Renoprotective effect of liraglutide on diabetic nephropathy by modulation of Krüppel-like transcription factor 5 expression in rats.

OBJECTIVES: Diabetic nephropathy (DN) is a serious consequence of diabetes that can develop through the lysophosphatidic acid axis. The purpose of this study was to determine whether the antidiabetic drug liraglutide can slow the development of diabetic kidney damage by altering the lysophosphatidic acid axis via KLF5. METHODS: Wistar albino rats were divided into nondiabetic and diabetic rats (resulting from an intraperitoneal streptozotocin dose of 30 mg/kg and a high-fat diet). These rats were further divided into four groups: nondiabetic control, liraglutide-treated nondiabetic, diabetic control, and liraglutide-treated diabetic. The nondiabetic and diabetic control groups received normal saline for 42 days, while the liraglutide-treated nondiabetic and diabetic groups received normal saline for 21 days, followed by a subcutaneous dose of liraglutide (200 µg/kg/day) for 21 days. Subsequently, serum levels of DN biomarkers were evaluated, and kidney tissues were histologically examined. The protein expression of PCNA, autotaxin, and KLF5 was detected. KEY FINDINGS: Liraglutide treatment in diabetic rats decreased DN biomarkers, histological abnormalities in kidney tissues, and the protein expression of PCNA, autotaxin, and KLF5. CONCLUSION: Liraglutide can slow the progression of DN by modulating KLF5-related lysophosphatidic acid axis. Thus, liraglutide may be an effective treatment for preventing or mitigating diabetes-related kidney damage.

Interplay between Senescence and Macrophages in Diabetic Cardiomyopathy: A Review of the Potential Role of GDF-15 and Klotho.

Type 2 diabetes mellitus (T2DM) is a critical health problem, with 700 million diagnoses expected worldwide by 2045. Uncontrolled high blood glucose levels can lead to serious complications, including diabetic cardiomyopathy (DCM). Diabetes induces cardiovascular aging and inflammation, increasing cardiomyopathy risk. DCM is characterized by structural and functional abnormalities in the heart. Growing evidence suggests that cellular senescence and macrophage-mediated inflammation participate in the pathogenesis and progression of DCM. Evidence indicates that growth differentiation factor-15 (GDF-15), a protein that belongs to the transforming growth factor-beta (TGF-ß) superfamily, is associated with age-related diseases and exerts an anti-inflammatory role in various disease models. Although further evidence suggests that GDF-15 can preserve Klotho, a transmembrane antiaging protein, emerging research has elucidated the potential involvement of GDF-15 and Klotho in the interplay between macrophages-induced inflammation and cellular senescence in the context of DCM. This review explores the intricate relationship between senescence and macrophages in DCM while highlighting the possible contributions of GDF-15 and Klotho.

Liraglutide Attenuates Diabetic Cardiomyopathy via the ILK/PI3K/AKT/PTEN Signaling Pathway in Rats with Streptozotocin-Induced Type 2 Diabetes Mellitus.

One of the possible candidates for the treatment of diabetic cardiomyopathy is liraglutide, a glucagon-like peptide-1 receptor (GLP1R) agonist. In this study, the impacts of liraglutide on the integrin-linked kinase (ILK)-related PI3K/AKT axis in rats with type 2 diabetes induced via streptozotocin were examined. Twenty-four Wistar albino rats were distributed in four different groups, and a high-fat diet and streptozotocin were used to induce type 2 in two groups. Rats in the untreated control groups were administered 0.9% NaCl solution over a 6-week period, and those in the treatment groups were administered 0.9% NaCl for 3 weeks, followed by subcutaneous injection of liraglutide (150 µg/kg) for an additional 3 weeks. In the liraglutide-treated diabetic group, the heart-to-body weight ratio was significantly reduced, levels of cardiac biomarkers, troponin I and creatine-kinase-MB, were improved; activities of antioxidant enzymes, glutathione peroxidase and superoxide dismutase, were increased; and levels of malondialdehyde were decreased. Western blotting and immunohistochemical studies revealed increased levels of ILK, P-PI3K, P-AKT, and BCL2, as well as those of caspase 3, BAX, and P-PTEN, indicating mitigation of cardiomyocyte apoptosis. Our results show that liraglutide, by targeting GLP1Rs, enhances the expression of proteins in the ILK/PI3K/AKT/PTEN pathway and thereby exerts its cardioprotective effects in rats with DCM.

Role of the integrin-linked kinase/TGF-ß/SMAD pathway in sitagliptin-mediated cardioprotective effects in a rat model of diabetic cardiomyopathy.

