Complement C5 activation promotes type 2 diabetic kidney disease via activating STAT3 pathway and disrupting the gut-kidney axis.

Diabetic kidney disease (DKD) is a severe DM complication. While complement C5 up-regulation and gut dysbiosis are found in T2DM, their roles in DKD are unclear. Here, we investigated the effect of C5 on the gut microbiota during DKD development. Renal C5a/C5a receptor (C5aR) expression changes were measured in T2DM patients and db/db mice. Db/db mice were treated with a C5aR antagonist (C5aRA), and renal function, gut microbiota and renal genome changes were analysed. The effects of C5a and short-chain fatty acids (SCFAs) on the signal transducer and activator of transcription 3 (STAT3) pathway were examined in vitro. C5a was up-regulated in glomerular endothelial cells (GECs) of T2DM patients and db/db mice. Although glucose and lipid metabolism were unchanged, C5aR blockade alleviated renal dysfunction, ECM deposition, macrophage infiltration and proinflammatory factor expression in db/db mice. C5aRA partly reversed the declines in gut microbiota diversity and abundance and gut SCFA levels in db/db mice. C5aRA down-regulated the expression of many immune response-related genes, such as STAT3, in db/db mouse kidneys. C5aRA and SCFAs suppressed C5a-induced STAT3 activation in human renal glomerular endothelial cells (HRGECs). Based on our results, C5 hyperactivation promotes DKD by activating STAT3 in GECs and impairing the gut-kidney axis, suggesting that this hyperactivation is a potential target for the treatment of DKD.

Anti-Inflammatory Pyranochalcone Derivative Attenuates LPS-Induced Acute Kidney Injury via Inhibiting TLR4/NF-κB Pathway.

Treatment of septic acute kidney injury (AKI) has still been beyond satisfaction, although anti-inflammatory therapy is beneficial for sepsis-induced AKI. Compound 5b was derived from natural pyranochalcones and exhibited potent anti-inflammatory activity in adjuvant-induced arthritis. In this study, we aimed to investigate the renoprotective effects and potential mechanism of 5b against lipopolysaccharide (LPS)-induced AKI. C57BL/6 mice and human renal proximal tubule cell line (HK-2 cell) were treated with LPS, respectively. Compound 5b was orally administrated at a dose of 25 mg/kg/day for 5 days before LPS (10 mg/kg) intraperitoneal injection. Cells were pretreated with 25 µg/mL 5b for 30 min before LPS (1 µg/mL) treatment. Pretreatment with 5b markedly alleviated tubular injury and renal dysfunction in LPS-induced AKI. The expression of IL-1ß, IL-6, and TNF-α both in renal tissue of AKI mice and in the LPS-stimulated HK-2 cell culture medium were reduced by 5b treatment (p < 0.05). The results of immunohistochemistry staining showed that 5b reduced the expression of NF-κB p65 in kidneys. Similarly, 5b decreased the LPS-induced levels of NF-κB p65 and TLR4 proteins in kidneys and HK-2 cells. These data demonstrated that a potent pyranochalcone derivative, 5b, exhibited renoprotective effect against LPS-induced AKI, which was associated with anti-inflammatory activity by inhibiting the TLR4/NF-κB pathway.

[Ambulatory arterial stiffness index and associated factors in patients with diabetic kidney disease].

OBJECTIVE: To compare arterial stiffness between diabetic kidney disease and non-diabetic kidney diseaseand to identify factors predicting ambulatory arterial stiffness index (AASI). METHODS: Forty-four patients with diabetic kidney disease (DKD group) and thirty-one patients with non-diabetic kidney disease (NDKD group) were recruited for this study. All of the participants had hypertension. The AASI (indirect reflex global arterial stiffness)and short-term blood pressure variability (BPV) were measured using a 24-h ambulatory BP monitoring, and compared.between DKD and NDKD groups using analyses of covariance, correlation analysis and multivariate linear regression model. RESULTS: DKD patients had significantly higher levels of AASI than NDKD patients (0.55 +/- 0.14 vs. 0.45 +/- 0.16, P < 0.05). The 24-h systolic and daytime systolic BP variability of DKD patients was also higher than NDKD patients. In DKD patients, the correlation analysis revealed that the AASI showed association with 24-h systolic BP variability (24 hSBPV), 24-h diastolic BP variability (24 hDBPV),daytime diastolic BP variability (dDBPV), nighttime systolic BP variability (nSBPV) and nighttime diastolic BP variability (nDBPV), and nDBPV and age showed strong associations with AASI. CONCLUSION: Although both DKD and NDKD patients suffered from arterial stiffness, greater AASI and short-term BPV was detected in DKD patients. AASI is associated with nDBPV and age. Optimal short-term BPV control in hypertensive type 2 diabetic patients with overt nephropathy may improve arterial elasticity.

