The role of TRPC6 calcium channels and P2 purinergic receptors in podocyte mechanical and metabolic sensing

Podocyte calcium (Ca2+) signaling plays important roles in the (patho)physiology of the glomerular filtration barrier. Overactivation of podocyte transient receptor potential canonical (TRPC) channels including TRPC6 and purinergic signaling via P2 receptors that are known mechanosensors can increase podocyte intracellular Ca2+ levels ([Ca2+]i) and cause cell injury, proteinuria and glomerular disease including in diabetes. However, important mechanistic details of the trigger and activation of these pathways in vivo in the intact glomerular environment are lacking. Here we show direct visual evidence that podocytes can sense mechanical overload (increased glomerular capillary pressure) and metabolic alterations (increased plasma glucose) via TRPC6 and purinergic receptors including P2Y2. Multiphoton microscopy of podocyte [Ca2+]i was performed in vivo using wild-type and TRPC6 or P2Y2 knockout (KO) mice expressing the calcium reporter GCaMP3/5 only in podocytes and in vitro using freshly dissected microperfused glomeruli. Single-nephron intra-glomerular capillary pressure elevations induced by obstructing the efferent arteriole lumen with laser-induced microthrombus in vivo and by a micropipette in vitro triggered >2-fold increases in podocyte [Ca2+]i. These responses were blocked in TRPC6 and P2Y2 KO mice. Acute elevations of plasma glucose caused >4-fold increases in podocyte [Ca2+]i that were abolished by pharmacological inhibition of TRPC6 or P2 receptors using SAR7334 or suramin treatment, respectively. This study established the role of Ca2+ signaling via TRPC6 channels and P2 receptors in mechanical and metabolic sensing of podocytes in vivo, which are promising therapeutic targets in conditions with high intra-glomerular capillary pressure and plasma glucose, such as diabetic and hypertensive nephropathy.

Effect of vanillic acid and exercise training on fatty liver and insulin resistance in rats: Possible role of fibroblast growth factor 21 and autophagy

Background and aims The prevalence of non-alcoholic fatty liver disease has been alarmingly increased with no lines of effective treatment. Vanillic acid is a naturally occurring polyphenol with promising therapeutic effects. Exercise is well known to be an effective tool against obesity and its consequences. Thus, we aim to study the effect of vanillic acid alone and along with exercise on fatty liver induced by a high-fat diet in a rat model and to investigate possible novel mechanisms involved in their action. Methods In this study, 40 male rats were divided equally into five groups: control (standard chow diet), HFD (high-fat diet), HFD+VA (HFD+ vanillic acid (50 mg/kg/day orally), HFD+EX (HFD+ swimming exercise 5 days/week), HFD+VA+EX (HFD+ vanillic acid+ swimming exercise) for eight weeks. Results Body mass, liver weight, liver enzymes, cholesterol, and triglycerides were significantly decreased in the combined VA+EX group, with marked improvement in hyperglycemia, hyperinsulinemia, and consequently HOMA-IR index compared to the HFD group. These improvements were also reflected in the pathological view. VA and swimming, either solely or in combination, markedly increased hepatic and circulating fibroblast growth factor 21. Additionally, VA and swimming increased the immunohistochemical expression of the autophagosomal marker LC3 and decreased the expression of P62, which is selectively degraded during autophagy. Conclusions These results suggest the hepatoprotective effect of VA and swimming exercise against fatty liver and the involvement of FGF21 and autophagy in their effect.