OBJECTIVES: Diabetic cardiomyopathy is a known complication of diabetes mellitus. Herein, we aimed to determine whether glycemic control mediated by sitagliptin, a dipeptidyl peptidase-4 inhibitor, can ameliorate diabetic myocardial abnormalities by modulating TGF-ß signaling via the SMAD and integrin-linked kinase (ILK) pathways. METHODS: Four groups of male Wistar albino rats were used, with six rats in each group. Two nondiabetic and two diabetic (produced by a single intraperitoneal dose of streptozotocin (55 mg/kg)) groups were administered either normal saline or sitagliptin (100 mg/kg) orally for 6 weeks. Subsequently, HW/BW ratios and cardiac enzymes were assessed, along with a histological examination of cardiac tissues. Levels of TGF-ß, collagen I, p-SMAD2/3, TNF-α, MMP-9, and ILK were detected. RESULTS: Compared with the diabetic control group, sitagliptin-treated diabetic rats exhibited considerably reduced HW/BW ratios and troponin I and creatine kinase-MB levels, with improvements in histopathological changes in cardiac tissues. TGF-ß, collagen I, p-SMAD2/3, TNF-α, and MMP-9 levels were significantly decreased in the sitagliptin-treated diabetic group, whereas ILK was elevated following sitagliptin treatment. CONCLUSION: Sitagliptin could afford cardioprotective effects for the first time by altering ILK-associated TGF-ß/SMAD signaling pathways. Thus, sitagliptin may be a promising therapeutic target for the prevention of diabetic cardiomyopathy.

Cardioprotective Effects of the GRK2 Inhibitor Paroxetine on Isoproterenol-Induced Cardiac Remodeling by Modulating NF-κB Mediated Prohypertrophic and Profibrotic Gene Expression.

Pathological cardiac remodeling is associated with cardiovascular disease and can lead to heart failure. Nuclear factor-kappa B (NF-κB) is upregulated in the hypertrophic heart. Moreover, the expression of the G-protein-coupled receptor kinase 2 (GRK2) is increased and linked to the progression of heart failure. The inhibitory effects of paroxetine on GRK2 have been established. However, its protective effect on IκBα/NFκB signaling has not been elucidated. This study investigated the cardioprotective effect of paroxetine in an animal model of cardiac hypertrophy (CH), focusing on its effect on GRK2-mediated NF-κB-regulated expression of prohypertrophic and profibrotic genes. Wistar albino rats were administered normal saline, paroxetine, or fluoxetine, followed by isoproterenol to induce CH. The cardioprotective effects of the treatments were determined by assessing cardiac injury, inflammatory biomarker levels, histopathological changes, and hypertrophic and fibrotic genes in cardiomyocytes. Paroxetine pre-treatment significantly decreased the HW/BW ratio (p < 0.001), and the expression of prohypertrophic and profibrotic genes Troponin-I (p < 0.001), BNP (p < 0.01), ANP (p < 0.001), hydroxyproline (p < 0.05), TGF-ß1 (p < 0.05), and αSMA (p < 0.01) as well as inflammatory markers. It also markedly decreased pIκBα, NFκB(p105) subunit expression (p < 0.05) and phosphorylation. The findings suggest that paroxetine prevents pathological cardiac remodeling by inhibiting the GRK2-mediated IκBα/NF-κB signaling pathway.

Investigating Behavioral and Neuronal Changes in Adolescent Mice Following Prenatal Exposure to Electronic Cigarette (E-Cigarette) Vapor Containing Nicotine.

A substantial percentage of pregnant smokers stop using traditional cigarettes and switch to alternative nicotine-related products such as e-cigarettes. Prenatal exposure to tobacco increases the risk of psychiatric disorders in children. Adolescence is a complex phase in which higher cognitive and emotional processes undergo maturation and refinement. In this study, we examined the behavioral and molecular effects of first-trimester prenatal exposure to e-cigarettes. Adult female mice were divided into normal air, vehicle, and 2.5%-nicotine-exposed groups. Our analyses indicated that the adolescents in the 2.5%-nicotine-exposed group exhibited a significant lack of normal digging behavior, elevated initial sucrose intake, and reduced recognition memory. Importantly, we identified a substantial level of nicotine self-administration in the 2.5%-nicotine-exposed group. At a molecular level, the mRNAs of metabotropic glutamate receptors and transporters in the nucleus accumbens were not altered. This previously undescribed work indicates that prenatal exposure to e-cigarettes might increase the risk of nicotine addiction during adolescence, reduce cognitive capacity, and alter normal adolescent behavior. The outcome will aid in translating research and assist healthcare practitioners in tackling addiction and mental issues caused by toxicological exposure. Further, it will inform relevant policymaking, such as recommended taxation, labeling e-cigarette devices with more detailed neurotoxic effects, and preventing their sale to pregnant women and adolescents.

