Short-Term Preconditioning with Insulin and Glucose Efficiently Protected the Kidney Against Ischemia-Reperfusion Injury via the P-AKT-Bax-Caspase-3 Signaling Pathway in Mice.

Objective: Insulin attaches insulin receptor to activate the PI3-kinase/Akt signaling to maintain glucose homeostasis and inhibit apoptosis. This study determined whether preconditioning with insulin and glucose protects the kidney against ischemia-reperfusion injury (IRI). Methods: Kidney IRI was performed in C57BL/6 mice by clamping the renal vessels for 30 min, followed by reperfusion for 24 h. A total subcutaneous 0.1 unit of insulin along with 10% glucose in drinking water was treated on the mice for 24 h before kidney IRI. The kidney function and injuries were investigated through the determination of BUN and Cr in blood plasma, as well as the apoptosis and the expression of P-AKT, BAX, and caspase-3 in the kidneys. The role of P-AKT in insulin-treated IRI kidneys was tested using an AKT inhibitor. The effects of the preconditional duration of insulin and glucose on IRI kidneys were investigated by expanding the treatment duration to 1, 3, and 6 days. Results: Preconditioning with insulin and glucose protected the kidney against IRI as manifested by a decrease in creatinine and BUN and a reduction of kidney tubular injury. The protection effect was mediated by P-AKT-BAX-caspase-3 signaling pathway resulting in suppression of apoptotic cell death. An AKT inhibitor partially reversed the protective effects of preconditional insulin. The preconditional duration for 1, 3, and 6 days had no differences in improving kidney functions and pathology. Conclusion: A short-term preconditioning with insulin and glucose protected the kidney from IRI through the activation of p-AKT and subsequent reduction of BAX-caspase-3-induced apoptosis. The short-term precondition provides a practicable strategy for protecting the kidney against predictable IRI, such as kidney transplant and major surgical operations with high risk of hypotension.

Erector spinae plane block versus paravertebral block on postoperative quality of recovery in obese patients undergoing laparoscopic sleeve gastrectomy: a randomized controlled trial.

Purpose: To compare the impact of erector spinae plane block (ESPB) and paravertebral block (PVB) on the quality of postoperative recovery (QoR) of patients following laparoscopic sleeve gastrectomy (LSG). Methods: A total of 110 patients who underwent elective LSG under general anesthesia were randomly assigned to receive either ultrasound-guided bilateral ESPB or PVB at T8 levels. Before anesthesia induction, 40 mL of 0.33% ropivacaine was administered. The primary outcome was the QoR-15 score at 24 hours postoperatively. Results: At 24 hours postoperatively, the QoR-15 score was comparable between the ESPB and PVB groups (131 (112-140) vs. 124 (111-142.5), P = 0.525). Consistently, there was no significant difference in QoR-15 scores at 48 hours postoperatively, numerical rating scale (NRS) pain scores at any postoperative time points, time to first ambulation, time to first anal exhaust, postoperative cumulative oxycodone consumption, and incidence of postoperative nausea and vomiting (PONV) between the two groups (all P > 0.05). No nerve block-related complications were observed in either group. Conclusion: In patients undergoing LSG, preoperative bilateral ultrasound-guided ESPB yields comparable postoperative recovery to preoperative bilateral ultrasound-guided PVB.

Preperitoneal pelvic balloon tamponade-an effective intervention to control pelvic injury hemorrhage in a swine model.

