Increased rho kinase activity in mononuclear cells of dialysis and stage 3-4 chronic kidney disease patients with left ventricular hypertrophy: Cardiovascular risk implications

Glucose-Free Solutions Mediated Inhibition of Oxidative Stress and Oxidative Stress-Related Damages in Peritoneal Dialysis: A Promising Solution

Oxidative stress (OxSt) and inflammation are common in end-stage renal disease and dialysis patients; they are known risk factors for cardiovascular disease and mortality. In peritoneal dialysis (PD), OxSt and inflammation are even further increased compared to the already increased oxidative stress of their pre-dialysis phase. This is due to the high glucose-based solutions currently used, whose continuous contact with the peritoneal membrane can induce significant long-term morphological and functional changes (mesothelial to mesenchymal transition, thickening, neo-angiogenesis and fibrosis) of the peritoneal membrane. Oxidative stress plays a very important role in these processes, which may compromise the peritoneal dialysis procedure. There is, therefore, the need for more biocompatible dialysis fluids with polymers other than glucose to prevent and treat OxSt and inflammation. The most known and used of such glucose-free and more biocompatible peritoneal dialysis solutions is icodextrin, which has shown a protective effect from oxidative stress. This has supported the consideration of the use of glucose-free-based peritoneal dialysis fluids in order to reduce oxidative stress and improve peritoneal membrane survival. Studies investigating peritoneal dialysis with the use of osmo-metabolic agents (L-carnitine, xylitol and their combination) in peritoneal fluids replacing glucose-based fluids are, in fact, ongoing. They represent a promising strategy to reduce OxSt, preserve the peritoneal membrane's integrity and improve patients' outcome.

Oxidative stress reduction by icodextrin-based glucose-free solutions in peritoneal dialysis: Support for new promising approaches

BACKGROUND

Oxidative stress (OxSt) and inflammation are common in CKD and are known CV and mortality risk factors. In peritoneal dialysis (PD) OxSt and Inflammation even increase due to the use of glucose-based solutions.

PATIENTS AND METHODS

This study analyzed in 15 PD patients the effect of 3 and 6 months of treatment with icodextrin-based glucose-free solutions on OxSt and inflammation, evaluating p22phox protein expression (Western blot), NADPH oxidase subunit, essential for OxSt activation, MYPT-1 phosphorylation state, marker of RhoA/Rho kinase pathway (ROCK) activity, involved in the induction of OxSt (Western blot) and Malondialdehyde (MDA) production (fluorimetric assay). Interleukin (IL)-6 blood level (chemiluminescence assay) has been measured and used as a marker of inflammation.

RESULTS

p22phox protein expression, MYPT 1 phosphorylation, and MDA were reduced after 3 months from the start of icodextrin (1.28 ± 0.18 d.u. vs. 1.50 ± 0.19, p = 0.049; 0.89 ± 0.03 vs. 0.98 ± 0.03, p = 0.004; 4.20 ± 0.18 nmol/mL vs. 4.84 ± 0.32 nmol/mL, p = 0.045, respectively). In a subgroup of 9 patients who continued the treatment up to 6 months, MYPT-1 phosphorylation was further reduced at 6 months compared to baseline (0.84 ± 0.06 vs. 0.99 ± 0.04, p = 0.043), while p22phox protein expression was reduced only at 6 months versus baseline (1.03 ± 0.05 vs. 1.68 ± 0.22, p = 0.021). In this subgroup, MDA was reduced at 6 months versus baseline (4.03 ± 0.24 nmol/mL vs. 4.68 ± 0,32, p = 0.024) and also versus 3 months (4.03 ± 0.24 vs. 4.35 ± 0.21, p = 0.008). IL-6 level although reduced both at 3 and 6 months, did not reach statistical significance.

CONCLUSIONS

The reduction of OxSt with icodextrin-based PD solutions, although obtained in a small patients cohort and in a limited time duration study, strongly supports the rationale of using osmo-metabolic agents-based fluids replacing glucose-based fluids. Ongoing studies with these agents will provide information regarding preservation of peritoneal membrane integrity, residual renal function, and reduction of CVD risk factors such as OxSt and inflammation.

Oxidants and Cardiorenal Vascular Remodeling—Insights from Rare Genetic Tubulopathies: Bartter’s and Gitelman’s Syndromes

Two human genetic tubulopathies, Bartter’s (BS) and Gitelman’s (GS) syndromes, have normo/hypotension and absent cardiac remodeling despite their apparent angiotensin system (RAS) activation. This seeming contradiction has led to an extensive investigation of BSGS patients, the result of which is that BSGS represents a mirror image of hypertension. BSGS’s unique set of properties has then permitted their use as a human model to probe and characterize RAS system pathways and oxidative stress in cardiovascular and renal remodeling and pathophysiology. This review details the results using GSBS patients that provide a deeper understanding of Ang II signaling and its associated oxidants/oxidative stress in humans. By providing a more complete and complex picture of cardiovascular and renal remodeling pathways and processes, studies of GSBS can inform the identification and selection of new targets and therapies to treat these and other oxidant-related disorders.