ARHGEF19 promotes the growth of breast cancer in vitro and in vivo by the MAPK pathway

Objective To assess the expression of ARHGEF19 in human breast cancer, investigate its role in breast cancer, and clarify the mechanism. Methods Bioinformatics analysis, immunoblot, quantitative PCR, and immunohistochemical (IHC) assays were performed to assess ARHGEF19 expression in breast cancer. CCK-8 and Edu assays were conducted to reveal its role in breast cancer cell proliferation. Flow cytometry (FCM) assays and immunoblot were performed to confirm its effects on breast cancer apoptosis. Immunoblot was also performed to clarify the mechanism. Finally, tumor growth assays were aimed to confirm the role of ARHGEF19 in mice. Results We observed that ARHGEF19 was highly expressed in human breast cancer. ARHGEF19 promoted breast cancer cell growth in vitro, and suppressed apoptosis. In addition, we found that ARHGEF19 could activate the MAPK pathway in breast cancer cells. Our findings further confirmed that ARHGEF19 contributed to breast cancer growth in mice. Conclusion We observed that ARHGEF19 promoted the growth of breast cancer in vitro and in vivo via MAPK pathway, and presume it could serve as a breast cancer therapeutic target.

The use of near-infrared spectroscopy for the evaluation of a 4-week rehabilitation program in patients with COPD

Background Near-infrared spectroscopy (NIRS) technology can evaluate muscle metabolism and oxygenation. NIRS-based oximeters can measure skeletal muscle oxygen delivery and utilization during static and dynamic work non-invasively. Our goal was to assess the value and usability of NIRS technology in chronic obstructive pulmonary disease (COPD) rehabilitation program. Methods Forty patients with COPD participated in a 4-week inpatient rehabilitation program that included breathing exercises and personalized cycle/treadmill training adjusted to the functional capacity, physical activity and comorbidities of the patients. A NIRS muscle oxygen monitor was used to measure tissue oxygenation and hemoglobin levels. Total hemoglobin index, average muscle oxygenation, minimal and maximal muscle oxygenation were recorded before and after the rehabilitation program. Results Rehabilitation resulted improvement in 6 min walking distance (6MWD:335.3 ± 110. vs. 398.3 ± 126.2 m; P < 0.01), maximal inspiratory pressure (MIP: 57.7 ± 22.7 vs. 63.6 ± 18.0 cmH2O; P < 0.01), chest wall expansion (CWE: 2.84 ± 1.26 vs, 4.00 ± 1.76 cm; P < 0.01), breath hold time (BHT: 25.8 ± 10.6 vs. 29.2 ± 11.6 s; P < 0.01) and grip strength (GS: 24.9 ± 11.9 vs. 27.0 ± 11.4 kg; P < 0.01). Quality of life improvement was monitored by COPD Assessment Test (CAT: 17.00 ± 8.49 vs. 11.89 ± 7.3, P < 0.05). Total hemoglobin index (tHb: 12.8 ± 1.3% vs. 12.8 ± 1.4), average muscle oxygenation (SmO2: 67.5 ± 14.4% vs. 65.2 ± 20.4%) showed a tendency for improvement. Maximal muscle oxygenation decreased (SmO2 max: 98.0 ± 20.5% vs. 90.1 ± 14.3%; P < 0.01). Minimal muscle oxygenation increased (SmO2 min: 42.6 ± 12.6% vs. 54.8 ± 14.3%; P < 0.01). Conclusions NIRS results showed that muscle oxygenation and microcirculation can be described as a high-risk factor in COPD patients. The 4-week rehabilitation improves functional parameters, quality of life and tissue oxygenation levels in COPD patients.

Depression among predictors of intermittent claudication: A cross-sectional study

Purpose The aim of the present cross-sectional study was to investigate the relationship between depression and intermittent claudication (IC), independently of traditional risk factors. Main methods The sample consisted of 300 individuals (M age = 65.3 ± 8.7 years, 61.0% female) recruited from the offices of 33 general practitioners. Participants’ medical history and the presence of major cardiovascular risk factors were recorded. Participants completed the Edinburgh Claudication Questionnaire. The role of depression (assessed by a shortened version of the Beck Depression Inventory) in predicting IC was examined using a binary logistic regression analysis – controlled for sex, age, hypertonia, diabetes, smoking, hypercholesterinemia, hazardous drinking, and body mass index (BMI). Results The descriptive data indicated that the prevalence of depression was 57.9% in the IC subgroup and 16.1% in those free of IC. The bivariate analyses indicated that hypercholesterinemia, smoking, hazardous drinking, BMI, and depression were significantly associated with IC. Male sex and age showed a trend toward being a significant correlate of IC. Results of the multivariate analyses indicated that depressive symptomatology was significant in predicting IC (OR: 1.08 (1.05–1.11)), even after controlling for lifestyle and traditional risk factors such as smoking, hazardous drinking, and BMI. Among traditional risk factors, smoking (OR: 2.44 (1.26–4.74)), hazardous drinking (OR: 1.19 (1.02–1.40)), and hypercholesterinemia (OR: 2.17 (1.26–3.75)) showed a significant, positive relationship with IC. Conclusions These results underscore the importance of a multidisciplinary approach that focuses on supporting health-related behavioral changes and managing mental health symptoms when providing care for patients with IC.