Objective: This study aimed to estimate the effects of the volume of preperitoneal balloon (PPB) on arterial and venous hemorrhage in a swine pelvic fracture model. Methods: Twenty-four swine were randomized into 0-mL, 500-mL, 800-mL, and 1000-mL intra-hematoma PPB groups. They were subjected to open-book pelvic fracture and reproducible injuries in the external iliac artery and vein. The pelvic binder and IH-PPBs with different volumes of fluid were applied to control the active hemorrhage after arterial and venous injuries. The survival time and rate during 60-min observation and digital subtraction angiography (DSA) images were the primary endpoints in this study. Secondary endpoints included survival rate within 70 min, peritoneal pressure, hemodynamics, blood loss, infusion fluid, blood pH, and lactate concentration. Results: Our results indicated that the 800-mL and 1000-mL groups had a higher survival rate (0%, 50%, 100% and 100% for 0, 500, 800, and 1000-mL groups respectively; p < 0.0001) and longer survival time (13.83 ± 2.64, 24.50 ± 6.29, 55.00 ± 6.33, and 60.00 ± 0.00 min for 0, 500, 800, and 1,000 groups respectively; p < 0.0005) than the 0-mL or 500-mL groups during the 60 min observation. Contrastingly, survival rate and time were comparable between 800-mL and 1000-mL groups during the 60-min observation. The IH-PPB volume was associated with an increase in the pressure of the balloon and the preperitoneal pressure but had no effect on the bladder pressure. Lastly, the 1000-mL group had a higher mean arterial pressure and systemic vascular resistance than the 800-mL group. Conclusion: IH-PPB volume-dependently controls vascular bleeding after pelvic fracture in the swine model. IH-PPB with a volume of 800 mL and 1000 mL efficiently managed pelvic fracture-associated arterial and venous hemorrhage and enhanced survival time and rate in the swine model without evidences of visceral injury.

RESUSCITATIVE RECTAL BALLOON COMPRESSION COMBINED WITH PELVIC BINDER EFFICIENTLY CONTROLLED FATAL VENOUS HEMORRHAGE IN A HEMODYNAMICALLY UNSTABLE PELVIC FRACTURE CANINE MODEL.

ABSTRACT: Objective: This study evaluated the feasibility of a combination of pelvic binder and rectal balloon compression in managing fatal venous hemorrhage in a canine model of pelvic fracture. Methods: Rectums from humans (rectal cancer patients), swine, and canines were retrieved to determine their elasticity by measuring their stress and strain. Canines were selected as the animal model in this study because their rectum demonstrated more reversible strain than swine rectum. Doppler ultrasound was used to assess the effect of rectal balloon volume on the blood flow of pelvic iliac blood vessels in three canines. A rectal balloon of 250 mL was chosen to control pelvic venous bleeding as it could provide a peak effect in reducing the blood flow of bilateral internal iliac veins. Then, the open-book pelvic fracture with fatal bleeding of both internal iliac veins animal model was built. The animals were divided into four groups after the modeled surgery to undergo no treatment, pelvic binder, rectal balloon compression, or a combination of pelvic binder and rectal balloon compression. The treatment efficacy was evaluated based on their survival time, survival rate, blood loss, bleeding rate, infusion rate, blood pH, lactate concentration, the stability of hemodynamics, blood loss, and fluid infusion volume. Results: Our results showed that after the reproducible injuries in both internal iliac veins, the combination of pelvic binder and rectal balloon compression was associated with the best survival rate and survival time compared with the other treatment groups. In addition, the combination of pelvic binder and rectal balloon compression exhibited more stable hemodynamics than the pelvic binder or rectal balloon compression treatment alone. Conclusions: This study demonstrated the potential feasibility of using pelvic binder combined with rectal balloon compression to manage the fatal venous bleeding in pelvic fractures.

Combined spinal-epidural analgesia and epidural analgesia induced maternal fever with a similar timing during labor-A randomized controlled clinical trial.

