Combination of exercise and losartan enhances renoprotective and peripheral effects in spontaneously type 2 diabetes mellitus rats with nephropathy

Renal Rehabilitation: Present and Future Perspectives

Chronic kidney disease (CKD) is a global health problem. In patients with CKD, exercise endurance is decreased, especially as renal dysfunction advances. This is due to the combined effects of protein-energy wasting, uremic acidosis, and inflammatory cachexia, which lead to sarcopenia and are aggravated by a sedentary lifestyle, resulting in a progressive downward spiral of deconditioning. Renal rehabilitation (RR) is a coordinated, multifaceted intervention designed to optimize a patient's physical, psychological, and social functioning, as well as to stabilize, slow, or even reverse the progression of renal deterioration, improving exercise tolerance and preventing the onset and worsening of heart failure, thereby reducing morbidity and mortality. This review focused on the history and benefits of RR in patients with CKD. Based on current evidence, RR is an effective, feasible, and safe secondary prevention strategy in CKD. RR is a promising model for a new field of rehabilitation. Therefore, efforts to increase RR implementation rates are urgently needed.

Effects of bisphosphonates and treadmill exercise on bone and kidney in adenine-induced chronic kidney disease rats

INTRODUCTION

The increasing prevalence of osteoporosis and chronic kidney disease (CKD) due to the aging of society has highlighted the need for development of effective treatments for elderly patients. This study examined whether the combination of treadmill exercise therapy and alendronate (ALN) can improve bone mineral density (BMD) and bone strength without worsening renal function in adenine-induced CKD model rats.

MATERIALS AND METHODS

8-week-old male Wistar rats (n = 70) were divided into experimental groups based on the treatment protocol, i.e., non-CKD (control), vehicle only (CKD), ALN only, exercise only, and combined ALN plus exercise. A 0.75% adenine diet was used to induce CKD. Groups were killed at either 20 or 30 weeks of age. Comprehensive assessments included serum and urine biochemistry tests, renal histology, bone histomorphometry, BMD measurement, micro-computed tomography examinations, and biomechanical testing.

RESULTS

Blood biochemistry tests, urine analyses and histological evaluations of the kidney demonstrated that ALN treatment did not worsen renal function or kidney fibrosis in moderate-stage CKD model rats. Both ALN and treadmill exercise significantly suppressed bone resorption (p < 0.05-p < 0.01). Moreover, ALN monotherapy and combined ALN and treadmill exercise significantly improved BMD of the lumbar spine and femur, bone microstructure, and trabecular bone strength (p < 0.05-p < 0.01). Treadmill exercise was also shown to decrease cortical porosity at the mid-diaphysis of the femur and improve kidney fibrosis.

CONCLUSION

The combination of ALN and treadmill exercise is effective in improving BMD, the microstructure of trabecular and cortical bone, and bone strength, without compromising renal function in adenine-induced CKD model rats.

Effects of Exercise Training on Mitochondrial Fatty Acid β-Oxidation in the Kidneys of Dahl Salt-Sensitive Rats

Exercise training (Ex) has anti-hypertensive and renal protective effects. In this study, we investigate the effects of Ex on mitochondrial fatty acid metabolism in the kidneys of Dahl salt-sensitive (Dahl-S) rats fed a high-salt (HS) diet. Eight-week-old, male Dahl-S rats were divided into three groups: (1) normal-salt diet, sedentary (NS-Sed), (2) HS diet, sedentary (HS-Sed), and (3) HS-Ex. The NS and HS groups were fed a diet containing 0.6% and 8% NaCl, respectively. The HS-Ex group performed treadmill running for 8 weeks (5 days/week; 60 min/day at 16-20 m/min, 0% gradient). Renal function and the expression of enzymes and regulators of β-oxidation and electron transport chain (ETC) complexes were assessed. HS increased systolic blood pressure and proteinuria, and Ex ameliorated these defects. HS also reduced creatinine clearance, and Ex ameliorated it. HS reduced the renal expression of enzymes of β-oxidation (carnitine palmitoyltransferase type I (CPTI) and acyl-CoA dehydrogenases (CADs)) and the related transcription factors peroxisome proliferator-activated receptor α (PPARα) and PPARγ-coactivator-1α (PGC-1α), and Ex restored this. HS also reduced the renal expression of enzymes in ETC complexes, and Ex restored this expression. Ex ameliorates HS-induced renal damage by upregulating enzymes involved in fatty acid β-oxidation and ETC complexes via increases in PPAR-α and PGC-1α expressions in the kidneys of Dahl-S rats. These results suggest that Ex may have beneficial effects on HS-induced mitochondrial dysfunction in the kidney.

Exercise Training Prevents High Fructose-Induced Hypertension and Renal Damages in Male Dahl Salt-Sensitive Rats

INTRODUCTION

High-fructose diet (HFr) causes metabolic syndrome, and HFr-induced hypertension and renal damage are exaggerated in Dahl salt-sensitive (DS) rats. Exercise training (Ex) has antihypertensive and renal protective effects in rats fed HFr; however, there has been little discussion about the DS rats, which exhibit metabolic disturbances. This study thus examined the effects of Ex on DS rats fed HFr.

METHODS

Male DS rats were divided into three groups. The control group was fed a control diet, and both the HFr group and the HFr-Ex group were fed an HFr (60% fructose). The HFr-Ex group also underwent treadmill running (20 m·min -1 , 60 min·d -1 , 5 d·wk -1 ). After 12 wk, renal function, histology, and renin-angiotensin system were examined.

RESULTS

HFr increased blood pressure, urinary albumin, and creatinine clearance, and Ex inhibited these increases. HFr induced glomerular sclerosis, podocyte injury, afferent arteriole thickening, and renal interstitial fibrosis, and Ex ameliorated them. HFr reduced plasma renin activity, and Ex further reduced the activity. HFr also increased the expression of angiotensinogen, renin, angiotensin-converting enzyme (ACE), and angiotensin II type 1 receptor, and Ex restored the ACE expression to the control levels. HFr decreased the expression of ACE2, angiotensin II type 2 receptor, and Mas receptor, and Ex restored the ACE2 and Mas receptor expressions to the control levels and further decreased the angiotensin II type 2 receptor expression. HFr increased the ACE activity and decreased the ACE2 activity, and Ex restored these activities to the control levels.

