Metformin and ascorbic acid combination therapy ameliorates type 2 diabetes mellitus and comorbid depression in rats

Antioxidant Carbon Dots Nanozymes Alleviate Stress-induced Depression by Modulating Gut Microbiota

Depression is a debilitating mental illness that severely threatens millions of individuals and public health. Because of the multifactorial etiologies, there is currently no cure for depression; thus, it is urgently imperative to find alternative antidepressants and strategies. Growing evidence underscores the prominent role of oxidative stress as key pathological hallmarks of depression, making oxidative stress a potential therapeutic target. In this study, we report a N-doped carbon dot nanozyme (CDzyme) with excellent antioxidant capacity for treating depression by remodeling redox homeostasis and gut microbiota. The CDzymes prepared via microwave-assisted fast polymerization of histidine and glucose exhibit superior biocompatibility. Benefiting from the unique structure, CDzymes can provide abundant electrons, hydrogen atoms, and protons for reducing reactions, as well as catalytic sites to mimic redox enzymes. These mechanisms collaborating endow CDzymes with broad-spectrum antioxidant capacity to scavenge reactive oxygen and nitrogen species (•OH, O2-•, H2O2, ONOO-), and oxygen/nitrogen centered free radicals. A depression animal model was established by chronic unpredictable mild stress (CUMS) to evaluate the therapeutic efficacy of CDzymes from the behavioral, physiological, and biochemical index and intestinal flora assessments. CDzymes can remarkably improve depression-like behaviors and key neurotransmitters produced in hippocampus tissues and restore the gut microbiota compositions and the amino acid metabolic functions, proving the potential in treating depression through the intestinal-brain axis system. This study will facilitate the development of intestinal flora dysbiosis nanomedicines and treatment strategies for depression and other oxidative stress related multifactorial diseases.

Vitamin C Alleviates the Risk of Gestational Diabetes Mellitus Associated With Exposure to Metals

Background: Exposure to heavy metals has been suggested to increase the risk of gestational diabetes mellitus (GDM) through the oxidative stress pathway. The study is aimed at examining whether vitamin C could modify the association between exposure to heavy metals and risk of GDM. Methods: We conducted a case-control study in Taiyuan, China, with 776 GDM cases and 776 controls. Data on vitamin C intake from diet and supplements were collected through questionnaires. Concentrations of metals in participants' blood were measured using inductively coupled plasma-mass spectrometry (ICP-MS). Unconditional logistic regression models were applied to estimate effect modification of vitamin C on the association between heavy metals and GDM. Results: Women with higher blood levels of mercury (Hg) (odds ratio (OR) = 2.36, 95% confidence interval (CI): 1.43, 3.92 and 2.04, 95% CI: 1.20, 3.46 for the second and third vs. the first tertile) and arsenic (As) (OR = 2.46, 95% CI: 1.37, 4.43 and 2.16, 95% CI: 1.12, 4.17 for the second and third vs. the first tertile) exposure were associated with increased risk of GDM among women without vitamin C supplement use and having dietary vitamin C intake < 85 mg/day. We found no significant association with metals among women who took vitamin C supplements and/or dietary vitamin C ≥ 85 mg/day. Significant interactions were observed between vitamin C and exposures to metals (i.e., Hg and As) on the risk of GDM (P interaction = 0.048 and 0.045, respectively). Conclusions: Our study, for the first time, suggests that vitamin C supplement use or higher dietary vitamin C intake during preconception and early pregnancy could alleviate the risk of GDM associated with exposure to As and Hg. The results warrant further investigation.

Concomitant Effects of Metformin and Vitamin C on Indomethacin-Induced Gastric Ulcer in Rats: Biochemical and Histopathological Approach

INTRODUCTION

Gastric ulcer is one of the most common and serious conditions in the gastrointestinal tract. One of the main causes of gastric ulcers is using of non-steroidal anti-inflammatory drugs (NSAIDs) which have limited their use in clinical practice. Several studies have revealed that metformin and Vitamin C (Vit C) exhibit protective effects against gastric mucosal damage in different animal models. However, no studies indicate their combination's effect on gastric ulcer models. Therefore, this study aims to investigate the protective effects of metformin and Vit C combination on indomethacin-induced gastric ulcers.

MATERIAL AND METHODS

In total, thirty rats were divided into six groups, including the control group, rats received indomethacin (50 mg/kg, i.p.), rats received indomethacin and pretreated with ranitidine (100 mg/kg), metformin (100 mg/kg, i.p.), Vit C (100 mg/kg), or metformin combined with Vit C. Four hours after indomethacin administration, rats were euthanized, and gastric tissues were removed for macroscopic, histopathologic, and biochemical examinations.

RESULTS

All therapeutics used in this study were found to alleviate gastric mucosal injury caused by indomethacin, as observed in histopathologic and macroscopic evaluations. Both Vit C and metformin were observed to significantly decrease lipid peroxidation and enhance the activity of anti-oxidative enzymes, SOD, GPx, and catalase. However, a more significant effectiveness was observed in catalase and GPx activities when Vit C was co-administered with metformin.

CONCLUSIONS

In conclusion, the present study revealed that metformin and Vit C combination therapy could potentially treat gastric ulcers associated with indomethacin.

Environmental enrichment and the combined interventions of EE and metformin enhance hippocampal neuron survival and hippocampal-dependent memory in type 2 diabetic rats under stress through the BDNF-TrkB signaling pathways

BACKGROUND

Type 2 diabetes (T2D) with depression causes severe cognitive impairments. The devastating conditions will further compromise the overall quality of life. The overconsumption of high-fat and high-sucrose (HFS) diet is one of the modifiable risk factors for T2D, depression, and cognitive impairments. Thus, it is essential to identify effective therapeutic strategies to overcome the cognitive impairments in T2D with depression. We proposed environmental enrichment (EE) which encompasses social, cognitive, and physical components as the alternative treatment for such impairments. We also investigated the potential neuroprotective properties of the antidiabetic drug metformin. This study aimed to investigate the effects of EE and metformin interventions on hippocampal neuronal death, and hippocampal-dependent memory impairment in T2D rats under stress.

METHODS

Thirty-two male rats (200-250 g) were divided into four groups: C group (standard diet + conventional cage), DS group [HFS-induced T2D + restraint stress (RS)], DSE group [HFS-induced T2D + RS + EE] and DSEM group [HFS + RS + EE + metformin]. Serum corticosterone (CORT) was measured to evaluate stress levels. The serum Free Oxygen Radicals Testing (FORT) and Free Oxygen Radicals Defence Test (FORD) were measured to evaluate the systemic oxidative status (OS). Serum brain-derived neurotrophic factor (BDNF) and T-maze tasks were performed to evaluate cognitive functions. Rats were humanely sacrificed to collect brains for histological, morphometric, and hippocampal gene expression studies.

RESULTS

The CORT and the serum FORT levels in the DSE and DSEM groups were lower than in the DS group. Meanwhile, the serum BDNF, T-maze scores, histological, and morphometric analysis were improved in the DSE and DSEM groups than in the DS group. These findings supported that EE and the combined interventions of EE and metformin had neuroprotective properties. The hippocampal gene expression analysis revealed that the DSE and DSEM groups showed improved regulation of BDNF-TrkB signalling pathways, including the BDNF/TrkB binding, PI3K - Akt pathway, Ras-MAPK pathway, PLCγ-Ca2+ pathway, and CREB transcription.

CONCLUSION

EE and the combined interventions of EE and metformin improved hippocampal neuron survival and hippocampal-dependent memory in T2D rats under stress by enhancing gene expression regulation of neurogenesis and synaptic plasticity.

Emerging Perspectives on the Impact of Diabetes Mellitus and Anti-Diabetic Drugs on Premenstrual Syndrome. A Narrative Review

Diabetes mellitus (DM) and premenstrual syndrome (PMS) are global health challenges. Both disorders are often linked to a range of physical and psychological symptoms that significantly impact the quality of life of many women. Yet, the exact relation between DM and PMS is not clear, and the management of both conditions poses a considerable challenge. In this review, we aimed to investigate the interplay between DM, anti-diabetic drugs, and the different theories and symptoms of PMS. Female sex hormones are implicated in the pathophysiology of PMS and can also impair blood glucose control. In addition, patients with diabetes face a higher susceptibility to anxiety and depression disorders, with a significant number of patients experiencing symptoms such as fatigue and difficulty concentrating, which are reported in patients with PMS as well. Complications related to diabetic medications, such as hypoglycemia (with sulfonylurea) and fluid retention (with thiazolidinediones) may also mediate PMS-like symptoms. DM can, in addition, disturb the normal gut microbiota (GM), with a consequent loss of beneficial GM metabolites that guard against PMS, particularly the short-chain fatty acids and serotonin. Among the several available anti-diabetic drugs, those (1) with an anti-inflammatory potential, (2) that can preserve the beneficial GM, and (3) possessing a lower risk for hypoglycemia, might have a favorable outcome in PMS women. Yet, well-designed clinical trials are needed to investigate the anti-diabetic drug(s) of choice for patients with diabetes and PMS.