Background: Both epidural and combined spinal-epidural (EA and CSEA) analgesia can induce intrapartum maternal fever. CSEA has a more rapid onset and wider nerve block than EA. Therefore, CSEA might have a different profile of intrapartum maternal fever, including higher temperatures or earlier occurrence. This randomized clinical trial was to determine whether CSEA could cause maternal fever earlier than EA. Methods: A randomized, double-blind, controlled clinical trial was performed on 233 nulliparous full-term pregnant women during vaginal delivery. The pregnant women were randomly allocated into the EA group (n = 113) and the CSEA group (n = 120). The fever latent period, from analgesia start to fever occurrence, was the primary endpoint in this study. The temperature was measured every 30 min using an eardrum thermometer during labor analgesia. The fever was defined as an eardrum temperature of ≥38 °C. Results: No difference was found in the maternal fever rate between the EA and the CSEA groups (10/113 vs. 7/120, P = 0.356). There was no significant difference in the fever latent period between the two groups (4.75 ± 0.86 h vs. 3.79 ± 2.2 h, p = 0.305). The temperatures at all points had no differences between EA and CSEA. Conclusion: CSEA had a similar latent fever period as EA. A further study is warranted to confirm the similar characteristic between CSEA and EA in the development of intrapartum maternal fever. Clinical trial registration: www.chictr.org.cn, identifier ChiCTR2000038793.

Midazolam Attenuates Esketamine-Induced Overactive Behaviors in Mice Before the Sedation, but Not During the Recovery.

Esketamine showed more potency, more rapid recovery from anesthesia, and less psychotomimetic side effects when compared with ketamine. However, the patients still experience psychotomimetic side effects of esketamine. In order to investigate whether midazolam can attenuate the esketamine-induced overactive behaviors and neuronal hyperactivities, midazolam 0, 40, 80, and 120 mg/kg combined with esketamine 50 mg/kg were administrated on Kunming mice to assess the behaviors changes during anesthesia. The indicators, including action time, duration of agitation before the sedation, duration of sedation, duration of loss of pedal withdrawal reaction (PWR), duration of loss of righting reaction (RR), duration of agitation during the recovery, and recovery time, were monitored for up to 3-4 h after intraperitoneal administration. The results demonstrated that midazolam 40, 80, and 120 mg/kg efficiently decreased the esketamine-induced overactive behaviors including ataxia, excitation, and catalepsy before sedation. Midazolam and esketamine synergically improved the anesthesia quality assessed by PWR and RR. However, even high doses of midazolam were not able to suppress the esketamine-induced psychotomimetic effects during the recovery.

Phosphoinositide 3 Kinase γ Plays a Critical Role in Acute Kidney Injury.

Inflammatory cells contribute to the pathogenesis of renal ischemia-reperfusion injury (IRI). However, the signaling mechanisms underlying the infiltration of inflammatory cells into the kidney are not well understood. In this study, we examined the effects of phosphoinositide 3 kinase γ (PI3Kγ) on inflammatory cells infiltration into the kidney in response to ischemia-reperfusion injury. Compared with wild-type mice, PI3Kγ knockout mice displayed less IRI in the kidney with fewer tubular apoptotic cell. Furthermore, PI3Kγ deficiency decreased the number of infiltrated neutrophils, macrophages, and T cells in the kidney, which was accompanied by a decrease in the expression of pro-inflammatory cytokines in the kidney. Moreover, wild-type mice treated with AS-605240, a selective PI3Kγ inhibitor, displayed less tubular damage, accumulated fewer inflammatory cells, and expressed less proinflammatory molecules in the kidney following IRI. These results demonstrate that PI3Kγ has a critical role in the pathogenesis of kidney damage in IRI, indicating that PI3Kγ inhibition may serve as a potential therapeutic strategy for the prevention of ischemia-reperfusion-induced kidney injury.

The mechanisms of nucleotide actions in insulin resistance.

Insulin resistance contributes to metabolic disorders in obesity and type 2 diabetes. In mechanisms of insulin resistance, the roles of glucose, fatty acids, and amino acids have been extensively documented in literature. However, the activities of nucleotides remain to be reviewed comprehensively in the regulation of insulin sensitivity. Nucleotides are well known for their activities in biosynthesis of DNA and RNA as well as their signaling activities in the form of cAMP and cGAMP. Their activities in insulin resistance are dependent on the derivatives and corresponding receptors. ATP and NADH, derivatives of adenosine, inhibit insulin signaling inside cells by downregulation of activities of AMPK and SIRT1, respectively. ATP, ADP and AMP, the well-known energy carriers, regulate cellular responses to insulin outside cells through the purinergic receptors in cell surface. Current evidence suggests that ATP, NADH, cGAMP, and uridine are potential biomarkers of insulin resistance. However, GTP and cGMP are likely the markers of insulin sensitization. Here, studies crossing the biomedical fields are reviewed to characterize nucleotide activities in the regulation of insulin sensitivity. The knowledge brings new insights into the mechanisms of insulin resistance.