Pterostilbene, a Bioactive Component of Blueberries, Alleviates Renal Interstitial Fibrosis by Inhibiting Macrophage-Myofibroblast Transition.

Pterostilbene (PTB) is a derivative of resveratrol present in grapes and blueberries. PTB is structurally similar to resveratrol, possessing properties such as being analgesic, anti-aging, antidiabetic, anti-inflammatory, anti-obesity, anti-oxidation, cholesterol-reductive, and neuroprotective. However, there have not been reports on the effect of PTB on macrophage-myofibroblast transition (MMT) induced fibrosis in kidney. In this study, we investigated the antifibrotic effects of PTB on the in vivo mouse unilateral ureteral obstruction (UUO) model and in vitro MMT cells. Kidneys subjected to UUO with PTB treatment were collected for the investigation of PTB mediating MMT derived renal interstitial fibrosis. We conducted kidney RNA-seq transcriptomes and TGF-[Formula: see text]1-induced bone marrow-derived macrophages assays to determine the mechanisms of PTB. We found that PTB treatment suppressed the interstitial fibrosis in UUO mice. PTB also attenuated the number of MMT cells in vivo and in vitro. The transcriptomic analysis showed that CXCL10 may play a central role in the process of PTB-treated renal fibrosis. The siRNA-mediated CXCL10 knockdown decreased the number of MMT cells in TGF-[Formula: see text]1-induced bone marrow-derived macrophages. Our results suggested that PTB attenuated renal interstitial fibrosis by mediating MMT by regulating transcriptional activity of CXCL10.

Inhibition of Fatty Acid-Binding Protein 4 Attenuated Kidney Fibrosis by Mediating Macrophage-to-Myofibroblast Transition.

The macrophage-to-myofibroblast transition (MMT) process is an important pathway that contributing to renal interstitial fibrosis (RIF). Fatty acid-binding protein 4 (FABP4) deteriorated RIF via promoting inflammation in obstructive nephropathy. However, the clinical significance of FABP4 in fibrotic kidney disease remains to be determined and little is known of the FABP4 signaling in MMT. Biopsy specimens of chronic kidney disease patients and kidneys subjected to unilateral ureteral obstruction (UUO) of FABP4-deficient mice or FABP4 inhibitor-treated mice were collected for the investigation of FABP4 mediating MMT of RIF. We conducted kidney RNA-seq transcriptomes and TGF-ß1-induced bone marrow-derived macrophage (BMDM) assays to determine the mechanisms of FABP4. We found that FABP4 expression correlated with RIF in biopsy specimens and the injured kidneys of UUO mice where FABP4 was co-expressed with MMT cells. In UUO mice, FABP4 deficiency and a highly selective FABP4 inhibitor BMS309403 treatment both suppressed RIF. FABP4 ablation also attenuated the UUO-induced number of MMT cells and serum amyloid A1 (Saa1) expression. The siRNA-mediated Saa1 knockdown decreased the number of MMT cells in vitro. In conclusion, FABP4 is an important factor contributing to RIF by mediating MMT, and genetic/pharmacological inhibition of FABP4 provides a novel approach for the treatment of kidney fibrosis.

Targeted delivery of celastrol to renal interstitial myofibroblasts using fibronectin-binding liposomes attenuates renal fibrosis and reduces systemic toxicity.

