Long-term aerobic exercise protects against cisplatin-induced nephrotoxicity by modulating the expression of IL-6 and HO-1

Renoprotective mechanisms of exercise training against acute and chronic renal diseases - A perspective based on experimental studies

Regular exercise training can lead to several health benefits, reduce mortality risk, and increase life expectancy. On the other hand, a sedentary lifestyle is a known risk factor for chronic diseases and increased mortality. Acute kidney injury (AKI) and chronic kidney disease (CKD) represent a significant global health problem, affecting millions of people worldwide. The progression from AKI to CKD is well-recognized in the literature, and exercise training has emerged as a potential renoprotective strategy. Thus, this article aims to review the main molecular mechanisms underlying the renoprotective actions of exercise training in the context of AKI and CKD, focusing on its antioxidative, anti-inflammatory, anti-apoptotic, anti-fibrotic, and autophagy regulatory effects. For that, bibliographical research was carried out in Medline/PubMed and Scielo databases. Although the pathophysiological mechanisms involved in renal diseases are not fully understood, experimental studies demonstrate that oxidative stress, inflammation, apoptosis, and dysregulation of fibrotic and autophagic processes play central roles in the development of tissue damage. Increasing evidence has suggested that exercise can beneficially modulate these mechanisms, potentially becoming a safe and effective non-pharmacological strategy for kidney health protection and promotion. Thus, the evidence base discussed in this review suggests that an adequate training program emerges as a valuable tool for preserving renal function in experimental animals, mainly through the production of antioxidant enzymes, nitric oxide (NO), irisin, IL-10, and IL-11. Future research can continue to explore these mechanisms to develop specific guidelines for the prescription of exercise training in different populations of patients with kidney diseases.

Physical exercise as a friend not a foe in acute kidney diseases through immune system modulation

Regular and moderate exercise is being used for therapeutic purposes in treating several diseases, including cancer, cardiovascular diseases, arthritis, and even chronic kidney diseases (CKDs). Conversely, extenuating physical exercise has long been pointed out as one of the sources of acute kidney injury (AKI) due to its severe impact on the body's physiology. AKI development is associated with increased tubular necrosis, which initiates a cascade of inflammatory responses. The latter involves cytokine production, immune cell (macrophages, lymphocytes, and neutrophils, among others) activation, and increased oxidative stress. AKI can induce prolonged fibrosis stimulation, leading to CKD development. The need for therapeutic alternative treatments for AKI is still a relevant issue. In this context arises the question as to whether moderate, not extenuating, exercise could, on some level, prevent AKI. Several studies have shown that moderate exercise can help reduce tissue damage and increase the functional recovery of the kidneys after an acute injury. In particular, the immune system can be modulated by exercise, leading to a better recovery from different pathologies. In this review, we aimed to explore the role of exercise not as a trigger of AKI, but as a modulator of the inflammatory/immune system in the prevention or recovery from AKI in different scenarios. In AKI induced by ischemia and reperfusion, sepsis, diabetes, antibiotics, or chemotherapy, regular and/or moderate exercise could modulate the immune system toward a more regulatory immune response, presenting, in general, an anti-inflammatory profile. Exercise was shown to diminish oxidative stress, inflammatory markers (caspase-3, lactate dehydrogenase, and nitric oxide), inflammatory cytokines (interleukin (IL)-1b, IL-6, IL-8, and tumor necrosis factor-α (TNF-α)), modulate lymphocytes to an immune suppressive phenotype, and decrease tumor necrosis factor-β (TGF-β), a cytokine associated with fibrosis development. Thus, it creates an AKI recovery environment with less tissue damage, hypoxia, apoptosis, or fibrosis. In conclusion, the practice of regular moderate physical exercise has an impact on the immune system, favoring a regulatory and anti-inflammatory profile that prevents the occurrence of AKI and/or assists in the recovery from AKI. Moderate exercise should be considered for patients with AKI as a complementary therapy.

Benefits of high-intensity interval training compared to continuous training to reduce apoptotic markers in female rats with cisplatin nephrotoxicity - possible modulatory role of IL-11

Apoptotic signaling pathways are involved in acute kidney injury (AKI) induced by the antineoplastic drug cisplatin (Cis). Mechanical stress is known to increase interleukin (IL) -11, a pleiotropic cytokine with antiapoptotic and antinecrotic effects. We compared the impact of high-intensity interval training (HIIT) with low-intensity continuous training (LICT) and moderate-intensity continuous training (MICT) on renal levels of IL-11 and the expression of apoptotic markers in female rats with nephrotoxicity induced by Cis. For that, the animals were divided into five groups (n = 7): control and sedentary (C + S); Cis and sedentary (Cis + S); Cis and LICT (Cis + LICT); Cis and MICT (Cis + MICT) and Cis and HIIT (Cis + HIIT). At the end of 8 weeks of treadmill running, the rats received a single injection of Cis (5 mg/kg), and 7 days later they were euthanized. Serum and kidney samples were collected to assess the blood urea nitrogen (BUN), gene expression of TNF receptor 1 (TNFR1) and 2 (TNFR2), caspase-3, (p38) MAPK (MAPK14), p53, Bax, Bak, Bcl-2, and Bcl-xL, renal levels of IL-11, IL-8, and p53, and immunolocalization of cleaved caspase-3, Bax, Bcl-2, and (p38) MAPK in renal tissue. Our data indicate that all trained groups showed a significant intensity-dependent increase in renal levels of IL-11 associated with reduced local expression of proapoptotic and increased antiapoptotic markers, but these effects were more pronounced with HIIT. So, HIIT appears to provide superior renoprotection than traditional continuous training by modulating apoptotic signaling pathways, and this effect can be related to the increase in renal levels of IL-11.