CONCLUSIONS

Ex prevents HFr-induced hypertension and renal damages in DS rats. The changes in renal renin-angiotensin system may be involved in the mechanism of the antihypertensive and renal protective effects of Ex.

Exercise in the Prevention and Treatment of Type 2 Diabetes

Type 2 diabetes is a systemic, multifactorial disease that is a leading cause of morbidity and mortality globally. Despite a rise in the number of available medications and treatments available for management, exercise remains a first-line prevention and intervention strategy due to established safety, efficacy, and tolerability in the general population. Herein we review the predisposing risk factors for, prevention, pathophysiology, and treatment of type 2 diabetes. We emphasize key cellular and molecular adaptive processes that provide insight into our evolving understanding of how, when, and what types of exercise may improve glycemic control. © 2023 American Physiological Society. Compr Physiol 13:1-27, 2023.

Effect of exercise on renal function in diabetic nephropathy-a systematic review and meta-analysis

Diabetic nephropathy causes cardiovascular complications among individuals with diabetes which results in decreased kidney function and overall physical decline. The objective of this systematic review was to determine effects of exercise on various renal function parameters amond individuals with type 2 diabetes and nephropathy. It was registered with PROSPERO (CRD42020198754). Total 6 databases (PubMed/Medline, Scopus, Web of Science, CINAHL, ProQuest, and Cochrane) were searched. Among 1734 records, only four randomized controlled trials were included. The review included a total of 203 participants (103 in the intervention group and 100 in the control/standard group) with type 2 diabetic nephropathy or stage 2,3, or 4 of chronic kidney disease. The meta-analysis showed no effects of exercise on serum creatinine, serum cystatin c and varied eGFR equations. However, exercise decreased urinary albumin to creatinine ratio, urinary protein to creatinine ratio, serum urea nitrogen, creatinine clearance, and urinary protein excretion while increasing urea clearance. Limited evidence on the reno-protective role of exercise demands future research in this direction.

Effects of Exercise Training on the Renin-Angiotensin System in the Kidneys of Dahl Salt-Sensitive Rats

PURPOSE

Exercise training (Ex) has antihypertensive and renal protective effects; however, the precise mechanisms remain unclear. The renal renin-angiotensin system (RAS) plays a vital role in renal function and pathology. Therefore, we investigated the effects of Ex on the renal RAS components in Dahl salt-sensitive (Dahl-S) rats.

METHODS

Male Dahl-S rats were divided into four groups: normal salt diet + sedentary, normal salt diet + Ex, high-salt diet (HS, 8% NaCl) + sedentary, and HS + Ex. Treadmill running was performed for 8 wk in the Ex groups.

RESULTS

Ex attenuated the HS-induced renal dysfunction and glomerular injury without causing blood pressure alterations. HS increased urinary excretion of both total and intact angiotensinogen. Ex decreased the HS-induced increased urinary excretion of total angiotensinogen. However, it did not change the HS-induced urinary excretion of intact angiotensinogen, indicating reduced intact angiotensinogen cleaving. Ex restored the HS-induced increased angiotensinogen and angiotensin II type 1 receptor expressions in the outer medulla and the HS-induced increased angiotensin-converting enzyme expression in the cortex. Ex restored the HS-induced decreased renin expression in the cortex and outer medulla, and the HS-induced decreased angiotensin-converting enzyme 2, angiotensin II type 2 receptor, and Mas receptor expressions in the outer medulla.

CONCLUSIONS

Ex attenuates HS-induced renal dysfunction, glomerular injury, and renal RAS dysregulation in Dahl-S rats.

Reviewing physical exercise in non-obese diabetic Goto-Kakizaki rats

There is a high incidence of non-obese type 2 diabetes mellitus (non-obese-T2DM) cases, particularly in Asian countries, for which the pathogenesis remains mainly unclear. Interestingly, Goto-Kakizaki (GK) rats spontaneously develop insulin resistance (IR) and non-obese-T2DM, making them a lean diabetes model. Physical exercise is a non-pharmacological therapeutic approach to reduce adipose tissue mass, improving peripheral IR, glycemic control, and quality of life in obese animals or humans with T2DM. In this narrative review, we selected and analyzed the published literature on the effects of physical exercise on the metabolic features associated with non-obese-T2DM. Only randomized controlled trials with regular physical exercise training, freely executed physical activity, or skeletal muscle stimulation protocols in GK rats published after 2008 were included. The results indicated that exercise reduces plasma insulin levels, increases skeletal muscle glycogen content, improves exercise tolerance, protects renal and myocardial function, and enhances blood oxygen flow in GK rats.

Chronic Exercise Protects against the Progression of Renal Cyst Growth and Dysfunction in Rats with Polycystic Kidney Disease

Introduction

Polycystic kidney disease (PKD) is a genetic disorder characterized by the progressive enlargement of renal epithelial cysts and renal dysfunction. Previous studies have reported the beneficial effects of chronic exercise on chronic kidney disease. However, the effects of chronic exercise have not been fully examined in PKD patients or models. The effects of chronic exercise on the progression of PKD were investigated in a polycystic kidney (PCK) rat model.

Methods

Six-week-old male PCK rats were divided into a sedentary group and an exercise group. The exercise group underwent forced treadmill exercise for 12 wk (28 m·min⁻¹, 60 min·d⁻¹, 5 d·wk⁻¹). After 12 wk, renal function and histology were examined, and signaling cascades of PKD progression, including arginine vasopressin (AVP), were investigated.

Results

Chronic exercise reduced the excretion of urinary protein, liver-type fatty acid–binding protein, plasma creatinine, urea nitrogen, and increased plasma irisin and urinary AVP excretion. Chronic exercise also slowed renal cyst growth, glomerular damage, and interstitial fibrosis and led to reduced Ki-67 expression. Chronic exercise had no effect on cAMP content but decreased the renal expression of B-Raf and reduced the phosphorylation of extracellular signal-regulated kinase (ERK), mammalian target of rapamycin (mTOR), and S6.

Conclusion

Chronic exercise slows renal cyst growth and damage in PCK rats, despite increasing AVP, with the downregulation of the cAMP/B-Raf/ERK and mTOR/S6 pathways in the kidney of PCK rats.