Renal fibrosis often occurs in chronic kidney disease, and effective treatment is needed. Celastrol (CEL) may attenuate renal fibrosis, but it distributes throughout the body, leading to severe systemic toxicities. Here we designed a system to deliver CEL specifically to interstitial myofibroblasts, which is a key driver of renal fibrogenesis. Fibronectin is highly expressed in fibrotic kidney. The pentapeptide CREKA, which specifically binds fibronectin, was conjugated to PEGylated liposomes (CREKA-Lip). CREKA-coupled liposomes significantly increased the uptake of unmodified liposomes by activated NRK-49F renal fibroblasts. Systemic administration of CREKA-Lip to mice led to their accumulation in fibrotic kidney, where they were specifically internalized by interstitial myofibroblasts. Loading CEL into CREKA-Lip effectively inhibited the activation and proliferation of NRK-49F cells in vitro, and they markedly alleviated renal fibrosis, injury and inflammation induced by unilateral ureteral obstruction in mice. Besides, CEL-loaded CREKA-Lip was associated with significantly lower toxicity to major organs than free CEL. These results suggest that encapsulating CEL in CREKA-Lip can increase its therapeutic efficacy and reduce its systemic toxicity as a potential treatment for renal fibrosis.

Citrate versus heparin lock for prevention of hemodialysis catheter-related complications: updated systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: To provide updated evidence, we conducted a systematic review and meta-analysis to compare citrate lock with heparin in the prevention of hemodialysis catheter-related complications. METHODS: A systematic review and meta-analysis of randomized controlled trials were obtained by searching PubMed, EMBASE, Ovid, Cochrane library, and the Web of Science databases. Primary outcomes were catheter-related bloodstream infections (CRBI), exit-site infections, bleeding events, catheter removal for poor flow, and thrombolytic treatment. Secondary outcomes were thrombocytopenia, access-related admission, and all-cause mortality. RESULTS: The meta-analysis showed that the citrate lock containing antimicrobials can reduce the risk of CRBI when compared with heparin lock (RR: 0.34, 95% CI 0.24-0.49; I2 = 0%; P < 0.00001), and a tunneled cuffed catheter (TCC) was more beneficial for the prevention of CRBI (RR: 0.42, 95% CI 0.25-0.69; I2 = 40%; P = 0.0007) when compared with non-tunneled cuffed catheters (NTCC). The microbiological correlation analysis suggests that the occurrence of CRBI is closely related to S. aureus in catheters locked by citrate (P = 0.015) rather than by heparin (P = 0.868). In the analysis of exit-site infection, citrate lock with NTCC was more effective in preventing exit-site infection than heparin (RR: 0.48, 95% CI 0.31-0.75; I2 = 0%; P = 0.001). In addition, the risk of bleeding episodes was reduced in hemodialysis patients using citrate lock with TCC (RR: 0.53, 95% CI 0.32-0.86; I2 = 0%; P = 0.01) and patients with citrate alone (RR: 0.51, 95% CI 0.30-0.85; I2 = 12%; P = 0.010). The risk of catheter removal for poor flow (P = 0.91), thrombolytic treatment (P = 0.76), thrombocytopenia (P = 0.37), access-related admission (P = 0.10), and all-cause mortality (P = 0.62) was not significantly different. CONCLUSIONS: Antimicrobial-containing citrate lock solutions could reduce the risk of CRBI in hemodialysis patients. The occurrence of CRBI is closely related to S. aureus in catheters locked by citrate rather than by heparin. Citrate lock was effective in reducing exit-site infection in NTCC and bleeding events in TCC.

Efficacy and Safety of Dual Blockade of the Renin-Angiotensin-Aldosterone System in Diabetic Kidney Disease: A Meta-Analysis.