Tracing angiotensin II's yin-yang effects on cardiovascular-renal pathophysiology

Adverse changes in cardiovascular and renal systems are major contributors to overall morbidity and mortality. Human cardiovascular and renal systems exhibit a complex network of positive and negative feedback that is reflected in the control of vascular tone via angiotensin II (Ang II) based signaling. This review will examine in some depth, the multiple components and processes that control the status and reflect the health of these various cardiovascular and renal systems, such as pathways associated to monomeric G proteins, RhoA/Rho kinase system and ERK, oxidative stress and NO balance. It will specifically emphasize the "yin-yang" nature of Ang II signaling by comparing and contrasting the effects and activity of various systems, pathways and components found in hypertension to those found in Gitelman's and Bartter's syndromes (GS/BS), two rare autosomal recessive tubulopathies characterized by electrolytic imbalance, metabolic alkalosis, sodium wasting and prominent activation of the renin-angiotensin-aldosterone system. Notwithstanding the activation of the renin-angiotensin-aldosterone system, GS/BS are normo-hypotensive and protected from cardiovascular-renal remodeling and therefore can be considered the mirror image, the opposite of hypertension.

ROCK (RhoA/Rho Kinase) Activation in Atrial Fibrillation: Molecular Pathways and Clinical Implications

Among the complex mechanisms of AF pathogenesis, intracellular calcium overload and oxidative stress play a major role, both triggered by inflammatory processes. The additional basic event taking place in AF is atrial fibrotic remodeling, again triggered by oxidative stress, which is determined by connexins rearrangement and differentiation of fibroblasts into active collagensecreting myofibroblasts. RhoA/ROCK system is the final pathway of a wide spectrum of molecular effectors such as Angiotensin II, platelet-derived growth factor, connective tissue growth factor and transforming growth factor β, that overall determine calcium dysregulation and pro-fibrotic remodeling. Both in experimental and clinical studies, RhoA/ROCK activation has been linked to superoxide ion production, fibrotic remodeling and connexins rearrangement, with important consequences for AF pathogenesis. ROCK pathway inhibition may therefore be a therapeutic or preventive target for special AF subgroups of patients.

Pathomechanism of oxidative stress in cardiovascularrenal remodeling and therapeutic strategies

The high prevalence of cardiovascular disease in patients with chronic kidney disease indicates significant interactions between pathogenic pathways operating in the kidney and heart. These interactions involve all cell types (endothelial cells, smooth muscle cells, macrophages, and others), components of the vasculature, glomeruli, and heart that are susceptible to oxidative damage and structural alterations. A vicious cycle occurs whereby harmful factors such as reactive oxygen species and inflammation damage of vascular structures that themselves become sources of additional dangerous/toxic components released into the local environment. The evidence of this vicious cycle in chronic kidney disease should therefore lead to add other factors to both traditional and nontraditional risk factors. This review will examine the processes occurring during progressive kidney dysfunction with regard to vascular injury, renal remodeling, cardiac hypertrophy, and the transversal role of oxidative stress in the development of these complications.

Pleiotropic Benefits of Statins in Cardiovascular Diseases

In 1976, Japanese microbiologist Akira Endo discovered the first statin as a product of the fungus Penicillium citrinum that inhibited the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase. Their primary mode of action is to lower the blood cholesterol by decreasing hepatic cholesterol production, which upregulates hepatic low-density lipoprotein (LDL) receptors and increases LDL-cholesterol clearance. In addition to cholesterol lowering, statins inhibit other downstream products of the mevalonate pathway, causing the so-called pleiotropic effects. As a result of their pleiotropic effects statins modulate virtually all known processes of atherosclerosis and have beneficial effects outside the cardiovascular system Statins inhibit the post-translational prenylation of small GTP-binding proteins such as Rho, Rac, as well as their downstream effectors such as Rho kinase and nicotinamide adenine dinucleotide phosphate oxidases since they suppress the synthesis of isoprenoid intermediates in the cholesterol biosynthetic pathway altering the expression of endothelial nitric oxide synthase, the stability of atherosclerotic plaques, production of proinflammatory cytokines, reactive oxygen species, platelet reactivity, development of cardiac hypertrophy and fibrosis in cell culture and animal experiments. Inhibition of Rho and Rho-associated coiled-coil containing protein kinase (ROCK), has emerged as the principle mechanisms underlying the pleiotropic effects of statins. However, the relative contributions of statin pleiotropy to clinical outcomes are debatable and difficult to measure because the amount of isoprenoid inhibition by statins corresponds to some extent with the amount of LDL-cholesterol decrease. This article examines some of the existing molecular explanations underlying statin pleiotropy and discusses if they have clinical relevance in cardiovascular diseases.

