Rho Kinase Inhibitor, Fasudil, Attenuates Contrast‐induced Acute Kidney Injury

Mechanism of tacrolimus in the treatment of lupus nephritis

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder, with more than half of the patients developing lupus nephritis (LN), which significantly contributes to chronic kidney disease (CKD) and end-stage renal disease (ESRD). The treatment of lupus nephritis has always been challenging. Tacrolimus (TAC), an effective immunosuppressant, has been increasingly used in the treatment of LN in recent years. This review aims to explore the mechanisms of action of tacrolimus in treating LN. Firstly, we briefly introduce the pharmacological properties of tacrolimus, including its role as a calcineurin (CaN) inhibitor, exerting immunosuppressive effects by inhibiting T cell activation and cytokine production. Subsequently, we focus on various other immunomodulatory mechanisms of tacrolimus in LN therapy, including its effects on T cells, B cells, and immune cells in kidney. Particularly, we emphasize tacrolimus' regulatory effect on inflammatory mediators and its importance in modulating the Th1/Th2 and Th17/Treg balance. Additionally, we review its effects on actin cytoskeleton, angiotensin II (Ang II)-specific vascular contraction, and P-glycoprotein activity, summarizing its impacts on non-immune mechanisms. Finally, we summarize the efficacy and safety of tacrolimus in clinical studies and trials. Although some studies have shown significant efficacy of tacrolimus in treating LN, its safety remains a challenge. We outline the potential adverse reactions of long-term tacrolimus use and provide suggestions on effectively monitoring and managing these adverse reactions in clinical practice. In general, tacrolimus, as a novel immunosuppressant, holds promising prospects for treating LN. Of course, further research is needed to better understand its therapeutic mechanisms and ensure its safety and efficacy in clinical practice.

P16INK4a deletion alleviates contrast-induced acute kidney injury by ameliorating renal cell apoptosis and suppressing inflammation and oxidative stress

Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of hospital-acquired acute kidney injury. Cellular senescence is associated with CI-AKI. P16INK4a (p16) is a cell cycle regulator and link to aging and senescence. We found that the expression of p16 was elevated in CI-AKI renal tissues, however its role in CI-AKI remains insufficiently understood. In this study, we used p16 knockout (p16KO) mice and wild-type (WT) littermates to establish CI-AKI mice model to elucidate the impact of p16 on CI-AKI. The results showed that serum creatinine (SCr), blood urea nitrogen (BUN), and serum neutrophil gelatinase-associated lipocalin (NGAL) levels were markedly reduced in p16KO CI-AKI mice. Both immunohistochemistry and western blot analyses confirmed that p16 knockout alleviated renal cell apoptosis. Furthermore, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) were attenuated by downregulating NLRP3 and NF-κB inflammasomes. Additionally, ROS levels were diminished via activating Nrf2/Keap-1 pathway in p16KO CI-AKI mice. Collectively, our findings suggest that p16 deletion exerts protective effects against apoptosis, inflammation, and oxidative stress in CI-AKI mice model, p16 deletion might be a potential therapeutic strategy for ameliorating CI-AKI.

Fasudil inhibits the expression of C/EBP homologous protein to protect against liver injury in acetaminophen-overdosed mice

Acetaminophen (APAP) overdoses can cause severe liver injury. In this study, the protective effect of fasudil against APAP-induced liver injury was investigated. APAP (400 mg/kg) was administered to male C57BL/6J mice to induce liver injury, and fasudil (20 or 40 mg/kg) was injected 30 min before APAP administration. Fasudil markedly suppressed APAP-induced elevation in serum transaminase activity and hepatic necrosis and significantly reduced an increase in nitrotyrosine and DNA fragmentation. However, fasudil did not affect cytochrome P450 2E1 expression, N-acetyl-p-benzoquinone imine production or c-jun N-terminal kinase activation. In contrast, fasudil significantly inhibited an APAP-induced increase in expression of the transcription factor C/EBP homologous protein (CHOP) in the liver, accompanied by transcriptional suppression of ER stress-related molecules such as Ero1α, Atf4 and Grp78. These findings indicate that suppression of CHOP expression by fasudil exhibits a remarkable protective effect against APAP liver injury by regulating ER stress. We suggest that fasudil is a promising therapeutic candidate for treating APAP-induced liver injury.

