The effects of exercise training on cardiac matrix metalloproteinases activity and cardiac function in mice with diabetic cardiomyopathy

Exercise preconditioning mitigates brain injury after cerebral ischemia-reperfusion injury in rats by restraining TIMP1

BACKGROUND

Cerebral ischemic disease is a common cerebrovascular disease, especially ischemic stroke. Exercise has protective functions on brain tissues following cerebral ischemia-reperfusion injury (CIRI), but its preventive effects and mechanisms in CIRI remain unclear. We aimed to investigate the effects and mechanisms of exercise preconditioning on CIRI.

METHODS

The middle cerebral artery occlusion (MCAO) operation was prepared to establish CIRI rats. All rats were randomized into the MCAO, exercise (exercise preconditioning plus MCAO operation), vector (exercise preconditioning, MCAO operation plus intraventricular injection of empty vector), and tissue inhibitor of metalloprotease 1 overexpression (OE-TIMP1, exercise preconditioning, MCAO operation plus intraventricular injection of OE-TIMP1) groups.

RESULTS

The results indicated that exercise preconditioning suppressed approximately 66.67% of neurological deficit scores and 73.79% of TIMP1 mRNA expression in MCAO rats, which were partially offset by OE-TIMP1. The protective effects of exercise against neuron death status and cerebral infarction size in MCAO rats were reversed by OE-TIMP1. It also confirmed that exercise weakened apoptosis and oxidative stress damage, with notable increases of B-cell lymphoma-2, superoxide dismutase, and glutathione peroxidase production, and evident decreases of BCL2-associated X, caspase 3, and malondialdehyde in MCAO rats, while these effects were partially reversed by OE-TIMP1. Additionally, the inhibitory effects of exercise on the protein levels of TIMP1, hypoxia-inducible factor-alpha, vascular endothelial growth factor receptor 2, vascular endothelial growth factor, and neurogenic locus notch homolog protein 1 in MCAO rats were partially reversed by OE-TIMP1.

CONCLUSION

Altogether, exercise preconditioning had protective effects on CIRI by restraining TIMP1, which provided new therapeutic strategies for preventing CIRI.

Realistic Aspects of Cardiac Ultrasound in Rats: Practical Tips for Improved Examination

Echocardiography is a reliable and non-invasive method for assessing cardiac structure and function in both clinical and experimental settings, offering valuable insights into disease progression and treatment efficacy. The successful application of echocardiography in murine models of disease has enabled the evaluation of disease severity, drug testing, and continuous monitoring of cardiac function in these animals. However, there is insufficient standardization of echocardiographic measurements for smaller animals. This article aims to address this gap by providing a guide and practical tips for the appropriate acquisition and analysis of echocardiographic parameters in adult rats, which may also be applicable in other small rodents used for scientific purposes, like mice. With advancements in technology, such as ultrahigh-frequency ultrasonic transducers, echocardiography has become a highly sophisticated imaging modality, offering high temporal and spatial resolution imaging, thereby allowing for real-time monitoring of cardiac function throughout the lifespan of small animals. Moreover, it allows the assessment of cardiac complications associated with aging, cancer, diabetes, and obesity, as well as the monitoring of cardiotoxicity induced by therapeutic interventions in preclinical models, providing important information for translational research. Finally, this paper discusses the future directions of cardiac preclinical ultrasound, highlighting the need for continued standardization to advance research and improve clinical outcomes to facilitate early disease detection and the translation of findings into clinical practice.

RNA sequencing reveals the potential mechanism of exercise preconditioning for cerebral ischemia reperfusion injury in rats

INTRODUCTION

Cerebral ischemia reperfusion injury (CIRI) often leads to deleterious complications after stroke patients receive reperfusion therapy. Exercise preconditioning (EP) has been reported to facilitate brain function recovery. We aim to explore the specific mechanism of EP in CIRI.

METHODS

Sprague-Dawley rats were randomized into Sham, middle cerebral artery occlusion (MCAO), and EP groups (n = 11). The rats in the EP group received adaptive training for 3 days (10 m/min, 20 min/day, with a 0° incline) and formal training for 3 weeks (6 days/week, 25 m/min, 30 min/day, with a 0° incline). Then, rats underwent MCAO surgery to establish CIRI models. After 48 h, neurological deficits and cerebral infarction of the rats were measured. Neuronal death and apoptosis in the cerebral cortices were detected. Furthermore, RNA sequencing was conducted to investigate the specific mechanism of EP on CIRI, and qPCR and Western blotting were further applied to confirm RNA sequencing results.