Effects of Tolvaptan on Oxidative Stress in ADPKD: A Molecular Biological Approach

Autosomal dominant polycystic disease (ADPKD) is the most frequent monogenic kidney disease. It causes progressive renal failure, endothelial dysfunction, and hypertension, all of which are strictly linked to oxidative stress (OxSt). Treatment with tolvaptan is known to slow the renal deterioration rate, but not all the molecular mechanisms involved in this effect are well-established. We evaluated the OxSt state in untreated ADPKD patients compared to that in tolvaptan-treated ADPKD patients and healthy subjects. OxSt was assessed in nine patients for each group in terms of mononuclear cell p22^phox protein expression, NADPH oxidase key subunit, MYPT-1 phosphorylation state, marker of Rho kinase activity (Western blot) and heme oxygenase (HO)-1, induced and protective against OxSt (ELISA). p22^phox protein expression was higher in untreated ADPKD patients compared to treated patients and controls: 1.42 ± 0.11 vs. 0.86 ± 0.15 d.u., p = 0.015, vs. 0.53 ± 0.11 d.u., p < 0.001, respectively. The same was observed for phosphorylated MYPT-1: 0.96 ± 0.28 vs. 0.68 ± 0.09 d.u., p = 0.013 and vs. 0.47 ± 0.13 d.u., p < 0.001, respectively, while the HO-1 expression of untreated patients was significantly lower compared to that of treated patients and controls: 5.33 ± 3.34 vs. 2.08 ± 0.79 ng/mL, p = 0.012, vs. 1.97 ± 1.22 ng/mL, p = 0.012, respectively. Tolvaptan-treated ADPKD patients have reduced OxSt levels compared to untreated patients. This effect may contribute to the slowing of renal function loss observed with tolvaptan treatment.

The Pivotal Role of Oxidative Stress in the Pathophysiology of Cardiovascular-Renal Remodeling in Kidney Disease

The excessive activation of the renin-angiotensin system in kidney disease leads to alteration of intracellular pathways which concur altogether to the induction of cardiovascular and renal remodeling, exposing these patients since the very beginning of the renal injury to chronic kidney disease and progression to end stage renal disease, a very harmful and life threatening clinical condition. Oxidative stress plays a pivotal role in the pathophysiology of renal injury and cardiovascular-renal remodeling, the long-term consequence of its effect. This review will examine the role of oxidative stress in the most significant pathways involved in cardiovascular and renal remodeling with a focus on the detrimental effects of oxidative stress-mediated renal abnormalities on the progression of the disease and of its complications. Food for thoughts on possible therapeutic target are proposed on the basis of experimental evidences.

Oxidative stress, inflammation, and peritoneal dialysis: A molecular biology approach

The key role of oxidative stress (OxSt) and inflammation for the induction of cardiovascular disease, the leading cause of excess morbidity/mortality in chronic kidney disease and dialysis patients, is known and both the activations of NADPH oxidase and RhoA/Rho kinase (ROCK) pathway are pivotal for their effects. While specific hemodialysis procedures, such as hemodiafiltration with on‐line reinfusion of ultrafiltrate and/or the use of vitamin E‐coated dialyzers, are beneficial for OxSt and inflammation, studies in peritoneal dialysis (PD) are instead scarce and results seem not favorable. In nine patients under PD OxSt in terms of mononuclear cell protein level of p22^phox (Western blot), subunit of NADPH oxidase, essential for the generation of OxSt, and MYPT‐1 phosphorylation state (Western blot), a marker of ROCK activity, have been measured at the beginning and after 3 and 6 months of PD. Blood levels of interleukin 6 (IL‐6), ferritin, and albumin have been considered for evaluating the inflammatory state. p22^phox protein expression, MYPT‐1‐phosphorylation, and ferritin level were increased both at baseline vs healthy subjects (P = .02, P < .0001, P = .004, respectively) and vs baseline after 3 and 6 months of peritoneal dialysis (P = .007, P < .001, P = .004, respectively). Albumin was lower after 6 months of PD (P = .0014). IL‐6 was increased at baseline vs reference values and remained unchanged at 3 and 6 months. OxSt and inflammation increase during PD confirming via molecular biology approach a report at biochemical level. To improve OxSt state in PD, a multitarget approach is necessary. It might include the use of more physiologic pH, low glucose degradation products, low lactate and iso‐osmolar PD solutions, patients’ strict glycemic control, optimal volume management, and antioxidant administration, such as N‐acetylcysteine.