INTRODUCTION: Current guidelines recommend renin-angiotensin-aldosterone system (RAAS) inhibitors in the treatment of diabetic kidney disease (DKD). However, evidence suggests that the combined use of RAAS blockers may be associated with increased rates of adverse events. OBJECTIVES: Our objective was to examine the efficacy and safety of dual blockade of the RAAS in patients with DKD. METHODS: This was a systematic review and meta-analysis of randomized controlled trials (RCTs) published between January 1990 and January 2018 sourced via the PubMed, EMBASE, and Cochrane Library databases. RCTs were included if they investigated the efficacy and safety of dual blockade therapy compared with monotherapy in patients with DKD. Random effects models were used in meta-analysis to account for heterogeneities in effect sizes across the reviewed studies. Analyses were stratified by blood pressure and albuminuria. We further conducted subgroup analyses by considering various combinations of RAAS inhibitors. RESULTS: Based on 42 RCTs with 14,576 patients, dual RAAS blockade therapy was associated with significant decreases in blood pressure, albuminuria, and proteinuria. However, dual therapy was not superior to monotherapy in terms of reductions in all-cause mortality, cardiovascular mortality, or progression to end-stage renal disease (ESRD). Significant increases in serum potassium and rates of hyperkalemia and hypotension were more common in patients treated with dual therapy. However, glomerular filtration rates (GFR) did not decrease significantly with dual therapy. In subgroup analysis, an angiotensin-converting enzyme inhibitor (ACEI) plus an angiotensin-receptor blocker (ARB) or a direct renin inhibitor (DRI) plus an ACEI/ARB did not significantly increase the risk of hyperkalemia, hypotension, and adverse events, and the risk of hypotension increased significantly within the normotensive subgroup but not within the hypertensive subgroup. The risk of hyperkalemia increased significantly in patients with DKD with macroalbuminuria but not in those with microalbuminuria. CONCLUSION: Dual inhibition therapy is superior to monotherapy for blood pressure control and urine protein reduction, though such superiority does not translate into improvements in longer-term outcomes, such as reduced progression to ESRD, all-cause mortality, and cardiovascular mortality. An ACEI plus an ARB or a DRI plus an ACEI/ARB may be a safe and effective therapy for patients with DKD, and combination therapy may be suitable for patients with DKD and hypertension and microalbuminuria.

Pterostilbene, a bioactive component of blueberries, alleviates renal fibrosis in a severe mouse model of hyperuricemic nephropathy.

Accumulating evidences indicated that hyperuricemia was an independent risk factor for kidney diseases and contributed to kidney fibrosis. Preventing and treating renal fibrosis was an optimal treatment for hyperuricemia-induced kidney diseases. In the study, pterostilbene (PTE) as a bioactive component of blueberries was confirmed to possess lowering serum uric acid and renal protective functions by the decrease of serum creatinine, BUN, urine albumin, and urine albumin-to-creatinine ratio (uACR) in a mouse model of hyperuricemic nephropathy (HN). Importantly, PTE treatment remarkably alleviated renal fibrosis of HN mice indicated by the downregulation of fibronectin, collagen I and α-SMA production. Furthermore, PTE could suppress the fibrosis-related protein expressions of TGF-ß1/Smad3, Src and STAT3 in the kidneys of HN mice. In conclusion, PTE suppressed the activation of TGF-ß1/Smad3, Src and STAT3 signaling pathway to alleviate renal fibrosis of HN mice, highlighting that PTE was a potential antifibrotic strategy for hyperuricemic nephropathy.

2-methylquinazoline derivative F7 as a potent and selective HDAC6 inhibitor protected against rhabdomyolysis-induced acute kidney injury.