Possible role of metformin as an antidepressant in diabetes

OBJECTIVE

Metformin (MET) is a drug used in the treatment of type 2 diabetes due to its insulin receptor sensitizing properties and anti-hepatic gluconeogenesis effect. One of the comorbidities in diabetes is the depression. This review aimed at summarizing the results of the available MET, depression and diabetes studies to clarify the possible role of MET in the depression during diabetes.

METHODS

A bibliographic search on PubMed, Embase, PsycINFO, Web of Science, Cochrane Central for studies referring to MET, depression and diabetes.

RESULTS

Several studies have associated depression to the chronic inflammation that characterizes diabetes. Additionally MET is an anti-inflammatory molecule that generally acts by activating AMPK and inhibiting the NF-kB factor. In the context of diabetes, MET can act directly as an anti-inflammatory drug as well as inhibiting other pro-inflammatory molecules. In this regard, MET may inhibit the pro-inflammatory effects of angiotensin II. By facilitating the action of insulin and reducing hepatic gluconeogenesis, MET reduces circulating glucose levels, decreasing the formation of advanced glycation end products and therefore inflammation. During diabetes, the gut microbiota and the permeability of the intestinal barrier are altered, causing high levels of circulating lipopolysaccharides (LPS), which induce inflammation. MET can normalize the microbiota and the intestinal barrier permeability reducing the levels of LPS and inflammation. Clinical and experimental studies show the anti-depressant effect of MET mediated by different mechanisms both at the peripheral level and in the central nervous system.

CONCLUSION

Therefore, MET as an anti-inflammatory drug can decrease symptoms of depression and represents a therapeutic approach to improve the psychological state of patients with diabetes. Additionally, insulin also has an anti-inflammatory effect that could act together with MET.

Neurological and metabolic related pathophysiologies and treatment of comorbid diabetes with depression

BACKGROUND

The comorbidity between diabetes mellitus and depression was revealed, and diabetes mellitus increased the prevalence of depressive disorder, which ranked 13th in the leading causes of disability-adjusted life-years. Insulin resistance, which is common in diabetes mellitus, has increased the risk of depressive symptoms in both humans and animals. However, the mechanisms behind the comorbidity are multi-factorial and complicated. There is still no causal chain to explain the comorbidity exactly. Moreover, Selective serotonin reuptake inhibitors, insulin and metformin, which are recommended for treating diabetes mellitus-induced depression, were found to be a risk factor in some complications of diabetes.

AIMS

Given these problems, many researchers made remarkable efforts to analyze diabetes complicating depression from different aspects, including insulin resistance, stress and Hypothalamic-Pituitary-Adrenal axis, neurological system, oxidative stress, and inflammation. Drug therapy, such as Hydrogen Sulfide, Cannabidiol, Ascorbic Acid and Hesperidin, are conducive to alleviating diabetes mellitus and depression. Here, we reviewed the exact pathophysiology underlying the comorbidity between depressive disorder and diabetes mellitus and drug therapy.

METHODS

The review refers to the available literature in PubMed and Web of Science, searching critical terms related to diabetes mellitus, depression and drug therapy.

RESULTS

In this review, we found that brain structure and function, neurogenesis, brain-derived neurotrophic factor and glucose and lipid metabolism were involved in the pathophysiology of the comorbidity. Obesity might lead to diabetes mellitus and depression through reduced adiponectin and increased leptin and resistin. In addition, drug therapy displayed in this review could expand the region of potential therapy.

CONCLUSIONS

The review summarizes the mechanisms underlying the comorbidity. It also overviews drug therapy with anti-diabetic and anti-depressant effects.

Role of Inflammatory Mechanisms in Major Depressive Disorder: From Etiology to Potential Pharmacological Targets

The involvement of central and peripheral inflammation in the pathogenesis and prognosis of major depressive disorder (MDD) has been demonstrated. The increase of pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, IL-18, and TNF-α) in individuals with depression may elicit neuroinflammatory processes and peripheral inflammation, mechanisms that, in turn, can contribute to gut microbiota dysbiosis. Together, neuroinflammation and gut dysbiosis induce alterations in tryptophan metabolism, culminating in decreased serotonin synthesis, impairments in neuroplasticity-related mechanisms, and glutamate-mediated excitotoxicity. This review aims to highlight the inflammatory mechanisms (neuroinflammation, peripheral inflammation, and gut dysbiosis) involved in the pathophysiology of MDD and to explore novel anti-inflammatory therapeutic approaches for this psychiatric disturbance. Several lines of evidence have indicated that in addition to antidepressants, physical exercise, probiotics, and nutraceuticals (agmatine, ascorbic acid, and vitamin D) possess anti-inflammatory effects that may contribute to their antidepressant properties. Further studies are necessary to explore the therapeutic benefits of these alternative therapies for MDD.

Review of the direct and indirect effects of hyperglycemia on the HPA axis in T2DM and the co-occurrence of depression

Type 2 diabetes mellitus (T2DM) is characterized by persistent hyperglycemia which is further associated with hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. Several studies have shown that HPA axis hyperactivity is heightened in the chronic hyperglycemic state with severe hyperglycemic events more likely to result in a depressive disorder. The HPA axis is also regulated by the immune system. Upon stress, under homeostatic conditions, the immune system is activated via the sympatho-adrenal-medullary axis resulting in an immune response which secretes proinflammatory cytokines. These cytokines aid in the activation of the HPA axis during stress. However, in T2DM, where there is persistent hyperglycemia, the immune system is dysregulated resulting in the elevated concentrations of these cytokines. The HPA axis, already activated by the hyperglycemia, is further activated by the cytokines which all contribute to a diagnosis of depression in patients with T2DM. However, the onset of T2DM is often preceded by pre-diabetes, a reversible state of moderate hyperglycemia and insulin resistance. Complications often seen in T2DM have been reported to begin in the pre-diabetic state. While the current management strategies have been shown to ameliorate the moderate hyperglycemic state and decrease the risk of developing T2DM, research is necessary for clinical studies to profile these direct effects of moderate hyperglycemia in pre-diabetes on the HPA axis and the indirect effects moderate hyperglycemia may have on the HPA axis by investigating the components of the immune system that play a role in regulating this pathway.

The development and benefits of metformin in various diseases

Metformin has been used for the treatment of type II diabetes mellitus for decades due to its safety, low cost, and outstanding hypoglycemic effect clinically. The mechanisms underlying these benefits are complex and still not fully understood. Inhibition of mitochondrial respiratory-chain complex I is the most described downstream mechanism of metformin, leading to reduced ATP production and activation of AMP-activated protein kinase (AMPK). Meanwhile, many novel targets of metformin have been gradually discovered. In recent years, multiple pre-clinical and clinical studies are committed to extend the indications of metformin in addition to diabetes. Herein, we summarized the benefits of metformin in four types of diseases, including metabolic associated diseases, cancer, aging and age-related diseases, neurological disorders. We comprehensively discussed the pharmacokinetic properties and the mechanisms of action, treatment strategies, the clinical application, the potential risk of metformin in various diseases. This review provides a brief summary of the benefits and concerns of metformin, aiming to interest scientists to consider and explore the common and specific mechanisms and guiding for the further research. Although there have been countless studies of metformin, longitudinal research in each field is still much warranted.

Is metformin neuroprotective against diabetes mellitus-induced neurodegeneration? An updated graphical review of molecular basis

Diabetes mellitus (DM) is a metabolic disease that activates several molecular pathways involved in neurodegenerative disorders. Metformin, an anti-hyperglycemic drug used for treating DM, has the potential to exert a significant neuroprotective role against the detrimental effects of DM. This review discusses recent clinical and laboratory studies investigating the neuroprotective properties of metformin against DM-induced neurodegeneration and the roles of various molecular pathways, including mitochondrial dysfunction, oxidative stress, inflammation, apoptosis, and its related cascades. A literature search was conducted from January 2000 to December 2022 using multiple databases including Web of Science, Wiley, Springer, PubMed, Elsevier Science Direct, Google Scholar, the Core Collection, Scopus, and the Cochrane Library to collect and evaluate peer-reviewed literature regarding the neuroprotective role of metformin against DM-induced neurodegenerative events. The literature search supports the conclusion that metformin is neuroprotective against DM-induced neuronal cell degeneration in both peripheral and central nervous systems, and this effect is likely mediated via modulation of oxidative stress, inflammation, and cell death pathways.