Possible correlated signaling pathways with chronic urate nephropathy: A review

Hyperuricemia nephropathy, also known as gouty nephropathy, refers to renal damage induced by hyperuricemia caused by excessive production of serum uric acid or low excretion of uric acid. the persistence of symptoms will lead to changes in renal tubular phenotype and accelerate the progress of renal fibrosis. The existence and progressive aggravation of symptoms will bring a heavy burden to patients, their families and society, affect their quality of life and reduce their well-being. With the increase of reports on hyperuricemia nephropathy, the importance of related signal pathways in the pathogenesis of hyperuricemia nephropathy is becoming more and more obvious, but most studies are limited to the upper and lower mediating relationship between 1 or 2 signal pathways. The research on the comprehensiveness of signal pathways and the breadth of crosstalk between signal pathways is limited. By synthesizing the research results of signal pathways related to hyperuricemia nephropathy in recent years, this paper will explore the specific mechanism of hyperuricemia nephropathy, and provide new ideas and methods for the treatment of hyperuricemia nephropathy based on a variety of signal pathway crosstalk and personal prospects.

Fasudil Ameliorates Osteoporosis Following Myocardial Infarction by Regulating Cardiac Calcitonin Secretion

We hypothesis that Rho kinase inhibitor fasudil ameliorates osteoporosis following myocardial infarction (MI) by regulating cardiac calcitonin secretion. A mice model of MI and cultured neonatal cardiomyocytes exposed to hypoxia and serum deprivation (H/SD), and fibroblasts exposed to TGF-β were used, respectively. Cardiac function in vivo was assessed with echocardiography. Osteoporosis in vivo was assessed with X-ray and micro-CT. In vivo and in vitro studies used histological and immunohistochemical techniques, along with western blots. In mice post-MI, fasudil ameliorates the microstructure and bone metabolism of the lumbar, improved cardiac function, and attenuated myocardial fibrosis. In vitro, fasudil or αCGRP could effectively inhibit the proliferation of primary fibroblasts treated with TGF-β. Moreover, fasudil ameliorates the cardiac calcitonin secretion induced by MI in vivo or by H/SD in vitro. Our findings suggest that fasudil improved MI-induced osteoporosis by promoting cardiac secreting calcitonin.

Tacrolimus Causes Hypertension by Increasing Vascular Contractility via RhoA (Ras Homolog Family Member A)/ROCK (Rho-Associated Protein Kinase) Pathway in Mice

BACKGROUND

To provide tacrolimus is first-line treatment after liver and kidney transplantation. However, hypertension and nephrotoxicity are common tacrolimus side effects that limit its use. Although tacrolimus-related hypertension is well known, the underlying mechanisms are not. Here, we test whether tacrolimus-induced hypertension involves the RhoA (Ras homolog family member A)/ROCK (Rho-associated protein kinase) pathway in male C57Bl/6 mice.

METHODS

Intra-arterial blood pressure was measured under anesthesia. The reactivity of renal afferent arterioles and mesenteric arteries were assessed in vitro using microperfusion and wire myography, respectively.

RESULTS

Tacrolimus induced a transient rise in systolic arterial pressure that was blocked by the RhoA/ROCK inhibitor Fasudil (12.0±0.9 versus 3.2±0.7; P<0.001). Moreover, tacrolimus reduced the glomerular filtration rate, which was also prevented by Fasudil (187±20 versus 281±8.5; P<0.001). Interestingly, tacrolimus enhanced the sensitivity of afferent arterioles and mesenteric arteries to Ang II (angiotensin II), likely due to increased intracellular Ca²⁺ mobilization and sensitization. Fasudil prevented increased Ang II-sensitivity and blocked Ca²⁺ mobilization and sensitization. Preincubation of mouse aortic vascular smooth muscle cells with tacrolimus activated the RhoA/ROCK/MYPT-1 (myosin phosphatase targeting subunit 1) pathway. Further, tacrolimus increased cytoplasmic reactive oxygen species generation in afferent arterioles (107±5.9 versus 163±6.4; P<0.001) and in cultured mouse aortic vascular smooth muscle cells (100±7.5 versus 160±23.2; P<0.01). Finally, the reactive oxygen species scavenger Tempol inhibited tacrolimus-induced Ang II hypersensitivity in afferent arterioles and mesenteric arteries.

CONCLUSIONS

The RhoA/ROCK pathway may play an important role in tacrolimus-induced hypertension by enhancing Ang II-specific vasoconstriction, and reactive oxygen species may participate in this process by activating the RhoA/ROCK pathway.

Assessment of Fasudil on Contrast-Associated Acute Kidney Injury Using Multiparametric Renal MRI

Aims: To evaluate the utility of fasudil in a rat model of contrast-associated acute kidney injury (CA-AKI) and explore its underlying mechanism through multiparametric renal magnetic resonance imaging (mpMRI).