Histone deacetylases 6 (HDAC6) has been reported to be involved in the pathogenesis of rhabdomyolysis-induced acute kidney injury (AKI). Selective inhibition of HDAC6 activity might be a potential treatment for AKI. In our lab, N-hydroxy-6-(4-(methyl(2-methylquinazolin-4-yl)amino)phenoxy)nicotinamide (F7) has been synthesized and inhibited HDAC6 activity with the IC50 of 5.8 nM. However, whether F7 possessed favorable renoprotection against rhabdomyolysis-induced AKI and the involved mechanisms remained unclear. In the study, glycerol-injected mice developed severe AKI symptoms as indicated by acute renal dysfunction and pathological changes, accompanied by the overexpression of HDAC6 in tubular epithelial cells. Pretreatment with F7 at a dose of 40 mg/kg/d for 3 days significantly attenuated serum creatinine, serum urea, renal tubular damage and suppressed renal inflammatory responses. Mechanistically, F7 enhanced the acetylation of histone H3 and α-tubulin to reduce HDAC6 activity. Glycerol-induced AKI triggered multiple signal mediators of NF-κB pathway as well as the elevation of ERK1/2 protein and p38 phosphorylation. Glycerol also induced the high expression of proinflammatory cytokine IL-1ß and IL-6 in kidney and human renal proximal tubule HK-2 cells. Treatment of F7 notably improved above-mentioned inflammatory responses in the injured kidney tissue and HK-2 cell. Overall, these data highlighted that 2-methylquinazoline derivative F7 inhibited renal HDAC6 activity and inflammatory responses to protect against rhabdomyolysis-induced AKI.

Microbial and metabolomic remodeling by a formula of Sichuan dark tea improves hyperlipidemia in apoE-deficient mice.

Medicine-food homology is a long-standing concept in traditional Chinese medicine. YiNianKangBao (YNKB) tea is a medicine-food formulation based on Sichuan dark tea (Ya'an Tibetan tea), which is traditionally used for its lipid-lowering properties. In this study, we evaluated the effects of YNKB on dyslipidemia and investigated the mechanism underlying its correlation with gut microbiota and serum metabolite regulation. Wild-type mice were fed a normal diet as a control. Male ApoE-/- mice were randomly divided into three high-fat diet (HFD) groups, a model group, and two treated groups (100, 400 mg/kg/d for low, high-dose), and fed by gavage for 12 weeks. Serum lipid levels, composition of gut microbiota, and serum metabolites were then analyzed before treatment with YNKB. We extracted the ingredients of YNKB in boiled water for one hour. YNKB supplementation at a high dose of 400 mg/kg/day reduced bodyweight gains (relative epididymal fat pad and liver weight), and markedly attenuated serum lipid profiles and atherosclerosis index, with no significant differences present between the low-dose treatment and HFD groups. Gut microbiota and serum metabolic analysis indicated that significant differences were observed between normal, HFD, and YNKB treatment groups. These differences in gut microbiota exhibited strong correlations with dyslipidemia-related indexes and serum metabolite levels. Oral administration of high-dose YNKB also showed significant lipid-lowering activity against hyperlipidemia in apoE-deficient mice, which might be associated with composition alterations of the gut microbiota and changes in serum metabolite abundances. These findings highlight that YNKB as a medicine-food formulation derived from Sichuan dark tea could prevent dyslipidemia and improve the understanding of its mechanisms and the pharmacological rationale for preventive use.

SKLB023 hinders renal interstitial fibrosis in obstructive nephropathy by interfering TGF-ß1/Smad3 signaling.

Renal fibrosis is the principal process underlying the progression of chronic kidney disease to end-stage renal disease. It is a relatively uniform response involving glomerulosclerosis, tubulointerstitial fibrosis and changes in renal vasculature. A considerable number of studies have confirmed that inducible nitric oxide synthase (iNOS) was highly expressed in renal interstitial fibrosis and the overexpression of iNOS played a negative role in kidney disease progression. In our previous study, SKLB023 as a novel small-molecule inhibitor of iNOS, blocked joint inflammation and cartilage destruction in arthritis. However, the pharmacological role and function of SKLB023 in renal fibrosis remained poorly understood. In the study, oral administration of SKLB023 (25 and 50 mg per kg per day) for 7 day exhibited potent anti-fibrotic effects against the model UUO using the pathological assessment of H & E and Masson's trichrome staining. SKLB023 inhibited the expression of α-SMA, col I, col IV, fibronectin and further decreased iNOS expression as well as TGF-ß1/Smad3 phosphorylation in the injured kidney tissues of UUO mice. Similarly, SKLB023 suppressed in vitro features of fibrosis in TGF-ß1-induced NRK-49F by the inhibition of the corresponding fibrotic protein expression. These findings confirmed that SKLB023 hindered renal interstitial fibrosis by interfering with TGF-ß1/Smad3 signaling, highlighting that SKLB023 has potential in therapeutic strategies.