Nephroprotective effect of exercise training in cisplatin-induced renal damage in mice: influence of training protocol

Cisplatin is an effective antineoplastic agent, but its use is limited by its nephrotoxicity caused by the oxidative stress in tubular epithelium of nephrons. On the other hand, regular exercise provides beneficial adaptations in different tissues and organs. As with many drugs, dosing is extremely important to get the beneficial effects of exercise. Thus, we aimed to investigate the influence of exercise intensity and frequency on cisplatin-induced (20 mg/kg) renal damage in mice. Forty male Swiss mice were divided into five experimental groups (n=8 per group): 1) sedentary; 2) low-intensity forced swimming, three times per week; 3) high-intensity forced swimming, three times per week; 4) low-intensity forced swimming, five times per week; and 5) high-intensity forced swimming, five times per week. Body composition, renal structure, functional indicators (plasma urea), lipid peroxidation, antioxidant enzyme activity, expression of genes related to antioxidant defense, and inflammatory and apoptotic pathways were evaluated. Comparisons considered exercise intensity and frequency. High lipid peroxidation was observed in the sedentary group compared with trained mice, regardless of exercise intensity and frequency. Groups that trained three times per week showed more benefits, as reduced tubular necrosis, plasma urea, expression of CASP3 and Rela (NFkB subunit-p65) genes, and increased total glutathione peroxidase activity. No significant difference in Nfe2l2 (Nrf2) gene expression was observed between groups. Eight weeks of regular exercise training promoted nephroprotection against cisplatin-mediated oxidative injury. Exercise frequency was critical for nephroprotection.

The Role of Vascular-Immune Interactions in Modulating Chemotherapy Induced Neuropathic Pain

Chemotherapy causes sensory disturbances in cancer patients that results in neuropathies and pain. As cancer survivorships has dramatically increased over the past 10 years, pain management of these patients is becoming clinically more important. Current analgesic strategies are mainly ineffective and long-term use is associated with severe side effects. The issue being that common analgesic strategies are based on ubiquitous pain mediator pathways, so when applied to clinically diverse neuropathic pain and neurological conditions, are unsuccessful. This is principally due to the lack of understanding of the driving forces that lead to chemotherapy induced neuropathies. It is well documented that chemotherapy causes sensory neurodegeneration through axonal atrophy and intraepidermal fibre degeneration causing alterations in pain perception. Despite the neuropathological alterations associated with chemotherapy-induced neuropathic pain being extensively researched, underlying causes remain elusive. Resent evidence from patient and rodent studies have indicated a prominent inflammatory cell component in the peripheral sensory nervous system in effected areas post chemotherapeutic treatment. This is accompanied by modulation of auxiliary cells of the dorsal root ganglia sensory neurons such as activation of satellite glia and capillary dysfunction. The presence of a neuroinflammatory component was supported by transcriptomic analysis of dorsal root ganglia taken from mice treated with common chemotherapy agents. With key inflammatory mediators identified, having potent immunoregulatory effects that directly influences nociception. We aim to evaluate the current understanding of these immune-neuronal interactions across different cancer therapy drug classes. In the belief this may lead to better pain management approaches for cancer survivors.

The effects of exercise on kidney injury: the role of SIRT1

In patients with kidney injury, muscle mass and strength decrease with altered muscle protein synthesis and degradation along with complications such as inflammation and low physical activity. A treatment strategy to maintain muscle metabolism in kidney injury is important. One of the proposed strategies in this regard is exercise, which in addition to inducing muscle hypertrophy, reducing plasma creatinine and urea and decreasing the severity of tubal injuries, can boost immune function and has anti-inflammatory effects. One of the molecules that have been considered as a target in the treatment of many diseases is silent information regulator 1 (SIRT1). Exercise increases the expression of SIRT1 and improves its activity. Therefore, studies that examined the effect of exercise on kidney injury considering the role of SIRT1 in this effect were reviewed to determine the direction of kidney injury research in future regarding to its prevalence, especially following diabetes, and lack of definitive treatment. In this review, we found that SIRT1 can be one of renoprotective target pathways of exercise. However, further studies are needed to determine the role of SIRT1 in different kidney injuries following exercise according to the type and severity of exercise, and the type of kidney injury.

Associations between physical activity levels and renal recovery following acute kidney injury stage 3: a feasibility study

BACKGROUND

Acute kidney injury (AKI) can lead to chronic kidney disease, which results in poor long-term outcomes. There is plausibility that increased levels of physical activity may promote renal recovery post-AKI. This study aimed to investigate associations between physical activity levels and renal recovery following stage 3 AKI, and to assess the feasibility of measuring physical activity levels in this population.

METHODS

Forty One hospitalised patients with AKI stage 3 were enrolled. Serum creatinine and estimated glomerular filtration rate (eGFR) were collected at 12 months prior to the development of AKI, during the hospital admission when the episode of AKI stage 3 occurred, and at 1-, 3- and 6-months post discharge. All participants completed the General Practice Activity Questionnaire (GPPAQ) to assess physical activity levels. A pedometer was also worn for 7 days immediately following discharge and at 6-months post discharge to ascertain an average daily step count. Feasibility outcomes including eligibility, recruitment and retention rates, and losses to follow up were also assessed.

RESULTS

The average (± SD) baseline eGFR and median (IQR) serum creatinine was 71 ± 20 mL/min/1.73m² and 85 (49) μmol/L respectively. A threefold increase in creatinine occurred during hospitalisation 436 (265) μmol/L. Greatest renal recovery occurred prior to discharge, with recovery continuing for a further three months. Inactive individuals (low GPPAQ scores) had consistently higher serum creatinine values compared to those who were active: 1 months 122 (111) μmol/L vs 70 (0) μmol/L, 6 months 112 (57) μmol/L vs 68 (0) μmol/L. Individuals with higher step counts also displayed better renal recovery 6-months post discharge (r = -0.600, p = 0.208).

CONCLUSIONS

Higher levels of physical activity are associated with improved renal recovery after 6- months following an episode of stage 3 AKI. A future randomised controlled trial is feasible and would be required to confirm these initial findings.