Methods: Experimental rats (n = 72) were grouped as follows: controls (n = 24), CA-AKI (n = 24), or CA-AKI + Fasudil (n = 24). All animals underwent two mpMRI studies (arterial spin labeling, T1 and T2 mapping) at baseline and post iopromide/fasudil injection (Days 1, 3, 7, and 13 respectively). Relative change in renal blood flow (ΔRBF), T1 (ΔT1) and T2 (ΔT2) values were assessed at specified time points. Serum levels of cystatin C (CysC) and interleukin-1β (IL-1β), and urinary neutrophil gelatinase-associated lipocalin (NGAL) concentrations were tested as laboratory biomarkers, in addition to examining renal histology and expression levels of various proteins (Rho-kinase [ROCK], α-smooth muscle actin [α-SMA]), hypoxia-inducible factor-1α (HIF-1α), and transforming growth factor-β1 (TGF-β1) that regulate renal fibrosis and hypoxia.

Results: Compared with the control group, serum levels of CysC and IL-1β, and urinary NGAL concentrations were clearly increased from Day 1 to Day 13 in the CA-AKI group (all p < 0.05). There were significant reductions in ΔT2 values on Days 1 and 3, and ΔT1 reductions were significantly more pronounced at all time points (Days 1–13) in the CA-AKI + Fasudil group (vs. CA-AKI) (all p < 0.05). Fasudil treatment lowered expression levels of ROCK-1, and p-MYPT1/MYPT1 proteins induced by iopromide, decreasing TGF-β1 expression and suppressing both extracellular matrix accumulation and α-SMA expression relative to untreated status (all p < 0.05). Fasudil also enhanced PHD2 transcription and inhibition of HIF-1α expression after CA-AKI.

Conclusions: In the context of CA-AKI, fasudil appears to reduce renal hypoxia, fibrosis, and dysfunction by activating (Rho/ROCK) or inhibiting (TGF-β1, HIF-1α) certain signaling pathways and reducing α-SMA expression. Multiparametric MRI may be a viable noninvasive tool for monitoring CA-AKI pathophysiology during fasudil therapy.

The Pathophysiology and the Management of Radiocontrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is an impairment of renal function that occurs after the administration of an iodinated contrast medium (CM). Kidney dysfunction in CIN is considered transient and reversible in most cases. However, it is the third most common cause of hospital-acquired acute kidney injury and is associated with increased morbidity and mortality, especially in high-risk patients. Diagnostic and interventional procedures that require intravascular CM are being used with increasing frequency, especially among the elderly, who can be particularly susceptible to CIN due to multiple comorbidities. Therefore, identifying the exact mechanisms of CIN and its associated risk factors is crucial not only to provide optimal preventive management for at-risk patients, but also to increase the feasibility of diagnostic and interventional procedure that use CM. CM induces kidney injury by impairing renal hemodynamics and increasing the generation of reactive oxygen species, in addition to direct cytotoxicity. Periprocedural hydration is the most widely accepted preventive strategy to date. Here, we review the latest research results on the pathophysiology and management of CIN.

Involvement of necroptosis in contrast-induced nephropathy in a rat CKD model

BACKGROUND

The risk of contrast-induced nephropathy (CIN) is high in patients with chronic kidney disease (CKD). However, the mechanism of CIN in CKD is not fully understood. Here, we prepared a clinically relevant model of CIN and examined the role of necroptosis, which potentially cross-talks with autophagy, in CIN.

METHODS

In Sprague-Dawley rats, CKD was induced by subtotal nephrectomy (SNx, 5/6 nephrectomy) 4 weeks before induction of CIN. CIN was induced by administration of a contrast medium (CM), iohexol, following administration of indomethacin and N-omega-Nitro-L-arginine methyl ester. Renal function and tissue injuries were assessed 48 h after CM injection.

RESULTS

Serum creatinine (s-Cre) and BUN were increased from 0.28 ± 0.01 to 0.52 ± 0.02 mg/dl and from 15.1 ± 0.7 to 29.2 ± 1.2 mg/dl, respectively, after SNx alone. CM further increased s-Cre and BUN to 0.69 ± 0.03 and 37.2 ± 2.1, respectively. In the renal tissue after CM injection, protein levels of receptor-interacting serine/threonine-protein kinase (RIP) 1, RIP3, cleaved caspase 3, and caspase 8 were increased by 64 ~ 212%, while there was reduction in LC3-II and accumulation of p62. Necrostatin-1, an RIP1 inhibitor, administered before and 24 h after CM injection significantly suppressed elevation of s-Cre, BUN and urinary albumin levels, kidney injury molecule-1 expression and infiltration of CD68-positive macrophages in renal tissues after CM injection.

