Abstract: In the past decade, researches on Wnt signaling in cell biology have made remarkable progress regarding our understanding of embryonic development, bone formation, muscle injury and repair, neurogenesis, and tumorigenesis. The study also showed that physical activity can reverse age-dependent decline in skeletal muscle, preventing osteoporosis, regenerative neurogenesis, hippocampal function, cognitive ability, and neuromuscular junction formation, and the age-dependent recession is highly correlated with Wnt signaling pathways. However, how the biological processes in cell and physical activity during/following exercise affect the Wnt signaling path of the locomotor system is largely unknown. In this study, we first briefly introduce the important features of the cellular biological processes of exercise in the locomotor system. Then, we discuss Wnt signaling and review the very few studies that have examined Wnt signaling pathways in cellular biological processes of the locomotor system during physical exercise.
Keywords: physical exercise, Wnt signaling, cell biological processes, locomotor system, neuromuscular junction
Abstract: This review discusses the potential role that glial cells may play in influencing the relationship between exercise and episodic memory function. A narrative review methodology is employed. Herein, the different types of glial cells, their implications in subserving episodic memory function, and how exercise can modulate glial cell activity, particularly astrocyte functionality, are discussed. Although additional experimental work is needed, astrocytes appear to play an important role in the exercise–memory interaction. Exercise may increase astrocytic size, attenuate astrogliodegeneration, improve astrocytic aquaporin-4 expression, and increase astrocytic transporter levels. These effects, in turn, may help to increase the number of synapses that neurons form, increase the number of synaptic structures, and increase presynaptic function and postsynaptic receptor localization. Ultimately, these effects may help influence long-term potentiation and episodic memory function.
Keywords: astrocyte, cognition, glial, long-term potentiation, physical activity, synaptic plasticity
Abstract: Purpose: We previously found that homocysteine (Hcy)-induced apoptosis in endothelial cells coincided with increased NADPH oxidase (NOX) activity. In addition, in ischemic endothelial cells present in the heart, we showed that loss of serine protease dipeptidyl peptidase IV (DPP4) expression was correlated with induction of tissue factor (TF) expression. Since Hcy can initiate thrombosis through the induction of TF expression, in this study, we evaluated whether the inverse relation of TF and DPP4 is also Hcy-dependent and whether NOX-mediated reactive oxygen species (ROS) is playing a role herein. Methods: Human umbilical vein endothelial cells (HUVECs) were incubated with 2.5 mM Hcy for 3 and 6 h. The effects of Hcy on DPP4 and TF expression and NOX2/p47phoxmediated nitrotyrosine (ROS) production were studied using digital-imaging microscopy. Results: In HUVECs, high levels of Hcy showed a significant increase of TF expression and a concomitant loss of DPP4 expression after 6 h. In addition, NOX subunits NOX2 and p47phox were also significantly increased after 6 h of Hcy incubation and coincided with nitrotyrosine (ROS) expression. Interestingly, inhibition of NOX-mediated nitrotyrosine (ROS) with the use of apocynin not only reduced these effects, but also counteracted the effects of Hcy on TF and DPP4 expression. Conclusion: These results indicate that the inverse relation of TF and DPP4 in endothelial cells is also Hcy-dependent and related to NOX activity.
Keywords: homocysteine, tissue factor, DPP4, endothelial cells, NADPH oxidase
Abstract: Objectives: Impaired angiogenesis in sciatic nerve is a major complication of diabetic neuropathy. Protein kinase B (AKT) and extracellular signal regulated kinase (ERK) signaling pathways play critical roles during capillary-like network formation in the angiogenesis process. Methods: Twenty-four adult male Wistar rats (weight: 250–300 g) were used in the research. The rats were randomly divided into four groups (n = 6): (1) diabetic (Dia), (2) diabetic + castration (Dia-Cas), (3) diabetic + exercise (Dia-E), and (4) diabetic + castration + exercise (Dia-Cas-E). Type 1 diabetes (T1D) was induced with streptozotocin (50 mg/kg). After 6 weeks, sciatic nerve was separated and used for histological evaluation and determination of phosphorylated AKT (P-AKT) and phosphorylated ERK (P-ERK) levels by ELISA method. Results: Glucose levels decreased in the Dia-E group compared to the Dia-Cas group (p < 0.01). In addition, our finding shows that exercise in the Dia-Cas group diminished blood glucose levels compared to the Dia-Cas group but this effect of exercise was not significant. Voluntary exercise in the diabetic castrated group decreased P-AKT protein and increased P-ERK 1/2 protein levels in the sciatic tissue compared to the diabetes group significantly (p < 0.05). Histopathological findings showed that Dia-Cas group with 6-week exercise training significantly raised the number of microvascular density in the sciatic tissue of diabetic rats compared to the diabetic group (p < 0.05). Conclusions: Voluntary exercise in diabetic rats increases angiogenesis in the sciatic nerve. The possible mechanism is the increase of P-ERK 1/2 but not P-AKT levels in the sciatic nerve of T1D rats.