Metformin attenuates depressive-like behaviour of methamphetamine withdrawal in mice: A mechanistic approach

OBJECTIVES

Methamphetamine (METH) as a potent psychostimulant drug with a high potency of dependence rate that results in neurotoxicity has become a major drug of abuse in many parts of the world. Unfortunately, there is limited evidence regarding treatment of METH withdrawal syndrome. Therefore, we aimed to investigate whether metformin mitigate the methamphetamine (METH) withdrawal syndrome in male mice. Based on the literature, depression and anxiety are the major METH withdrawal symptoms.

METHODS

Here, METH (2 mg/kg) was administered to mice twice a day for 14 constitutive days to induce animal model of METH-induced withdrawal syndrome. To do this, mice in control group and those with METH withdrawal syndrome were divided into treatment (receiving metformin in 3 doses of 50, 100 and 200 mg/kg for 10 days) and non-treatment sub-groups. Following the behavioural test, the animals were sacrificed; their hippocampus was dissected to measure oxidative stress parameters and expression of cellular energy homeostasis and immune-inflammatory genes.

RESULTS

Our data revealed that metformin provoked antidepressant effects in behavioural tests through AMPK overexpression as an important mitochondrial energetic sensor and inhibition of Tlr4 overexpression in the immune system gene expression. In addition, metformin was able to improve oxidative stress biomarkers and neuronal damage in the hippocampus and restore cellular energy homeostasis and immune system gene expression.

CONCLUSIONS

The data suggested that metformin can influence the hippocampus through targeting mitochondria and their performance, and consequently, neuroinflammation responses and brain metabolic changes. It is supposed to be a new therapeutic option in clinical trials of depression and anxiety following METH withdrawal treatment.

Effects of RF and ELF Radiation on Oxidative Stress of Brain Tissue and Plasma of Diabetic Rats

Objective: Exposure to Radio Frequency (RF) and Extremely Low Frequency (ELF) radiation is increasing steadily with the progress of technology and industrialization. The aim of this study was to investigate whether RF and ELF radiation are oxidative stress effects in the plasma and brain tissue of diabetic and non-diabetic rats. Methods: Experiment groups were designed as follows; C (control), S (sham), ELF (ELF radiation exposure), RF (RF radiation exposure), ELF+RF (ELF and RF radiation exposure), D-C (Diabetic Control), D-S (Diabetic Sham), D-ELF (Diabetic ELF), D-RF (Diabetic RF), D-ELF+RF (Diabetic ELF+RF). The experimental diabetes model was induced with a single dose of 65mg/kg streptozotocin (STZ). 2100 MHz RF and 50 Hz ELF radiation groups exposed for 1 month. Total nitric oxide (NOx), malondialdehyde (MDA) and total sulfhydryl groups (RSH) / glutathione (GSH) levels were measured in plasma and brain tissue. Results: RF + ELF radiation exposure caused an increase in NOx and MDA levels in plasma and brain tissue of diabetic and non-diabetic rats (p&lt;0.05). Exposure to RF and RF + ELF radiation caused a decrease in plasma RSH / tissue GSH levels in non-diabetic rats (p&lt;0.05). Conclusion: The most prominent effect was seen in the diabetic group with RF + ELF radiation exposure.

The potential antidepressant effect of antidiabetic agents: New insights from a pharmacovigilance study based on data from the reporting system databases FAERS and VigiBase

Background: Growing evidence supports a bidirectional association between diabetes and depression; promising but limited and conflicting data from human studies support the intriguing possibility that antidiabetic agents may be used to relieve effectively depressive symptoms in diabetic patients. We investigated the potential antidepressant effects of antidiabetic drugs in a high-scale population data from the two most important pharmacovigilance databases, i.e., the FDA Adverse Event Reporting System (FAERS) and the VigiBase. Material and methods: From the two primary cohorts of patients treated with antidepressants retrieved from FDA Adverse Event Reporting System and VigiBase we identified cases (depressed patients experiencing therapy failure) and non-cases (depressed patients experiencing any other adverse event). We then calculated the Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Empirical Bayes Geometric Mean (EBGM), and Empirical Bayes Regression-Adjusted Mean (ERAM) for cases versus non-cases in relation with the concurrent exposure to at least one of the following antidiabetic agent: A10BA Biguanides; A10BB Sulfonylureas; A10BG Thiazolidinediones; A10BH DPP4-inhibitors; A10BJ GLP-1 analogues; A10BK SGLT2 inhibitors (i.e., those agents for which preliminary evidence from literature supports our pharmacological hypothesis). Results: For GLP-1 analogues, all the disproportionality scores showed values <1, i.e., statistically significant, in both analyses [from the FAERS: ROR confidence interval of 0.546 (0.450-0.662); PRR (p-value) of 0.596 (0.000); EBGM (CI) of 0.488 (0.407-0.582); ERAM (CI) of 0.480 (0.398-0.569) and VigiBase: ROR (CI) of 0.717 (0.559-0.921); PRR (p-value) of 0.745 (0.033); EBGM (CI) of 0.586 (0.464-0.733); ERAM of (CI): 0.515 (0.403-0.639)]. Alongside GLP-1 analogues, DPP-4 Inhibitors and Sulfonylureas showed the greatest potential protective effect. With regard to specific antidiabetic agents, liraglutide and gliclazide were associated with a statistically significant decrease in all disproportionality scores, in both analyses. Conclusion: The findings of this study provide encouraging results, albeit preliminary, supporting the need for further clinical research for investigating repurposing of antidiabetic drugs for neuropsychiatric disorders.

Association of metformin and depression in patients with type 2 diabetes

BACKGROUND

Emerging evidence showed metformin may have pleiotropic effects on ameliorating depression. However, whether metformin was associated with decreased risk of depression remains unclear.

METHODS

A historical cohort study was conducted based on a medical claim database from 2010 to 2017 in Beijing, China. Patients newly diagnosed with T2D were classified into the metformin and non-metformin groups according to their initial antidiabetic prescription. The incidences of depression between the groups were compared using Cox proportional regression model.

RESULTS

There were 193,624 (37.4 %) and 323,930 (62.6 %) T2D patients in the metformin and non-metformin groups. The mean age was 54.9 (SD: 13.1) years and 53.9% were females. With a median follow-up of 3.2 years, 64,963 patients developed depression. The adjusted incidence of depression in the metformin group (30.6, 95 % CI: 30.1, 31.0 per 1000 person-years) was significantly lower than in the non-metformin group (39.6, 95 % CI: 39.3, 40.0 per 1000 person-years, P < 0.001). The metformin group was significantly associated with a lower risk of depression compared with the overall non-metformin group (HR: 0.77, 95% CI: 0.75, 0.78), as well as compared with α-glucosidase inhibitors (HR: 0.73, 95 % CI: 0.71, 0.74), sulfonylureas (HR: 0.84, 95 % CI: 0.82, 0.86), and glinides (HR: 0.85, 95 % CI: 0.82, 0.88), except for thiazolidinediones (HR: 0.96, 95 % CI: 0.91, 1.01). The association between metformin and lower depression risk was significant in all the age and sex subgroups.

CONCLUSIONS

Metformin was associated with a lower risk of depression compared with other oral hypoglycemic agents, indicating a potential pleiotropic effect on depression.

Antidepressant effects of cherry leaf decoction on a chronic unpredictable mild stress rat model based on the Glu/GABA-Gln metabolic loop

Cherry leaves (Prunus pseudocerasus Lindl. [Rosaceae]), a traditional Chinese herbal medicine, can regulate the factors closely related to depression including inflammatory cytokines, oxidative stress and blood glucose level. However, the antidepressant effects of cherry leaves and underlying neuromodulatory mechanisms remain relatively have not been elucidated explicitly. The present study investigated the antidepressant effects of cherry leaf decoction (CLD). The underlying neuromodulatory mechanism was explored by examining the glutamate (Glu)/γ-aminobutyric acid (GABA)-glutamine (Gln) metabolic loop. The chronic unpredictable mild stress (CUMS) rodent model was used in this study. The main flavonoids components of CLD were identified using high-performance liquid chromatography (HPLC). The antidepressant effects of CLD were assessed throughout behavioural tests including the bodyweight, sucrose preference test (SPT), forced swimming test (FPT) and tail suspension test (TST). Moreover, The baseline levels of serum adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were quantified. The expression of proteins integrally involved in the Glu/GABA-Gln metabolic loop were observed and quantified by Western blotting, reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. This study found that CLD ameliorated depressive-like behaviours induced by CUMS. The increase of serum ACTH and CORT baseline levels induced by CUMS was also reversed after CLD intervention. Furthermore, CUMS reduced the expression of GAD65, GAD67, GLT-1, GS and GABA_A and increased NMDAR1 levels in the rat hippocampus, which was normalized by CLD treatment. The findings demonstrated that CLD could ameliorate the depression-like behaviours induced by CUMS, potentially through the inhibition of hypothalamic-pituitary-adrenal (HPA) axis hyperactivity and the regulation of Glu/GABA-Gln metabolic loop.