Sitagliptin Mitigates Diabetic Nephropathy in a Rat Model of Streptozotocin-Induced Type 2 Diabetes: Possible Role of PTP1B/JAK-STAT Pathway.

Diabetic nephropathy (DN) is a microvascular complication of diabetes mellitus. This study examined the therapeutic effects of sitagliptin, a dipeptidyl peptidase inhibitor, on DN and explored the underlying mechanism. Male Wistar albino rats (n = 12) were intraperitoneally administered a single dose of streptozotocin (30 mg/kg) to induce diabetes. Streptozotocin-treated and untreated rats (n = 12) were further divided into normal control, normal sitagliptin-treated control, diabetic control, and sitagliptin-treated diabetic groups (n = 6 in each). The normal and diabetic control groups received normal saline, whereas the sitagliptin-treated control and diabetic groups received sitagliptin (100 mg/kg, p.o.). We assessed the serum levels of DN and inflammatory biomarkers. Protein tyrosine phosphatase 1 B (PTP1B), phosphorylated Janus kinase 2 (P-JAK2), and phosphorylated signal transducer activator of transcription (P-STAT3) levels in kidney tissues were assessed using Western blotting, and kidney sections were examined histologically. Sitagliptin reduced DN and inflammatory biomarkers and the expression of PTP1B, p-JAK2, and p-STAT3 (p < 0.001) and improved streptozotocin-induced histological changes in the kidney. These results demonstrate that sitagliptin ameliorates inflammation by inhibiting DPP-4 and consequently modulating the PTP1B-related JAK/STAT axis, leading to the alleviation of DN.

α1A Adrenoreceptor blockade attenuates myocardial infarction by modulating the integrin-linked kinase/TGF-ß/Smad signaling pathways.

BACKGROUND: Myocardial infarction (MI) is considered a public health problem. According to the World Health Organization, MI is a leading cause of death and comorbidities worldwide. Activation of the α1A adrenergic receptor is a contributing factor to the development of MI. Tamsulosin, an α1A adrenergic blocker, has gained wide popularity as a medication for the treatment of benign prostatic hyperplasia. Limited evidence from previous studies has revealed the potential cardioprotective effects of tamsulosin, as its inhibitory effect on the α1A adrenoceptor protects the heart by acting on the smooth muscle of blood vessels, which results in hypotension; however, its effect on the infarcted heart is still unclear. The mechanisms of the expected cardioprotective effects mediated by tamsulosin are not yet understood. Transforming growth factor-beta (TGF-ß), a mediator of fibrosis, is considered an attractive therapeutic target for remodeling after MI. The role of α1A adrenoceptor inhibition or its relationships with integrin-linked kinase (ILK) and TGF-ß/small mothers against decapentaplegic (Smad) signaling pathways in attenuating MI are unclear. The present study was designed to investigate whether tamsulosin attenuates MI by modulating an ILK-related TGF-ß/Smad pathway. METHODS: Twenty-four adult male Wistar rats were randomly divided into 4 groups: control, ISO, TAM, and ISO + TAM. ISO (150 mg/kg, intraperitoneally) was injected on Days 20 and 21 to induce MI. Tamsulosin (0.8 mg/kg, orally) was administered for 21 days, prior to ISO injection for 2 consecutive days. Heart-to-body weight ratios and cardiac and fibrotic biomarker levels were subsequently determined. ILK, TGF-ß1, p-Smad2/3, and collagen III protein expression levels were determined using biomolecular methods. RESULTS: Tamsulosin significantly attenuated the relative heart-to-body weight index (p < 0.5) and creatine kinase-MB level (p < 0.01) compared with those in the ISO control group. While ISO resulted in superoxide anion production and enhanced oxidative damage, tamsulosin significantly prevented this damage through antioxidant defense mechanisms, increasing glutathione and superoxide dismutase levels (p < 0.05) and decreasing lipid peroxide oxidation levels (p < 0.01). The present data revealed that tamsulosin reduced TGF-ß/p-Smad2/3 expression and enhanced ILK expression. CONCLUSION: Tamsulosin may exert a cardioprotective effect by modulating the ILK-related TGF-ß/Smad signaling pathway. Thus, tamsulosin may be a useful therapeutic approach for preventing MI.

