Pharmacotherapeutic strategies for managing comorbid depression and diabetes

Transcutaneous vagus nerve stimulation modulates depression-like phenotype induced by high-fat diet via P2X7R/NLRP3/IL-1β in the prefrontal cortex

BACKGROUND

Depression is a common psychiatric disorder in diabetic patients. Depressive mood associated with obesity/metabolic disorders is related to the inflammatory response caused by long-term consumption of high-fat diets, but its molecular mechanism is unclear. In this study, we investigated whether the antidepressant effect of transcutaneous auricular vagus nerve stimulation (taVNS) in high-fat diet rats works through the P2X7R/NLRP3/IL-1β pathway.

METHODS

We first used 16S rRNA gene sequencing analysis and LC-MS metabolomics assays in Zucker diabetic fatty (ZDF) rats with long-term high-fat diet (Purina #5008) induced significant depression-like behaviors. Next, the forced swimming test (FST) and open field test (OFT) were measured to evaluate the antidepressive effect of taVNS. Immunofluorescence and western blotting (WB) were used to measure the microglia state and the expression of P2X7R, NLRP3, and IL-1β in PFC.

RESULTS

Purina#5008 diet induced significant depression-like behaviors in ZDF rats and was closely related to purine and inflammatory metabolites. Consecutive taVNS increased plasma insulin concentration, reduced glycated hemoglobin and glucagon content in ZDF rats, significantly improved the depressive-like phenotype in ZDF rats through reducing the microglia activity, and increased the expression of P2X7R, NLRP3, and IL-1β in the prefrontal cortex (PFC).

CONCLUSION

The P2X7R/NLRP3/IL-1β signaling pathway may play an important role in the antidepressant-like behavior of taVNS, which provides a promising mechanism for taVNS clinical treatment of diabetes combined with depression.

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.

The role of metformin as a treatment for neuropsychiatric illness

Advances in psychopharmacology have been significantly slower to evolve than in other disciplines of medicine and therefore investigation into novel therapeutic approaches is required. Additionally, concurrent metabolic conditions are prevalent among people with mental disorders. Metformin is a widely used hypoglycaemic agent that is now being studied for use beyond diabetes management. Evidence is emerging that metformin has multiple effects on diverse neurobiological pathways and consequently may be repurposed for treating mental illness. Metformin may have beneficial neuroimmunological, neuroplastic, neuro-oxidative and neuro-nitrosative effects across a range of psychiatric and neurodegenerative illnesses. Mechanisms include glucose lowering effects and effects on AMP-activated protein kinase (AMPK) signalling, however the best evidence for clinical benefit is through the glucose lowering effects, with other mechanisms less supported by the current evidence base. This narrative review aims to draw together the existing evidence for use of metformin as a psychopharmaceutical and present the role of metformin in the context of physical and psychiatric ill health, including metabolic, endocrinological and cancer domains. It not only has therapeutic potential in medical comorbidity but may have potential in core illness domains.

Antidepressants for depressed patients with type 2 diabetes mellitus: A systematic review and network meta-analysis of short-term randomized controlled trials

This network meta-analysis compared the short-term treatment effects of different antidepressants on depression severity and HbA1c in depressed patients with type 2 diabetes mellitus (T2DM). We searched 8- to 24-week randomized-controlled trials (RCTs) in PubMed, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov on November 22, 2021. We included 12 RCTs (N = 792) studying agomelatine, citalopram, escitalopram, fluoxetine, nortriptyline, no treatment, paroxetine, sertraline, vortioxetine, and placebo. Compared to placebo, the standardized mean differences and 95% confidence intervals (SMD, 95%CIs) for depression severity reduction revealed that escitalopram ranked first (-2.93, -3.92 to -1.94), followed by agomelatine (-0.68, -1.15 to -0.20). Compared to placebo, the mean differences (MDs, 95%CIs) for HbA1c reduction suggested that vortioxetine ranked first (-2.35, -4.13 to -0.57), followed by escitalopram (-1.00, -1.42 to -0.57) and agomelatine (-0.79, -1.16 to -0.42). Limited evidence from short-term trials in depressed patients with T2DM suggests that escitalopram and agomelatine may have a favorable profile in reducing depression and controlling glycemic goals, but more trials are required.

Prevalence of Depression among Type-II Diabetic Patients Attending the Diabetic Clinic at Arar National Guard Primary Health Care Center, Saudi Arabia

Background

Depression is a common comorbidity in type-II diabetic patients, which if undiagnosed leads to poor clinical outcomes.

Objectives

To determine the prevalence and risk factors of depression among type-II diabetic patients attending the National Guard Diabetic Clinic in Arar city. Subjects and methods. This cross-sectional study included every third type-II diabetic patient attending the National Guard Primary Health Care Center between the 1^st of January and 31^st of March 2019. Participants were interviewed using the Patient Health Questionnaire 9 (PHQ-9). Patients who scored ≥5 were considered to have depression. Chi-square test (χ²) was used to compare differences between categorical variables. P ≤ 0.05 was considered statistically significant.

Results

Of the total 422 diabetic patients approached for this study, 397 provided complete responses (94% response rate). Of these, 37% had depression: 23% mild, 9% moderate, and 5% severe. Diabetic patients with low education, poor income, and long duration of diabetes mellitus were found to be at higher risk of depression. Poor compliance with physical activities, diet regimen, family history of DM, and the presence of complications was also significantly associated with depression. On logistic regression analysis, low family income, duration of DM, poor compliance to physical activity, and presence of complications as neuropathy or libido were the main predictors of depression in diabetic patients.

Conclusion

More than one-third of type-II diabetic patients had depression. Regular screening of type-II diabetic patients for depression is a necessity, as it can affect the clinical outcome.