALT), and aspartate aminotransferase (AST) level in serum were performed. APAP induces pro-oxidant markers as well as reduces anti-oxidant markers in blood and liver. Hepatic tissues degeneration and vacuolization of hepatocytes were evident after APAP treatment. Metformin treatment reduces pro-oxidant markers as well as increases anti-oxidant markers in both tissues. It also improves liver tissue architecture after treatment. The outcome of this study suggests that metformin has protective capability against APAP-induced blood and liver toxicity. Thus, metformin co-treatment with APAP attenuates oxidative stress and its consequences.

Effects of guanylurea, the transformation product of the antidiabetic drug metformin, on the health of brown trout (Salmo trutta f. fario)

Background

Guanylurea is the main transformation product of the antidiabetic drug metformin, which is one of the most prescribed pharmaceuticals worldwide. Due to the high rate of microbial degradation of metformin in sewage treatment plants, guanylurea occurs in higher concentrations in surface waters than its parent compound and could therefore affect aquatic wildlife. In this context, data for fish are scarce up to now which made us investigate the health of brown trout (Salmo trutta f. fario) in response to guanylurea.

Methods

In two experiments, eggs plus developing larvae and juvenile brown trout were exposed to three different concentrations of guanylurea (10, 100 and 1,000 µg/L) and, as a negative control, filtered tap water without this compound. Low internal concentrations were determined. The investigated parameters were mortality, length, weight, condition factor, tissue integrity of the liver and kidney, levels of stress proteins and lipid peroxides, as well as behavioural and developmental endpoints. It was found that guanylurea did not significantly change any of these parameters in the tested concentration range.

Results

In conclusion, these results do not give rise to concern that guanylurea could negatively affect the health or the development of brown trout under field conditions. Nevertheless, more studies focusing on further parameters and other species are highly needed for a more profound environmental risk assessment of guanylurea.

Combination of metformin with sodium selenite induces a functional phenotypic switch of human GM-CSF monocyte-derived macrophages

OBJECTIVES

We evaluated the effects of metformin (Met, 1,1‑dimethylbiguanide hydrochloride) combined or not with sodium selenite (Ss, Na₂SeO₃) on the functional activities of LPS-activated GM-CSF monocyte-derived macrophages (GM-MDM).

MATERIALS AND METHODS

Human GM-MDMs from three healthy donors were treated with Met or Ss alone, or with the combination of Met and Ss, and assayed for various biological activities and cytokines expression.

RESULTS

Met alone and Ss alone had significantly different effects on phagocytosis and killing capacities and IL-β production, but had similar effects on the downregulation of inducible nitric oxide synthase (iNOS) activity, relative nicotinamide adenine dinucleotide reduced (NADH) dehydrogenase (Complex I), intracellular free calcium ions (_ifCa²⁺), and on the upregulation of arginase activity. Additionally, iNOS activity-to-arginase activity ratio was downregulated in Met or Ss treated-GM-MDMs, and, conversely, upregulated in GM-MDMs treated with Met + Ss in combination, indicating that arginase activity dominates that of iNOS when the two treatments are associated. Moreover, combination of Met with Ss significantly upregulated hydrogen peroxide (H₂O₂) production and phagocytic capacity, but significantly downregulated the production of IL-1β, iNOS activity and killing capacity. On the contrary, we show that Met alone induced significant downregulation of phagocytic capacity and slight upregulation of killing capacity. Nevertheless, Ss seems to accentuate the effect of Met on the downregulation of NO production, as well as to reverse its effect on both phagocytic and killing capacities. On the other hand, all treatments induced a sharp decrease in relative levels of NADH dehydrogenase, and a marked decrease in the levels of _ifCa²⁺. Finally, we found that GM-MDMs treated with Met or Ss, or Met combined with Ss exhibited different functional activation phenotypes, as indicated by the surface expression of co-stimulatory and cell activation and presentation molecules CD14, CD80, CD86 and HLA-DR.

CONCLUSIONS

Our results demonstrated that Met/Ss combination can play an important role in the modulation of functional activities of human LPS-activated GM-MDMs. Additionally, the overall effects of Met and the induction of "M2" GM-MDMs-associated arginase could be influenced by its combination with Ss.