P2X7 purinergic receptor: A potential target in heart diseases (Review).

The P2X7 purinergic receptor (P2X7R) is a non­selective cation channel activated by high levels of adenosine triphosphate that are commonly present in serious conditions. Activation of this purinergic receptor is closely related to the development of various disease states including inflammatory and neurodegenerative disorders, orthopedic diseases and types of cancer. Accumulating evidence has shown that the P2X7R plays a crucial role in the development of various heart diseases. For example, activation of P2X7Rs may alleviate myocardial ischemia­reperfusion injury by releasing endogenous cardiac protective substances. In contrast to these findings, activation of P2X7Rs can promote the development of acute myocardial infarction and myocarditis by inducing inflammatory responses. Activation of these receptors can also contribute to the development of different types of cardiomyopathies including diabetic cardiomyopathy, dilated cardiomyopathy and hypertrophic cardiomyopathy by inducing cardiac hypertrophy, fibrosis and apoptosis. Notably, inhibition of P2X7Rs can improve cardiac structure and function abnormalities following acute myocardial infarction, reduction of inflammatory responses following myocarditis and attenuation of the cardiomyopathy process. Furthermore, recent evidence has demonstrated that P2X7Rs are highly active in patients infected with coronavirus disease­2019 (COVID­19). Hyperactivation of P2X7Rs in COVID­19 may induce severe myocardial injury through the activation of several signaling pathways. The present study reviewed the important role of the P2X7R in cardiac dysfunctions and discusses its use as a possible new therapeutic approach for the prevention and treatment of several myocardial diseases.

Inflammation and Treatment-Resistant Depression from Clinical to Animal Study: A Possible Link?

The aim of this study was to investigate the relationship between treatment-resistant depression (TRD) and inflammation in humans and experimental models. For the human study, a retrospective cohort study was conducted with 206 participants; half were on antidepressants for major depressive disorder. The patients were divided into healthy and depressed groups. Inflammation was assessed based on the values of the main inflammatory biomarkers (CRP, WBC and ESR). For the animal experiments, 35 adult male Wistar rats were assigned to stressed and non-stressed groups. Inflammation and stress were induced using lipopolysaccharide and chronic unpredictable mild stress. A 10 mg/kg intraperitoneal injection of fluoxetine (FLX), a known antidepressant, was simultaneously administered daily for 4 weeks. Behavioral tests were performed. The plasma levels of inflammatory and stress biomarkers were measured and were significantly higher in the stressed and non-responsive groups in both studies. This study provides evidence of the link between inflammation and TRD. We further observed a possible link via the Phosphorylated Janus Kinase 2 and Phosphorylated Signal Transducer and Activator of Transcription 3 (P-JAK2/P-STAT3) signaling pathway and found that chronic stress and high inflammation hinder the antidepressant effects of FLX. Thus, non-response to antidepressants could be mitigated by treating inflammation to improve the antidepressant effect in patients with TRD.

Examining Anxiety, Sleep Quality, and Physical Activity as Predictors of Depression among University Students from Saudi Arabia during the Second Wave of the COVID-19 Pandemic.

Conducted during the second wave of the pandemic, this cross-sectional study examined the link between sleep quality, physical activity, exposure, and the impact of COVID-19 as predictors of mental health in Saudi undergraduate students. A convenience sample of 207 participants were recruited, 89% of whom were females and 94% were single. The measures included questionnaires on the level of exposure and the perceived impact of COVID-19, a physical activity measure, GAD-7, PHQ-9, and PSQI. The results indicated that approximately 43% of participants exhibited moderate anxiety, and 50% were at risk of depression. Overall, 63.93% of students exposed to strict quarantine for at least 14 days (n = 39) exhibited a high risk of developing depression (χ2(1) = 6.49, p < 0.05, ϕ = 0.18). A higher risk of depression was also found in students whose loved ones lost their jobs (χ2(1) = 4.24, p < 0.05, ϕ = 0.14). Moreover, there was also a strong association between depression and anxiety (ß = 0.33, p < 0.01), sleep quality (ß = 0.32, p < 0.01), and the perceived negative impact of COVID-19 on socio-economic status (ß = 0.26, p < 0.05), explaining 66.67% of depression variance. Our study highlights the socio-economic impact of this pandemic and the overwhelming prevalence of depression.