A Single Low Dose of Dexmedetomidine Efficiently Attenuates Esketamine-Induced Overactive Behaviors and Neuronal Hyperactivities in Mice.

Introduction: Esketamine (Esk) (S(+)-ketamine) is now used as an alternative to its racemic mixture, i. e., ketamine in anesthesia. Esk demonstrated more powerful potency and rapid recovery in anesthesia and less psychotomimetic side effects comparing with ketamine, but Esk could still induce psychological side effects in patients. This study was to investigate whether dexmedetomidine (Dex) can attenuate the Esk-induced neuronal hyperactivities in Kunming mice. Methods: Dexmedetomidine 0.25, 0.5, and 1 mg/kg accompanied with Esk 50 mg/kg were administrated on Kunming mice to assess the anesthesia quality for 1 h. The indicators, such as time to action, duration of agitation, duration of ataxia, duration of loss pedal withdrawal reaction (PWR), duration of catalepsy, duration of righting reflex (RR) loss, duration of sedation, were recorded for 1 h after intraperitoneal administration. The c-Fos expression in the brain was detected by immunohistochemistry and Western Blot after 1 h of administration. Considering the length of recovery time for more than 1 h in Dex and Dex with Esk groups, other mice were repeatedly used to evaluate recovery time from the administration to emerge from anesthesia. Results: Dexmedetomidine dose-dependently increased recovery time when administrated with Esk or alone. Dex combined with Esk efficiently attenuated the duration of agitation, ataxia, and catalepsy. Dex synergically improved the anesthesia of Esk by increasing the duration of sedation, loss of RR, and loss of PWR. Esk induced the high expression of c-Fos in the cerebral cortex, hippocampus, thalamus, amygdala, hypothalamus, and cerebellum 1 h after administration. Western Blot results indicated that Dex at doses of 0.25, 0.5, and 1 mg/kg could significantly alleviate the Esk-induced c-Fos expression in the mice brain. Conclusion: Dexmedetomidine ranged from 0.25 to 1 mg/kg could improve the anesthesia quality and decreased the neuronal hyperactivities and the overactive behaviors when combined with Esk. However, Dex dose-dependently increased the recovery time from anesthesia. It demonstrated that a small dose of Dex 0.25 mg/kg could be sufficient to attenuate Esk-induced psychotomimetic side effects without extension of recovery time in Kunming mice.

Effect of different administration and dosage of dexmedetomidine in the reduction of emergence agitation in children: a meta-analysis of randomized controlled trials with sequential trial analysis.

BACKGROUND: Beneficial effects of dexmedetomidine (DEX) against emergence agitation (EA) in children remain controversial. We performed a more comprehensive meta-analysis to evaluate the protective effect of different administration routes, timing, patterns, and doses of DEX on EA in children. METHODS: The randomized controlled trials about DEX preventing EA in children were searched in PubMed, Cochrane Library, Embase, and Web of Sciences up to October 7, 2020. The traditional meta-analysis and subgroup analysis were performed to study the influence of DEX on EA in children. The sequential trial analysis (TSA) further analyzed the pooled results to evaluate meta-analyses' robustness. Grading of recommendation, assessment, development, and evaluation (GRADE) was used to assess evidence quality. RESULTS: Sixty-seven studies with 5,688 pediatric patients were included. DEX significantly decreased EA in children compared to placebo [RR 0.29, 95% confidence intervals (CI): 0.25-0.34] and midazolam (RR 0.34, 95% CI: 0.25-0.45), with firm evidence from TSA. Notably, using DEX significantly reduced severe EA incidence (RR 0.23, 95% CI: 0.16-0.32), with firm evidence by TSA and high quality of GRADE. Pre-specified subgroup analyses revealed firm and high-quality evidence for a reduction of EA, only if the perineural route administers DEX (RR 0.24, 95% CI: 0.14-0.41), as premedication (RR 0.27, 95% CI: 0.20-0.36), as continuous dosage (RR 0.25, 95% CI: 0.18-0.33), at high dose (RR 0.24, 95% CI: 0.18-0.31). The pooled results also showed that DEX reduced the incidence of PONV compared to placebo (RR 0.43, 95% CI: 0.33-0.55). Evidence for DEX's influence on other secondary outcomes (emergence time, time in PACU, rescue analgesia, hypotension, and bradycardia) is insufficient to draw any conclusion. CONCLUSIONS: Our findings confirm the beneficial effects of DEX on EA, severe EA, and PONV in children. There was firm and high-quality evidence for the efficacy of DEX in preventing EA in children when perineural routes administered DEX, as premedication, as continuous dosage, and at a high dose. The best dose, route, patterns, and timing of DEX and influence on other outcomes call for further studies.