Low-Dose Tacrolimus Prevents Dysregulated Peri-Conceptional Ovarian and Systemic Immune Cellular Homeostasis in Subjects with PCOS

Polycystic ovary syndrome (PCOS) is characterized by failure of ovulation and is associated with obesity and chronic inflammation. Recent evidence suggests that anomalous activation of ovarian macrophages and numerical and functional deficits in the Th17 (CD4+IL17A+) and the CD4+CD25+CD127^low Tregs plays crucial role in PCOS. We have shown that the pre-pregnancy use of tacrolimus prevents adverse reproductive outcomes in a mouse model of PCOS. Here we used the HFD-NONcNZO mice to test a hypothesized beneficial use of tacrolimus relative to metformin in favorably influencing the ovarian and systemic immune milieux conducive to gestational success in subjects with PCOS. Compared to normative controls, our data revealed an aberrant peri-conceptional suppression of the CD4⁺CD25⁺CD127^low Tregs together with an overexpression of the Th17 T cells and lack of coordinated activation of ovarian macrophages in untreated HFD-dNONcNZO mice. Significant variances in treatment outcomes favoured the use of tacrolimus over metformin in treated mice. Consistent with the human fertility studies, this investigation reveals a beneficial systemic use of tacrolimus (0.1 mg/kg) in promoting early pregnancy in individuals with PCOS and suggests the need for further research into the selective inhibition of IL17A as a plausibly alternative immunotherapeutic approach in the clinical management of infertile individuals with PCOS.

Metformin as a Radiation Modifier; Implications to Normal Tissue Protection and Tumor Sensitization

BACKGROUND

Nowadays, ionizing radiation is used for several applications in medicine, industry, agriculture, and nuclear power generation. Besides the beneficial roles of ionizing radiation, there are some concerns about accidental exposure to radioactive sources. The threat posed by its use in terrorism is of global concern. Furthermore, there are several side effects to normal organs for patients who had undergone radiation treatment for cancer. Hence, the modulation of radiation response in normal tissues was one of the most important aims of radiobiology. Although, so far, several agents have been investigated for protection and mitigation of radiation injury. Agents such as amifostine may lead to severe toxicity, while others may interfere with radiation therapy outcomes as a result of tumor protection. Metformin is a natural agent that is well known as an antidiabetic drug. It has shown some antioxidant effects and enhances DNA repair capacity, thereby ameliorating cell death following exposure to radiation. Moreover, through targeting endogenous ROS production within cells, it can mitigate radiation injury. This could potentially make it an effective radiation countermeasure. In contrast to other radioprotectors, metformin has shown modulatory effects through induction of several genes such as AMPK, which suppresses reduction/ oxidation (redox) reactions, protects cells from accumulation of unrepaired DNA, and attenuates initiation of inflammation as well as fibrotic pathways. Interestingly, these properties of metformin can sensitize cancer cells to radiotherapy.

CONCLUSION

In this article, we aimed to review the interesting properties of metformin such as radioprotection, radiomitigation and radiosensitization, which could make it an interesting adjuvant for clinical radiotherapy, as well as an interesting candidate for mitigation of radiation injury after a radiation disaster.

Reactive oxygen species (ROS) in macrophage activation and function in diabetes

In a diabetic milieu high levels of reactive oxygen species (ROS) are induced. This contributes to the vascular complications of diabetes. Recent studies have shown that ROS formation is exacerbated in diabetic monocytes and macrophages due to a glycolytic metabolic shift. Macrophages are important players in the progression of diabetes and promote inflammation through the release of pro-inflammatory cytokines and proteases. Because ROS is an important mediator for the activation of pro-inflammatory signaling pathways, obesity and hyperglycemia-induced ROS production may favor induction of M1-like pro-inflammatory macrophages during diabetes onset and progression. ROS induces MAPK, STAT1, STAT6 and NFκB signaling, and interferes with macrophage differentiation via epigenetic (re)programming. Therefore, a comprehensive understanding of the impact of ROS on macrophage phenotype and function is needed in order to improve treatment of diabetes and its vascular complications. In the current comprehensive review, we dissect the role of ROS in macrophage polarization, and analyze how ROS production links metabolism and inflammation in diabetes and its complications. Finally, we discuss the contribution of ROS to the crosstalk between macrophages and endothelial cells in diabetic complications.