Extraction of functional extracts from berries and their high quality processing: a comprehensive review

Berry fruits have attracted increasing more attention of the food processing industry as well as consumers due to their widely acclaimed advantages as highly effective anti-oxidant properties which may provide protection against some cancers as well as aging. However, the conventional extraction methods are inefficient and wasteful of solvent utilization. This paper presents a critical overview of some novel extraction methods applicable to berries, including pressurized-liquid extraction, ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, enzyme-assisted extraction as well as some combined extraction methods. When combined with conventional methods, the new technologies can be more efficient and environmentally friendly. Additionally, high quality processing of the functional extracts from berry fruits, such as refined processing technology, is introduced in this review. Finally, progress of applications of berry functional extracts in the food industry is described in detail; this should encourage further scientific research and industrial utilization.

Unlocking the Role of Exercise on CD4+ T Cell Plasticity

A hallmark of T cell ageing is a loss of effector plasticity. Exercise delays T cell ageing, yet the mechanisms driving the effects of exercise on T cell biology are not well elucidated. T cell plasticity is closely linked with metabolism, and consequently sensitive to metabolic changes induced by exercise. Mitochondrial function is essential for providing the intermediate metabolites necessary to generate and modify epigenetic marks in the nucleus, thus metabolic activity and epigenetic mechanisms are intertwined. In this perspective we propose a role for exercise in CD4+ T cell plasticity, exploring links between exercise, metabolism and epigenetic reprogramming.

Effects of exercise on AKT/PGC1-α/FOXO3a pathway and muscle atrophy in cisplatin-administered rat skeletal muscle

Cisplatin has been reported to cause side effects such as muscle wasting in humans and rodents. The physiological mechanisms involved in preventing muscle wasting, such as the regulation of AKT, PGC1-α, and autophagy-related factor FOXO3a by MuRF 1 and Atrogin-1, remain unclear following different types of exercise and in various skeletal muscle types. Eight-week-old male Wistar rats (n = 34) were assigned to one of four groups: control (CON, n = 6), cisplatin injection (1 mg/kg) without exercise (CC, n = 8), cisplatin (1 mg/kg) + resistance exercise (CRE, n = 9) group, and cisplatin (1 mg/kg) + aerobic exercise (CAE, n = 11). The CRE group performed progressive ladder exercise (starting with 10% of body weight on a 1-m ladder with 2-cm-interval grids, at 85°) for 8 weeks. The CAE group exercised by treadmill running (20 m/min for 60 min daily, 4 times/week) for 8 weeks. Compared with the CC group, the levels of the autophagy-related factors BNIP3, Beclin 1, LC3-II/I ratio, p62, and FOXO3a in the gastrocnemius and soleus muscles were significantly decreased in the CRE and CAE groups. The CRE and CAE groups further showed significantly decreased MuRF 1 and Atrogin-1 levels and increased phosphorylation of AKT, FOXO3a, and PGC1-α. These results suggest that both ladder and aerobic exercise directly affected muscle wasting by modulating the AKT/PGC1-α/FOXO3a signaling pathways regardless of the skeletal muscle type.

Chemotherapy-induced toxicity in patients with testicular germ cell tumors: The impact of physical fitness and regular exercise

BACKGROUND

Testicular germ cell tumors (TGCTs) represent ∼95% of testicular malignancies and are the most common type of malignancy in young male adults. While the incidence of TGCTs has increased during the last decades, the advances in treatment, namely introducing cisplatin into the chemotherapy regimen, have made TGCTs highly curable with the 10-year survival rate exceeding 95%. However, in parallel with increased cure rates, survivors may experience acute and late adverse effects of treatment, which increase morbidity, reduce the quality of life, and can be potentially life-threatening. Chemotherapy-related toxicities include cardiovascular and metabolic diseases, secondary cancer, avascular necrosis, cognitive impairment, cancer-related fatigue, poor mental health-related quality of life, nephrotoxicity, hypogonadism, neurotoxicity, pulmonary toxicity, anxiety, and depression. These treatment-related adverse effects have emerged as important survivorship dilemmas in TGCT cancer survivors. Recently, regular physical exercise has increasingly attracted research and clinical attention as an adjunct therapy for cancer patients.

PURPOSE

Herein, we review the most common chemotherapy-related adverse effects in TGCT survivors and clinical relevance of exercise and increased cardio-respiratory fitness in modulating chemotherapy-related toxicity and quality of life in this population.

RESULTS AND CONCLUSION

Exercise has positive effects on a spectrum of physical and psychosocial outcomes during and after cancer treatment, and current guidelines on exercise prescription in chronic diseases define the recommended dose (volume and intensity) of regular exercise for cancer survivors, highlighting regular, sufficiently intensive physical activity as an essential part of patients' care.

Effects of Exercise in Patients Undergoing Chemotherapy for Head and Neck Cancer: A Pilot Randomized Controlled Trial

Background: Cisplatin administration may induce muscle atrophy, thereby reducing the fitness level of patients with head and neck cancer (HNC). To date, only animal studies have been conducted to test the effectiveness of exercise interventions in diminishing side effects of cisplatin. Aim: To determine whether exercise training improves physical fitness and health-related quality of life (HRQoL) in patients receiving chemotherapy for Head & Neck (H&N). Material and methods: This pilot-randomized controlled trial was conducted on 57 participants receiving chemotherapy for HNC. The participants were randomized into an exercise group and a control group. The exercise group received moderate-intensity combined aerobic, resistance and flexibility exercises three times a week for eight weeks during chemotherapy. The control group received no specific information regarding exercise. The outcome measures including body composition, muscle strength, balance, flexibility, cardiovascular fitness and health-related quality of life (HRQoL) were assessed at baseline and eight weeks following baseline. Results: The body composition (body fat percentage, p = 0.002; skeletal muscle percentage, p = 0.008), dynamic balance (p = 0.01), muscle strength (upper extremity, p = 0.037; lower extremity, p = 0.025) and HRQoL (p = 0.001) showed a significant difference between the exercise group and the control group eight weeks following baseline. Significant deteriorations were noted in flexibility, muscle strength, cardiovascular fitness and several domains of HRQoL scale in the control group at eight weeks following baseline. Conclusions: This study found that a combined aerobic, resistance and flexibility exercise program during chemotherapy may improve physical fitness (i.e., muscle strength, balance, flexibility and body composition) and HRQoL and alleviate the deterioration of cardiovascular fitness in patients with HNC. Further research studies with large sample sizes are warranted to investigate the long-term effects of exercise in this population.