Effects of Long-Term Exercise on Liver Cyst in Polycystic Liver Disease Model Rats

BACKGROUND

Polycystic liver disease (PLD) is a hereditary liver disease with progressive enlargement of fluid-filled liver cysts, which causes abdominal discomfort and worsens quality of life. Long-term exercise has beneficial effects in various organs, but the effects of long-term exercise on PLD are unclear. Therefore, the aim of this study was to investigate whether long-term exercise inhibits liver cyst formation and fibrosis.

METHODS

Polycystic kidney (PCK) rats, a model of PLD, were randomly divided into a sedentary group and a long-term exercise group, which underwent treadmill running for 12 wk (28 m·min, 60 min·d, 5 d·wk). Sprague-Dawley (SD) rats were set as a control group. After 12 wk, exercise capacity, histology, and signaling cascades of PLD were examined.

RESULTS

Compared with control SD rats, PCK rats showed a low exercise capacity before exercise protocol. After 12 wk, the exercise improved the exercise capacity and ameliorated liver cyst formation and fibrosis. The exercise significantly decreased the number of Ki-67-positive cells; the expression of cystic fibrosis transmembrane conductance regulator, aquaporin 1, transforming growth factor β, and type 1 collagen; and the phosphorylation of extracellular signal-regulated kinase, mammalian target of rapamycin and S6. It also increased the phosphorylation of AMP-activated protein kinase in the liver of PCK rats.

CONCLUSIONS

The present results indicated that long-term moderate-intensity exercise ameliorates liver cyst formation and fibrosis with the inhibition of signaling cascades responsible for cellular proliferation and fibrosis in PCK rats.

Combination of Exercise Training and SOD Mimetic Tempol Enhances Upregulation of Nitric Oxide Synthase in the Kidney of Spontaneously Hypertensive Rats

Both exercise training (Ex) and superoxide dismutase (SOD) mimetic tempol have antihypertensive and renal protective effects in rodent models of several hypertensions. We recently reported that Ex increases nitric oxide (NO) production and the expression levels of endothelial and neuronal NO synthase (eNOS and nNOS) in the kidney and aorta of the spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto rats (WKY). We also found that endogenous hydrogen peroxide (H₂O₂) upregulates the expression levels of eNOS and nNOS in SHR. To elucidate the mechanism of the Ex-upregulated NO system in the kidney, we examined the additive effect of Ex and tempol on the renal NO system in SHR and WKY. Our data showed that, in SHR, both Ex and tempol increase the levels of H₂O₂ and nitrate/nitrite (NOx) in plasma and urine. We also observed an increased renal NOS activity and upregulated expression levels of eNOS and nNOS with decreased NADPH oxidase activity. The effects of the combination of Ex and tempol on these variables were cumulate in SHR. On the other hand, we found that Ex increases these variables with increased renal NADPH oxidase activity, but tempol did not change these variables or affect the Ex-induced upregulation in the activity and expression of NOS in WKY. The SOD activity in the kidney and aorta was activated by tempol only in SHR, but not in WKY; whereas Ex increased SOD activity only in the aorta in both SHR and WKY. These results indicate that Ex-induced endogenous H₂O₂ produced in the blood vessel and other organs outside of the kidney may be carried to the kidney by blood flow and stimulates the NO system in the kidney.

Effects of exercise training on renal interstitial fibrosis and renin-angiotensin system in rats with chronic renal failure

OBJECTIVE

To clarify the mechanisms of the renal protective effects of exercise training, we examined the effects of exercise training on the renal interstitial fibrosis and renin-angiotensin system (RAS) in rats with chronic renal failure.

METHODS

Six-week-old male Sprague-Dawley rats were divided into three groups: sham operation; 5/6 nephrectomy + sedentary; 5/6 nephrectomy + exercise training. The 5/6 nephrectomy + exercise training group underwent treadmill running (20 m/min, 60 min/day, 5 days/week). After 12 weeks, renal function, histology and protein expression of collagen type I, transforming growth factor-β1 (TGF-β1), matrix metalloproteinase (MMP), tissue inhibitors of metalloproteinase (TIMP) and RAS components in the renal cortex were examined.

RESULTS

Exercise training ameliorated the 5/6 nephrectomy-induced hypertension, proteinuria, renal dysfunction, glomerular sclerosis and renal interstitial fibrosis. 5/6 Nephrectomy increased the expression of collagen type I, TGF-β1, MMP-2, MMP-9, TIMP-1, angiotensinogen, angiotensin-converting enzyme (ACE), (pro)renin receptor and angiotensin II type 1 receptor, and exercise training inhibited the 5/6 nephrectomy-increased expression of collagen type I, TGF-β1, TIMP-1, angiotensinogen and ACE expressions. 5/6 Nephrectomy decreased the expression of renin, ACE2, angiotensin II type 2 receptor and Mas receptor, and exercise training inhibited the 5/6 nephrectomy-decreased expressions.

CONCLUSION

These results indicated that exercise training attenuates the progression of glomerular sclerosis and renal interstitial fibrosis in chronic renal failure rats. The renal protective effects of exercise training may be mediated by ameliorating the renal collagen turnover and the exacerbation of renal RAS.

Exercise training delays renal disorders with decreasing oxidative stress and increasing production of 20-hydroxyeicosatetraenoic acid in Dahl salt-sensitive rats

OBJECTIVE

Exercise training has antihypertensive and renoprotective effects in humans and rats. However, the effects of exercise training on renal disorders that occur with salt-sensitive hypertension remains unclear. The study aim was to investigate the effects and mechanisms of exercise training on renal function in a rat model of salt-sensitive hypertension.

METHODS

Six-week-old male Dahl salt-sensitive rats were divided into normal-salt (0.6% NaCl) diet, high-salt (8% NaCl) diet, and high-salt diet with exercise training groups. The high-salt diet with exercise training group underwent daily treadmill running for 8 weeks.

RESULTS

The high-salt diet induced severe hypertension and renal dysfunction. Exercise training significantly improved high-salt diet-induced urinary protein, albumin, and L-type fatty acid-binding protein excretion, and glomerulosclerosis but not renal interstitial fibrosis without changing blood pressure. Exercise training significantly attenuated high-salt diet-induced oxidative stress in the kidneys and decreased high-salt diet-stimulated xanthine oxidoreductase activity but not nicotinamide adenine dinucleotide phosphate oxidase activity. The high-salt diet did not change urinary excretion of 20-hydroxyeicosatetraenoic acid and decreased cytochrome P450 4A protein expression in the kidneys. Exercise training increased urinary 20-hydoroxyeicosatetraenoic acid excretion and renal cytochrome P450 4A protein expression.