Prophylactic administration of rosmarinic acid ameliorates depression-associated cardiac abnormalities in Wistar rats: Evidence of serotonergic, oxidative, and inflammatory pathways

Psychiatric disorders and associated cardiac comorbidities have increased the risk of mortality worldwide. Researchers reported that depression increases the possibility of future cardiac abnormalities by approximately 30%. Therefore, there is an unmet need to develop therapeutic interventions to treat depression and associated cardiac abnormalities. The present study was conducted to evaluate the prophylactic effect of rosmarinic acid (RA) against chronic unpredictable stress (CUS)-induced depression associated cardiac abnormalities in Wistar rats. The CUS paradigm, which comprised several stressors, was employed for 40 days to induce depressive-like behavior and associated cardiac abnormalities in rats. Along with CUS, RA at a dose of 25 and 50 mg/kg was administered orally to two groups of animals for 40 days. Behavioral tests (forced swim test and sucrose consumption test) and molecular biomarkers (corticosterone and serotonin) were performed. Electrocardiography was performed before CUS (Day 0), Day 20, and Day 40 to study electrocardiogram parameters. Furthermore, changes in body weight, organ weight, tissue lipid peroxidation, glutathione, catalase, cTn-I, MMP-2, and proinflammatory cytokines (TNF-α and IL-6) were estimated. Our results showed that RA treatment caused a reduction in immobility period, adrenal hyperplasia, corticosterone level, tissue lipid peroxidation, cTn-I, MMP-2, proinflammatory cytokines, and QRS complex duration, while an increase in sucrose consumption, brain serotonin level, T-wave width, glutathione, and catalase activity as compared with the CUS-control group. The results of our study proved that RA administration ameliorates CUS-induced depression-associated cardiac abnormalities in rats via serotonergic, oxidative, and inflammatory pathways.

Evaluation of rosmarinic acid against myocardial infarction in maternally separated rats

Depression and coronary heart diseases are the common comorbid disorder affecting humans globally. The present study evaluated the effectiveness of rosmarinic acid (RA) against myocardial infarction (MI) in comorbid depression induced by maternal separation in rats. Maternal stress is one of the childhood crises that may be a potential risk factor for coronary heart disease in later part of life. As per protocol, 70-80% of pups were separated daily for 3 h between postnatal day 1 (PND1) and postnatal day 21 (PND21). Forced-swim test, sucrose preference test, and electrocardiography were performed during the experiment. Body weight was measured on PND0, PND35, and PND55. Orally rosmarinic acid (25 mg/kg and 50 mg/kg) and fluoxetine (10 mg/kg) was done from PND35 to PND55. On PND53 and PND54, isoproterenol (100 mg/kg, subcutaneously) was administered to induce myocardial infarction. On PND55, blood was collected and animals sacrificed, and plasma corticosterone, brain-derived neurotrophic factor, cardiac biomarkers, interleukine-10, and anti-oxidant parameters were measured. Rosmarinic acid and fluoxetine ameliorated the maternal separation-induced increase in immobility period, anhedonia, body weight, ST elevation, corticosterone, creatine kinase-MB (CK-MB), and lactate dehydrogenase (LDH). At the same time, both drugs elevated the tissue levels of BDNF, IL-10, glutathione, and superoxide dismutase activity. This study provides the first experimental evidence that maternal stress is an independent risk factor of cardiac abnormalities in rats. Moreover, maternal stress synergistically increases the severity of cardiac abnormalities induced by isoproterenol. Interestingly, fluoxetine and rosmarinic acid effectively ameliorated behavioral anomalies and myocardial infarction in maternally separated rats. Schematic representation of possible molecular mechanism of action of rosmarinic acid against MS-induced myocardial infarction. RA, rosmarinic acid; MS, maternal separation; PND, postnatal days; ISO, isoproterenol; BDNF, brain-derived neurotrophic factor; GSH, glutathione; SOD, superoxide dismutase; IL-10, interleukin-10; MI, myocardial infarction.

A Pathophysiological Intersection of Diabetes and Alzheimer's Disease

Diabetes is among the most prevalent diseases of the modern world and is strongly linked to an increased risk of numerous neurodegenerative disorders, although the exact pathophysiological mechanisms are not clear yet. Insulin resistance is a serious pathological condition, connecting type 2 diabetes, metabolic syndrome, and obesity. Recently, insulin resistance has been proven to be connected also to cognitive decline and dementias, including the most prevalent form, Alzheimer's disease. The relationship between diabetes and Alzheimer's disease regarding pathophysiology is so significant that it has been proposed that some presentations of the condition could be termed type 3 diabetes.

ROS-Targeted Depression Therapy via BSA-Incubated Ceria Nanoclusters

Depression is one of the most fatal mental diseases, and there is currently a lack of efficient drugs for the treatment of depression. Emerging evidence has indicated oxidative stress as a key pathological feature of depression. We targeted reactive oxygen species (ROS) and synthesized CeO₂@BSA nanoclusters as a novel antidepression nanodrug via a convenient, green, and highly effective bovine serum albumin (BSA) incubation strategy. CeO₂@BSA has ultrasmall size (2 nm) with outstanding ROS scavenging and blood-brain barrier crossing capacity, rapid metabolism, and negligible adverse effects in vitro and in vivo. CeO₂@BSA administration alleviates depressive behaviors and depression-related pathological changes of the chronic restraint stress-induced depressive model, suggesting promising therapeutic effects of CeO₂@BSA for the treatment of depression. Our study proved the validity by directly using nanodrugs as antidepression drugs instead of using them as a nanocarrier, which greatly expands the application of nanomaterials in depression treatment.

Identification of Ascorbic Acid and Gallic Acid as Novel Inhibitors of Secreted Frizzled-Related Protein for the Treatment of Obesity-Induced Type 2 Diabetes

Type 2 diabetes mellitus (T2D) has been reported as major public health issue rising at an alarming rate worldwide, and obesity is the leading risk factor for the development of T2D. Secreted frizzled-related protein 4 (SFRP4) released with inflammatory mediators from adipose tissues constrains the exocytosis of insulin containing granules from the pancreatic islets that leads towards the development to T2D. The significant overexpression of SFRP4 in diabetic patients and its involvement in islet dysfunction suggest its critical role in the development of diabetes. Thus, this study was designed to explore the potential of ascorbic acid (AA) and gallic acid (GA) against SFRP4 for the treatment of diabetes. Molecular docking approach was used for the prediction of binding interactions of AA and GA at the active pocket of SFRP4. Docking analysis indicated strong binding interactions of AA and GA to the amino acid residues at the active site of SFRP4. A significant reduction in the level of SFRP4 was observed in transfected cells treated with AA and GA. For the evaluation of the cytotoxicity of AA and GA against HepG2 cells, MTT assay was performed. The results of MTT assay demonstrated that AA and GA are non-cytotoxic towards HepG2 cells at concentration of 15 μM. The oral administration of AA and GA to diet-induced obese mice caused significant reduction in body weight, blood glucose level, and SFRP4 expression. The results of this study suggest that AA and GA have potential for the treatment of obesity-induced T2D.

Shared metabolic and neuroimmune mechanisms underlying Type 2 Diabetes Mellitus and Major Depressive Disorder

Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic disease with symptoms that go beyond the domain of glucose metabolism. In fact, research has shown that T2DM is accompanied by neurodegeneration and neuroinflammation. Interestingly, Major Depressive Disorder (MDD), a mood disorder characterized mainly by depressed mood and anhedonia is a key feature of T2DM. A body of evidence demonstrates that there are many shared neuroimmune mechanisms underlying the pathophysiology of T2DM and MDD. Therefore, here we review the state-of-art regarding the underlying factors common to both T2DM and MDD. Furthermore, we briefly discuss how depressive symptoms in diabetic patients could be tackled by using novel therapeutic approaches uncovered by these shared mechanisms. Understanding the comorbidity of depression in diabetic patients is essential to fully address T2DM pathophysiology and treatment.