High-intensity interval training is more effective than continuous training to reduce inflammation markers in female rats with cisplatin nephrotoxicity

AIMS

Cisplatin (CP) is an antineoplastic widely used in the treatment of various solid tumors, however, its clinical application is limited by nephrotoxicity. Here, we compared the impact of preconditioning with high-intensity interval training (HIIT) with continuous training of low (LIT) and moderate (MIT) intensity on innate immunity markers in female rats with CP-induced acute kidney injury.

MATERIALS AND METHODS

The rats were divided into five groups (n = 7): saline control and sedentary (C + S); CP and sedentary (CP + S); CP and LIT (CP + LIT); CP and MIT (CP + MIT) and CP and HIIT (CP + HIIT). The training intensity was determined by a maximum running test. At the end of training, the rats received a single dose of CP (5 mg/kg), and 7 days later they were euthanized. We evaluated renal function parameters (serum creatinine, glomerular filtration rate and proteinuria), renal structure, macrophage tissue infiltration, immunolocalization of nuclear transcription factor kappa B (NF-κB), renal levels of tumor necrosis factor-alpha (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6), and gene expression of monocyte chemoattractant protein-1 (MCP-1), toll-like receptor 4 (TLR4), and NF-κB in renal tissue.

KEY FINDINGS

Although both MIT and HIIT attenuated the degree of renal injury, only the HIIT prevented changes in renal function. The three training protocols mitigated the increase in expression of all inflammatory markers, however, this effect was more pronounced in HIIT.

SIGNIFICANCE

All training protocols promoted renoprotective actions, but HIIT was more effective in mitigating CP-induced acute kidney injury, in part by modulation of important markers of the innate immune response.

Physical Training Is a Potential Modifier of Risk for Contrast-Induced Acute Kidney Injury in Diabetes Mellitus

Background

Iodinated contrast (IC) is a leading cause of hospital-based acute kidney injury (AKI). Contrast-induced acute kidney injury (CI-AKI) is a decline in renal function due to iodinated contrast administration and occurs more frequently in individuals with increasingly common risk factors, such as diabetes mellitus (DM). Physical training (PT) can have renoprotective effects on CI-AKI in diabetic nephropathy. The aim of this study was to evaluate the injury in kidneys of diabetic rats submitted to treatment with IC, evaluating the impact of PT on hemodynamics and renal function in addition to oxidative profile in diabetic rats submitted to IC-AKI.

Materials and Methods

Adult male Wistar rats are randomized into four groups: citrate (n = 7): control group, citrate buffer (streptozotocin-STZ vehicle), intravenous tail (iv), single dose; DM (n = 7): STZ, 60 mg/kg, iv, single dose; DM+IC (n = 7): DM rats treated with IC (sodium meglumine ioxithalamate, 6 mL/kg, intraperitoneal (ip), single dose); DM+IC+PT (n = 7): DM rats treated with IC as mentioned and submitted to physical training. Renal function parameters (inulin clearance, neutrophil gelatinase-associated lipocalin (NGAL), serum creatinine, and urinary albumin), hemodynamics (renal blood flow and renal vascular resistance), and oxidative profile (urinary peroxides, urinary TBARS, urinary nitric oxide, and renal tissue thiols) were evaluated.

Results

It was possible to observe a decrease in inulin clearance, renal blood flow, and thiols in renal tissue accompanied by an increase in urinary flow, serum creatinine, urinary albumin, renal vascular resistance, urinary peroxides, urinary nitrate, and TBARS in the DM group compared to the citrate group. The DM+IC group showed a reduction in inulin clearance, and the renal dysfunction was also seen by the increased NGAL. Renal hemodynamics and oxidative profile compared were also worsened in the DM group. PT improved renal function by increasing renal blood flow and thiol levels in renal tissue and reduced renal vascular resistance, metabolites of reactive oxygen, nitrogen species, and lipid peroxidation in the DM+IC+PT group compared to DM+IC.

Conclusions

Our results confirmed that DM induction increases renal vulnerability to the toxicity of IC and an association between DM with IC predisposes to severe AKI with reduced renal function alongside with renal hemodynamic alterations and oxidative mechanism of injury. The PT showed a renoprotective effect in DM animals subjected to damage with IC by modulating renal hemodynamics and oxidative profile, confirming a potential to modify the risk of CI-AKI when diabetes mellitus is present.

Exercise as a therapeutic option for acute kidney injury: mechanisms and considerations for the design of future clinical studies

Acute kidney injury (AKI) is a known risk factor for chronic kidney disease (CKD) and end stage kidney disease (ESKD). The progression from AKI to CKD, despite being well recognised, is not completely understood, although sustained inflammation and fibrosis are implicated. A therapeutic intervention targeting the post AKI stage could reduce the progression to CKD, which has high levels of associated morbidity and mortality. Exercise has known anti-inflammatory effects with animal AKI models demonstrating its use as a therapeutic agent in abrogating renal injury. This suggests the use of an exercise rehabilitation programme in AKI patients following discharge could attenuate renal damage and improve long term patient outcomes. In this review article we outline considerations for future clinical studies of exercise in the AKI population.