The “GG” genotype of rs26802 variant in the ghrelin gene is a potential protective factor against nonalcoholic fatty liver disease

Background Nonalcoholic fatty liver disease (NAFLD) is an emerging global chronic liver disease worldwide. Considering the powerful association between NAFLD, insulin resistance (IR) and obesity, as well as the key role of ghrelin in these metabolic disorders, we hypothesized that some single nucleotide polymorphisms (SNPs) of the ghrelin (GHRL) and ghrelin receptor (GHSR) genes might be associated with NAFLD. Methods We conducted a case-control retrospective study of 150 cases with biopsy-proven NAFLD and 155 controls. The diagnosis of NAFLD was established before the start of the genotyping process. All the 305 subjects were genotyped for GHRL SNP rs26802 or -501T>G and GHSR SNP rs572169 or Arg159Arg using the PCR-RFLP method. Results The GHRL rs26802 “GG” genotype compared with the “TT” genotype and “TT+TG” genotype appears to be a marker of decreased NAFLD susceptibility even after adjustment for confounding factors (P = 0.006; OR = 0.14, 95% CI = 0.03–0.56 and P = 0.003; OR = 0.16, 95% CI = 0.05–0.53, respectively). However, we observed no significant difference in genotype or allele frequencies between the cases and controls for GHSR SNP rs572169. Conclusions These findings proposed, for the first time, that the GHRL rs26802 “GG” genotype has a protective effect against NAFLD. Nonetheless, this observation warrants further investigations in other populations.

Perturbation-based balance assessment: Examining reactive balance control in older adults with mild cognitive impairments

Background Older adults with mild cognitive impairment (OAwMCI) present subtle balance and gait deficits along with subjective memory decline. Although these presentations might not affect activities of daily living (ADLs), they attribute to a two-folded increase in falls. While changes occurring in volitional balance control during ADLs have been extensively examined among OAwMCI, reactive balance control, required to recover from external perturbations, has received little attention. Therefore, this study examined reactive balance control in OAwMCI compared to their healthy counterparts. Methods Fifteen older adults with mild cognitive impairment (OAwMCI), fifteen cognitively intact older adults (CIOA) (>55 years), and fifteen young adults (18–30 years) were exposed to stance perturbations at three different intensities. Behavioral outcomes postural COM state stability, step length, step initiation, and step execution were computed. Results Postural COM state stability was the lowest in OAwMCI compared to CIOA and young adults, and it deteriorated at higher perturbation intensities (P < 0.001). Step length was the lowest among OAwMCI and was significantly different from young adults (P < 0.001) but not from CIOA. Unlike OAwMCI, CIOA and young adults increased their step length at higher perturbation intensities (P < 0.001). OAwMCI showed longer recovery step initiation times and shorter execution times compared to CIOA and young adults at higher perturbation intensities (P < 0.001). Conclusion OAwMCI exhibit exacerbated reactive instability and are unable to modulate their responses as the threat to balance control altered. Thus, they are at a significantly higher risk of falls than their healthy counterparts.