CONCLUSION

Exercise training improved renal disorders without lowering blood pressure in Dahl salt-sensitive rats. Exercise training also decreased oxidative stress and increased 20-hydroxyeicosatetraenoic acid production in the kidneys. These results suggest that improvements in oxidative stress and 20-hydroxyeicosatetraenoic acid production may be potential mechanisms by which exercise training improved renal disorders in Dahl salt-sensitive rats.

Carnosinase-1 overexpression, but not aerobic exercise training, affects the development of diabetic nephropathy in BTBR ob/ob mice

Manipulation of circulating histidine-containing dipeptides (HCD) has been shown to affect the development of diabetes and early-stage diabetic nephropathy (DN). The aim of the present study was to investigate whether such interventions, which potentially alter levels of circulating HCD, also affect the development of advanced-stage DN. Two interventions, aerobic exercise training and overexpression of the human carnosinase-1 (hCN1) enzyme, were tested. BTBR ob/ob mice were either subjected to aerobic exercise training (20 wk) or genetically manipulated to overexpress hCN1, and different diabetes- and DN-related markers were compared with control ob/ob and healthy (wild-type) mice. An acute exercise study was performed to elucidate the effect of obesity, acute running, and hCN1 overexpression on plasma HCD levels. Chronic aerobic exercise training did not affect the development of diabetes or DN, but hCN1 overexpression accelerated hyperlipidemia and aggravated the development of albuminuria, mesangial matrix expansion, and glomerular hypertrophy of ob/ob mice. In line, plasma, kidney, and muscle HCD were markedly lower in ob/ob versus wild-type mice, and plasma and kidney HCD in particular were lower in ob/ob hCN1 versus ob/ob mice but were unaffected by aerobic exercise. In conclusion, advanced glomerular damage is accelerated in mice overexpressing the hCN1 enzyme but not protected by chronic exercise training. Interestingly, we showed, for the first time, that the development of DN is closely linked to renal HCD availability. Further research will have to elucidate whether the stimulation of renal HCD levels can be a therapeutic strategy to reduce the risk for developing DN.

Chronic exercise provides renal-protective effects with upregulation of fatty acid oxidation in the kidney of high fructose-fed rats

Excessive fructose intake causes metabolic syndrome and lipid accumulation in the kidney and leads to renal dysfunction and damage. Exercise (Ex) improves lipids regulation, but the mechanisms are unclarified in the kidney. In the present study, male Sprague-Dawley rats were allocated to groups fed with control or high-fructose (HFr) diet. Part of rats in each group underwent aerobic treadmill Ex for 12 wk. Drug treatment was performed as the fenofibrate gavage during the last 4 wk on HFr diet-fed rats. Renal function, histological changes, and expression of regulators involved in fatty acid (FA) metabolism were assessed. In CON diet-fed groups, Ex did not affect renal function or histology and significantly increased renal expression of FA β-oxidation regulators including acyl-CoA dehydrogenases (CADs), acyl-CoA oxidase, peroxisome proliferator-activated receptor (PPAR)-α, and PPAR-γ coactivator (PGC)-1α and lipogenic factors including acetyl-CoA carboxylase (ACCα), FA synthase (FAS), and sterol regulatory element-binding protein 1c. HFr caused albuminuria, lipid accumulation, and renal pathohistological changes, which were attenuated by Ex but not by fenofibrate. HFr decreased renal expression of medium- and short-chain CADs and PPAR-α and increased renal expression of ACCα, FAS, and sterol regulatory element-binding protein 1c. Ex increased expression of CADs, carnitine palmitoyltransferase type I, acyl-CoA oxidase, PPAR-α, and PGC-1α and decreased renal expression of ACCα and FAS in HFr diet-fed rats. The Ex-induced FA metabolism alteration was similar to that in the fenofibrate-treated group. In conclusion, the present study indicates that Ex enhanced renal FA metabolism, which might protect the kidney in lipid dysregulation diseases.

Swimming exercise demonstrates advantages over running exercise in reducing proteinuria and glomerulosclerosis in spontaneously hypertensive rats

Experimental studies in animal models have described the benefits of physical exercise (PE) to kidney diseases associated with hypertension. Land- and water-based exercises induce different responses in renal function. Our aim was to evaluate the renal alterations induced by different environments of PE in spontaneously hypertensive rats (SHRs). The SHRs were divided into sedentary (S), swimming exercise (SE), and running exercise (RE) groups, and were trained for 8 weeks under similar intensities (60 min/day). Arterial pressure (AP) and heart rate (HR) were recorded. The renal function was evaluated through urinary volume at each week of training; sodium and potassium excretions, plasma and urinary osmolarities, glomerular filtration rate (GFR), levels of proteinuria, and renal damage were determined. SE and RE rats presented reduced mean AP, systolic blood pressure, and HR in comparison with S group. SE and RE rats showed higher urine osmolarity compared with S. SE rats showed higher free water clearance (P < 0.01), lower urinary density (P < 0.0001), and increased weekly urine volume (P < 0.05) in comparison with RE and S groups. GFR was increased in both SE and RE rats. The proteinuria of SE (7.0 ± 0.8 mg/24 h) rats was decreased at the 8th week of the PE in comparison with RE (9.6 ± 0.8 mg/24 h) and S (9.8 ± 0.5 mg/24 h) groups. The glomerulosclerosis was reduced in SE rats (P < 0.02). SE produced different response in renal function in comparison with RE, in which only swimming-trained rats had better profile for proteinuria and glomerulosclerosis.

Update of pathophysiology and management of diabetic kidney disease

Diabetic kidney disease (DKD) is a major cause of morbidity and mortality in patients with diabetes mellitus and the leading cause of end-stage renal disease in the world. The most characteristic marker of DKD is albuminuria, which is associated with renal disease progression and cardiovascular events. Renal hemodynamics changes, oxidative stress, inflammation, hypoxia and overactive renin-angiotensin-aldosterone system (RAAS) are involved in the pathogenesis of DKD, and renal fibrosis plays the key role. Intensified multifactorial interventions, including RAAS blockades, blood pressure and glucose control, and quitting smoking, help to prevent DKD development and progression. In recent years, novel agents are applied for preventing DKD development and progression, including new types of glucose-lowering agents, pentoxifylline, vitamin D analog paricalcitol, pyridoxamine, ruboxistaurin, soludexide, Janus kinase inhibitors and nonsteroidal minerocorticoid receptor antagonists. In this review, recent large studies about DKD are also summarized.