Mechanisms of Adiponectin in Regulation of Proinflammatory Cytokine Production and Migration in Macrophages.

INTRODUCTION: Evidence indicate that adiponectin may exert pro-inflammatory effects on inflammatory cells. We have found that adiponectin knockout decreased inflammatory reaction and tubular damage in the ischemia-reperfusion kidney in APN-knockout mice. Globular adiponectin and full-length adiponectin (g-APN and f-APN) were used in this study to investigate the effects of adiponectin on proinflammatory cytokines production and migration in Raw 264.7 cells. METHODS: Proinflammatory cytokines production was detected by real-time RT-PCR. NF-kappaB activation was interrupted through Ad-DN-IκBα or SN-50 to confirm how g-APN induces proinflammatory cytokines production. The siRNA against AdipoR1 and AdipoR2 was investigated to uncover the signaling pathway that may involve in NF-kappaB activation and migration in Raw 264.7 cells. RESULTS: g-APN, not f-APN, was found triggering the production of inflammatory cytokine MIP-2, IL-6, TNFα, and MCP-1 in Raw 264.7 cells. NF-kappaB Inhibition by Ad-DN-IκBα expression or cell-permeable NF-κB inhibitor SN-50 could decrease NF-kappaB nuclear translocation and subsequently decrease inflammatory cytokine expression triggered by globular ANP. However, AdipoR1 and AdipoR2 were not found involved in NF-kappaB activation in this study. Full-length APN, not g-APN, was involved in the promotion of macrophage migration. The migration induced by full-length APN could be inhibited by knockdown of AdipoR1 expression with siRNA. The migration effect could also be inhibited by PI3Kγ inhibitor, AS-605240. DISCUSSION: These results suggested that full-length adiponectin increases macrophage migration through Adiponectin-AdipoR1-PI3Kgamma signaling pathway. However, NF-κB activation induced by g-APN in this study was independent of AdipoR1 or AdipoR2. The exact signaling pathway of NF-κB activation by adiponectin should be further studied to find a new anti-inflammatory target.

AMP-activated protein kinase contributes to cisplatin-induced renal epithelial cell apoptosis and acute kidney injury.

Cisplatin, a commonly used anticancer drug, has been shown to induce acute kidney injury, which limits its clinical use in cancer treatment. Emerging evidence has suggested that AMP-activated protein kinase (AMPK), which functions as a cellular energy sensor, is activated by various cellular stresses that deplete cellular ATP. However, the potential role of AMPK in cisplatin-induced apoptosis of renal tubular epithelial cells has not been studied. In this study, we demonstrated that cisplatin activates AMPK (Thr172 phosphorylation) in cultured renal tubular epithelial cells in a time-dependent manner, which was associated with p53 phosphorylation. Compound C, a selective AMPK inhibitor, suppressed cisplatin-induced AMPK activation, p53 phosphorylation, Bax induction, and caspase 3 activation. Furthermore, silencing AMPK expression by siRNA attenuated cisplatin-induced p53 phosphorylation, Bax induction, and caspase 3 activation. In a mouse model of cisplatin-induced kidney injury, compound C inhibited p53 phosphorylation, Bax expression, caspase 3 activation, and apoptosis, protecting the kidney from injury and dysfunction. Taken together, these results suggest that the AMPK-p53-Bax signaling pathway plays a crucial role in cisplatin-induced tubular epithelial cell apoptosis.