Pharmacological inhibition of fatty acid-binding protein 4 (FABP4) protects against renal ischemia-reperfusion injury.

Fatty acid-binding protein 4 (FABP4) is a key mediator of endoplasmic reticulum (ER) stress and apoptosis in diabetes and atherosclerosis. Studies also confirmed that circulating FABP4 depended on renal function in chronic kidney disease (CKD) and acute kidney injury (AKI) patients. However, the function of FABP4 in AKI remains poorly understood and the aim of this study was to investigate the role of FABP4 in ischemia-reperfusion (I/R)-induced AKI. In the present study, renal I/R injury triggered the high expression of the FABP4 gene and protein in the nucleus and cytoplasm of tubular cells of mouse kidney tissue compared to that of Sham. Pretreatment with BMS309403, a highly selective inhibitor of FABP4 at a dose of 20 mg kg-1 d-1 for 4 d, significantly reduced serum creatinine levels to improve acute renal dysfunction and attenuated renal tubular damage in injured kidneys. Pharmacological inhibition of FABP4 also decreased the number of TdT-mediated dUTP nick-end labeling (TUNEL) positive apoptotic tubular cells, accompanied by the down-regulation of cleaved-caspase-3 expression. Furthermore, oral administration of FABP4 inhibitor resulted in a significant attenuation of ER stress indicated by its maker proteins expression of glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and caspase-12 in I/R injured kidneys. In vitro, the increased expression of FABP4 in the human renal proximal tubule cell line (HK-2 cell) was induced by hypoxia followed by reoxygenation (HR) and the FABP4 inhibitor resulted in a significant attenuation of cell apoptosis and ER stress in HR-induced HK-2 cells. In summary, these findings indicated that FABP4 contributed to the pathogenesis of I/R-induced AKI and suggested that the inhibition of FABP4 might be a promising therapeutic strategy for AKI treatment.

SKLB023 as an iNOS inhibitor alleviated liver fibrosis by inhibiting the TGF-beta/Smad signaling pathway.

Nonalcoholic steatohepatitis (NASH)-related liver fibrosis has been suggested to be a physiological consequence of chronic hepatic injury, necrosis, inflammation and unbalanced intrahepatic lipid metabolism. Accumulated evidence demonstrates that inducible nitric oxide synthase (iNOS) is highly expressed in advanced liver fibrosis, and the knockout of iNOS inhibits the progression of hepatic fibrosis. In our previous study, (Z)-N-(3-chlorophenyl)-2-(4-((2,4-dioxothiazolidin-5-ylidene)methyl)phenoxy)acetamide (SKLB023), a novel small-molecule inhibitor of iNOS, blocked joint inflammation and cartilage destruction in arthritis. However, the role and function of SKLB023 in liver fibrosis have not been fully elucidated. In the present study, methionine- and choline-deficient (MCD) diet-induced NASH mice and LX-2 hepatic stellate cells were chosen to investigate the pharmacological effects of SKLB023 against liver fibrosis and the associated mechanism. Our results show that SKLB023 significantly alleviated MCD diet-induced liver injury, lipid accumulation and liver fibrosis. SKLB023 could suppress the activation of hepatic stellate cells by interfering with TGF-ß/Smad pathways. Importantly, SKLB023 inhibited the level of TGF-ß1 and Smad2/3 phosphorylation by blocking the expression of iNOS. These results suggest that SKLB023 might be an effective drug candidate for the treatment of liver fibrosis.

Protective effects of SKLB023 on a mouse model of unilateral ureteral obstruction by the modulation of gut microbiota.