The Physiology, Pathology, and Therapeutic Interventions for ROCK Isoforms in Diabetic Kidney Disease

Rho-associated coiled-coil-containing protein kinase (ROCK) is a serine/threonine kinase that was originally identified as RhoA interacting protein. A diverse array of cellular functions, including migration, proliferation, and phenotypic modulation, are orchestrated by ROCK through a mechanism involving cytoskeletal rearrangement. Mammalian cells express two ROCK isoforms: ROCK1 (Rho-kinase β/ROKβ) and ROCK2 (Rho-kinase α/ROKα). While both isoforms have structural similarities and are widely expressed across multiple tissues, investigations in gene knockout animals and cell-based studies have revealed distinct functions of ROCK1 and ROCK2. With respect to the kidney, inhibiting ROCK activity has proven effective for the preventing diabetic kidney disease (DKD) in both type 1 and type 2 diabetic rodent models. However, despite significant progress in the understanding of the renal ROCK biology over the past decade, the pathogenic roles of the ROCK isoforms is only beginning to be elucidated. Recent studies have demonstrated the involvement of renal ROCK1 in mitochondrial dynamics and cellular transdifferentiation, whereas ROCK2 activation leads to inflammation, fibrosis, and cell death in the diabetic kidney. This review provides a conceptual framework for dissecting the molecular underpinnings of ROCK-driven renal injury, focusing on the differences between ROCK1 and ROCK2.

The Pleiotropic Effects of Statins - From Coronary Artery Disease and Stroke to Atrial Fibrillation and Ventricular Tachyarrhythmia

Statins, 3-hydroxy-methylglutaryl coenzyme A reductase inhibitors, have been used for decades for the prevention of coronary artery disease and stroke. They act primarily by lowering serum cholesterol through the inhibition of cholesterol synthesis in the liver, which results in the upregulation of low-density lipoprotein receptors in the liver. This results in the removal of low-density lipoproteincholesterol. Studies have suggested that statins may demonstrate additional effects that are independent of their effects on low-density lipoprotein-cholesterol. These have been termed "pleiotropic" effects. Pleiotropic effects may be due to the inhibition of isoprenoid intermediates by statins. Isoprenoid inhibition has effects on the small guanosine triphosphate binding proteins Rac and Rho which in turn effects nicotinamide adenine dinucleotide phosphate oxidases. Therefore, there are changes in endothelial nitric oxide synthase expression, atherosclerotic plaque stability, pro-inflammatory cytokines and reactive oxygen species production, platelet reactivity, and cardiac fibrosis and hypetrophy development. Recently, statins have been compared to the ezetimibe and the recently published outcomes data on the proprotein convertase subtilisin kexin type 9 inhibitors has allowed for a reexamination of statin pleiotropy. As a result of these diverse effects, it has been suggested that statins also have anti-arrhythmic effects. This review focuses on the mechanisms of statin pleiotropy and discusses evidence from the statin clinical trials as well as examining the possible anti-arrhythmic effects atrial fibrillation and ventricular tachyarrhythmias.

ROCK (RhoA/Rho Kinase) in Cardiovascular-Renal Pathophysiology: A Review of New Advancements

Rho-associated, coiled-coil containing kinases (ROCK) were originally identified as effectors of the RhoA small GTPase and found to belong to the AGC family of serine/threonine kinases. They were shown to be downstream effectors of RhoA and RhoC activation. They signal via phosphorylation of proteins such as MYPT-1, thereby regulating many key cellular functions including proliferation, motility and viability and the RhoA/ROCK signaling has been shown to be deeply involved in arterial hypertension, cardiovascular–renal remodeling, hypertensive nephropathy and posttransplant hypertension. Given the deep involvement of ROCK in cardiovascular–renal pathophysiology and the interaction of ROCK signaling with other signaling pathways, the reports of trials on the clinical beneficial effects of ROCK’s pharmacologic targeting are growing. In this current review, we provide a brief survey of the current understanding of ROCK-signaling pathways, also integrating with the more novel data that overall support a relevant role of ROCK for the cardiovascular–renal physiology and pathophysiology.

Increased ROCK1 not ROCK2 in circulating leukocytes in rats with myocardial ischemia/reperfusion

BACKGROUND

Rho-associated protein kinase (ROCK) plays a vital role in the pathogenesis of many cardiovascular diseases. Previous studies have demonstrated that ROCK is overactivated and involved in myocardial ischemia/reperfusion in vivo. But the role of ROCK in circulating leukocytes during myocardial ischemia/reperfusion is not well studied.

MATERIAL AND METHODS

This study was performed to evaluate ROCK activity in circulating leukocytes in rats with myocardial ischemia/reperfusion injury. Myocardial ischemia/reperfusion Wistar rats were subjected to 30-min ischemia followed by 180-min reperfusion. ROCK activity in circulating leukocytes was examined by the phosphorylation state of myosin phosphatase targeting subunit 1, a substrate of ROCK.

RESULTS

ROCK activity significantly increased in leukocytes in rat ischemia/reperfusion models compared to the sham group. ROCK1 not ROCK2 level in circulating leukocytes was significantly elevated in ischemia/reperfusion. Administration of the selective inhibitor of ROCK, fasudil, significantly reduced myocardial infarct size, myocyte apoptosis, and inflammatory cytokine, including interleukin 6 and tumor necrosis factor α. Furthermore, fasudil upregulated ischemia/reperfusion-induced reduction of nitric oxide production.