Physical Exercise Exacerbates Acute Kidney Injury Induced by LPS via Toll-Like Receptor 4

Introduction: Lipopolysaccharide (LPS) is a systemic response-triggering endotoxin, which has the kidney as one of its first targets, thus causing acute injuries to this organ. Physical exercise is capable of promoting physiological alterations and modulating inflammatory responses in the infectious process through multiple parameters, including the toll-like receptor (TLR)-4 pathway, which is the main LPS signaling in sepsis. Additionally, previous studies have shown that physical exercise can be both a protector factor and an aggravating factor for some kidney diseases. This study aims at analyzing whether physical exercise before the induction of LPS endotoxemia can protect kidneys from acute kidney injury.

Methods: C57BL/6J male mice, 12 weeks old, were distributed into four groups: (1) sedentary (control, N = 7); (2) sedentary + LPS (N = 7); (3) trained (N = 7); and (4) trained + LPS (N = 7). In the training groups, the animals exercised 5×/week in a treadmill, 60 min/day, for 4 weeks (60% of max. velocity). Sepsis was induced in the training group by the application of a single dose of LPS (5 mg/kg i.p.). Sedentary animals received LPS on the same day, and the non-LPS groups received a saline solution instead. All animals were euthanized 24 h after the administration of LPS or saline.

Results: The groups receiving LPS presented a significant increase in serum urea (p < 0.0001) and creatinine (p < 0.001) concentration and renal gene expression of inflammatory markers, such as tumor necrosis factor alpha and interleukin-6, as well as TLRs. In addition, LPS promoted a decrease in reduced glutathione. Compared to the sedentary + LPS group, trained + LPS showed overexpression of a gene related to kidney injury (NGAL, p < 0.01) and the protein levels of LPS receptor TLR-4 (p < 0.01). Trained + LPS animals showed an expansion of the tubulointerstitial space in the kidney (p < 0.05) and a decrease in the gene expression of hepatic AOAH (p < 0.01), an enzyme involved in LPS clearance.

Conclusion: In contrast to our hypothesis, training was unable to mitigate the renal inflammatory response caused by LPS. On the contrary, it seems to enhance injury by accentuating endotoxin-induced TLR-4 signaling. This effect could be partly due to the modulation of a hepatic enzyme that detoxifies LPS.

Non-invasive Assessment of Fecal Stress Biomarkers in Hunting Dogs During Exercise and at Rest

Intense exercise causes to organisms to have oxidative stress and inflammation at the gastrointestinal (GI) level. The reduction in intestinal blood flow and the exercise-linked thermal damage to the intestinal mucosa can cause intestinal barrier disruption, followed by an inflammatory response. Furthermore, the adaptation to exercise may affect the gut microbiota and the metabolome of the biofluids. The aim of the present research was to evaluate the presence of a GI derangement in hunting dogs through a non-invasive sampling as a consequence of a period of intense exercise in comparison with samples collected at rest. The study included nine dogs that underwent the same training regime for hunting wild boar. In order to counterbalance physiological variations, multiple-day replicates were collected and pooled at each experimental point for each dog. The samples were collected immediately at rest before the training (T0), after 60 days of training (T1), after 60 days of hunting wild boar (T2), and finally, at 60 days of rest after hunting (T3). A number of potential stress markers were evaluated: fecal cortisol metabolites (FCMs) as a major indicator of altered physiological states, immunoglobulin A (IgA) as an indicator of intestinal immune protection, and total antioxidant activity [total antioxidant capacity (TAC)]. Since stool samples contain exfoliated cells, we investigated also the presence of some transcripts involved in GI permeability [occludin (OCLN), protease-activated receptor-2 (PAR-2)] and in the inflammatory mechanism [interleukin (IL)-8, IL-6, IL-1b, tumor necrosis factor alpha (TNFα), calprotectin (CALP), heme oxygenase-1 (HO-1)]. Finally, the metabolome and the microbiota profiles were analyzed. No variation in FCM and IgA content and no differences in OCLN and CALP gene expression between rest and training were observed. On the contrary, an increase in PAR-2 and HO-1 transcripts, a reduction in total antioxidant activity, and a different profile of microbiota and metabolomics data were observed. Collectively, the data in the present study indicated that physical exercise in our model could be considered a mild stressor stimulus.

Recent Advances in Models, Mechanisms, Biomarkers, and Interventions in Cisplatin-Induced Acute Kidney Injury

Cisplatin is a widely used chemotherapeutic agent used to treat solid tumours, such as ovarian, head and neck, and testicular germ cell. A known complication of cisplatin administration is acute kidney injury (AKI). The development of effective tumour interventions with reduced nephrotoxicity relies heavily on understanding the molecular pathophysiology of cisplatin-induced AKI. Rodent models have provided mechanistic insight into the pathophysiology of cisplatin-induced AKI. In the subsequent review, we provide a detailed discussion of recent advances in the cisplatin-induced AKI phenotype, principal mechanistic findings of injury and therapy, and pre-clinical use of AKI rodent models. Cisplatin-induced AKI murine models faithfully develop gross manifestations of clinical AKI such as decreased kidney function, increased expression of tubular injury biomarkers, and tubular injury evident by histology. Pathways involved in AKI include apoptosis, necrosis, inflammation, and increased oxidative stress, ultimately providing a translational platform for testing the therapeutic efficacy of potential interventions. This review provides a discussion of the foundation laid by cisplatin-induced AKI rodent models for our current understanding of AKI molecular pathophysiology.

Muscle changes with high-intensity aerobic training in an animal model of renal disease

Purpose:

To analyze the muscle changes with high-intensity aerobic training (HIAT) in an animal model of renal disease (RD).

Methods:

Twenty one adult Wistar rats were divided into 3 groups: healthy sedentary (HS), RD sedentary (RDS), RD aerobic training (RDAT). RDS and RDAT were subjected to unilateral renal ischemia-reperfusion (10 min) and 21days after that, RDAT was subjected to 6 weeks HIAT (swimming). Serum creatinine (Cr) and muscle morphometry (cross-sectional area = CSA) of gastrocnemius were analyzed.