Can regular moderate exercise lead to changes in miRNA-146a and its adapter proteins in the kidney of streptozotocin-induced diabetic male rats?

Objective. The aim of this study was to assess whether microRNA-146a and its adapter proteins TNF receptor associated factor6 (TRAF6) and interleukin-1 receptor-associated kinase-1 (IRAK1) may be changed in the kidney of streptozotocin-induced diabetic rats, following regular moderate exercise.

Methods. Forty adult male Wistar rats were allocated randomly into four groups (n=10), including sedentary control (SC), sedentary diabetic (SD), healthy sixty-day exercise (H60E), and diabetic sixty-day exercise (D60E) groups. Diabetes was induced by an intraperitoneal injection of 60 mg/kg streptozotocin. After 48 h, blood glucose levels >250 mg/dl was included to diabetic rats. After 2 days of diabetes induction, the exercise protocol began. Animals were exposed to 5 days of consecutive treadmill exercise for 60 min/day with the 22 m/min speed for 60 days. The kidneys of the rats were removed and microRNA was extracted from them using the miRCURYTM RNA isolation kit.

Results. In diabetic rats, statistical analysis revealed a significant decrease in miR-146a expression, non-significant decrease in IRAK1 mRNA expression, and non-significant increase in TRAF6 and NF-kB mRNA expression compared to the SC group. Exercise led to a non-significant increase in the expression of miR-146a and NF-kB mRNA in the kidneys of the diabetic group as compared to the SD group, significant increase in TRAF6 and IRAK1 mRNA expression compared to the H60E group, and significant increase in TRAF6 mRNA expression compared to the SD group.

Conclusion. The present data indicate that exercise might be able to help in the prevention in the diabetic nephropathy development.

Chronic Running Exercise Alleviates Early Progression of Nephropathy with Upregulation of Nitric Oxide Synthases and Suppression of Glycation in Zucker Diabetic Rats

Exercise training is known to exert multiple beneficial effects including renal protection in type 2 diabetes mellitus and obesity. However, the mechanisms regulating these actions remain unclear. The present study evaluated the effects of chronic running exercise on the early stage of diabetic nephropathy, focusing on nitric oxide synthase (NOS), oxidative stress and glycation in the kidneys of Zucker diabetic fatty (ZDF) rats. Male ZDF rats (6 weeks old) underwent forced treadmill exercise for 8 weeks (Ex-ZDF). Sedentary ZDF (Sed-ZDF) and Zucker lean (Sed-ZL) rats served as controls. Exercise attenuated hyperglycemia (plasma glucose; 242 ± 43 mg/dL in Sed-ZDF and 115 ± 5 mg/dL in Ex-ZDF) with increased insulin secretion (plasma insulin; 2.3 ± 0.7 and 5.3 ± 0.9 ng/mL), reduced albumin excretion (urine albumin; 492 ± 70 and 176 ± 11 mg/g creatinine) and normalized creatinine clearance (9.7 ± 1.4 and 4.5 ± 0.8 mL/min per body weight) in ZDF rats. Endothelial (e) and neuronal (n) NOS expression in kidneys of Sed-ZDF rats were lower compared with Sed-ZL rats (p<0.01), while both eNOS and nNOS expression were upregulated by exercise (p<0.01). Furthermore, exercise decreased NADPH oxidase activity, p47phox expression (p<0.01) and α-oxoaldehydes (the precursors for advanced glycation end products) (p<0.01) in the kidneys of ZDF rats. Additionally, morphometric evidence indicated renal damage was reduced in response to exercise. These data suggest that upregulation of NOS expression, suppression of NADPH oxidase and α-oxoaldehydes in the kidneys may, at least in part, contribute to the renal protective effects of exercise in the early progression of diabetic nephropathy in ZDF rats. Moreover, this study supports the theory that chronic aerobic exercise could be recommended as an effective non-pharmacological therapy for renoprotection in the early stages of type 2 diabetes mellitus and obesity.

Impact of Lifestyle Modification on Diabetic Kidney Disease

Kidney disease is common in patients with type 1 and type 2 diabetes mellitus and is associated with adverse health outcomes, including progression to end-stage renal disease. In the general population, adherence to a healthy lifestyle is known to reduce the risk of cardiovascular events and death. Among individuals with diabetic kidney disease, modifications in lifestyle factors, including diet, physical activity, smoking habits, and body mass index, represent a promising cost-effective therapeutic adjunct to pharmacologic treatment of kidney disease incidence and progression.

The renin-angiotensin system and prevention of age-related functional decline: where are we now?

Declining physical function is a major health problem for older adults as it is associated with multiple comorbidities and mortality. Exercise has been shown to improve physical function, though response to exercise is variable. Conversely, drugs targeting the renin-angiotensin system (RAS) pathway, including angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs), are also reported to improve physical function. In the past decade, significant strides have been made to understand the complexity and specificity of the RAS system as it pertains to physical function in older adults. Prior findings have also determined that interactions between antihypertensive medications and exercise may influence physical function above and beyond either factor alone. We review the latest research on RAS, exercise, and physical function for older adults. We also outline future research aims in this area, including genetic influences and clinical phenotyping, for the purpose of maintaining or improving physical function through tailored treatments.

Lifestyle intervention: nutrition therapy and physical activity

Diabetes now affects more than 29 million Americans, and more than 9 million of these people do not know they have diabetes. In adults, type 2 diabetes accounts for about 90% to 95% of all diagnosed cases of diabetes and is the focus of this article. Lifestyle intervention is part of the initial treatment as well as the ongoing management of type 2 diabetes. Lifestyle intervention encompasses a healthful eating plan, physical activity, and often medication to assist in achievement of glucose, lipid, and blood pressure goals. Patient education and self-care practices are also important aspects of disease management.