CONCLUSION

The results suggest that necroptosis of proximal tubular cells contributes to CIN in CKD and that suppression of protective autophagy by pro-necroptotic signaling may also be involved.

Rho Kinase Inhibition by Fasudil Attenuates Adriamycin-Induced Chronic Heart Injury

Adriamycin (ADR)-induced chronic heart injury (CHI) is a serious complication of chemotherapy. The present study was designed to assess the ability of fasudil, a Rho kinase inhibitor, to prevent ADR-induced CHI. Forty male 6-week-old C57BL6 mice were randomly divided into the following four groups: (1) control group, (2) CHI induced by adriamycin (ADR group), (3) CHI plus low dose fasudil (ADR + L group), and (4) CHI plus high dose fasudil (ADR + H group). Animals from groups 2-4 received ADR (2.5 mg/kg, i.p.) once a week for 8 weeks, and the control group received saline. Meanwhile, the animals in groups 3-4 received 2 mg/kg/day or 10 mg/kg/day fasudil, respectively. After measurement of cardiac functions, blood samples were collected for biochemical assays. The hearts were excised for histological, immunohistochemistry and western blot study, respectively. Adriamycin produced evident cardiac damage revealed by cardiac functions changes: decreased left ventricular fractional shortening (FS), left ventricular ejection fraction (EF), increased left ventricular volume, cardiac injury marker changes (increased creatine kinase, lactate dehydrogenase), antioxidant enzymes activity changes (decreased superoxide dismutase), and lipid peroxidation (elevated malondialdehyde) to the control group. Fasudil treatment notably ameliorated ADR-induced cardiac damage, restored heart function, suppressed cell apoptosis and senescence, ameliorated redox imbalance, and DNA damage. Fasudil has a protective effect on ADR-induced chronic heart injury, which partially attributed to its antioxidant, anti-apoptotic effects of inhibiting the RhoA/Rho kinase (ROCK) signaling pathway.

Alleviation of the doxorubicin-induced nephrotoxicity by fasudil in vivo and in vitro

OBJECTIVE

Treatment with the chemotherapeutic agent, doxorubicin (DOX), is limited by side effects. We have previously demonstrated that fasudil, a Rho/ROCK inhibitor, has antioxidant, anti-inflammatory and anti-apoptotic effects in contrast-induced acute kidney injury model. The present study to investigated the possible protective effect of fasudil, on DOX-induced nephrotoxicity.

MATERIALS AND METHOD

In vivo: Forty male C57BL/6 male mice were randomly divided into 4 groups: Control group, DOX treatment group (DOX group), DOX + low dose fasudil (DOX + L group), DOX + high dose fasudil (DOX + H group). Mice in 2-4 groups received DOX (2.5 mg/kg, i.p.) once a week for 8 weeks. The 3 and 4 group were given 2 mg/kg/d or 10 mg/kg/d fasudil before DOX injection. respectively. Meanwhile, the control group received saline. At the end of week eight, blood samples were collected for biochemical testing. The kidneys were removed for histological, immunohistochemical, Western blot, quantitative real-time PCR (qRT-PCR), and molecular detection. In vitro: NRK-52E cells were treated with 40 uM fasudil for 12 h, then incubated with 1 uM DOX for 24 h. Cells then collected for qRT-PCR and Western blot.

RESULTS

In vivo, fasudil treatment ameliorated DOX-induced immunofluorescence reaction of DNA damage-related factors (8-OHdG), decreased the expression of Bax, Caspase-3, p16, p21 and p53, and increased the expression of protein of Bcl-2, Bmi-1 and Sirt-1. In the mouse model, administration of fasudil significantly ameliorated DOX-induced kidney damage, suppressed cell apoptosis and senescence, ameliorated redox imbalance and DNA damage. At the same time, DOX produced obvious kidney damage revealed by kidney functions changes: increased serum creatinine (SCr) and blood urea nitrogen (BUN) concentrations. In addition, kidney tissue staining in the DOX group showed abnormal structure and fibroproliferative disorders. And DOX could promote the oxidation and senescence of kidney cells, leading to increased expression of 8-OHdG and senescence and apoptosis-related factors. On the contrary, fasudil treatment can effectively inhibit redox imbalance and DNA damage caused by DOX, and inhibit cell senescence and apoptosis. Fasudil can inhibit excessive activation of Rho/ROCK signaling pathway, thereby improving kidney tissue fibrosis and recovery kidney function.