Results:

Cr was higher (p = 0.0053) in RDS (0.82 ± 0.04) than in the others (RDAT 0.55 ± 0.04; HS 0.55 ± 0.04). Morphometric analysis (class interval of CSA in μm²/absolute frequency of muscle fibers in each class) indicated that 50th percentile occurred in: HS 7th class (3000.00-3499.00/515), RDS, 8th class (3500.00-3999.00/484), RDAT 5th class (2000.00-2499.00/856). CSA of largest fibers in RDS, RDAT, HS was 9953.00 μm², 9969.00 μm²,11228.00 μm², respectively. High frequency of fibers with lower CSA occurred in 4th, 5th, 6th and 7th class in RDA, absence of fibers into 22nd, 23rd classes (RDS and RDAT).

Conclusion:

HIAT in an animal model of RD resulted in increased the number of muscle fibers with smaller CSA.

High-intensity aerobic training lowers blood pressure and modulates the renal renin-angiotensin system in spontaneously hypertensive rats

Background: This study aimed to verify the effects of high-intensity aerobic training (HIAT) on BP control and renin-angiotensin system (RAS) components in renal tissue of SHR. Ten SHRs received HIAT or control for 8-weeks. At the end of the training, the SBP showed a reduction of ~ 30mmHg (p < .01) in HIAT and increased by ~ 15 mmHg in the  control group. HIAT resulted in a higher release of nitrite, IL-6, ACE2 and ATR2. These results indicated an association between BP, NO and renal RAS.Abbreviations: JAA: writing, carried out all experimental procedures, performed statistical analysis, original draft and revised manuscript DMS: data interpretation, formal analysis, writing, editing and revised manuscript BAP: carried all experimental procedures, revised manuscritpt CPCG: carried all experimental procedures, revised manuscritpt MEN: experimental procedures, revised manuscript and data interpretation RWP: drafted and revised manuscript RCA: writing, experimental procedures, revised manuscript JP: writing, data interpretation and revised manuscript OLF: writing, original draft and revised manuscript.

Resistance training downregulates macrophages infiltration in the kidney of 5/6 nephrectomized rats

INTRODUCTION

Chronic kidney disease (CKD) is considered a significant world health problem with elevated mortality rates. Patients with CKD are restricted to mild physical activity, present chronic inflammatory state and loss of muscle strength. Currently, the influence of resistance exercise (RE) on the progression of renal disease has not being fully elucidated.

PURPOSE

To evaluate the effects of RE on the progression of CKD in a remnant kidney model (5/6Nx) in rats.

METHODS

Eight-week-old Wistar rats were submitted to 5/6 nephrectomy and were divided into four groups: Sham sedentary (Sham SD); Sham RE (Sham RE); 5/6Nx SD and 5/6Nx RE. The animals were trained for 8 weeks in a vertical climbing ladder for 3 days per week, on non-consecutive days.

RESULTS

As expected, 5/6Nx SD group presented a markedly loss of renal function, increased plasma inflammatory cytokines and increased oxidative stress with a reduced activity of nitric oxide. The higher macrophage infiltration and fibrosis confirmed these conditions. RE attenuated systolic blood pressure and renal function decrease and also improved serum lipid parameters in 5/6 Nx animals. It was evident the increase of muscle strength and mass in the trained groups while the sedentary group showed reduced muscle weight and strength compared to Sham SD.

CONCLUSIONS

RE implemented following 5/6Nx retard the progression of chronic kidney injury while simultaneously allowed the maintenance of skeletal muscle strength.

TLR2 and TLR4 play opposite role in autophagy associated with cisplatin-induced acute kidney injury

Acute kidney injury (AKI) is considered an inflammatory disease in which toll-like receptors (TLRs) signaling pathways play an important role. The activation of TLRs results in production of several inflammatory cytokines leading to further renal damage. In contrast, TLRs are key players on autophagy induction, which is associated with a protective function on cisplatin-induced AKI. Hence, the present study aimed to evaluate the specific participation of TLR2 and TLR4 molecules on the development of cisplatin-induced AKI. Complementarily, we also investigated the link between TLRs and heme oxygenase-1 (HO-1), a promisor cytoprotective molecule. First, we observed that only the absence of TLR2 but not TLR4 in mice exacerbated the renal dysfunction, tissue injury and mortality rate, even under an immunologically privileged microenvironment. Second, we demonstrated that TLR2 knockout (KO) mice presented lower expression of autophagy-associated markers when compared with TLR4 KO animals. Similar parameter was confirmed in vitro, using tubular epithelial cells derived from both KO mice. To test the cross-talking between HO-1 and TLRs, hemin (an HO-1 internal inducer) was administrated in cisplatin-treated TLR2 and TLR4 KO mice and it was detected an improvement in the global renal tissue parameters. However, this protection was less evident at TLR2 KO mice. In summary, we documented that TLR2 plays a protective role in cisplatin-induced AKI progression, in part, by a mechanism associated with autophagy up-regulation, considering that its interplay with HO-1 can promote renal tissue recover.