Daily exercise training protects against albuminuria and angiotensin converting enzyme 2 shedding in db/db diabetic mice

Angiotensin II (Ang II) is involved in induction and progression of renal damage in diabetes. Angiotensin converting enzyme 2 (ACE2) is highly expressed in the kidney and has been shown to be renoprotective by degrading Ang II to Ang-(1-7). A disintegrin and metalloproteinase 17 (ADAM17)-mediated shedding of renal ACE2 contribute to diabetic nephropathy pathogenesis. Lifestyle modification and metformin are recommended as initial therapies for most patients with type 2 diabetes. The aim of this study was to investigate whether exercise training and/or metformin improve glucose homeostasis and albuminuria and downregulate renal ADAM17 and ACE2 shedding in db/db mice. Seven-week-old normal and db/db mice were subjected either to a sedentary existence or exercise training with and without metformin (150 mg/kg per day) for 10 weeks. Exercise training significantly lowered blood glucose, urinary albumin and ACE2 excretion in db/db mice. ADAM17 and ACE2 proteins were co-localized in cortical tubules of the kidney, indicating a possible interaction. Metformin treatment was effective in lowering hyperglycemia only during the first 2 weeks of treatment. Increased renal ADAM17 in 17-week-old db/db mice was corrected by physical exercise but not metformin. In addition, exercise training reduced plasma triglycerides and enhanced insulin levels of db/db mice. In conclusion, exercise training alone and in combination with metformin prevented shedding of renal ACE2 by decreasing ADAM17 protein. Urinary ACE2 could serve as a prognostic tool for the progression of kidney damage and its attenuation by exercise may partially contribute to its renal protection.

Exercise training upregulates nitric oxide synthases in the kidney of rats with chronic heart failure

There is an interaction between heart and kidney diseases, which is a condition termed cardiorenal syndrome. Exercise training has cardioprotective effects, involving upregulation of endothelial (e) nitric oxide synthase (NOS) in the cardiovascular system. However, the effects of exercise training on NOS in the kidney with heart disease are unknown. The aim of the present study was to investigate whether exercise training upregulates NOS in the kidney, left ventricle and aorta of rats with chronic heart failure (CHF). Male Sprague-Dawley rats underwent left coronary artery ligation (LCAL) to induce CHF and were randomly assigned to sedentary or treadmill exercise groups 4 weeks after LCAL. Three days after exercising for 4 weeks, urine samples were collected for 24 h and blood samples were collected following decapitation. Nitric oxide synthase activity and protein expression were examined. Significant interactions between CHF and exercise training were observed on parameters of cardiac and renal function. Exercise training improved cardiac function, decreased plasma B-type natriuretic peptide levels, decreased urinary albumin excretion and increased creatinine clearance in CHF rats. Nitric oxide synthase activity, eNOS expression and neuronal (n) NOS expression were significantly decreased in the left ventricle and kidney of CHF rats. Exercise training significantly increased NOS activity and eNOS and nNOS expression. Upregulation of NOS in the kidney and left ventricle may contribute, in part, to the renal and cardiac protective effects of exercise training in cardiorenal syndrome in CHF rats.

The influence of physical activity on vascular complications and mortality in patients with type 2 diabetes mellitus

AIMS

There is limited evidence regarding the association between physical activity and vascular complications, particularly microvascular disease, in patients with type 2 diabetes.

METHODS

From the 11 140 patients in the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron modified release Controlled Evaluation) trial, the effect of physical activity, categorized as none, mild, moderate or vigorous, and the number of sessions within a week, was examined in multivariable regression models adjusted for potential confounders. The study end-points were major cardiovascular events, microvascular complications and all-cause mortality.

RESULTS

Forty-six percent of participants reported undertaking moderate to vigorous physical activity for >15 min at least once in the previous week. During a median of 5 years of follow-up, 1031 patients died, 1147 experienced a major cardiovascular event and 1136 a microvascular event. Compared to patients who undertook no or mild physical activity, those reporting moderate to vigorous activity had a decreased risk of cardiovascular events (HR: 0.78, 95% CI: 0.69-0.88, p < 0.0001), microvascular events (HR: 0.85, 95% CI: 0.76-0.96, p = 0.010) and all-cause mortality (HR: 0.83, 95% CI: 0.73-0.94, p = 0.0044).

CONCLUSIONS

Moderate to vigorous, but not mild, physical activity is associated with a reduced incidence of cardiovascular events, microvascular complications and all-cause mortality in patients with type 2 diabetes.

Physical activity and type 2 diabetes. Recommandations of the SFD (Francophone Diabetes Society) diabetes and physical activity working group

Although regular physical activity is an integral part of T2D management, few diabetic patients have a sufficient level of physical activity. However over the past decade or so, the beneficial effects of regular physical activity have been well demonstrated, both in T2D prevention (50% reduction in the incidence of T2D in subjects with high metabolic risk) as well as T2D management for the improvement of glycaemic control (mean 0.7% improvement of HbA1c) and the reduction of T2D-related comorbidities (improvement in blood pressure values and lipid profile, decrease in insulin resistance). Physical activity has both acute effects (effects of one exercise session) and more prolonged effects of exercise when it is repeated on a regular basis (training effect). In addition, the physical activity recommendations have been extended to a wide range of physical activities (by combining both endurance and muscle strengthening exercises), thus varying the physical activity practiced according to the patient's available time, practice sites, preferences and interests. Following a pathophysiology review, the effects of physical activity will be discussed and presented in terms of evidence-based medicine. The recommendations will be defined and practical prescribing information will be suggested, while taking into account that clinicians are concerned with answering questions regarding how, where and with whom: how can patients be motivated to practice a physical activity over the long-term? And how can qualified exercise trainers and appropriate practice settings be found?