Role of Adaptive and Innate Immunity in Type 2 Diabetes Mellitus

After the recognition of the essential role of the immune system in the progression of type 2 diabetes mellitus, more studies are focused on the effects produced by the abnormal differentiation of components of the immune system. In patients suffering from obesity or T2DM, there were alterations in proliferation of T cells and macrophages, and impairment in function of NK cells and B cells, which represented abnormal innate and adaptive immunity. The abnormality of either innate immunity, adaptive immunity, or both was involved and interacted with each other during the progression of T2DM. Although previous studies have revealed the functional involvement of T cells in T2DM, and the regulation of metabolism by the innate or adaptive immune system during the pathogenesis of T2DM, there has been a lack of literature reviewing the relevant role of adaptive and innate immunity in the progression of T2DM. Here, we will review their relevant roles, aiming to provide new thought for the development of immunotherapy in T2DM.

Metformin Protects Against Radiation-Induced Heart Injury and Attenuates the Upregulation of Dual Oxidase Genes Following Rat's Chest Irradiation

Radiation-induced heart toxicity is one of the serious side effects after a radiation disaster or radiotherapy for patients with chest cancers, leading to a reduction in the quality of life of the patients. Evidence has shown that infiltration of inflammatory cells plays a key role in the development of functional damages to the heart via chronic upregulation of some pro-fibrotic and pro-inflammatory cytokines. These changes are associated with continuous free radical production and increased stiffness of heart muscle. IL-4 and IL-13 are two important pro-fibrotic cytokines which contribute to the side effects of ionizing radiation exposure. Recent studies have proposed that IL-4 through upregulation of DUOX2, and IL-13 via stimulation of DUOX1 gene expression, are involved in the development of radiation late effects. In the present study, we aimed to detect changes in the expression of these pathways following irradiation of rat’s heart. Furthermore, we evaluated the possible protective effect of metformin on the development of these abnormal changes. 20 male rats were divided into 4 groups (control, radiation, metformin treated, metformin + radiation). These rats were irradiated with 15 Gy ⁶⁰Co gamma rays, and sacrificed after 10 weeks for evaluation of the changes in the expression of IL4R1, IL-13R2a, DUOX1 and DUOX2. In addition, the levels of IL-4 and IL-13 cytokines, as well as infiltration of macrophages and lymphocytes were detected. Results showed an upregulation of both DUOX1 and DUOX2 pathways in the presence of metformin, while the level of IL-13 did not show any significant change. This was associated with infiltration of macrophages and lymphocytes. Also, treatment with metformin could significantly attenuate accumulation of inflammatory cells, and upregulate these pathways. Therefore, suppression of dual oxidase genes by metformin may be a contributory factor to its protective effect.

Effects of lipopolysaccharide (LPS) challenge on antioxidant capability of broiler chickens

This study was designed to investigate the effects of lipopolysaccharide (LPS) challenge on antioxidant capability (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX; and reduced glutathione to oxidized glutathione, GSH/GSSG) and induce the model of immunological stress in broiler chickens. Day-old, yellowfeathered broilers (140) were randomly assigned to 2 treatments with 7 replicates of 10 chicks each. At day 21, 23, 25 and 27, chicks were injected with LPS and blood samples were collected after 24 h. Chicks (2) from each replicate were killed, and liver and jejunum samples were collected. The activities and gene expression of SOD, CAT, and GPX, were determined. The results showed that LPS challenge reduced serum SOD at day 22 and 26, serum CAT at day 24, 26, and 28, and serum GPX at day 26. LPS challenge decreased liver SOD, liver GPX, liver GSH/GSSG ratio at day 26 and 28. LPS challenge also decreased jejunum SOD at day 26, and jejunum CAT, GPX and GSH/GSSG ratio at day 26 and 28.The expressions of liver CAT, liver GPX1, and jejunum SOD1 were down regulated at day 26. The expressions of jejunum CAT, and jejunum GPX1 were down regulated at day 26. Meanwhile, LPS reduced the expression of liver SOD1 at day 22 and the expression of jejunum GPX1 at day 28. In conclusion, three times of LPS challenge could result in serious oxidative damage and induce immune stress model.

Metabolic Effects of Metformin in the Failing Heart

Accumulating evidence shows that metformin is an insulin-sensitizing antidiabetic drug widely used in the treatment of type 2 diabetes mellitus (T2DM), which can exert favorable effects on cardiovascular risk and may be safely used in patients with heart failure (HF), and even able to reduce the incidence of HF and to reduce HF mortality. In failing hearts, metformin improves myocardial energy metabolic status through the activation of AMP (adenosine monophosphate)-activated protein kinase (AMPK) and the regulation of lipid and glucose metabolism. By increasing nitric oxide (NO) bioavailability, limiting interstitial fibrosis, reducing the deposition of advanced glycation end-products (AGEs), and inhibiting myocardial cell apoptosis metformin reduces cardiac remodeling and hypertrophy, and thereby preserves left ventricular systolic and diastolic functions. While a lot of preclinical and clinical studies showed the cardiovascular safety of metformin therapy in diabetic patients and HF, to confirm observed benefits, the specific large-scale trials configured for HF development in diabetic patients as a primary endpoints are necessary.