RESULTS

EP improved neurological deficit scores and reduced cerebral infarction in MCAO rats. Additionally, pre-ischemic exercise also alleviated neuronal death and apoptosis of the cerebral cortices in MCAO rats. Importantly, 17 differentially expressed genes (DEGs) were identified through RNA sequencing, and these DEGs were mainly enriched in the HIF-1 pathway, cellular senescence, proteoglycans in cancer, and so on. qPCR and Western blotting further confirmed that EP could suppress TIMP1, SOCS3, ANGPTL4, CDO1, and SERPINE1 expressions in MCAO rats.

CONCLUSION

EP can improve CIRI in vivo, the mechanism may relate to TIMP1 expression and HIF-1 pathway, which provided novel targets for CIRI treatment.

The Anti-Atherosclerotic Effects of Endothelin Receptor Antagonist, Bosentan, in Combination with Atorvastatin-An Experimental Study

Bosentan, an endothelin receptor antagonist (ERA), has potential anti-atherosclerotic properties. We investigated the complementary effects of bosentan and atorvastatin on the progression and composition of the atherosclerotic lesions in diabetic mice. Forty-eight male ApoE-/- mice were fed high-fat diet (HFD) for 14 weeks. At week 8, diabetes was induced with streptozotocin, and mice were randomized into four groups: (1) control/COG: no intervention; (2) ΒOG: bosentan 100 mg/kg/day per os; (3) ATG: atorvastatin 20 mg/kg/day per os; and (4) BO + ATG: combined administration of bosentan and atorvastatin. The intra-plaque contents of collagen, elastin, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-a (TNF-a), matrix metalloproteinases (MMP-2, -3, -9), and TIMP-1 were determined. The percentage of lumen stenosis was significantly lower across all treated groups: BOG: 19.5 ± 2.2%, ATG: 12.8 ± 4.8%, and BO + ATG: 9.1 ± 2.7% compared to controls (24.6 ± 4.8%, p < 0.001). The administration of both atorvastatin and bosentan resulted in significantly higher collagen content and thicker fibrous cap versus COG (p < 0.01). All intervention groups showed lower relative intra-plaque concentrations of MCP-1, MMP-3, and MMP-9 and a higher TIMP-1concentration compared to COG (p < 0.001). Importantly, latter parameters presented lower levels when bosentan was combined with atorvastatin compared to COG (p < 0.05). Bosentan treatment in diabetic, atherosclerotic ApoE-/- mice delayed the atherosclerosis progression and enhanced plaques' stability, showing modest but additive effects with atorvastatin, which are promising in atherosclerotic cardiovascular diseases.

Effects of Dapagliflozin on Myocardial Gene Expression in BTBR Mice with Type 2 Diabetes

BACKGROUND

Dapagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, is approved for the treatment of type 2 diabetes, heart failure, and chronic kidney disease. DAPA-HF and DELIVER trial results demonstrate that the cardiovascular protective effect of dapagliflozin extends to non-diabetic patients. Hence, the mechanism-of-action may extend beyond glucose-lowering and is not completely elucidated. We have previously shown that dapagliflozin reduces cardiac hypertrophy, inflammation, fibrosis, and apoptosis and increases ejection fraction in BTBR mice with type 2 diabetes.

METHODS

We conducted a follow-up RNA-sequencing study on the heart tissue of these animals and performed differential expression and Ingenuity Pathway analysis. Selected markers were confirmed by RT-PCR and Western blot.

RESULTS

SGLT2 had negligible expression in heart tissue. Dapagliflozin improved cardiac metabolism by decreasing glycolysis and pyruvate utilization enzymes, induced antioxidant enzymes, and decreased expression of hypoxia markers. Expression of inflammation, apoptosis, and hypertrophy pathways was decreased. These observations corresponded to the effects of dapagliflozin in the clinical trials.