Disruption of CXCR6 Ameliorates Kidney Inflammation and Fibrosis in Deoxycorticosterone Acetate/Salt Hypertension.

Circulating cells have a pathogenic role in the development of hypertensive nephropathy. However, how these cells infiltrate into the kidney are not fully elucidated. In this study, we investigated the role of CXCR6 in deoxycorticosterone acetate (DOCA)/salt-induced inflammation and fibrosis of the kidney. Following uninephrectomy, wild-type and CXCR6 knockout mice were treated with DOCA/salt for 3 weeks. Blood pressure was similar between wild-type and CXCR6 knockout mice at baseline and after treatment with DOCA/salt. Wild-type mice develop significant kidney injury, proteinuria, and kidney fibrosis after three weeks of DOCA/salt treatment. CXCR6 deficiency ameliorated kidney injury, proteinuria, and kidney fibrosis following treatment with DOCA/salt. Moreover, CXCR6 deficiency inhibited accumulation of bone marrow-derived fibroblasts and myofibroblasts in the kidney following treatment with DOCA/salt. Furthermore, CXCR6 deficiency markedly reduced the number of macrophages and T cells in the kidney after DOCA/salt treatment. In summary, our results identify a critical role of CXCR6 in the development of inflammation and fibrosis of the kidney in salt-sensitive hypertension.

TAK1 deficiency attenuates cisplatin-induced acute kidney injury.

Cisplatin can cause acute kidney injury (AKI), but the molecular mechanisms are not well understood. The objective of the present study was to examine the role of transforming growth factor-ß-activated kinase-1 (TAK1) in the pathogenesis of cisplatin-induced AKI. Wild-type mice and proximal tubule TAK1-deficient mice were treated with vehicle or cisplatin. Compared with wild-type control mice, proximal tubule TAK1-deficient mice had less severe kidney dysfunction, tubular damage, and apoptosis after cisplatin-induced AKI. Furthermore, conditional disruption of TAK1 in proximal tubular epithelial cells reduced caspase-3 activation, proinflammatory molecule expression, and JNK phosphorylation in the kidney in cisplatin-induced AKI. Taken together, cisplatin activates TAK1-JNK signaling pathway to promote tubular epithelial cell apoptosis and inflammation in cisplatin-induced AKI. Targeting TAK1 could be a novel therapeutic strategy against cisplatin-induced AKI.

Endogenous nitric oxide inhibits spinal NMDA receptor activity and pain hypersensitivity induced by nerve injury.

The role of nitric oxide (NO) in nociceptive transmission at the spinal cord level remains uncertain. Increased activity of spinal N-methyl-d-aspartate (NMDA) receptors contributes to development of chronic pain induced by peripheral nerve injury. In this study, we determined how endogenous NO affects NMDA receptor activity of spinal cord dorsal horn neurons in control and spinal nerve-ligated rats. Bath application of the NO precursor l-arginine or the NO donor S-nitroso-N-acetylpenicillamine (SNAP) significantly inhibited NMDA receptor currents of spinal dorsal horn neurons in both sham control and nerve-injured rats. Inhibition of neuronal nitric oxide synthase (nNOS) or blocking the S-nitrosylation reaction with N-ethylmaleimide abolished the inhibitory effects of l-arginine on NMDA receptor currents recorded from spinal dorsal horn neurons in sham control and nerve-injured rats. However, bath application of the cGMP analog 8-bromo-cGMP had no significant effects on spinal NMDA receptor currents. Inhibition of soluble guanylyl cyclase also did not alter the inhibitory effect of l-arginine on spinal NMDA receptor activity. Furthermore, knockdown of nNOS with siRNA abolished the inhibitory effects of l-arginine, but not SNAP, on spinal NMDA receptor activity in both groups of rats. Additionally, intrathecal injection of l-arginine significantly attenuated mechanical or thermal hyperalgesia induced by nerve injury, and the l-arginine effect was diminished in rats treated with a nNOS inhibitor or nNOS-specific siRNA. These findings suggest that endogenous NO inhibits spinal NMDA receptor activity through S-nitrosylation. NO derived from nNOS attenuates spinal nociceptive transmission and neuropathic pain induced by nerve injury.