Renal interstitial fibrosis is the common pathway underlying the progression of chronic kidney disease (CKD) to end-stage renal disease (ESRD) and the corresponding therapies are limited. Quantitative and qualitative alterations in gut microbiota are noted in patients with CKD and ESRD. In our previous study, SKLB023 exhibited antifibrotic effects by interfering TGF-ß1/Smad3 signaling in obstructive nephropathy. However, it remained unclear that oral administration of SKLB023 drives the alteration of gut microbiota to attenuate renal fibrosis. In the study, the marked inflammation and interstitial fibrosis were found in the kidney tissues of unilateral ureteral obstruction (UUO) mice. While treatment with SKLB023 significantly alleviated renal interstitial fibrosis and reduced serum proinflammatory cytokines TNF-α, IL-6 levels. Importantly, SKLB023 derived the modulation of gut microbiota with the increasing similarity between the composition of gut microbiota in the control and UUO. The number of Turicibacter and Candidatus_Arthromitus was significantly decreased following UUO surgery and recovered by SKLB023, which positively correlated with pro-inflammatory cytokine expression. These results indicated the potential relationship between the antifibrotic benefits of SKLB023 and gut microbiota alteration, which provided new insights into drug therapy via gut microbiota modulation in obstructive nephropathy.

Pharmacological Inhibition of Fatty Acid-Binding Protein 4 (FABP4) Protects Against Rhabdomyolysis-Induced Acute Kidney Injury.

Acute kidney injury (AKI) is a common and potentially life-threatening complication. Studies confirmed that circulating FABP4 depended on renal function of AKI patients. In our previous study, FABP4 was involved in the pathogenesis of I/R-induced AKI. However, the function of FABP4 in rhabdomyolysis-induced AKI remained poorly understood. In the study, we further investigated the effect of FABP4 in a murine model of glycerol injection-induced rhabdomyolysis. Following glycerol injection, the mice developed severe AKI as indicated by acute renal dysfunction and histologic changes, companied by the increased FABP4 expression in the cytoplasm of tubular epithelial cells. Pharmacological inhibition of FABP4 by a highly selective inhibitor BMS309403 significantly reduced serum creatinine level, proinflammatory cytokine mRNA expression of tumor necrosis factor-α, interleukin-6, and monocyte chemoattractant protein 1 as well as attenuated renal tubular damage in glycerol-injured kidneys. Oral administration of FABP4 inhibitor also resulted in a significant attenuation of ER stress indicated by transmission electron microscope analysis and its maker proteins expression of GRP78, CHOP, p-perk, and ATF4 in kidneys of AKI. Furthermore, BMS309403 could attenuate myoglobin-induced ER stress and inflammation in renal proximal tubular epithelial cell line (HK-2). Overall, these data highlighted that renal protection of selective FABP4 inhibitor was substantiated by the reduction of ER stress and inflammation in tubular epithelial cells of rhabdomyolysis-induced injured kidneys and suggested that the inhibition of FABP4 might be a promising therapeutic strategy for AKI treatment.

Selective Histone Deacetylase 6 Inhibitor 23BB Alleviated Rhabdomyolysis-Induced Acute Kidney Injury by Regulating Endoplasmic Reticulum Stress and Apoptosis.

Histone deacetylase 6 (HDAC6) contributed to the pathogenesis of rhabdomyolysis-induced acute kidney injury (AKI) and selective inhibition of HDAC6 activity may be a promising strategy for the treatment of AKI. Compound 23BB as a highly selective HDAC6 inhibitor was designed, synthesized by our lab and exhibited therapeutic potential in various cancer models with good safety. However, it remained unknown whether 23BB as a drug candidate could offer renal protective effect against rhabdomyolysis-induced AKI. In the present study, we investigated the effect of 23BB in a murine model of glycerol (GL) injection-induced rhabdomyolysis. Following GL injection, the mice developed severe AKI as indicated by acute renal dysfunction and histologic changes, accompanied by increased HDAC6 expression in the cytoplasm of tubular epithelial cells. Pharmacological inhibition of HDAC6 by 23BB pretreatment significantly reduced serum creatinine and serum blood urea nitrogen (BUN) levels as well as attenuated renal tubular damage in GL-injured kidneys. HDAC6 inhibition also resulted in reduced TdT-mediated dUTP nick-end labeling (TUNEL)-positive tubular cells, suppressed BAX, BAK, cleaved caspase-3 levels, and preserved Bcl-2 expression, indicating that 23BB exerted potent renoprotective effects by the regulation of tubular cell apoptosis. Moreover, GL-induced kidney injury triggered multiple signal mediators of endoplasmic reticulum (ER) stress including GRP78, CHOP, IRE1α, p-eIF2α, ATF4, XBP1, p-JNK, and caspase-12. Oral administration of 23BB improved above-mentioned responses in injured kidney tissues and suggested that 23BB modulated tubular cell apoptosis via the inactivation of ER stress. Overall, these data highlighted that renal protection of novel HDAC6 inhibitor 23BB is substantiated by the reduction of ER stress-mediated apoptosis in tubular epithelial cells of rhabdomyolysis-induced AKI.