CONCLUSION

Increased ROCK1 not ROCK2 in circulating leukocytes plays a role in the pathogenesis of myocardial ischemia/reperfusion injury. Inhibition of ROCK1 in circulating leukocytes has an important role in fasudil-induced cardioprotective effects. ROCK1 in circulating leukocytes might be a new biomarker in myocardial ischemia/reperfusion injury.

Cardiac Remodeling in Chronic Kidney Disease

Cardiac remodeling occurs frequently in chronic kidney disease patients and affects quality of life and survival. Current treatment options are highly inadequate. As kidney function declines, numerous metabolic pathways are disturbed. Kidney and heart functions are highly connected by organ crosstalk. Among others, altered volume and pressure status, ischemia, accelerated atherosclerosis and arteriosclerosis, disturbed mineral metabolism, renal anemia, activation of the renin-angiotensin system, uremic toxins, oxidative stress and upregulation of cytokines stress the sensitive interplay between different cardiac cell types. The fatal consequences are left-ventricular hypertrophy, fibrosis and capillary rarefaction, which lead to systolic and/or diastolic left-ventricular failure. Furthermore, fibrosis triggers electric instability and sudden cardiac death. This review focuses on established and potential pathophysiological cardiorenal crosstalk mechanisms that drive uremia-induced senescence and disease progression, including potential known targets and animal models that might help us to better understand the disease and to identify novel therapeutics.

Rho Kinase Activity, Connexin 40, and Atrial Fibrillation: Mechanistic Insights from End-Stage Renal Disease on Dialysis Patients

Evidence on cellular/molecular mechanisms leading to atrial fibrillation (AF) are scanty. Increased expression of Rho kinase (ROCK) and myosin-phosphatase-target subunit-1 (MYPT-1), ROCK activity’s marker, were shown in AF patients, which correlated with connexin 40 (Cx40) expression, membrane protein of heart gap junctions, key for rapid action potential’s cell–cell transfer. AF is the most frequent arrhythmia in dialysis patients who present increased MYPT-1 phosphorylation, which correlates with left ventricular (LV) mass. Given ROCK’s established role in cardiovascular–renal remodeling, induction of impaired cell-to-cell coupling/potential conduction promoting AF initiation/perpetuation, we evaluated in dialysis patients with AF, MYPT-1 phosphorylation, Cx40 expression, and their relationships to support their involvement in AF. Mononuclear cells’ MYPT-1 phosphorylation, Cx40 expression, and the ROCK inhibitor fasudil’s effect were assessed in dialysis patients with AF (DPAFs), dialysis patients with sinus rhythm (DPs), and healthy subjects (C) (western blot). M-mode echocardiography assessed LV mass and left atrial systolic volume. DPAF’s phospho-MYPT-1 was increased vs. that of DPs and C (1.57 ± 0.17 d.u. vs. 0.69 ± 0.04 vs. 0.51 ± 0.05 respectively, p < 0.0001). DP’s phospho-MYPT-1 was higher vs. that of C, p = 0.009. DPAF’s Cx40 was higher vs. that of DPs and C (1.23 ± 0.12 vs. 0.74 ± 0.03 vs. 0.69 ± 0.03, p < 0.0001). DPAF’s phospho-MYPT-1 correlated with Cx40 (p < 0.001), left atrial systolic volume (p = 0.013), and LV mass (p = 0.014). In DPAFs, fasudil reduced MYPT-1 phosphorylation (p < 0.01) and Cx40 expression (p = 0.03). These data point toward ROCK and Cx40’s role in the mechanism(s) leading to AF in dialysis patients. Exploration of the ROCK pathway in AF could contribute to AF generation’s mechanistic explanations and likely identify potential pharmacologic targets for translation into treatment.

Oxidative Stress and Cardiovascular-Renal Damage in Fabry Disease: Is There Room for a Pathophysiological Involvement?

Fabry disease is an X-linked lysosomal storage disease caused by mutations in the GLA gene that lead to a reduction or an absence of the enzyme α-galactosidase A, resulting in the progressive and multisystemic accumulation of globotriaosylceramide. Clinical manifestation varies from mild to severe, depending on the phenotype. The main clinical manifestations are cutaneous (angiokeratomas), neurological (acroparesthesias), gastrointestinal (nausea, diarrhea abdominal pain), renal (proteinuria and kidney failure), cardiovascular (cardiomyopathy and arrhythmias), and cerebrovascular (stroke). A diagnosis of Fabry disease can be made with an enzymatic assay showing absent or reduced α-galactosidase A in male patients, while in heterozygous female patients, molecular genetic testing is needed. Enzyme replacement therapy (ERT) with recombinant human α-galactosidase is nowadays the most-used disease-specific therapeutic option. Despite ERT, cardiocerebrovascular-renal irreversible organ injury occurs, therefore additional knowledge and a deeper understanding of further pathophysiological mechanisms leading to end organ damage in Fabry disease are needed. Recent data point toward oxidative stress, oxidative stress signaling, and inflammation as some such mechanisms. In this short review, the current knowledge on the involvement of oxidative stress in cardiovascular-renal remodeling is summarized and related to the most recent evidence of oxidative stress activation in Fabry disease, and clearly points toward the involvement of oxidative stress in the pathophysiology of the medium- to long-term cardiovascular-renal damage of Fabry disease.