Examining bedtime procrastination, study engagement, and studyholism in undergraduate students, and their association with insomnia.

Introduction: Compulsive overstudying, known as studyholism, is an emerging behavioral addiction. In this study, we examine the prevalence of, and the relationships between, insomnia, study engagement, studyholism, bedtime procrastination among undergraduate students. Methods: The Studyholism (SI-10), Athens Insomnia (AIS), and bedtime procrastination scales were administered to a convenience sample of 495 university students. Results: Our findings indicate that the prevalence of insomnia was 75.31%, high studyholism was found in 15.31% of the sample, and increased study engagement was detected in 16.94%. Gender differences analysis revealed that females reported higher studyholism and bedtime procrastination than males. Fifth-year students had higher levels of studyholism than internship (p < 0.001), first-year (p < 0.01), and sixth-year students (p < 0.05). Insomnia was positively related to studyholism and bedtime procrastination. Furthermore, insomnia can be positively predicted by studyholism and bedtime procrastination. Participants with a medium level of studyholism were twice as likely to experience insomnia as those with a low level. Studyholics were six times more susceptible to insomnia than students with low studyholism levels. Compared to individuals with low bedtime procrastination levels, those with medium and high bedtime procrastination were twice as likely to report insomnia. Conclusion: Our study highlights the interplay between insomnia, studyholism, and bedtime procrastination. Further, the findings indicate the need to increase awareness of insomnia.

Examining the central effects of chronic stressful social isolation on rats.

Stress-related disorders are extremely complex and current treatment strategies have limitations. The present study investigated alternative pathological mechanisms using a combination of multiple environmental approaches with biochemical and molecular tools. The aim of the present study was to evaluate blood-brain-barrier (BBB) integrity in socially manipulated animal housing conditions. Multiple environmentally-related models were employed in the current study. The main model proposed (chronically isolated rats) was biochemically validated using the level of peripheral corticosterone. The current study examined and compared the mRNA levels of certain inflammatory and BBB markers in the hippocampal tissue of chronically isolated rats, including claudin-5 (cldn5) and tight junction protein (tjp). Animals were divided into four groups: i) Standard housed rats (controls); ii) chronically isolated rats; iii) control rats treated with fluoxetine, which is a standard selective serotonin reuptake inhibitor; and iv) isolated rats treated with fluoxetine. To further examine the effect of environmental conditions on BBB markers, the current study assessed BBB markers in enriched environmental (EE) housing and short-term isolation conditions. The results demonstrated a significant increase in cldn5 and tjp levels in the chronically isolated group. Despite some anomalous results, alterations in mRNA levels were further confirmed in EE housing conditions compared with chronically isolated rats. This trend was also observed in rats subjected to short-term isolation compared with paired controls. Additionally, levels of IL-6, an inflammatory marker associated with neuroinflammation, were markedly increased in the isolated group. However, treatment with fluoxetine treatment reversed these effects. The results indicated that BBB integrity may be compromised in stress-related disorders, highlighting a need for further functional studies on the kinetics of BBB in stress-related models.

Analysis of the molecular and behavioral effects of acute social isolation on rats.

The mechanism underlying depression, anxiety, and stress-related psychiatric disorders is far from understood. The utilization of animal models of anxiety and stress can improve our knowledge of the pathology of these disorders as well as aiding in the identification of pharmacological therapeutic targets. The involvement of inflammation in the pathology of stress-related disorders is widely acknowledged. This study was therefore undertaken to assess depressive and anxiety-like behavior as well as neuroinflammation in acute-isolated rats. The study design comprised two main groups:1) rats in acute isolation (one rat per cage) and 2) standard housing (two rats per cage). Within ten days of acute isolation, we carried behavioral tests including Sucrose Neophobia (SNP), Sucrose Preference Test (SPT), Open field (OPF), and a Forced swim test (FST). In a separate set of experiments, we examined the molecular changes after five days of isolations, we examined the mRNA expression of Toll-like receptors (TLRs) and inflammatory markers in the hippocampal brain region. We found that acute social isolation did not have profound functional effects and the behavioral analysis revealed similarities between the isolated and standard housed rats. However, the molecular studies showed a significant increase in TLRs. An increase in Interleukin 6 (IL-6) and Tumor necrosis factor-alpha (TNF-alpha) was observed in the hippocampus of isolated rats but not the control rats. The results suggest that acute environmental isolation does not significantly affect depressive and anxiety-like behavior but does contribute to upregulations in neuroinflammatory responses. This indicates the initiation of neuronal insults following exposure to short-term isolation.