Resistance training attenuates inflammation and the progression of renal fibrosis in chronic renal disease

Patients with chronic kidney disease (CKD) have progressive renal fibrosis, inflammation, and reduced muscle mass and strength. Resistance training (RT) has been suggested to mitigate the loss of muscle mass, of strength and the inflammation in CKD, but the mechanisms are unknown. The aim of this study was to evaluate the influence of RT on renal fibrosis, renal cytokine expression, creatine kinase levels, and muscle mass and strength in CKD rats. A CKD model was obtained by 5/6 nephrectomy (Nx). Fifteen 8-week-old male rats were divided into 3 groups: Sham (control), Nx SED (CKD sedentary) and Nx RT (CKD trained). The RT consisted of ladder climbing at 70% of the animal's maximal carrying capacity for 10 weeks. Muscle strength, creatine kinase levels, renal fibrosis and mRNA interleukin (IL)-4, IL-6 and IL-10 were analyzed after the RT protocol. There was significant improvement in the muscle strength and creatine kinase levels in the Nx RT group. Moreover, renal fibrosis and inflammation were attenuated, with increased IL-4 and IL-10 expression and reduced IL-6 expression in the Nx RT group compared with that in the Nx SED group. No difference in muscle mass was observed among the groups. In conclusion, RT was effective in reducing fibrosis and inflammation, in addition to increasing muscle strength and creatine kinase levels, in rats with CKD, independent of muscle mass.

Heme oxygenase activity increases after exercise in healthy volunteers

Heme oxygenase (HO) is an essential, rate-limiting protein which catalyses the breakdown of heme to iron, carbon monoxide (CO), and biliverdin. The alpha methene bridge of the heme is eliminated as CO which can be measured as blood carboxyhaemoglobin (COHb). Using blood concentrations of COHb as a measure reflecting HO activity, we tested the postulate that the activity of HO changes with exercise. Ten healthy, nonsmoking volunteers (5 females and 5 males with a mean age ± standard deviation of 25.7 ± 3.2 years), lifetime nonsmokers with no history of respiratory diseases and not taking any medication, were included in the study. Subjects were exposed to filtered air for 2 hrs while alternating exercise for 15 minutes on a cycle ergometer with rest for 15 minutes. Workload was adjusted so that subjects breathed at a ventilatory rate, normalised for body surface area, of 25 L/m²/minute. Immediately before, immediately after, and the day following exercise, blood was drawn by standard venipuncture technique. COHb was determined using the interleukin (IL) 682 Co-Oximeter (Instrumentation Laboratory, Bedford, MA). COHb increased in each participant during the exercise session with the mean value (± standard deviation) almost doubling (1.1 ± 1.6 to 2.1 ± 1.6%) and returned to baseline by the following day (1.3 ± 1.3%). We conclude that exercise increases HO activity.

Inhibition of PTEN activity aggravates cisplatin-induced acute kidney injury

Cisplatin (cis-Diamminedichloroplatinum II) has been widely and effectively used in chemotherapy against tumors. Nephrotoxicity due to cisplatin is one of the most common clinical causes of acute kidney injury (AKI), which has a poor prognosis and high mortality. The signaling mechanisms underlying cisplatin-induced AKI are not completely understood. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor that negatively regulates the cell-survival pathway and is considered a double-edged sword in organ damage. In this study, we examined the effect that inhibiting PTEN activity in experimental models of cisplatin-induced AKI had on the degrees of AKI. Compared with vehicle mice, mice treated with bpV(pic) (specific inhibitor of PTEN) had exacerbated renal damage due to cisplatin-induced AKI. Furthermore, inhibition of PTEN activity increased cell apoptosis in the kidneys of mice induced by cisplatin. More inflammatory cytokines were activated after cisplatin treatment in mice of the bpV(pic)-treated group compared with vehicle mice, and these inflammatory cytokines may be partially derived from bone marrow cells. In addition, inhibiting PTEN activity decreased the phosphorylation of p53 in the pathogenesis of cisplatin-induced AKI. In summary, our study has demonstrated that inhibiting PTEN activity aggravates cisplatin-induced AKI via apoptosis, inflammatory reaction, and p53 signaling pathway. These results indicated that PTEN may serve as a novel therapeutic target for cisplatin-induced AKI.

Caloric Restriction Is More Efficient than Physical Exercise to Protect from Cisplatin Nephrotoxicity via PPAR-Alpha Activation

The antineoplastic drug cisplatin promotes renal injury, which limits its use. Protocols that reduce renal cisplatin toxicity will allow higher doses to be used in cisplatin treatment. Here, we compare physical exercise and caloric restriction (CR) as protocols to reduce cisplatin renal injury in mice. Male C57BL/6 were divided into four groups: Control, cisplatin, exercise + cisplatin, and 30% CR + cisplatin. Animals were injected with a single dose of cisplatin (20 mg/kg i.p.) and sacrificed 96 h after injection. Quantitative real time PCR, histological analyses, immunohistochemistry, and biochemical measurements were performed to investigate renal injury, necrosis, apoptosis, and inflammatory mechanisms. Both protocols protected against cisplatin renal injury, but CR was more effective in reducing uraemia and renal necrosis. The CR + Cisplatin group exhibited reduced serum IL-1β and TNF-α levels. No differences were noted in the renal mRNA expression of cytokines. Both interventions reduced apoptosis, but only the CR + Cisplatin group decreased TNFR2 protein expression. PPAR-α was activated in mice after CR. An antagonist of PPAR-α blocked the protective effect of CR. Both interventions attenuated the nephrotoxicity caused by cisplatin injection, but CR + Cisplatin showed a better response by modulating TNFR2. Moreover, part of the CR benefit depends on PPAR-α activation.

FVB/NJ Mice Are a Useful Model for Examining Cardiac Adaptations to Treadmill Exercise

Mice are commonly used to examine the mechanisms by which exercise improves cardiometabolic health; however, exercise compliance and adaptations are often strain-dependent or are variable due to inconsistency in exercise training protocols. In this study, we examined nocturnal/diurnal behavior, treadmill exercise compliance, and systemic as well as cardiac-specific exercise adaptations in two commonly used mouse strains, C57BL/6J, and FVB/NJ mice. Metabolic cage analysis indicated a strong nocturnal nature of C57BL/6J mice, whereas FVB/NJ mice showed no circadian element to activity, food or water intake, VO₂, or VCO₂. Initial exercise capacity tests revealed that, compared with C57BL/6J mice, FVB/NJ mice are capable of achieving nearly 2-fold higher workloads prior to exhaustion. FVB/NJ mice tested during the day were capable of achieving significantly more work compared with their night-tested counterparts. Following 4 weeks of training, FVB/NJ mice showed significant increases in exercise capacity as well as physiologic cardiac growth characterized by enlarged myocytes and higher mitochondrial DNA content. C57BL/6J mice showed no increases in exercise capacity or cardiac growth regardless of whether they exercised during the day or the night. This lack of adaptation in C57BL/6J mice was attributable, at least in part, to their progressive loss of compliance to the treadmill training protocol. We conclude that the FVB/NJ strain is a useful and robust mouse model for examining cardiac adaptations to treadmill exercise and that treadmill training during daytime hours does not negatively affect exercise compliance or capacity.