Albuminuria indicates the pressure-associated injury of juxtamedullary nephrons and cerebral strain vessels in spontaneously hypertensive stroke-prone rats

Albuminuria is an indicator of renal injury and is closely linked with cardiovascular disease (CVD). However, the mechanism by which albumin is excreted in the urine remains unclear. As the juxtamedullary region of the kidney is highly susceptible to pressure increase, juxtamedullary injury is observed from an early phase in hypertensive rat models. Anatomical similarities are observed between the pre-glomerular vessels of the juxtamedullary nephron and the cerebral vasculature. We previously named these ‘strain vessels' for their high vascular tone and exposure to higher pressures. The current studies were designed to determine whether albuminuria is the result of juxtamedullary nephron injury, indicating the presence of pressure injury to the strain vessels in spontaneously hypertensive stroke-prone rats (SHR-SP) fed a high-salt diet. Albuminuria was associated with juxtamedullary nephron injury, and the enhanced expression of monocyte chemotactic protein-1 (MCP-1) and tumor growth factor-beta (TGF-β) in 12-week-old SHR-SP rats fed a 4% high-salt diet from the age of 6 weeks. The wall thickness of the pre-glomerular vessels of the juxtamedullary nephron was also associated with that of the perforating artery of the middle cerebral artery. Reducing the blood pressure with nifedipine reduced the degree of albuminuria and juxtamedullary nephron injury as well as MCP-1 and TGF-β expression in the SHR-SP rats fed an 8% high-salt diet from the age of 9 weeks. Nifedipine inhibited stroke events in these animals until they were 14 weeks old. These results indicate that albuminuria is a result of juxtamedullary nephron injury and a marker of pressure-induced injury of the strain vessels.

Cardiac remodeling and function following exercise and angiotensin II receptor antagonism

The purpose of this study was to test the impact of chronic exercise training combined with selective angiotensin II receptor (AT1) antagonism on systolic blood pressure (SBP) and the left-ventricular pressure-volume relationship in normotensive, non-infarcted rat hearts. Wistar rats (N = 19) were randomly assigned to either a sedentary control group (N = 8) or an exercise-trained group (N = 11). Losartan was administered to individually caged rats via the drinking water (10 mg/kg/d). Exercise training consisted of running on a motorized driven treadmill for 6 weeks at 30 m/min, 60 min/day, 5 days/week. Tail cuff SBP was measured weekly. Left ventricular performance was assessed in an ex vivo Langendorff isovolumic mode. One week of losartan treatment significantly reduced SBP in both groups by 13% relative to baseline (P < 0.05). SBP was lower in exercise-trained animals versus sedentary animals in the later weeks of the protocol (P < 0.05) Body weight was significantly lower in exercise-trained animals versus sedentary animals, but heart weight, heart to body weight ratio, atrial weight, and absolute left ventricular mass and length were similar between groups. The LV systolic pressure-volume relationship (PV) and systolic elastance were significantly greater in exercise-trained animals versus sedentary controls (P < 0.05). The left ventricular end-diastolic PV and diastolic stiffness were similar between exercise-trained and sedentary animals. These data suggest that chronic aerobic exercise training can improve the Starling response in the presence of AT1 receptor blockade without altering absolute cardiac size.

Effects of training and nitric oxide on diabetic nephropathy progression in type I diabetic rats

The aim of the paper is to assess nitric oxide (NO) production during aerobic training and its role on the progression of diabetic nephropathy in rats. Induction of diabetes mellitus (DM) was achieved in adult male Wistar rats with streptozotocin. Half of the animals underwent training on a treadmill and the others (sedentary) stayed on a turned-off treadmill for the same period according to the following groups: sedentary control (CTL + SE); training control (CTL + EX); sedentary diabetic (DM + SE); and training diabetic (DM + EX) (n = 9 for all groups). The training on treadmill was carried out at a work rate of 16 m/min, 60 min/d, 5 d/week for eight weeks. Before and after the exercises, rats were placed in individual metabolic cages with standard chow and water ad libitum, for 24-h urine collection, followed by three hours' fasting blood sample withdrawal from the retro-orbital plexus, under anesthesia. Diabetic animals showed reduction of body weight, creatinine and urea depurations and NO excretion, increased blood glucose concentrations, albuminuria and thiobarbituric acid reactive substance (TBARS) excretion, when compared with the respective controls. All these alterations induced by DM were attenuated in the DM + EX versus DM + SE group. Analysis of insulin concentrations at the end of the protocol showed no significant change between the DM + SE and DM + EX groups. In conclusion, our data show that a routine physical exercise resulted in a better control of glycemia with an increased NO bioavailability and oxidative stress control, associated with an amelioration of renal function. We suggest aerobic training and the control of oxidative and nitrosative stress as useful non-pharmacological tools to delay the progression of diabetic nephropathy.

Exercise and type 2 diabetes: American College of Sports Medicine and the American Diabetes Association: joint position statement. Exercise and type 2 diabetes

Although physical activity (PA) is a key element in the prevention and management of type 2 diabetes mellitus (T2DM), many with this chronic disease do not become or remain regularly active. High-quality studies establishing the importance of exercise and fitness in diabetes were lacking until recently, but it is now well established that participation in regular PA improves blood glucose control and can prevent or delay T2DM, along with positively affecting lipids, blood pressure, cardiovascular events, mortality, and quality of life. Structured interventions combining PA and modest weight loss have been shown to lower T2DM risk by up to 58% in high-risk populations. Most benefits of PA on diabetes management are realized through acute and chronic improvements in insulin action, accomplished with both aerobic and resistance training. The benefits of physical training are discussed, along with recommendations for varying activities, PA-associated blood glucose management, diabetes prevention, gestational diabetes, and safe and effective practices for PA with diabetes-related complications.

Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: joint position statement

Although physical activity (PA) is a key element in the prevention and management of type 2 diabetes, many with this chronic disease do not become or remain regularly active. High-quality studies establishing the importance of exercise and fitness in diabetes were lacking until recently, but it is now well established that participation in regular PA improves blood glucose control and can prevent or delay type 2 diabetes, along with positively affecting lipids, blood pressure, cardiovascular events, mortality, and quality of life. Structured interventions combining PA and modest weight loss have been shown to lower type 2 diabetes risk by up to 58% in high-risk populations. Most benefits of PA on diabetes management are realized through acute and chronic improvements in insulin action, accomplished with both aerobic and resistance training. The benefits of physical training are discussed, along with recommendations for varying activities, PA-associated blood glucose management, diabetes prevention, gestational diabetes mellitus, and safe and effective practices for PA with diabetes-related complications.