Metformin and fluoxetine improve depressive-like behavior in a murine model of Parkinsońs disease through the modulation of neuroinflammation, neurogenesis and neuroplasticity

Thereabout 30-40% of patients with Parkinson's Disease (PD) also have depression contributing to the loss of quality of life. Among the patients who treat depression, about 50% do not show significant improvement due to the limited efficacy of the treatment. So far, there are no effective disease-modifying treatments that can impede its progression. The current clinical approach is based on symptom management. Nonetheless, the reuse of drugs with excellent safety profiles represents an attractive alternative strategy for treating of different clinical aspects of PD. In this study, we evaluated the effects of metformin separately and associated with fluoxetine on depressive like-behavior and motor alterations in experimental Parkinson's disease. C57BL6 mice were induced with rotenone (2.5 mg/kg/day) for 20 days and treated with metformin (200 mg/kg/day) and fluoxetine (10 mg/kg/day) from the 5th day of induction. The animals were submitted to Sucrose Preference, Tail Suspension, and rotarod tests. Hippocampus, prefrontal cortex, and substantia nigra were dissected for molecular and morphological analysis. Metformin and fluoxetine prevented depressive-like behavior and improved motor impairment and increased TH nigral positive cells. Metformin and fluoxetine also reduced IBA-1 and GFAP positive cells in the hippocampus. Moreover, metformin reduced the phospho-NF-kB, IL-1β in the prefrontal cortex and iNOS levels in the hippocampus. Both metformin and fluoxetine increased neurogenesis by increasing KI67, but only the combined treatment increased neuronal survival by NeuN positive cells in the hippocampus. In addition, fluoxetine reduced cell death, decreasing caspase-3 and PARP-1 levels. Lastly, metformin potentiated the effect of fluoxetine on neuroplasticity by increasing BDNF positive cells. Metformin has antidepressant and antiparkinsonian potential due to anti-inflammatory neurogenic, and neuroplasticity-inducing effects when combined with fluoxetine.

Adverse Effects of Metformin From Diabetes to COVID-19, Cancer, Neurodegenerative Diseases, and Aging: Is VDAC1 a Common Target?

Metformin has been used for treating diabetes mellitus since the late 1950s. In addition to its antihyperglycemic activity, it was shown to be a potential drug candidate for treating a range of other diseases that include various cancers, cardiovascular diseases, diabetic kidney disease, neurodegenerative diseases, renal diseases, obesity, inflammation, COVID-19 in diabetic patients, and aging. In this review, we focus on the important aspects of mitochondrial dysfunction in energy metabolism and cell death with their gatekeeper VDAC1 (voltage-dependent anion channel 1) as a possible metformin target, and summarize metformin's effects in several diseases and gut microbiota. We question how the same drug can act on diseases with opposite characteristics, such as increasing apoptotic cell death in cancer, while inhibiting it in neurodegenerative diseases. Interestingly, metformin's adverse effects in many diseases all show VDAC1 involvement, suggesting that it is a common factor in metformin-affecting diseases. The findings that metformin has an opposite effect on various diseases are consistent with the fact that VDAC1 controls cell life and death, supporting the idea that it is a target for metformin.

Quercetin and/or Ascorbic Acid Modulatory Effect on Phenobarbital-Induced Sleeping Mice Possibly through GABAA and GABAB Receptor Interaction Pathway

Depressive disorder is a recurrent illness that affects large numbers of the general population worldwide. In recent years, the goal of depression treatment has moved from symptomatic response to that of full remission. However, treatment-resistant depression is a major challenge in the treatment of depression or depression-related disorders. Consensus opinion, therefore, suggests that effective combined aggressive initial treatment is the most appropriate strategy. This study aimed to evaluate the effects of quercetin (QUR) and/or ascorbic acid (AA) on Phenobarbital-induced sleeping mice. QUR (50 mg/kg) and/or AA (25 mg/kg) with or without intraperitoneally pre-treated with GABA receptor agonist (diazepam: 2 mg/kg, i.p.) or antagonist (Flumazenil: 2.5 mg/kg, i.p.) to underscore the effects, as well as the possible involvement of the GABA receptor in the modulatory action of QUR and AA in sleeping mice. Additionally, an in silico study was undertaken to predict the involvement of GABA receptors in the sleep mechanism. Findings suggest that the pretreatment of QUR and AA modulated the onset and duration of action of the standard drugs in experimental animals. The acute administration of QUR and/or AA significantly (p < 0.05) reversed the DZP-mediated onset of action and slightly reversed the duration of sleep time in comparison to the vehicle (control) group. A further combination of QUR or AA with the FLU resulted in an enhancement of the onset of action while reducing the duration of action, suggesting a FLU-like effect on the test animals. In in silico studies, AA and QUR showed good to moderate binding affinities with GABA_A and GABA_B receptors. Both QUR and AA produced a stimulatory-like effect on mice, possibly through the GABA_A and GABA_B receptor interaction pathways. Further studies are necessary to verify this activity and clarify the exact mechanism of action(s) involved.

Psychological Distress and All-Cause, Cardiovascular Disease, Cancer Mortality Among Adults with and without Diabetes

Aim

To examine the association of psychological distress with all-cause, cardiovascular disease (CVD) and cancer mortality in US adults, and verified whether the associations differed between participants with and without diabetes.

Methods

A total of 485,864 adults (446,288 without diabetes and 39,576 with diabetes) who participated in the National Health Interview Survey from 1997 to 2013 were linked to the National Death Index through December 31, 2015. Psychological distress was measured by the Kessler 6 distress scale (K6). Multivariable Cox proportional hazards regression models were performed to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for the association between psychological distress and mortality.

Results

We ascertained 11,746 deaths (mean follow-up, 7. 7 years) among people with diabetes and 51,636 deaths (9.9 years) among those without diabetes. Psychological distress was associated with higher all-cause, CVD, and cancer mortality. Compared to non-diabetic adults without psychological distress, HRs (95% CI) were 1.07 (1.04 to 1.09) for mild, 1.26 (1.22 to 1.30) for moderate and 1.46 (1.38 to 1.55) for severe psychological distress. Compared to the same reference group, in diabetic participants the HRs were 1.39 (1.33 to 1.44) for no psychological distress, 1.59 (1.53 to 1.66) for mild, 1.90 (1.80 to 2.00) for moderate and 1.98 (1.82 to 2.17) for severe psychological distress. Similar associations were also observed for CVD and cancer mortality but with non-statistically significant interaction.

Conclusion

Psychological distress was associated with higher mortality, particularly in participants with diabetes. Strategies to ameliorate psychological distress may be important to reduce mortality in this population.

Metformin: A Growing Journey from Glycemic Control to the Treatment of Alzheimer's Disease and Depression

Metabolic stress, transduced as an altered cellular redox and energy status, presents as the main culprit in many diseases, including diabetes. However, its role in the pathology of neurological disorders is still not fully elucidated. Metformin, a biguanide compound, is an FDA approved antidiabetic drug generally used for the treatment of type 2 diabetes. The recently described wide spectrum of action executed by this drug suggests a potential therapeutic benefit in a panoply of disorders. Current studies imply that metformin could play a neuroprotective role by reversing hallmarks of brain injury (metabolic dysfunction, neuronal dystrophy and cellular loss), in addition to cognitive and behavioral alterations that accompany the onset of certain brain diseases such as Alzheimer's disease (AD) and depression. However, the mechanisms by which metformin exerts its protective effect in neurodegenerative disorders are not yet fully elucidated. The aim of this review is to reexamine the mechanisms through which metformin performs its function while concentrating on its effect on reestablishing homeostasis in a metabolically disturbed milieu. We will also highlight the importance of metabolic stress, not only as a component of many neurological disorders, but also as a primary driving force for neural insult. Of interest, we will explore the involvement of metabolic stress in the pathobiology of AD and depression. The derangement in major metabolic pathways, including AMPK, insulin and glucose transporters, will be explored and the potential therapeutic effects of metformin administration on the reversal of brain injury in such metabolism dependent diseases will be exposed.