Andrographolide-induced apoptosis in human renal tubular epithelial cells: Roles of endoplasmic reticulum stress and inflammatory response

Andrographolide sodium bisulfate as a kind of soluble derivative of andrographolide (AD), is obviously known to be nephrotoxicity, but AD has not been reported clearly. Our study aimed to investigate the induction of apoptosis in human renal tubular epithelial (HK-2) cells by AD and its possible mechanism. Our results demonstrated that AD (0-250μmol/L) inhibited Hk-2 cells proliferation in a dose- and time-dependent manner and induced apoptosis, accompanied by decreased of superoxide dismutase (SOD) activity and increased of malondialdehvde (MDA) content. Simultaneously, AD regulated the expression of endoplasmic reticulum (ER) molecular chaperone glucose-regulated protein 78 (GRP78/Bip) protein, elevated the expressions of C/EBP homologous protein (CHOP) and Caspase-4, indicating activation of ER stress signaling, and induced the alterative expression of kidney injury molecule-1 (KIM-1), tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6) proteins. It provided evidence that ER stress and inflammation would be significant mechanisms responsible for AD-induced apoptosis in addition to oxidative stress.

2,3,5,6-Tetramethylpyrazine (TMP) down-regulated arsenic-induced heme oxygenase-1 and ARS2 expression by inhibiting Nrf2, NF-κB, AP-1 and MAPK pathways in human proximal tubular cells

Our recent study demonstrated that sodium arsenite at a clinically relevant dose induced nephrotoxicity in human renal proximal tubular epithelial cell line HK-2, which could be inhibited by natural product 2,3,5,6-tetramethylpyrazine (TMP) with antioxidant activity. The present study demonstrated that arsenic exposure resulted in protein and enzymatic induction of heme oxygenase-1 (HO-1) in dose- and time-dependent manners in HK-2 cells. Blocking HO-1 enzymatic activity by zinc protoporphyrin (ZnPP) augmented arsenic-induced apoptosis, ROS production and mitochondrial dysfunction, suggesting a critical role for HO-1 as a renal protectant in this procession. On the other hand, TMP, upstream of HO-1, inhibited arsenic-induced ROS production and ROS-dependent HO-1 expression. TMP also prevented mitochondria dysfunction and suppressed activation of the intrinsic apoptotic pathway in HK-2 cells. Our results revealed that the regulation of arsenic-induced HO-1 expression was performed through multiple ROS-dependent signal pathways and the corresponding transcription factors, including p38 MAPK and JNK (but not ERK), AP-1, Nrf2 and NF-κB. TMP inhibited arsenic-induced activations of JNK, p38 MAPK, ERK, AP-1 and Nrf2 and block HO-1 protein expression. The present study, furthermore, demonstrated arsenic-induced expression of arsenic response protein 2 (ARS2) that was regulated by p38 MAPK, ERK and NF-κB. To our knowledge, this is the first report showing that ARS2 involved in arsenic-induced nephrotoxicity, while TMP pretreatment prevented such an up-regulation of ARS2 in HK-2 cells. Given ARS2 and HO-1 sharing the similar regulation mechanism, we speculated that ARS2 might also mediate cell survival in this procession. In summary, our study highlighted a role of HO-1 in the protection against arsenic-induced cytotoxicity downstream from the primary targets of TMP and further indicated that TMP may be used as a potential therapeutic agent in the treatment of arsenic-induced nephrotoxicity.

Nonpreventive Role of Aerobic Exercise Against Cisplatin-induced Nephrotoxicity in Female Rats

Background:

Cisplatin (CP) is a chemotherapy drug and nephrotoxicity is a major concern for CP therapy. CP-induced nephrotoxicity is gender-dependent, and the effect of aerobic exercise in females has not been reported yet while it has a beneficial effect in males. Hence, this study was designed to determine the protective role of aerobic exercise against CP-induced nephrotoxicity in female rats.

Methods:

Twenty-eight adult female rats were divided into four groups. Groups I and II had aerobic exercise on a treadmill for 8 weeks. Then, the exercise protocol was continued for another week in group I and stopped in group II. All animals in these groups received CP (2.5 mg/kg/day; i.p.) for 1-week. Groups III and IV were treated with CP and vehicle, respectively, without exercise. Finally, the animals were sacrificed for biochemical measurements and tissue histopathology investigations.

Results:

CP alone without exercise increased serum levels of blood urea nitrogen (BUN) and creatinine (Cr), kidney weight, and kidney tissue damage score (KTDS); while exercise could not attenuate these parameters in female rats. Exercise in females increased the serum levels of BUN and Cr and KTDS and weight loss (P < 0.05). Kidney nitrite levels reduce significantly in group I in compared to positive and negative control groups. Exercise also did not have beneficial effects on malondialdehyde levels in plasma and kidney.

Conclusions:

Aerobic exercise cannot reduce CP-induced nephrotoxicity in female rats. Increasing the damage in female rats may be related to female sex hormone estrogen or gender differences in renal hemodynamic and renin-angiotensin system activity in the presence of exercise. In general, it is recommended that the females under CP chemotherapy avoid exercising during treatment.