Regular moderate exercise reduces advanced glycation and ameliorates early diabetic nephropathy in obese Zucker rats

Advanced glycation end products (AGEs) play a key role in the pathogenesis of diabetes and its complications, including the diabetic nephropathy. The renoprotective effects of exercise are well known; however, the mechanisms remain elusive. Here we examined whether a regular moderate exercise in obese Zucker rats (OZR), a model of diabetes- and obesity-associated nephropathy, will affect the development of early renal injury in OZR possibly via alteration of AGEs formation. The OZR were left without exercise (sedentary) or subjected to 10 weeks intermittent treadmill running of moderate intensity. Compared with sedentary OZR, kidneys of running OZR had significantly less glomerular mesangial expansion and tubulointerstitial fibrosis. Running OZR had significantly lower plasma AGEs-associated fluorescence and N(epsilon)-carboxymethyllysine. Correspondingly, renal AGEs and N(epsilon)-carboxymethyllysine content were lower in running OZR. Systemically, exercise increased aerobic metabolism, as apparent from urinary metabolite profiling. No differences in plasma glucose, insulin, or lipid profile were found between the 2 groups. Apart from lower advanced oxidation protein products (a marker of myeloperoxidase activity), no other marker of inflammation was altered by exercise, either systemically or locally in kidneys. No indication of changed oxidative status was revealed between the groups. Exercise in OZR decreased advanced glycation. This might represent the early event of exercise-induced renoprotection in diabetic nephropathy in OZR. If confirmed in clinical studies, regular moderate exercise could represent an easy and effective nonpharmacologic approach to reduce advanced glycation.

Combination of chronic exercise and antihypertensive therapy enhances renoprotective effects in rats with renal ablation

BACKGROUND

We assessed the renal protective effects of treatment with moderate exercise (EX), with EX plus olmesartan (OLS), with EX plus azelnidipine (AZN), and with the three together in a rat model of chronic renal failure (CRF).

METHODS

Male 5/6-nephrectomized Wistar Kyoto (WKY) rats were divided into six groups according to the following treatments for: (i) no EX (C); (ii) moderate EX with treadmill running (20 m/min for 60 min/day, 5 days/week) (EX); (iii) EX+OLS (10 mg/kg/day); (iv) EX+AZN (3 mg/kg/day); (v) EX+OLS (5 mg/kg/day)+AZN (1.5 mg/kg/day); and (vi) sham operation (S). The rats were then treated for 12 weeks.

RESULTS

EX, EX+OLS, EX+AZN, and EX+OLS+AZN showed decreases in the serum creatinine (Scr), an index of glomerular sclerosis (IGS), the relative interstitial volume of the renal cortex (RIV), the number of ED-1 (monoclonal antibody) positive cells (ED1(+)) and the glomerular expression score of alpha-smooth muscle actin (alpha-SMA(+)). EX+OLS, EX+AZN, and EX+OLS+AZN blocked the development of hypertension, increased the number of Wilms' tumor-1 (WT-1) positive cells (WT1(+)); EX+OLS and EX+OLS+AZN blunted the increases in proteinuria. In particular, blood urea nitrogen (BUN), ED1(+), alpha-SMA(+), WT1(+), IGS, and RIV in the EX+OLS+AZN were the lowest among all the nephrectomized groups.

CONCLUSIONS

In the results, simultaneous treatment of EX, OLS, and AZN showed renal protective effects in this rat model suggesting that the treatment may affect the macrophage infiltration to the glomerulus, the fibroblast accumulation in the glomerulus, the mesangial activation, and the podocyte differentiation.

Administration of a substituted adamantyl urea inhibitor of soluble epoxide hydrolase protects the kidney from damage in hypertensive Goto-Kakizaki rats

Hypertension and Type 2 diabetes are co-morbid diseases that lead to the development of nephropathy. sEH (soluble epoxide hydrolase) inhibitors are reported to provide protection from renal injury. We hypothesized that the sEH inhibitor AUDA [12-(3-adamantan-1-yl-ureido)-dodecanoic acid] protects the kidney from the development of nephropathy associated with hypertension and Type 2 diabetes. Hypertension was induced in spontaneously diabetic GK (Goto-Kakizaki) rats using AngII (angiotensin II) and a high-salt diet. Hypertensive GK rats were treated for 2 weeks with either AUDA or its vehicle added to drinking water. MAP (mean arterial pressure) increased from 118+/-2 mmHg to 182+/-20 and 187+/-6 mmHg for vehicle and AUDA-treated hypertensive GK rats respectively. AUDA treatment did not alter blood glucose. Hypertension in GK rats resulted in a 17-fold increase in urinary albumin excretion, which was decreased with AUDA treatment. Renal histological evaluation determined that AUDA treatment decreased glomerular and tubular damage. In addition, AUDA treatment attenuated macrophage infiltration and inhibited urinary excretion of MCP-1 (monocyte chemoattractant protein-1) and kidney cortex MCP-1 gene expression. Taken together, these results provide evidence that sEH inhibition with AUDA attenuates the progression of renal damage associated with hypertension and Type 2 diabetes.

Reduced progression of adriamycin nephropathy in spontaneously hypertensive rats treated by losartan

BACKGROUND

The aim of the study was to investigate the antihypertensive effects of angiotensin II type-1 receptor blocker, losartan, and its potential in slowing down renal disease progression in spontaneously hypertensive rats (SHR) with adriamycin (ADR) nephropathy.

METHODS

Six-month-old female SHR were randomly selected in six groups. Two control groups (SH(6), SH(12)) received vehicle. Groups ADR(6), ADR+LOS(6) and ADR(12), and ADR+LOS(12) received ADR (2 mg/kg/b.w. i.v.) twice in a 3-week interval. Group ADR+LOS(6) received losartan (10 mg/kg/b.w./day by gavages) for 6 weeks and group ADR+LOS(12) for 12 weeks after second injection of ADR. Animals were killed after 6 or 12 weeks, respectively. Haemodynamic measurements were performed on anaesthetized animals, blood and urine samples were taken for biochemical analysis and the left kidney was processed for morphological studies.

RESULTS

Short-term losartan treatment, besides antihypertensive effect, improved glomerular filtration rate and ameliorated glomerulosclerosis resulting in decreased proteinuria. Prolonged treatment with losartan showed further reduction of glomerulosclerosis associated with reduced progression of tubular atrophy and interstitial fibrosis, thus preventing heavy proteinuria and chronic renal failure. Losartan reduced uraemia and increased urea clearance in advanced ADR nephropathy in SHR. Histological examination showed that losartan could prevent tubular atrophy, interstitial infiltration and fibrosis in ADR nephropathy.

CONCLUSION

Losartan reduces the rate of progression of ADR-induced focal segmental glomerulosclerosis to end-stage renal disease in SHR.