Protective effect of metformin against ovariectomy induced depressive- and anxiety-like behaviours in rats: role of oxidative stress

Several studies have shown that low estrogen levels can lead to an increase in the incidence of depression and anxiety during menopause. The hippocampus and prefrontal cortex are parts of the brain involved in depressive- and anxiety-like behaviors. Recent studies have revealed that metformin has neuroprotective effects mainly due to its antioxidant properties. The aim of the present study was to examine the therapeutic potential of metformin in depressive- and anxiety-like behavior as well as oxidative stress in the prefrontal cortex and hippocampus of ovariectomized rats. Young female Wistar Albino rats were distributed into four groups (n:8): control, metformin-administered control, ovariectomized and metformin administered ovariectomized groups. Metformin (25 mg/kg) was administered daily by oral gavage for 2 weeks. Forced swimming test and open field test were performed to evaluate depression- and anxiety-like behaviors, respectively. Following the treatment with metformin, the tissues of the hippocampus and prefrontal cortex were isolated for the measurement of malondialdehyde, reduced glutathione and ascorbic acid contents. Ovariectomy resulted in depressive- and anxiety-like behaviors, and besides, increased content of malondialdehyde in both prefrontal cortex and hippocampus. The levels of ascorbic acid and glutathione were found to be reduced in ovariectomized rats. Metformin treatment significantly decreased depressive behaviour and malondialdehyde content in the prefrontal cortex. Reducing oxidative stress of the prefrontal cortex was suggested as a possible mechanism implicated in the beneficial effects of metformin on ovariectomy-induced depressive-like behaviour. We believe that the therapeutic efficiency of metformin needs to be tested for potential clinical use in surgical menopause or gonadal hormone deficiency women with depression.

Reduction of Depression in Diabetes: A New Pleiotropic Action of Metformin?

Metformin remains the cornerstone of management for type 2 diabetes mellitus (T2DM). It is also known that it has beneficial pleiotropic actions. In addition, there is emerging evidence that this agent may prove beneficial in ameliorating depression in T2DM. The underlying mechanisms of this new action remain elusive, but experimental studies point to improved synaptic function and increased serotonin activity, along with the known inflammatory and antioxidant properties of metformin. Obviously, we need to further explore the potential utility of such antidepressant effects among T2DM subjects in everyday reality.

The impact of insulin on the serotonergic system and consequences on diabetes-associated mood disorders

The idea that insulin could influence emotional behaviours has long been suggested. However, the underlying mechanisms have yet to be solved and there is no direct and clear-cut evidence demonstrating that such action involves brain serotonergic neurones. Indeed, initial arguments in favour of the association between insulin, serotonin and mood arise from clinical or animal studies showing that impaired insulin action in type 1 or type 2 diabetes causes anxiety- and depressive symptoms along with blunted plasma and brain serotonin levels. The present review synthesises the main mechanistic hypotheses that might explain the comorbidity between diabetes and depression. It also provides a state of knowledge of the direct and indirect experimental evidence that insulin modulates brain serotonergic neurones. Finally, it highlights the literature suggesting that antidiabetic drugs present antidepressant-like effects and, conversely, that serotonergic antidepressants impact glucose homeostasis. Overall, this review provides mechanistic insights into how insulin signalling alters serotonergic neurotransmission and related behaviours bringing new targets for therapeutic options.

Involvement of agmatine in antidepressant-like effect of HMG-CoA reductase inhibitors in mice

3-Hydroxy-3-methyl-glutaryl-co-enzyme-A (HMG-CoA) reductase inhibitors (statins) are popularly used for the treatment of obesity and hypercholesterolemia with established safety profile. Statins exhibits a wide range of neurobehavioral effects in addition to their peripheral actions, and may be beneficial in treatment of psychiatric conditions. Present study investigated the role of agmatine and imidazoline receptors in antidepressant-like effect of statins in mouse forced swimming test (FST). The antidepressant-like effect of atorvastatin (5 mg/kg, p.o.) and simvastatin (10 mg/kg, p.o.) was potentiated by pretreatment with agmatine (5 mg/kg, i.p.) as well as the drugs known to increase endogenous agmatine levels in brain viz., L-arginine (40 μg/mouse, i.c.v.), an agmatine biosynthetic precursor; arcaine (50 μg/mouse, i.c.v), agmatinase inhibitor; and aminoguanidine (6.5 μg/mouse, i.c.v.), a diamine oxidase inhibitor. Further, both the statins increased agmatine levels within hippocampus and prefrontal cortex. Conversely, prior administration of I₁ receptor antagonist, efaroxan (1 mg/kg, i.p.) and I₂ receptor antagonist, idazoxan (0.25 mg/kg, i.p.) blocked the antidepressant-like effect of statins and their synergistic combination with agmatine. These results demonstrate the involvement of agmatine and imidazoline receptors in antidepressant-like effect of statins and suggest as a potential therapeutic target for the treatment of depressive disorders.

Metformin Ameliorates Lipopolysaccharide-Induced Depressive-Like Behaviors and Abnormal Glutamatergic Transmission

Simple Summary

Metformin is a promising drug for diabetes and has been reported to have antidepressant effects in depression patients or patients with comorbid depression and other diseases. However, it is largely unclear how metformin ameliorates depressive-like behaviors. To this end, we injected mice with a bacterial endotoxin (lipopolysaccharide) to induce depressive-like behaviors such as increased immobility in the forced swimming test and tail suspension test. In this depression mouse model, metformin administration ameliorated depressive-like behaviors. Glutamate is a major excitatory signal for the communications between neurons in the brain. Dysfunction of glutamatergic neurotransmission is implicated in the pathogenesis of depression. Glutamatergic transmission was elevated in our depression mouse model. Metformin administration also recovered the glutamatergic transmission deficit in the model. Taken together, our results suggest metformin had antidepressant effects and can correct abnormal glutamatergic transmission in the lipopolysaccharide-induced depression mouse model. These findings provide new insights into the underlying mechanism by which metformin acts against depression.

Abstract

Metformin, a first-line drug for type 2 diabetes mellitus (T2DM), has been found to reduce depressive symptoms in patients with comorbid depression and other diseases. However, it is largely unclear how metformin ameliorates depressive-like behaviors. Here, we used lipopolysaccharide (LPS) to induce depressive-like behaviors in mice and found that LPS-treated mice exhibited increased immobility in the forced swimming test (FST) and tail suspension test (TST), as well as increased glutamatergic transmission. Furthermore, metformin administration in the LPS-treated mice ameliorated depressive-like behaviors and elevated glutamatergic transmission. Our results suggest that metformin has antidepressant effects and can correct abnormal glutamatergic transmission, providing an insight into the underlying mechanism by which metformin acts against depression.

Antidepressant activity of anti-hyperglycemic agents in experimental models: A review

BACKGROUND AND AIMS

Diabetes Mellitus (DM) and depression occur comorbidly and share some pathophysiological mechanisms. The course of depression in patients with the two conditions is severe. Treatment of depression in diabetic patients requires special attention because most of psychopharmacological agents can worsen glycemic control. This article aims to review studies evaluating the antidepressant effect of anti-hyperglycemic agents from preclinical perspective.

METHODS

A literature search was performed with PubMed and Google Scholar using relevant keywords (antidiabetic; diabetes; depression; antidepressant; animals) to extract relevant studies evaluating the antidepressant activity of anti-hyperglycemic agents in experimental models.

RESULTS

Several studies have reported that some traditional anti-hyperglycemic agents reduce depression-like behavior in the absence or presence of diabetes. These drugs include insulin, glyburide, metformin, pioglitazone, vildagliptin, liraglutide, and exenatide. The antidepressant activity of anti-hyperglycemic agents may be mediated by reducing the blood glucose level, ameliorating the central oxidative stress and inflammation, and regulating the hypothalamic-pituitary-adrenal axis (HPAA).

CONCLUSIONS

Drugs which have both antidiabetic and antidepressant activities can provide better treatment strategy for patients with diabetes-associated depression. However, further research studies are still required in human subjects.

Impact of some oral hypoglycemic agents on type 2 diabetes-associated depression and reserpine-induced depression in rats: the role of brain oxidative stress and inflammation

Diabetes mellitus and depression are comorbid diseases affecting many patients all over the world. The current study was designed to compare the antidepressant effect of some antidiabetic drugs such as vildagliptin, pioglitazone, glyburide, and metformin on depression-related or unrelated to type 2 diabetes mellitus (T2DM). T2DM was induced by high-fat diet and streptozotocin, while diabetes-unrelated depression was induced by reserpine. Antidiabetic agents reduced diabetes-associated depression as indicated by the reduction in the immobility time in the forced swim test, elevation of cortical and hippocampal serotonin and brain-derived neurotrophic factor (BDNF), and the increase in serum β-Amyloid 1-42 (Aβ1-42) levels. Antidiabetic agents also reduced serum corticosterone levels suggesting their inhibitory effect on hypothalamus-pituitary-adrenal axis activity. The antidepressant activity of the tested compounds was associated with reduction of oxidative stress and inflammation in brain. Vildagliptin showed the highest, while glyburide showed the least antidiabetic and antidepressant activity. Antidepressant activities of pioglitazone and metformin were comparable. The difference in antioxidant and anti-inflammatory activities between groups showed the same pattern of the antidepressant effect suggesting that these two pathways may play role in ameliorating depression in diabetic rats. On the other hand, the administration of reserpine in small doses (0.2 mg/kg) induced depression associated with hyperglycemia in non-diabetic rats. Although all treatments improved glycemic parameters to similar levels, vildagliptin showed the greatest effect on Aβ1-42, serotonin, norepinephrine, and BDNF levels. In conclusion, vildagliptin seems to be the leading drug among the tested antidiabetics and may be the most appropriate antidiabetic for managing diabetes-associated depression.