Oxidative stress and the altered reaction to it in Fabry disease: A possible target for cardiovascular-renal remodeling?

BACKGROUND

Fabry disease is characterized by deficient expression/activity of α-GalA with consequent lysosomal accumulation in various organs of its substrate Gb3. Despite enzyme replacement therapy, Fabry disease progresses with serious myocardial, cerebral and renal manifestations. Gb3 accumulation may induce oxidative stress (OxSt), production of inflammatory cytokines and reduction of nitric oxide, which may impact on Fabry disease's clinical manifestations.

METHODS

OxSt status was characterized in 10 patients compared with 10 healthy subjects via protein expression of p22phox, subunit of NADH/NADPH oxidase, (Western blot), Heme oxygenase (HO)-1 levels (ELISA), antioxidant/anti-inflammatory, lipid peroxidation as malondialdehyde (MDA) production (colorimetric assay), phosphorylation state of Extracellular Signal Regulated Kinase (ERK)1/2 and Myosin Phosphatase Target Protein (MYPT)-1 (Western blot), marker of Rho kinase activation, both involved in OxSt signaling. Cardiac left ventricular (LV) mass was also evaluated (M-mode echocardiography).

RESULTS

LV mass was higher in Fabry's males (123.72±2.03SEM g/m2) and females (132.09±6.72g/m2). p22phox expression was also higher in patients (1.04±0.09 d.u. vs 0.54±0.05 d.u. p<0.01) as well as MDA levels (54.51±3.97 vs 30.05±7.11 nmol/mL p = 0.01) while HO-1 was reduced (8.84±0.79 vs 14.03±1.23 ng/mL, p<0.02). MYPT-1's phosphorylation was increased in patients (0.52±0.11 d.u. vs 0.03±0.08 d.u., p<0.01) while phosphorylation of ERK1/2 was reduced (0.91±0.08 d.u. vs 1.53±0.17 d.u., p = 0.004).

CONCLUSIONS

This study documents OxSt activation and the altered reaction to it in Fabry patients. Cardiac remodeling, Rho kinase signaling activation and reduction of protective HO-1 might suggest that, in addition to enzyme replacement therapy, OxSt inhibition by either pharmacological or nutritional measures, is likely to prove useful for the prevention/treatment of Fabry patients' cardiovascular-renal remodeling.

Oxidative stress - chronic kidney disease - cardiovascular disease: A vicious circle

Chronic kidney disease patient's progression to end-stage renal disease as well as their high mortality are linked to cardiovascular disease. However, the high incidence rate of cardiovascular morbidity and mortality in these patients is not fully accounted for by traditional cardiovascular risk factors such as diabetes, hypertension and obesity. Renal disease and CVD are associated with endothelial dysfunction, inflammation and oxidative stress and in this review we will examine what is known regarding their similar roles in both CVD and chronic kidney disease, specifically focusing on the interconnections between oxidative stress, inflammation and endothelial dysfunction. These interconnections are best visualized as a vicious circle wherein these entities coexist and communicate with each other, thereby exacerbating the processes underpinning these different entities with the end result of the high morbidity and mortality that characterize CKD patients. By exploring this vicious circle i.e. the mode and extent of the interrelationships as well as some of the underlying mechanisms involved, this review aims at outlining our current understanding as well as highlighting future avenues for research and potential targets for therapeutic intervention.

Rho kinase activation in circulating leukocytes is related to hypertensive myocardial remodeling

Rho-kinase has relevant functions in blood pressure modulation and cardiovascular remodeling. Rho-kinase activity is determined in circulating leukocytes measuring phosphorylation of its target myosin phosphatase target subunit 1 (MYPT1), but its relationship with Rho-kinase activity in the myocardium and in vasculature in hypertension has not been evaluated.The aim was to determine the degree of association between Rho-kinase cascade activation in circulating leukocytes with cardiac and aortic Rho-kinase pathway activation in a model of hypertension and to analyze it with a cause-effect perspective.Hypertensive deoxycorticosterone (DOCA)-salt rats received the Rho-kinase antagonist fasudil (DOCA-Fas, 100 mg/kg/day, 3 weeks). Results were compared with an untreated DOCA-salt and a sham group.Rho-kinase inhibition reduced significantly blood pressure, cardiac hypertrophy, myocardial collagen and macrophage infiltration, but not aortic wall hypertrophy. Fasudil decreased significantly Rho-kinase activity in peripheral blood mononucleated cells (PBMC), myocardium and aortic wall to similar levels as in the sham group. A significant correlation was found between PBMC Rho-kinase activity and cardiac remodeling, specifically with hypertrophy (r = 0.51, P≤0.01), myocardial collagen (r = 0.40, P≤0.05) and ED1 immunostaining (r = 0.48, P≤0.01). In the untreated hypertensive group, increased levels (P<0.05) of the proinflammatory molecules p65 NF-κB, vascular cell adhesion molecule 1 and interleukin-6 antibody in the myocardium, aortic wall and PBMC were observed and were reduced with fasudil (P<0.05).In conclusion, in this hypertension model, Rho-kinase and its pathway activation determined in circulating leukocytes reflect the activation of this pathway in the myocardium and in the aortic wall and are significantly related to myocardial remodeling (hypertrophy, fibrosis and inflammation).