CONCLUSION

Fasudil has a protective effect on DOX-induced nephrotoxicity in mice and NRK-52E cells, which can inhibit oxidative stress and DNA damage, inhibit apoptosis, and delays cell senescence by inhibiting RhoA/Rho kinase (ROCK) signaling pathway.

Contrast-induced nephropathy and oxidative stress: mechanistic insights for better interventional approaches

Contrast-induced nephropathy (CIN) or contrast-induced acute kidney injury (CI-AKI) is an iatrogenic acute kidney injury observed after intravascular administration of contrast media for intravascular diagnostic procedures or therapeutic angiographic intervention. High risk patients including those with chronic kidney disease (CKD), diabetes mellitus with impaired renal function, congestive heart failure, intraarterial intervention, higher volume of contrast, volume depletion, old age, multiple myeloma, hypertension, and hyperuricemia had increased prevalence of CIN. Although CIN is reversible by itself, some patients suffer this condition without renal recovery leading to CKD or even end-stage renal disease which required long term renal replacement therapy. In addition, both CIN and CKD have been associated with increasing of mortality. Three pathophysiological mechanisms have been proposed including direct tubular toxicity, intrarenal vasoconstriction, and excessive production of reactive oxygen species (ROS), all of which lead to impaired renal function. Reports from basic and clinical studies showing potential preventive strategies for CIN pathophysiology including low- or iso-osmolar contrast media are summarized and discussed. In addition, reports on pharmacological interventions to reduce ROS and attenuate CIN are summarized, highlighting potential for use in clinical practice. Understanding this contributory mechanism could pave ways to improve therapeutic strategies in combating CIN.

Attenuation of Diabetic Nephropathy in Diabetic Mice by Fasudil through Regulation of Macrophage Polarization

Inflammation and fibrosis induced by hyperglycemia are considered to play a critical role in the pathogenesis of diabetic nephropathy. As macrophage polarization may determine the severity and progression of inflammation, regulation of macrophage polarization may be an effective method to treat diabetic complications. Fasudil, a potent Rho-kinase inhibitor, reportedly exhibits anti-inflammatory activity. However, whether fasudil reduces hyperglycemia-induced diabetic nephropathy via regulation of macrophage polarization remains unclear. In this study, we investigate the effect of fasudil on diabetic nephropathy in streptozotocin-induced type 1 diabetic mice. Our data showed that fasudil significantly decreased urinary protein and serum creatinine in diabetic mice, whereas it had no effect on the body weight and blood glucose. We also found increased M1-type macrophages and related proinflammatory cytokines, adverse fibrosis in renal tissue of diabetic mice. Interestingly, treatment of diabetic mice with fasudil increased the number of M2-type macrophages and related anti-inflammatory cytokines, which attenuated renal injury in diabetic mice. Taken together, the results of this study suggest that fasudil could slow the progression of diabetic nephropathy. The possible mechanism might be associated with its induction of M2 macrophage polarization and the reduction of M1 macrophage polarization and inflammation.

Contrast Induced Acute Kidney Injury and Direct Cytotoxicity of Iodinated Radiocontrast Media on Renal Proximal Tubule Cells

The administration of intravenous iodinated radiocontrast media (RCM) to visualize internal structures during diagnostic procedures has increased exponentially since their first use in 1928. A serious side effect of RCM exposure is contrast-induced acute kidney injury (CI-AKI), which is defined as an abrupt and prolonged decline in renal function occurring 48-72 hours after injection. Multiple attempts have been made to decrease the toxicity of RCM by altering ionic strength and osmolarity, yet there is little evidence to substantiate that a specific RCM is superior in avoiding CI-AKI. RCM-associated kidney dysfunction is largely attributed to alterations in renal hemodynamics, specifically renal vasoconstriction; however, numerous studies indicate direct cytotoxicity as a source of epithelial damage. Exposure of in vitro renal proximal tubule cells to RCM has been shown to affect proximal tubule epithelium in the following manner: 1) changes to cellular morphology in the form of vacuolization; 2) increased production of reactive oxygen species, resulting in oxidative stress; 3) mitochondrial dysfunction, resulting in decreased efficiency of the electron transport chain and ATP production; 4) perturbation of the protein folding capacity of the endoplasmic reticulum (ER) (activating the unfolded protein response and inducing ER stress); and 5) decreased activity of cell survival kinases. The present review focuses on the direct cytotoxicity of RCM on proximal tubule cells in the absence of in vivo complications, such as alterations in renal hemodynamics or cytokine influence.