Potential effects of metformin in DNA BER system based on oxidative status in type 2 diabetes

Metformin is used to reduce hyperglycemia that induces energetic stress and leads to reduction in gluconeogenesis. Also, metformin inhibits complex I in oxidative phosphorylation, thereby decreasing cellular ATP levels. Activation of AMPK by the reduced ATP levels can induce inhibition of reactive oxygen species (ROS) production and activate p53-mediated DNA repair. DNA polymerase-β and XRCC1 function to repair DNA damages in the BER (base excision repair) system. In type 2 diabetes patients, metformin can enhance AMPK activation therefore suppress oxidative stress. The changes on oxidative stress may alter p53's function and effect many cellular pathways such as; DNA repair. In our project we aim to understand the effects of metformin on p53 and DNA-BER system based on the oxidative status in type 2 diabetes patients. Oxidative and antioxidative capacity, catalase, SOD, GPx activities and, DNA pol beta, XRCC1 and p53 levels were measured in metformin using or non-using type 2 diabetes patients and controls. Metformin enhanced SOD and GPx activities in type 2 diabetes patients but the reflection of this increase to the total antioxidant capacity was not significant. Although the increase in DNA pol beta was not significant, XRCC1 and p53 levels were significantly upregulated with metformin treatment in type 2 diabetes patients. Our study reinforces the potential benefit of metformin in antioxidative capacity to protect cells from diabetic oxidative stress and in regulation of DNA BER system.

Activating AMPK to Restore Tight Junction Assembly in Intestinal Epithelium and to Attenuate Experimental Colitis by Metformin

Adenosine monophosphate-activated protein kinase (AMPK), a crucial molecule in energy metabolism, is reported to play a potential role in gut epithelial differentiation and barrier function recently; however, its performance and mechanisms in the pathological process of inflammatory bowel diseases remain unidentified. In this study, we have found that the phosphorylation of AMPK in colonic tissues is negatively correlated with severity of disease during the initiation and development of experimental colitis induced by dextran sulfate sodium. Activation of AMPK by metformin significantly controls the progression of colitis, which is associated with the maintenance of tight junction in colonic epithelium in mice. Moreover, our in vitro data in colonic epithelial Caco2 cells shows that metformin promotes expression and assembly of tight junctions via an AMPK-dependent way. Overall, our results suggested that activating AMPK by a clinically safe drug metformin could be a beneficial choice for colitis treatment.

Comparative effect of melatonin and quercetin in counteracting LPS induced oxidative stress in bone marrow mononuclear cells and spleen of Funambulus pennanti

A majority of cellular diseases, independent of their origin, are characterized by a dramatic increase in Reactive Oxygen Species (ROS) in response to stress. In most cases, the uncontrolled detrimental ROS outburst is difficult to handle for the cellular machinery and eventually leads to cell mortality. In this study, we compare the antioxidant efficacy of quercetin and melatonin to find out a better alternative against lipopolysaccharide (LPS) induced tissue injury by oxidative stress in Funambulus pennanti. Transient exposure to LPS significantly increased ROS generation and lipid peroxidation levels in bone marrow mononuclear cells (MNCs) and spleen which was further corroborated by decreased activities of SOD, CAT and Gpx enzymes. It also downregulate the expression of cellular oxidative stress response proteins Nrf-2 and HO-1 in spleen and decreases the proliferation of bone marrow derived Granulocyte macrophage-colony forming unit cells (GM-CFU). Both melatonin and quercetin pre-treatments rescued these effects, however, our results indicated that the efficacy of melatonin to overcome oxidative stress was significantly better than quercetin. Our findings support the idea that melatonin is a better antioxidant and immunomodulator as compared to other alternatives and perhaps may be employed in the development of effective therapeutics against ROS dominated diseases.

Glutathione metabolism in type 2 diabetes and its relationship with microvascular complications and glycemia

Aims/Hypotheses

We hypothesized that there is decreased synthesis of glutathione (GSH) in type 2 diabetes (T2DM) especially in the presence of microvascular complications, and this is dependent on the degree of hyperglycemia.