The influence of external load variables on creatine kinase change during preseason training period

Objective The aim of the present study was to analyse the relationships between creatine kinase (CK) concentration, an indirect marker of muscle damage, and global positioning system (GPS)-derived metrics of a continuous two-week-long preseason training period in elite football. Design Twenty-one elite male professional soccer players were assessed during a 14-day preseason preparatory period. CK concentrations were determined each morning, and a GPS system was used to quantify the external load. A generalized estimating equation (GEE) model was established to determine the extent to which the external load parameter explained post-training CK levels. Results The GEE model found that higher numbers of decelerations (χ 2 = 7.83, P = 0.005) were most strongly associated with the post-training CK level. Decelerations and accelerations accounted for 62% and 11% of the post-training CK level, respectively, and considerable interindividual variability existed in the data. Conclusion The use of GPS to predict muscle damage could be of use to coaches and practitioners in prescribing recovery practices. Based on GPS data, more individualized strategies could be devised and could potentially result in better subsequent performance.

Aerobic interval training improves irisin and chemerin levels of both liver and visceral adipose tissues and circulating asprosin in rats with metabolic syndrome

The perturbation of adipokinetic hormones, such as irisin, chemerin, and asprosin has been reported to participate in pathological conditions (e.g., insulin resistance) and chronic inflammation. However, exercise training has been long established as an effective intervention for prevention and treatment of these chronic and metabolic diseases. This study was to examine the effects of aerobic continuous training (ACT) and aerobic interval training (AIT) on irisin and chemerin levels of liver tissue (LT) and visceral adipose tissue (VAT), circulating asprosin, and their relationships with cardiometabolic risk factors in rats with metabolic syndrome (MetS). Thirty-two male Wistar rats were randomly divided into four equal groups: normal control (N-Ctr), control (Ctr-MetS), ACT, and AIT. After familiarization, rats with exercise intervention performed either ACT or AIT five times a week over eight weeks. The level of irisin in both ACT and AIT groups was higher than the Ctr-MetS group in LT and VAT, with a greater improvement of LT level observed in AIT vs. ACT groups. Furthermore, the level of chemerin in LT and VAT was lower in both ACT and AIT groups than the Ctr-MetS group, whereas only AIT group exhibited a reduction of serum asprosin when compared to ACT and Ctr-MetS, along with the improvements of cardiometabolic markers, such as HOMA-IR and lipid profile. These findings may support the efficiency and effectiveness of AIT intervention in the modulation of these novel metabolic hormones and cardiometabolic risk factors for reduced risk of metabolic syndrome.

Ferulic acid attenuates osteoporosis induced by glucocorticoid through regulating the GSK-3β/Lrp-5/ERK signalling pathways

Objective To evaluate in-vivo and in-vitro effects of ferulic acid (FA) on glucocorticoid-induced osteoarthritis (GIO) to establish its possible underlying mechanisms. Methods The effects of FA on cell proliferation, cell viability (MTT assay), ALP activity, and mineralization assay, and oxidative stress markers (ROS, SOD, GSH LDH and MDA levels) were investigated by MC3T3-E1 cell line. Wistar rats received standard saline (control group) or dexamethasone (GC, 2 mg−1 kg) or DEX+FA (50 and 100 mg−1 kg) orally for 8 weeks. Bone density, micro-architecture, bio-mechanics, bone turnover markers and histo-morphology were determined. The expression of OPG, RANKL, osteogenic markers, and other signalling proteins was assessed employing quantitative RT-PCR and Western blotting. Results The findings indicated the elevation of ALP mRNA expressions, osteogenic markers (Runx-2, OSX, Col-I, and OSN), and the β-Catenin, Lrp-5 and GSK-3β protein expressions. FA showed the potential to increase MC3T3-E1 cell differentiation, proliferation, and mineralization. FA increased oxidative stress markers (SOD, MDA, and GSH) while decreasing ROS levels and lactate dehydrogenase release in GIO rats. The OPG/RANKL mRNA expression ratio was increased by FA, followed by improved GSK-3β and ERK phosphorylation with enhanced mRNA expressions of Lrp-5 and β-catenin. Conclusion These findings showed that FA improved osteoblasts proliferation with oxidative stress suppression by controlling the Lrp-5/GSK-3β/ERK pathway in GIO, demonstrating the potential pathways involved in the mechanism of actions of FA in GIO therapy.