Impacts of the DPP-4 Inhibitor Saxagliptin and SGLT-2 Inhibitor Dapagliflozin on the Gonads of Diabetic Mice

Diabetes mellitus is a metabolic disease that can cause systemic problems, including testicular dysfunction. Several diabetes medications have demonstrated potential adverse effects on the male reproductive system; however, the effects of saxagliptin and dapagliflozin have not been sufficiently examined. This investigation studied the impacts of saxagliptin and dapagliflozin treatments on the gonads in a male mouse model of diabetes. Testicular disturbances were assessed by sperm DNA damage, diakinesis-metaphase I chromosome examination, and spermiogram analysis. Our results showed more sperm DNA damage, more spermatocyte chromosome aberrations, lower sperm motility/count, and more sperm morphological anomalies in diabetic mice than in the control mice. Dapagliflozin significantly restored all examined measures to the control values in diabetic mice, unlike saxagliptin, which exacerbated the reduction in sperm count and motility. Both drugs significantly restored the gonadal redox imbalances in diabetic mice by decreasing reactive oxygen species accumulation and increasing glutathione levels. In conclusion, our study presents preliminary evidence for the safety and efficacy of dapagliflozin in alleviating testicular abnormalities induced by diabetes, making it a promising candidate drug for patients with diabetes in their reproductive age. As saxagliptin may have negative effects on fertility, its prescription should be avoided in young male diabetic patients.

Different exercise training intensities prevent type 2 diabetes mellitus-induced myocardial injury in male mice

Type 2 diabetes mellitus (T2DM) usually develop myocardial injury and that exercise may have a positive effect on cardiac function. However, the effect of exercise intensity on cardiac function has not yet been fully examined. This study aimed to explore different exercise intensities on T2DM-induced myocardial injury. 18-week-old male mice were randomly divided into four groups: a control group, the T2DM, T2DM + medium-intensity continuous training (T2DM + MICT), and T2DM + high-intensity interval training (T2DM + HIIT) groups. In the experimental group, mice were given high-fat foods and streptozotocin for six weeks and then divided into two exercise training groups, in which mice were subjected to exercise five days per week for 24 consecutive weeks. Finally, metabolic characteristics, cardiac function, myocardial remodeling, myocardial fibrosis, oxidative stress, and apoptosis were analyzed. HIIT treatment improved cardiac function and improved myocardial injury. In conclusion, HIIT may be an effective means to guard against T2DM-induced myocardial injury.

The anti-inflammatory effects of aerobic exercise training in patients with type 2 diabetes: A systematic review and meta-analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a low-grade, chronic inflammatory disease, associated with increased cardiovascular risk. The purpose of this systematic review/ meta-analysis was to evaluate the effects of aerobic exercise training (AET) on inflammatory markers in T2DM patients.

METHODS

The literature search was conducted utilizing PubMed, Web of Science, Embase, and the Cochrane Library from their inception up to April 2022. We screened only for randomized controlled trials (RCTs) investigating the effects of AET on C-reactive protein (CRP) and adipokines: adiponectin, resistin, interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-a), along with changes in anthropometric indices and glycemic control in adult T2DM patients. Pooled post-exercise weighted mean differences (WMDs) with 95% Confidence Intervals (CIs) were calculated for all outcomes of interest between exercise-treated patients and controls.

RESULTS

Twenty-six RCTs involving 1239 T2DM patients were retrieved from the databases for meta-analysis. The cumulative results showed that post-AET inflammatory markers were lower in exercise-treated patients compared to controls regarding CRP (mg/L): WMD: -0.91; 95%CIs: -1.43, -0.40; p < 0.001 resistin (mg/ml): (WMD: -2.08; 95%CIs: -3.32, -0.84; p < 0.001); TNF-a (pg/ml): (WMD: -2.70; 95%CIs: -4.26, -1.14; p < 0.001), and IL-6 (pg/ml): (WMD: -1.05; 95%CIs: -1.68, -0.43; p < 0.001). Those effects were accompanied by significant amelioration of fasting glucose (mg/dl) (WMD: -13.02; 95%CIs: -25.39, -0.66; p = 0.04), HbA1c (%) (WMD: -0.51; 95%CIs: -0.73, -0.28, p < 0.001), and fat mass (%) (WMD: -3.14; 95%CI: -4.71, -1.58; p < 0.001). Our meta-analysis demonstrated less-consistent results for adiponectin (μg/ml), (WMD: 1.00; 95%CI: -0.12, 2.12; p = 0.08) and body-mass index (kg/m²) (WMD: -1.34; 95%CI: -2.76, 0.08; p = 0.06) tending to differ between AET and control group.