Placement of tunneled cuffed vascular catheter through superior vena cava puncture.

OBJECTIVE: The purpose of this study was to assess the feasibility and safety of placement of tunneled cuffed catheters through direct percutaneous puncture of the superior vena cava (SVC) in patients with occluded right and left innominate veins. METHODS: This was a retrospective review of all patients with right and left innominate vein occlusions who underwent tunneled catheter placement with direct SVC puncture between January 2012 and December 2014. Under fluoroscopic guidance with the patient in a supine position, a 5F catheter was placed at the distal end of the SVC through the femoral vein, iliac vein, or hepatic vein. This catheter was used as a fluoroscopic target for the puncture. Following the guidance of fluoroscopy, the puncture needle and sheath were placed through a transcutaneous route with the insertion site 0.5 to 1.0 cm lateral-inferior to the clavicle head of the sternocleidomastoid, with the pathway inferior (caudal) to the clavicle, which allowed access of the guidewire and placement of a tunneled central venous catheter. RESULTS: The procedure succeeded in all 16 patients. During follow-up (mean, 12 months; range, 3-36 months), access failure due to thrombosis was observed in one patient. The remaining continued to function well until the end of the follow-up period or until the death of the patient (n = 3). No pneumothorax occurred. The most common complication was mediastinal hematoma after puncture failure in five patients. The diameter of the maximum hematoma was 2.2 cm, and all resolved spontaneously. CONCLUSIONS: In patients with central vein occlusion and exhaustion of conventional insertion sites, a tunneled central venous catheter can be safely placed through SVC puncture by the transcutaneous route.

Dual Blockade of the Renin-angiotensin-aldosterone System in Type 2 Diabetic Kidney Disease.

OBJECTIVE: To examine the efficacy and safety of dual blockade of the renin-angiotensin-aldosterone system (RAAS) among patients with type 2 diabetic kidney disease. DATA SOURCES: We searched the major literature repositories, including the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, for randomized clinical trials published between January 1990 and October 2015 that compared the efficacy and safety of the use of dual blockade of the RAAS versus the use of monotherapy, without applying any language restrictions. Keywords for the searches included "diabetic nephropathy," "chronic kidney disease," "chronic renal insufficiency," "diabetes mellitus," "dual therapy," "combined therapy," "dual blockade," "renin-angiotensin system," "angiotensin-converting enzyme inhibitor," "angiotensin-receptor blocker," "aldosterone blockade," "selective aldosterone blockade," "renin inhibitor," "direct renin inhibitor," "mineralocorticoid receptor blocker," etc. STUDY SELECTION: The selected articles were carefully reviewed. We excluded randomized clinical trials in which the kidney damage of patients was related to diseases other than diabetes mellitus. RESULTS: Combination treatment with an angiotensin-converting enzyme inhibitor supplemented by an angiotensin II receptor blocking agent is expected to provide a more complete blockade of the RAAS and a better control of hypertension. However, existing literature has presented mixed results, in particular, related to patient safety. In view of this, we conducted a comprehensive literature review in order to explain the rationale for dual blockade of the RAAS, and to discuss the pros and cons. CONCLUSIONS: Despite the negative results of some recent large-scale studies, it may be immature to declare that the dual blockade is a failure because of the complex nature of the RAAS surrounding its diversified functions and utility. Further trials are warranted to study the combination therapy as an evidence-based practice.