Increased Rho kinase activity in patients with heart ischemia/reperfusion

BACKGROUND/AIM:\

Rho kinase is a downstream effector of Rho GTPase that is known to regulate various pathological processes. The aim of this study was to evaluate the regulation of Rho kinase activity in leukocytes in patients with ischemia/reperfusion (I/R) injury.

PATIENTS AND METHODS

We investigated 38 patients with acute ST-segment elevation myocardial infarction (STEMI), 26 patients with atherosclerosis (AS) and 22 normal subjects. All patients underwent coronary angiography (CAG) and all STEMI patients received primary percutaneous coronary intervention (PPCI) of the left anterior descending artery (LAD) within 12 h after chest pain on-set. Blood samples for leukocyte Rho kinase activity were obtained before CAG and 3 and 24 hours after CAG/PCI.

RESULTS

Rho kinase activity increased in the I/R and AS groups. Compared with the AS group, Rho kinase activity was significantly higher in peripheral blood leukocytes in STEMI/PPCI. Furthermore, there was no correlation between changes in Rho kinase activity and changes in high-sensitivity troponin I (hs-TnI) and C-reactive protein (CRP). There was a negative correlation between Rho kinase activity and IL-6.

CONCLUSION

Rho kinase is involved in the pathogenesis of heart I/R injury in patients. Inhibition of Rho kinase may be an additional therapeutic intervention for the treatment of I/R.

Fasudil alleviates pressure overload-induced heart failure by activating Nrf2-mediated antioxidant responses

The RhoA/Rho-kinase cascade plays an important role in many aspects of cardiovascular function. This study aims to investigate the protective effects of fasudil, a Rho-kinase inhibitor, on pressure overload induced heart failure in rats. Pressure overload induced heart failure was induced in SD rats by banding the abdominal aorta for 8 weeks. The rats were divided into four groups: Sham, TAC, TAC plus low dose of fasudil, and TAC plus high dose of fasudil group. Low dose and high dose fasudil were 5 and 10 mg/kg/day, respectively. Rats in the Sham and TAC groups were treated with vehicle. Fasudil effectively inhibited TAC-induced heart failure, as evaluated by echocardiography and transmission electron microscopy. Fasudil could significantly promote superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity and significantly decrease malondialdehyde (MDA) content in a dose-dependent maner in TAC rats. Consistently, fasudil evoked significant nuclear translocation of Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) with increased DNA/promoter binding and transactivation of Nrf2 targets. In addition, fasudil increased the content of iron as well as transferrin receptor 1 (TfR1) in TAC rats. A mild oxidative stress induced by iron may activate the antioxidant enzymes by feedback response. Taken together, these results indicate that the protective effect of fasudil may be due to its strong antioxidative activities which related with the activated Nrf2 and its down-regulated genes. These findings provide a new treatment concept and support the benefit of fasudil treatment in heart failure.

Gαq/p63RhoGEF interaction in RhoA/Rho kinase signaling: investigation in Gitelman's syndrome and implications with hypertension

PURPOSE

Gitelman's syndrome (GS) presents normo-hypotension and absence of cardiovascular-renal remodeling despite high angiotensin II (Ang II), activation of renin-angiotensin-aldosterone system and is a human model of endogenous antagonism of Ang II signaling, opposite to hypertension. GS's clinical presentation leads to questions regarding what features might be responsible. One area of investigation involves Ang II signaling. In hypertensive patients, RhoA/Rho kinase (RhoA/ROCK) pathway activation by Ang II is involved in hypertension development/maintenance and induction of long-term consequences (cardiovascular-renal remodeling), while GS has reduced p63RhoGEF gene and protein levels and ROCK activity. Ang II signaling is mediated by Gαq, which interacts with p63RhoGEF via the α6-αN linker connecting p63RhoGEF's DH and PH domains acting as a conformational switch to activate RhoA/ROCK signaling.

METHODS

We have investigated in GS patients, the presence of mutations in either p63RhoGEF's α6-αN linker domain and in Gαq's Ala253, Trp263, and Tyr356 residues, crucial for p63RhoGEF-Gαq interplay.

RESULTS

No mutations have been found in specific aminoacids of p63RhoGEF α6-αN linker and Gαq, key for p63RhoGEF/Gαq interplay.