CXCL16 regulates renal injury and fibrosis in experimental renal artery stenosis.

Recent studies have shown that inflammation plays a critical role in the initiation and progression of hypertensive kidney disease, including renal artery stenosis. However, the signaling mechanisms underlying the induction of inflammation are poorly understood. We found that CXCL16 was induced in the kidney in a murine model of renal artery stenosis. To determine whether CXCL16 is involved in renal injury and fibrosis, wild-type and CXCL16 knockout mice were subjected to renal artery stenosis induced by placing a cuff on the left renal artery. Wild-type and CXCL16 knockout mice had comparable blood pressure at baseline. Renal artery stenosis caused an increase in blood pressure that was similar between wild-type and CXCL16 knockout mice. CXCL16 knockout mice were protected from RAS-induced renal injury and fibrosis. CXCL16 deficiency suppressed bone marrow-derived fibroblast accumulation and myofibroblast formation in the stenotic kidneys, which was associated with less expression of extracellular matrix proteins. Furthermore, CXCL16 deficiency inhibited infiltration of F4/80(+) macrophages and CD3(+) T cells in the stenotic kidneys compared with those of wild-type mice. Taken together, our results indicate that CXCL16 plays a pivotal role in the pathogenesis of renal artery stenosis-induced renal injury and fibrosis through regulation of bone marrow-derived fibroblast accumulation and macrophage and T-cell infiltration.

CXCR6 plays a critical role in angiotensin II-induced renal injury and fibrosis.

OBJECTIVE: Recent studies have shown that angiotensin II (Ang II) plays a critical role in the pathogenesis and progression of hypertensive kidney disease. However, the signaling mechanisms are poorly understood. In this study, we investigated the role of CXCR6 in Ang II-induced renal injury and fibrosis. APPROACH AND RESULTS: Wild-type and CXCR6-green fluorescent protein (GFP) knockin mice were treated with Ang II via subcutaneous osmotic minipumps at 1500 ng/kg per minute after unilateral nephrectomy for ≤ 4 weeks. Wild-type and CXCR6-GFP knockin mice had virtually identical blood pressure at baseline. Ang II treatment led to an increase in blood pressure that was similar between wild-type and CXCR6-GFP knockin mice. CXCR6-GFP knockin mice were protected from Ang II-induced renal dysfunction, proteinuria, and fibrosis. CXCR6-GFP knockin mice accumulated fewer bone marrow-derived fibroblasts and myofibroblasts and produced less extracellular matrix protein in the kidneys after Ang II treatment. Furthermore, CXCR6-GFP knockin mice exhibited fewer F4/80(+) macrophages and CD3(+) T cells and expressed less proinflammatory cytokines in the kidneys after Ang II treatment. Finally, wild-type mice engrafted with CXCR6(-/-) bone marrow cells displayed fewer bone marrow-derived fibroblasts, macrophages, and T cells in the kidney after Ang II treatment when compared with wild-type mice engrafted with CXCR6(+/+) bone marrow cells. CONCLUSIONS: Our results indicate that CXCR6 plays a pivotal role in the development of Ang II-induced renal injury and fibrosis through regulation of macrophage and T-cell infiltration and bone marrow-derived fibroblast accumulation.

The chemokine receptor CXCR6 contributes to recruitment of bone marrow-derived fibroblast precursors in renal fibrosis.