Keywords: angiogenesis, diabetic neuropathy, sciatic nerve, testosterone, voluntary exercise
Abstract: Objective: Low levels of testosterone in men with diabetes are associated with cardiovascular complications. We investigated the effect of testosterone and voluntary exercise on heart angiogenesis in castrated diabetic rats. Methods: Sixty-three diabetic rats were treated with testosterone 2 mg/kg/day or voluntary exercise alone or combination of these two for 6 weeks. At the end of the study, heart tissue samples were collected and used for CD31 detection by immunohistochemical method and determination of miR-132 levels. Results: miR-132 levels and CD31 of heart tissue were higher after testosterone administration and in the voluntary exercise group in diabetic rats after 6 weeks. Combination of testosterone and voluntary exercise had synergistic effect on angiogenesis and miR-132 level. In castrated diabetic rats, there were significantly lower levels of miR-132 and CD31 in heart tissue compared to the diabetic group, whereas testosterone and exercise reversed these effects. In addition, testosterone supplementation plus exercise had an additive effect on miR-132 levels and CD31 in castrated diabetic rats. Conclusions: It was concluded that castration in rats leads to reduced miR-132 levels and subsequently decreased angiogenesis in diabetes. Testosterone plus voluntary exercise improved angiogenesis possibly through enhancement of miR-132 levels in heart of castrated diabetic rats.
Keywords: testosterone, voluntary exercise, miR-132, angiogenesis, diabetes
Abstract: Introduction: Major depressive disorder is a serious mental disorder in which treatment with antidepressant medication is associated with incidence of adverse events, such as constipation, diarrhea, dry mouth, headache, insomnia, and sexual dysfunction (SDys). Escitalopram (ESC), an effective and safe selective serotonin reuptake inhibitor with good tolerability, was used in this study. In this study, we investigated the prospective effect of Pycnogenol (PYC), an antioxidant, anti-inflammatory, and vasodilator agent, on ESC-induced SDys. Methods: This was a randomized, parallel, open-label study. Seventy-two outpatients of both genders with depression were randomized into two groups as follows: 37 patients from the ESC + PYC group took 50 mg of PYC per day for 4 months in ESC co-treatment, and 35 subjects from the ESC group took ESC only. Five patients dropped out and were excluded from the analysis. The participants were examined every month (visits 1–4). Results: ESC use led to improvement of depressive symptoms and severity scored by standardized psychiatric tests. PYC co-treatment resulted in attenuation of SDys beginning at 1 month of treatment and continuing for two consecutive months. Furthermore, an increase in heart rate in the PYC group was registered. Conclusions: We propose that PYC-mediated SDys attenuation is based on its ability to improve endothelial functions by its antioxidant, anti-inflammatory, vasodilatory, and anticoagulant action. We assume that the action of PYC on heart rate is in accordance with the aforementioned vasodilatory action of PYC and consequent baroreflex-mediated heart rate response. PYC co-treatment reduced ESC-induced SDys and elevated heart rate.
Keywords: Pycnogenol, depression, sexual dysfunction, escitalopram, heart rate
Abstract: The aim of this study was to compare the effects of 8 weeks of aerobic versus resistance training programs on serum fetuin-A, fetuin-B, and fibroblast growth factor-21 (FGF-21) levels in males with type 2 diabetes mellitus. Participants (n = 34) were randomly assigned to a resistance training group (RTG; n = 12), an aerobic training group (ATG; n = 11), or a control group (n = 11). The ATG completed 30–45 min of aerobic running training at 65%–75% of the maximum heart rate. The RTG completed three sets of 10 repetitions maximum of leg press, bench press, knee extension, seated cable row, knee flexion, military press, and calf rise. Blood samples were taken before and after the training period to assess dependent variables. After 8 weeks, both the ATG and the RTG reduced fetuin- A (p < 0.05) and fetuin-B (p < 0.05), but increased FGF-21 (p < 0.05). Moreover, the RTG showed greater decrease than the ATG in fetuin-A (−18.3% vs. −7.9%), fetuin-B (−29.2% vs. −11.45%), and a lower increase in FGF-21 (42.2% vs. 25.1%), respectively. Aerobic and resistance exercise training significantly decreased serum fetuin-A, and fetuin-B, and increased FGF-21 levels in males with type 2 diabetes mellitus. However, more significant alterations in serum factors were observed from resistance training. Thus, resistance training may be considered a more suitable training strategy.
Keywords: exercise training, hepatokines, insulin, glucose, type 2 diabetes
Abstract: Purpose: The purpose of this study is to determine heart rate (HR) recovery after maximal test in elite athletes who compete in high dynamic, high static, and in mixed sport disciplines; to assess differences in HR recovery between these groups of athletes; and to measure the association of HR index (HRI) with heart adaptation variables to determine whether these values were correlated with the type of exercise. Methods: One hundred and ninety-four elite athletes were divided into three groups according to the predominant type of exercise performed: endurance (n = 40), strength-sprinter (n = 36), and ball-game players (n = 118). They performed maximal cardiopulmonary exercise testing on a treadmill and were subjected to echocardiography. The rate of decline (HR recovery) was calculated as the difference between maximum and recovery HRs (HRrec1 and HRrec3). The HRI was calculated as HRmax – 1-min post-exercise HR (HRrec1). Results: The most significant correlation of HRI was with posterior wall diameter and left ventricular (LV) mass index (r = 0.43 and r = 0.51; p = 0.012 and p = 0.003, respectively). LV mass index [Beta (B) = 0.354, p = 0.001] was an independent predictor of HRI and HRrec1. HRI may be an effective tool for discrimination of physiological and “gray zone” LV hypertrophy, with area under the curve of 0.545 (95% CI = 0.421–0.669, p = 0.0432). HRI displayed a sensitivity of 50% and specificity of 52.2% at the optimal cut-off value of 23.5. Conclusion: HR recovery pattern, especially HRI, may offer a timely and efficient tool to identify athletes with autonomous nervous system adaptive changes.
Keywords: heart rate recovery, heart rate index, athlete’s heart, cardiovascular adaptation, elite athletes