Catharanthus roseus Combined with Ursolic Acid Attenuates Streptozotocin-Induced Diabetes through Insulin Secretion and Glycogen Storage

Catharanthus roseus (C. roseus) and ursolic acid (UA) are ayurvedic medicines with multiple pharmacological activities including antidiabetic activity, but till date, no study is available on their combination. This study documented the antidiabetic efficacy of the combination of C. roseus and UA in rats. Rats were divided into six groups. All groups were given a single dose of Streptozotocin (STZ) at a dose of 50 mg/kg by intraperitoneal route for induction of diabetes, except the normal control group. Group 1 was treated as a normal control (NC) group and fed with saline water, Group 2 as a Diabetes Control group, Group 3 as a STZ+C. roseus ethanolic extract (CREE) group at 50 mg/kg p.o., Group 4 as a STZ+UA group orally at 50 mg/kg, Group 5 as a STZ+CREE (25 mg/kg p.o.)+UA (25 mg/kg p.o.) group, and Group 6 as a STZ+Glimepiride (0.1 mg/kg) group. Diabetes was confirmed after 72 hours by estimation of blood glucose level, and then treatment was given for the next 28 days. During the course of treatment, plasma insulin and blood glucose were measured regularly at the interval of 7 days. At the end of the protocol, blood was collected and animals were sacrificed. The glucose level, insulin level, liver glycogen storage level, and antioxidant enzymes (LPO, CAT, SOD, GPx, GST) were measured. The blood glucose level in Group 5 significantly (P < 0.001) reduced to 98.35 ± 2.45 mg/dl in comparison with that in Group 2 (321.75 ± 5.46 mg/dl). The level of plasma insulin in Group 5 increased (13.65 ± 0.10 μU/ml) significantly (P < 0.01) as compared with that in Group 2 (05.93 ± 0.31 μU/ml). In Group 5, the level of glycogen in liver was significantly (P < 0.01) increased as compared with that in Group 2 rats. The level of antioxidant enzymes in Group 5 restored toward normal values significantly (P < 0.01; P < 0.001) as compared with that in Group 2 animals. These findings suggest that low-dose combination of CREE and UA is effective in the treatment of diabetes.

Preventive and Therapeutic Effects of Astaxanthin on Depressive-Like Behaviors in High-Fat Diet and Streptozotocin-Treated Rats

The comorbidity of diabetes and depression has a negative impact on both lifestyle and quality of life. Astaxanthin (AST) has been demonstrated to improve glucose metabolism and has antidepressant-like effects, but it is not clear whether AST has potential for preventing depression in diabetes. The aim of this study is to observe the preventive and therapeutic effects of AST on glucose metabolism or depressive-like behaviors in a diabetic rat model produced by feeding with a high-fat diet for 10 weeks followed by injection of 25 mg/kg streptozotocin (STZ). Preventive treatment with AST at doses of 7.5, 15, and 25 mg/kg/day was given by intragastric gavage 4 weeks before STZ injection. Preventive plus therapeutic treatment also involved therapeutic AST treatments for 6 more weeks after STZ injection, whereas therapeutic-only treatment involved only the 6-week post-STZ treatment. Depressive-like behaviors were evaluated at the end of the treatment by using open field, locomotor activity, elevated plus maze, and forced swimming tests. Preventive and therapeutic treatment with AST both reduced the level of fasting glucose, improved glucose tolerance, and decreased total TCh and TG in diabetic rats. Preventive or preventative plus therapeutic treatment with AST decreased the immobility time and increased the time spent in the open arms of an elevated plus maze and locomotor activity in diabetic rats. However, therapeutic treatment with AST alone failed to affect the depressive-like behaviors. Preventive or preventative plus therapeutic treatment with AST at doses of 15 or 25 mg/kg significantly increased the expression of pERK, pAKT, pCREB, and BDNF in the prefrontal cortex (PFC) in diabetic rats. In contrast, therapeutic treatment with 25 mg/kg AST alone increased the expression of pERK in the PFC. This study indicates that AST may be used as a preventive or therapeutic approach for co-morbidity of diabetes and depression.

Metformin Improves the Depression Symptoms of Women with Polycystic Ovary Syndrome in a Lifestyle Modification Program

BACKGROUND

Metformin is commonly prescribed to manage polycystic ovary syndrome (PCOS), which is one of the most common endocrine disorders among women of childbearing age and is associated with high prevalence rates of depression and anxiety.

OBJECTIVE

This study's objective was to determine the impact of prescribed metformin on depression and anxiety levels of patients with PCOS.

METHODS

This prospective, multi-center, cohort study examined the impact of prescribed metformin on the depression and anxiety of women with PCOS in four gynecology clinics in Saudi Arabia and Jordan. The women had recently been prescribed metformin along with lifestyle modifications, such as diet and exercise, and were compared to another group of women with PCOS who were prescribed lifestyle modifications only. Depression and anxiety were assessed at baseline and three months later using the Patient Health Questionnaire (PHQ-9) and the Generalized Anxiety Disorder (GAD-7) scale, respectively. Health-related quality of life was measured using the Short Form Health Survey (SF-36). Multiple logistic regression analyses were conducted to examine the impact of metformin on depression and anxiety.

RESULTS

Eighty-six women participated in the study: 53 were prescribed metformin with lifestyle modifications, and 33 were prescribed lifestyle modifications only. The women on metformin had 70% lower odds of having major depression (PHQ-9≥10) (OR=0.302, P=0.045); however, no significant effect of metformin on anxiety (GAD-7≥10) was found.

CONCLUSION

Metformin may have a role in the management of depression symptoms among patients with PCOS; however, its potential antidepressant effect should be further examined in randomized double-blind placebo-controlled clinical trials.

A Systematic Review on Synthetic Drugs and Phytopharmaceuticals Used to Manage Diabetes

BACKGROUND

Diabetes is a multifactorial disease and a major cause for many microvascular and macrovascular complications. The disease will ultimately lead to high rate mortality if it is not managed properly. Treatment of diabetes without any side effects has always remained a major challenge for health care practitioners.

INTRODUCTION

The current review discusses the various conventional drugs, herbal drugs, combination therapy and the use of nutraceuticals for the effective management of diabetes mellitus. The biotechnological aspects of various antidiabetic drugs are also discussed.

METHODS

Structured search of bibliographic databases for previously published peer-reviewed research papers was explored and data was sorted in terms of various approaches that are used for the treatment of diabetes.

RESULTS

More than 170 papers including both research and review articles, were included in this review in order to produce a comprehensive and easily understandable article. A series of herbal and synthetic drugs have been discussed along with their current status of treatment in terms of dose, mechanism of action and possible side effects. The article also focuses on combination therapies containing synthetic as well as herbal drugs to treat the disease. The role of pre and probiotics in the management of diabetes is also highlighted.

CONCLUSION

Oral antihyperglycemics which are used to treat diabetes can cause many adverse effects and if given in combination, can lead to drug-drug interactions. The combination of various phytochemicals with synthetic drugs can overcome the challenge faced by the synthetic drug treatment. Herbal and nutraceuticals therapy and the use of probiotics and prebiotics are a more holistic therapy due to their natural origin and traditional use.

Metformin ameliorates stress-induced depression-like behaviors via enhancing the expression of BDNF by activating AMPK/CREB-mediated histone acetylation

BACKGROUND

Metformin, a first-line antiglycemic drug, has been reported to have anti-depressant effects in patients with type 2 diabetes; however, its exact role and underlying mechanism still need to be investigated.

METHOD

C57BL/6J mice were subjected to the Chronic social defeat stress (SDS) and drug administration (Control + Vehicle, SDS + Vehicle, SDS + MET (200 mg kg^-1), SDS + FLUOX (3 mg kg^-1), SDS + MET + FLUOX). And the depression phenotypes were evaluated by the sucrose preference test, social interaction, tail suspension test and forced swimming test. The potential mechanisms underlying the effects of metformin on depression was discussed by using Chromatin immunoprecipitation, Quantitative real-time PCR mRNA expression analysis and Western blot in vivo and in primary cultured hippocampal neurons.