Methods

In this case-control study, we recruited 16 patients with T2DM (7 without and 9 with microvascular complications), and 8 age- and sex-matched non-diabetic controls. We measured GSH synthesis rate using an infusion of [²H₂]-glycine as isotopic tracer and collection of blood samples for liquid chromatography mass spectrometric analysis.

Results

Compared to the controls, T2DM patients had lower erythrocyte GSH concentrations (0.90 ± 0.42 vs. 0.35 ± 0.30 mmol/L; P = 0.001) and absolute synthesis rates (1.03 ± 0.55 vs. 0.50 ± 0.69 mmol/L/day; P = 0.01), but not fractional synthesis rates (114 ± 45 vs. 143 ± 82%/day; P = 0.07). The magnitudes of changes in patients with complications were greater for both GSH concentrations and absolute synthesis rates (P-values ≤ 0.01) compared to controls. There were no differences in GSH concentrations and synthesis rates between T2DM patients with and without complications (P-values > 0.1). Fasting glucose and HbA1c did not correlate with GSH concentration or synthesis rates (P-values > 0.17).

Conclusions

Compared to non-diabetic controls, patients with T2DM have glutathione deficiency, especially if they have microvascular complications. This is probably due to reduced synthesis and increased irreversible utilization by non-glycemic mechanisms.

Recent novel approaches to limit oxidative stress and inflammation in diabetic complications

Diabetes is considered a major burden on the healthcare system of Western and non‐Western societies with the disease reaching epidemic proportions globally. Diabetic patients are highly susceptible to developing micro‐ and macrovascular complications, which contribute significantly to morbidity and mortality rates. Over the past decade, a plethora of research has demonstrated that oxidative stress and inflammation are intricately linked and significant drivers of these diabetic complications. Thus, the focus now has been towards specific mechanism‐based strategies that can target both oxidative stress and inflammatory pathways to improve the outcome of disease burden. This review will focus on the mechanisms that drive these diabetic complications and the feasibility of emerging new therapies to combat oxidative stress and inflammation in the diabetic milieu.

Glycaemic control in type 2 diabetic patients with chronic kidney disease: the impacts on enzymatic antioxidants and soluble RAGE

Background

Chronic kidney disease (CKD) is characterised by long-term kidney damage and renal function decline. Diabetic CKD is the principal subtype of kidney disease in Malaysia and is associated with oxidative stress which plays an important role in development and progression of the disease. Glycaemic control slows down the progression of diabetic complications, including diabetic CKD. However, the implication of glycaemic control on enzymatic antioxidants and soluble RAGE (sRAGE) in CKD patients remains elusive. The aim of this study was to investigate the effect of glycaemic control on the levels or activities of glutathione peroxidase (GPx), superoxide dismutase (SOD) and sRAGE in CKD patients.

Methods

A total of 150 CKD patients and 64 non-CKD patients were enrolled. The type 2 diabetic patients in the recruited study participants were categorised based on their glycaemic control; poor glycaemic control (GC) with haemoglobin A1c (HbA1c) > 7% and good GC with HbA1c ≤ 7%. The levels or activities of GPx, SOD and sRAGE in plasma were measured. These biochemical parameters were analysed using Mann-Whitney U test and two-way analysis of variance (ANOVA).

Results

The activities of GPx and SOD as well as plasma level of sRAGE were not significantly different among the CKD patients with varying glycaemic control status. Irrespective of diabetes status and glycaemic control status, CKD patients also exhibited lower plasma SOD activities compared with non-CKD patients. Among the non-CKD patients, SOD activities were significantly higher in diabetic patients with good GC than diabetic patients with poor GC. Two-way ANOVA revealed that both CKD status and glycaemic control had an interaction effect on SOD activities in diabetic subjects with and without CKD. Follow-up analysis showed that SOD activities were significantly higher in non-CKD patients with good GC. There were no overall significant differences in GPx activities among the study participants. Furthermore, plasma sRAGE levels were higher in diabetic patients with CKD than those without CKD, regardless of glycaemic control status. There were no interaction effects between CKD status and glycaemic control status on GPx and sRAGE. Instead, CKD status showed significant main effects on these parameters, indicating significant differences between diabetic subjects with CKD and diabetic subjects without CKD.

Conclusion

Glycaemic control did not quantitatively alter GPx, SOD and sRAGE in diabetic CKD patients. Despite the advantages of good glycaemic control, a well-controlled diabetes in CKD did not modulate the activities of enzymatic antioxidants and sRAGE levels, therefore may not be the primary mechanism to handle oxidative stress.