CONCLUSIONS

AET can significantly reduce the inflammatory burden in T2DM patients. by ameliorating the circulating levels of CRP, resistin, TNF-a and IL-6, even without accompanied significant weight-loss. The clinical impact of those anti-inflammatory effects of AET needs to be determined.

Feasibility study of automated cardiac motion quantification to assess left ventricular function in type 2 diabetes

The global incidence of diabetes and related complications is gradually increasing, with cardiovascular complications being the leading cause of death in the diabetic population. The purpose of this study was to examine left ventricular function in individuals with type 2 diabetes mellitus (T2D) and conduct a feasibility analysis using automated cardiac motion quantification (aCMQ) approach. A total of 150 T2D patients with a history of diabetes mellitus dating back more than 10 years were chosen, and we treated 87 patients with T2D that had been present for less than 15 years as group I, 63 patients with T2D that had been present for more than 15 years as group II, and 50 healthy volunteers as the control group. From the three groups, clinical information, conventional ultrasonography parameters, and mitral annular plane systolic excursion (MAPSE) parameters were gathered. aCMQ technique was used to collect longitudinal strain and circumferential strain in the left ventricle. Tissue motion mitral annular displacement technique (TMAD) in aCMQ was used to collect parameters related to TMAD, and cardiac motion quantification (CMQ) was used to collect two-dimensional global longitudinal strain (2D-GLS) to compare the degree of difference between the aforementioned three groups. The differences between longitudinal strain groups in aCMQ were all statistically significant and gradually decreased with increasing disease duration. Most TMAD parameters were lower in groups I and II than in the control group, and TMAD parameters gradually decreased with increasing disease duration. The results of the LV global longitudinal strain and 2D-GLS using Bland-Altman analyses showed high agreement between and within groups, Pearson correlation analysis showed a significant positive correlation (r = 0.18, P < 0.05), and the AUC of ROC curves predicting the value of left ventricular function in patients with T2D was 0.723 and 0.628, respectively. With significant positive correlations between MAPSE, s', and the majority of the TAMD parameters (P < 0.05), TAMD, MAPSE, and s' demonstrated high inter- and intra-group agreement using Bland-Altman analyses, and the three had predictive value in assessing left ventricular function in T2D patients by ROC curve. Reduced longitudinal strain and reduced mitral annular displacement were seen in patients with different disease stages of T2D, so the application of aCMQ and TAMD was effective in detecting altered left ventricular function in patients with T2D. aCMQ had higher value in predicting left ventricular function in patients with T2D compared to CMQ for overall longitudinal strain, and the software performed the depiction automatically, reducing manual errors. MAPSE parameters and s ' can replace the TMAD technique for assessing mitral annular motion and was simpler to perform, saving operational time.

Hypermethylation of the Promoter Region of miR-23 Enhances the Metastasis and Proliferation of Multiple Myeloma Cells via the Aberrant Expression of uPA

Multiple myeloma has a long course, with no obvious symptoms in the early stages. However, advanced stages are characterized by injury to the bone system and represent a severe threat to human health. The results of the present work indicate that the hypermethylation of miR-23 promoter mediates the aberrant expression of uPA/PLAU (urokinase plasminogen activator, uPA) in multiple myeloma cells. miR-23, a microRNA that potentially targets uPA’s 3’UTR, was predicted by the online tool miRDB. The endogenous expressions of uPA and miR-23 are related to disease severity in human patients, and the expression of miR-23 is negatively related to uPA expression. The hypermethylation of the promoter region of miR-23 is a promising mechanism to explain the low level of miR-23 or aberrant uPA expression associated with disease severity. Overexpression of miR-23 inhibited the expression of uPA by targeting the 3’UTR of uPA, not only in MM cell lines, but also in patient-derived cell lines. Overexpression of miR-23 also inhibited in vitro and in vivo invasion of MM cells in a nude mouse model. The results therefore extend our knowledge about uPA in MM and may assist in the development of more effective therapeutic strategies for MM treatment.