RESULT

The metformin treatment counteracted the development of depression-like behaviors in mice suffering SDS when administered alone and enhanced the anti-depressant effect of fluoxetine when combined with fluoxetine. Further RNA sequencing analysis revealed that metformin treatment prevented the transcriptional changes in the medial prefrontal cortex (mPFC) of the animals and Golgi staining indicated favorable morphological changes in the neurite plasticity of CA1 pyramidal neurons, which approximated to those found in unstressed mice. At a molecular level, metformin significantly upregulated the expression of the brain-derived neurotrophic factor (BDNF) by increasing the histone acetylation along with the BDNF promoter, which was attributed to the activation of AMP-activated protein kinase (AMPK) and cAMP-response element binding protein (CREB).

CONCLUSION

Our findings suggest that metformin can produce antidepressant effects, which provides empirical insights into the clinical value of metformin in the prevention and therapy of depression.

Association between diabetes and mood disorders and the potential use of anti-hyperglycemic agents as antidepressants

Epidemiological and mechanistic studies support the association between Diabetes Mellitus and mood disorders, such as Major Depressive Disorder and Bipolar Disorder. This association is especially relevant in specific domains of depressive psychopathology, such as disturbances in reward systems and cognitive functions. Several anti-hyperglycemic agents have demonstrated effects on depressive symptoms and cognitive decline and this efficacy is probably the result of an action in shared brain targets between these two groups of conditions. These medications include subcutaneous insulin, intranasal insulin, metformin, and liraglutide. The study of the mechanisms involved in the relationship between Diabetes Mellitus and mood disorders offers a new avenue of investigation, and this understanding can be applied when examining whether antidiabetic agents can be repurposed as antidepressants and mood stabilizers. The objective of this narrative review is to critically appraise the literature surrounding drugs commonly used as anti-hyperglycemic agents and their effects on the brain, while discussing their potential as a new treatment for mental illnesses, and specifically, mood disorders.

Risk factors for depression in elderly diabetic patients and the effect of metformin on the condition

Background

At present, only a few studies have focused on the risk factors for depression in elderly diabetic patients, and there is little evidence for the effect of metformin in depressed elderly patients with diabetes than on its effect on blood glucose. The aim of the current work was to study the risk factors for depression in elderly diabetic patients and to ascertain the effects of metformin on the depressive state.

Methods

We initiated a 1:4 matched case–control study. The case group comprised 110 elderly diabetic patients with depression from nine communities in Shenyang in 2017. The control group comprised 440 non-depressed elderly diabetic patients from the same communities, which were matched by gender and age (± 2 years of age) with the case group. Depression was measured using the Geriatric Depression Scale-15, and we performed matched univariate and multivariate logistic regression analyses.

Results

In the multivariate analysis, overweight status, poor physical capabilities and low activity level, and the presence of more than two additional illnesses were risk factors for depression in elderly patients with diabetes. For these risk factors, the adjusted ORs (all P < 0.05) were as follows: an adjusted OR of 2.031 and 95% CI of 1.180–3.495; an adjusted OR of 2.342 and 95% CI of 1.465–3.743; and an adjusted OR of 5.350 and 95% CI of 2.222–12.883, respectively. Patients taking metformin had a lower risk of depression than those taking no medication, with an adjusted OR of 0.567 and 95% CI of 0.323–0.997 (P < 0.05).

Conclusions

Overweight status, poor physical capabilities and low activity level, and the presence of more than two additional illnesses were risk factors for depression in elderly diabetic patients, and metformin was a protective factor against depression in elderly diabetic patients.

Relationship of Oxidative Stress as a Link between Diabetes Mellitus and Major Depressive Disorder

Both conditions, major depressive disorder (MDD) and diabetes mellitus (DM) are chronic and disabling diseases that affect a very significant percentage of the world's population. Studies have been shown that patients with DM are more susceptible to develop depression, when compared to the general population. The opposite also happens; MDD could be a risk factor for DM development. Some mechanisms have been proposed to explain the pathophysiological mechanisms involved with these conditions, such as excess of glucocorticoids, hyperglycemia, insulin resistance, and inflammation. These processes can lead to an increase in damage to biomolecules and a decrease in antioxidant defense capacity, leading to oxidative stress.

Ascorbic acid therapy: A potential strategy against comorbid depression-like behavior in streptozotocin-nicotinamide-induced diabetic rats

This study examined the potency and efficacy of ascorbic acid (AA) in the management of depression-like behavior in diabetic rats. Diabetes mellitus was induced by single intraperitoneal injections of nicotinamide (120 mg/kg) and streptozotocin (65 mg/kg) administered 15 min apart. Diabetic (blood glucose ≥250 mg/dL) rats were subjected to intermittent foot-shocks to induce comorbid depression. Seven groups of diabetes comorbid depressed rats received vehicle (1 mL/kg) or AA (10, 25, 50, 100, 200, or 400 mg/kg) orally for eleven days. Three control groups namely- nondiabetic, diabetic, and depressed rats received the vehicles only. The potency (ED₅₀) and efficacy (E_max) of AA against immobility period, hypercorticosteronemia, adrenal hyperplasia, hyperglycemia, hypoinsulinemia, oxidative stress, and inflammatory response were estimated. AA administration caused a dose-dependent decrease (P < 0.05) in immobility period with maximum inhibition of 69% (efficacy) at 200 mg/kg and ED₅₀ of 14 mg/kg (potency). AA at 200 mg/kg produced the maximal reduction in hypercorticosteronemia (55.1%) and adrenal hyperplasia (52.6%) with ED₅₀ of 9.8 and 14.4 mg/kg, respectively. AA at 400 mg/kg produced the maximal reduction in hyperglycemia (35.5%), hypoinsulinemia (32.7%), and lipid peroxidation (82%) with ED₅₀ of 18.6, 13.7, and 20.7 mg/kg, respectively. Moreover, AA at 400 mg/kg produced the maximal increase in SOD content (83%), CAT activity (77.9%), and IL-10 level (63%) with ED₅₀ of 21.5, 21, and 21 mg/kg, respectively. In conclusion, the present results suggest that AA has therapeutic potential against diabetes comorbid depression but better regulation of hyperglycemia and hypoinsulinemia is required to achieve maximal benefits.

Discovering the Health Promoting Potential of Fermented Papaya Preparation—Its Future Perspectives for the Dietary Management of Oxidative Stress During Diabetes

The simplistic morphological characteristics of Carica papaya fruit or “pawpaw” should not be the cause for underestimating its potential as a nutraceutical. The market for papaya has been expanding at a staggering rate, partly due to its applicability as a biofortified product, but also due to its phytochemical properties and traditional health benefits. Papaya or formulations of fermented papaya promotion (FPP) display effective free radical scavenging abilities thought to be influenced by its phenolic, carotenoid, flavonoid, or amino acid profile. The antioxidant properties of FPP have been extensively reported in literature to potently target a broad spectrum of free radical-induced diseases ranging from neurological impairments, such as senile dementia, to systemic diseases, to its interference at the cellular level and the support of normal biological ageing processes. FPP has thus been extensively investigated for its ability to exert cellular protective effects and reduce oxidative stress via the mitigation of genetic damage, reduction of lipid peroxidation, and enzymatic inactivation in specific diseases. The focus of this review is to appraise the potential of oxidative stress reduction strategies of FPP and discuss its holistic approach in disease prevention and management, with a particular focus on diabetes and cancer. However, with the current lack of information surrounding its mechanism of action, this review wishes to set the stage and aspire researchers to more profoundly investigate molecular pathways related to how FPP can unequivocally contribute to wellness in an aging population.

Preventive and Therapeutic Potential of Vitamin C in Mental Disorders

In this review, we summarize the involvement of vitamin C in mental disorders by presenting available evidence on its pharmacological effects in animal models as well as in clinical studies. Vitamin C, especially its reduced form, has gained interest for its multiple functions in various tissues and organs, including central nervous system (CNS). Vitamin C protects the neuron against oxidative stress, alleviates inflammation, regulates the neurotransmission, affects neuronal development and controls epigenetic function. All of these processes are closely associated with psychopathology. In the past few decades, scientists have revealed that the deficiency of vitamin C may lead to motor deficit, cognitive impairment and aberrant behaviors, whereas supplement of vitamin C has a potential preventive and therapeutic effect on mental illness, such as major depressive disorder (MDD), schizophrenia, anxiety and Alzheimer's disease (AD). Although several studies support a possible role of vitamin C against mental disorders, more researches are essential to accelerate the knowledge and investigate the mechanism in this field.