Bone marrow-derived fibroblasts in circulation are of hematopoietic origin, and they proliferate, differentiate into myofibroblasts, and express the chemokine receptor CXCR6. As chemokines mediate the trafficking of circulating cells to sites of injury, we studied the role of CXCR6 in mouse models of renal injury. Significantly, the kidney of CXCR6 knockout mice accumulated fewer bone marrow-derived fibroblasts in response to injury, expressed less profibrotic chemokines and cytokines, displayed fewer myofibroblasts, and expressed less α-smooth muscle actin in the obstructed kidneys compared with wild-type (WT) mice. CXCR6 deficiency inhibited total collagen deposition and suppressed the expression of collagen I and fibronectin in the obstructed kidneys. Furthermore, WT mice engrafted with CXCR6(-/-) bone marrow cells displayed fewer bone marrow-derived fibroblasts in the kidneys with obstructive injury and showed less severe renal fibrosis compared with WT mice engrafted with CXCR6(+/+) bone marrow cells. Transplant of WT bone marrow into CXCR6(-/-) recipients restored recruitment of myeloid fibroblasts and susceptibility to fibrosis. Hematopoietic fibroblasts migrate into injured kidney and proliferate and differentiate into myofibroblasts. Thus, CXCR6, together with other chemokines and their receptors, may have important roles in the recruitment of bone marrow-derived fibroblast precursors into the kidney and contribute to the pathogenesis of renal fibrosis.

Genetic deficiency of adiponectin protects against acute kidney injury.

Adiponectin is a multifunctional cytokine that has a role in regulating inflammation. Here we determined whether adiponectin modulates ischemic acute kidney injury. Compared with wild-type mice, adiponectin-knockout mice were found to have lower serum creatinine and less tubular damage or apoptosis following ischemia/reperfusion injury. This latter process was associated with decreased Bax and reduced activation of p53 and caspase-3. Targeted disruption of adiponectin was also found to inhibit the infiltration of neutrophils, macrophages, and T cells into the injured kidneys. This was associated with inhibition of NF-κB activation and reduced expression of the proinflammatory molecules IL-6, TNF-α, MCP-1, and MIP-2 in the kidney after ischemia/reperfusion injury. Wild-type mice engrafted with adiponectin-null bone marrow had less kidney dysfunction and tubular damage than adiponectin-null mice engrafted with wild-type bone marrow. Conversely, adiponectin-null mice engrafted with wild-type bone marrow had similar renal dysfunction and tubular damage compared with wild-type mice engrafted with wild-type bone marrow. In cultured macrophages, adiponectin directly promoted macrophage migration: a process blocked by the PI3 kinase inhibitor, LY294002. Thus, our results show that adiponectin has a pivotal role in the pathogenesis of acute renal ischemia/reperfusion injury and may be a potential therapeutic target.

Isoflurane enhances the expression of cytochrome C by facilitation of NMDA receptor in developing rat hippocampal neurons in vitro.

This study examined the effects of clinically relevant concentrations of isoflurane on the amplitude of NMDA receptor current (I(NMDA)) and the expression of cytochrome C in cultured developing rat hippocampal neurons. The hippocampi were dissected from newborn Sprague-Dawley rats. Hippocampal neurons were primarily cultured for 5 days and then treated with different concentrations of isoflurane [(0.25, 0.5, 0.75, 1 minimum alveolar concentration (MAC))]. The peak of I(NMDA) was recorded by means of the whole cell patch clamp technique. The cytochrome C level was detected by Western blotting and quantitative real-time PCR. Our results showed that isoflurane (0.25, 0.5, 0.75 and 1 MAC) potentiated the amplitude of I(NMDA) by (116 ± 8.8)%, (122 ± 11.7)%, (135 ± 14.3)% and (132 ± 14.6)%, respectively, and isoflurane increased the mRNA expression of cytochrome C in a concentration-dependent manner. The cytochrome C mRNA expression reached a maximum after 0.5 MAC isoflurane stimulation for 6 h (P<0.05). It was concluded that isoflurane enhances the expression of cytochrome C in cultured rat hippocampal neurons, which may be mediated by facilitation of NMDA receptor.