CONCLUSIONS

Gitelman's syndrome normo/hypotension and lack of cardiovascular-renal remodeling are not due to mutations of p63RhoGEF α6-αN linker and Gαq interactions. This opens the way for investigations on different coding and no-coding regions (p63RhoGEF and Gαq promoters) and on altered transcriptional/post-transcriptional regulation. Clarification of how these biochemical/molecular mechanisms work/interact would provide insights into mechanisms involved in the GS's Ang II signaling fine tuning, in human physiology/pathophysiology in general and could also identify significant targets for intervention in the treatments of hypertension.

Pleiotropic Effects of Statins on the Cardiovascular System

The statins have been used for 30 years to prevent coronary artery disease and stroke. Their primary mechanism of action is the lowering of serum cholesterol through inhibiting hepatic cholesterol biosynthesis thereby upregulating the hepatic low-density lipoprotein (LDL) receptors and increasing the clearance of LDL-cholesterol. Statins may exert cardiovascular protective effects that are independent of LDL-cholesterol lowering called pleiotropic effects. Because statins inhibit the production of isoprenoid intermediates in the cholesterol biosynthetic pathway, the post-translational prenylation of small GTP-binding proteins such as Rho and Rac, and their downstream effectors such as Rho kinase and nicotinamide adenine dinucleotide phosphate oxidases are also inhibited. In cell culture and animal studies, these effects alter the expression of endothelial nitric oxide synthase, the stability of atherosclerotic plaques, the production of proinflammatory cytokines and reactive oxygen species, the reactivity of platelets, and the development of cardiac hypertrophy and fibrosis. The relative contributions of statin pleiotropy to clinical outcomes, however, remain a matter of debate and are hard to quantify because the degree of isoprenoid inhibition by statins correlates to some extent with the amount of LDL-cholesterol reduction. This review examines some of the currently proposed molecular mechanisms for statin pleiotropy and discusses whether they could have any clinical relevance in cardiovascular disease.

Indoxyl sulfate potentiates endothelial dysfunction via reciprocal role for reactive oxygen species and RhoA/ROCK signaling in 5/6 nephrectomized rats

Accumulative indoxyl sulfate (IS) retained in chronic kidney disease (CKD) can potentiate vascular endothelial dysfunction, and herein, we aim at elucidating the underlying mechanisms from the perspective of possible association between reactive oxygen species (ROS) and RhoA/ROCK pathway. IS-treated nephrectomized rats are administered with antioxidants including NADPH oxidase inhibitor apocynin, SOD analog tempol, and mitochondrion-targeted SOD mimetic mito-TEMPO to scavenge ROS, or ROCK inhibitor fasudil to obstruct RhoA/ROCK pathway. First, we find in response to IS stimulation, antioxidants treatments suppress increased aortic ROCK activity and expression levels. Additionally, ROCK blockade prevent IS-induced increased NADPH oxidase expression (mainly p22phox and p47phox), mitochondrial and intracellular ROS (superoxide and hydrogen peroxide) generation, and decreased Cu/Zn-SOD expression in thoracic aortas. Apocynin, mito-TEMPO, and tempol also reverse these markers of oxidative stress. These results suggest that IS induces excessive ROS production and ROCK activation involving a circuitous relationship in which ROS activate ROCK and ROCK promotes ROS overproduction. Finally, ROS and ROCK depletion attenuate IS-induced decrease in nitric oxide (NO) production and eNOS expression levels, and alleviate impaired vasomotor responses including increased vasocontraction to phenylephrine and decreased vasorelaxation to acetylcholine, thereby preventing cardiovascular complications accompanied by CKD. Taken together, excessive ROS derived from NADPH oxidase and mitochondria coordinate with RhoA/ROCK activation in a form of positive reciprocal relationship to induce endothelial dysfunction through disturbing endothelium-dependent NO signaling upon IS stimulation in CKD status.

Rho Kinases and Cardiac Remodeling

Hypertensive cardiac remodeling is characterized by left ventricular hypertrophy and interstitial fibrosis, which can lead to heart failure with preserved ejection fraction. The Rho-associated coiled-coil containing kinases (ROCKs) are members of the serine/threonine protein kinase family, which mediates the downstream effects of the small GTP-binding protein RhoA. There are 2 isoforms: ROCK1 and ROCK2. They have different functions in different types of cells and tissues. There is growing evidence that ROCKs contribute to the development of cardiovascular diseases, including cardiac fibrosis, hypertrophy, and subsequent heart failure. Recent experimental studies using ROCK inhibitors, such as fasudil, have shown the benefits of ROCK inhibition in cardiac remodeling. Mice lacking each ROCK isoform also exhibit reduced myocardial fibrosis in a variety of pathological models of cardiac remodeling. Indeed, clinical studies with fasudil have suggested that ROCKs could be potential novel therapeutic targets for cardiovascular diseases. In this review, we summarize the current understanding of the roles of ROCKs in the development of cardiac fibrosis and hypertrophy and discuss their therapeutic potential for deleterious cardiac remodeling. (Circ J 2016; 80: 1491-1498).