Use of FTY 720 and ICAM-1 antisense oligonucleotides for attenuating chronic renal damage secondary to ischemia-reperfusion injury

Magnesium isoglycyrrhizinate protects against renal‑ischemia‑reperfusion injury in a rat model via anti‑inflammation, anti‑oxidation and anti‑apoptosis

The present study aimed to investigate whether magnesium isoglycyrrhizinate protects against renal ischemia‑reperfusion injury (RIRI), and to verify the underlying mechanisms. An RIRI rat model was induced by removing the right kidney, and exposing and clamping the left kidney. RIRI model rats were administered 30 mg/kg magnesium isoglycyrrhizinate for 3 days. Blood urea nitrogen (BUN) and serum creatinine levels in the blood of RIRI model rat were examined, compared with sham‑operated controls. Magnesium isoglycyrrhizinate suppressed the activities of tumor necrosis factor‑α, interleukin (IL)‑1β, IL‑6, superoxide dismutase, glutathione peroxidase, inducible nitric oxide synthase (iNOS) and caspase‑3 in RIRI model rats. Renal iNOS, matrix metalloproteinase (MMP)‑2, phosphorylated‑signal transducers and activators of transcription 3 (STAT3) and intercellular adhesion molecule‑1 (ICAM‑1) protein expression levels were suppressed by magnesium isoglycyrrhizinate treatment in RIRI model rats. These findings suggested that magnesium isoglycyrrhizinate protects RIRI via anti‑inflammatory, ‑oxidative and ‑apoptotic mechanisms in an RIRI rat model. These results implicate magnesium isoglycyrrhizinate pretreatment as a potential approach to protect against RIRI via suppression of the iNOS, ICAM‑1, MMP‑2 and STAT3 signaling pathways.

Cysteinyl leukotriene receptor antagonism alleviates renal injury induced by ischemia-reperfusion in rats

BACKGROUND

Renal inflammation has an important role in the development of ischemia-reperfusion injury of the kidney. Cysteinyl leukotrienes have been implicated in many inflammatory conditions. The aim of this study was to investigate the ability of the cysteinyl leukotriene receptor blocker, zafirlukast, to alleviate renal dysfunction and injury in a rat model of renal ischemia-reperfusion injury.

METHODS

We induced renal ischemia for 45 min, followed by 24 h reperfusion. We gave zafirlukast at a dose of 20 mg/kg/d for 3 d before ischemia-reperfusion. At the end of the reperfusion (24 h), we collected blood samples to measure blood urea nitrogen, creatinine, tumor necrosis factor-α, intercellular adhesion molecule-1, and nitrite/nitrate. We took kidney samples for histological and immunohistochemical assessment, and to measure malondialdehyde, glutathione content, and myeloperoxidase activity.

RESULTS

Induction of renal ischemia-reperfusion resulted into renal dysfunction, as indicated by elevated levels of blood urea nitrogen and serum creatinine, serum nitrite and nitrate, serum tumor necrosis factor-α, and intercellular adhesion molecule-1. An oxidative stress marker, renal malondialdehyde concentration, was increased, whereas renal reduced glutathione content was decreased. Myeloperoxidase activity, suggestive of neutrophil infiltration, was elevated in renal tissues. Histological changes confirmed these biochemical changes, as did P-selectin overexpression in renal tissues subjected to ischemia-reperfusion. Administration of zafirlukast before ischemia-reperfusion improved renal functions and reduced serum levels of nitrite and nitrate, tumor necrosis factor-α, and intercellular adhesion molecule-1, renal concentration of myeloperoxidase activity, and malondialdehyde concentration, whereas increased renal reduced glutathione concentration. Moreover, zafirlukast reduced histopathological features of tubular injury and P-selectin overexpression in both cortex and medulla.

CONCLUSIONS

These results demonstrate that zafirlukast significantly reduces the severity of ischemic acute renal failure, probably via anti-inflammatory action, reduction of neutrophil infiltration into renal tissues, and oxidative stress subsequent to an attenuation of P-selectin expression.

The influence of sphingosine-1-phosphate receptor signaling on lymphocyte trafficking: how a bioactive lipid mediator grew up from an "immature" vascular maturation factor to a "mature" mediator of lymphocyte behavior and function

Since the initial observations that highlighted the importance of lymphocyte trafficking for immune responses, the pathways utilized by B and T lymphocytes to recirculate and properly position themselves have been intensely studied. Most of the chemoattractants along with their cognate receptors that affect lymphocyte trafficking have been identified. Some of their functions are promotion of lymphocyte ingress into immune organs, localization of cells to specific regions within those organs, maintenance of lymphocyte basal motility in immune organs, facilitation of lymphocyte egress from these organs, and control of migration and homing of lymphocytes in the periphery. Since the seminal discovery that agonism of sphingosine-1-phosphate receptors evokes changes in lymphocyte homing and trafficking, considerable effort has been undertaken to characterize the mechanism utilized by these receptors to influence lymphocyte behavior. This review will focus on the influence of sphingosine-1-phosphate signaling system on lymphocyte localization, egress from lymph organs, and its effects on the lymphatic vasculature.

Protective effect of an inhibitor of interleukin-8 (meraxin) from ischemia and reperfusion injury in a rat model of kidney transplantation

INTRODUCTION

Since the ischemia and reperfusion injury is one of the main causes of delayed graft function after transplantation, research efforts have focused on studying the molecules involved in this inflammatory process. The chemokine interleukin-8 (IL-8) seems to be the main one responsible through a chemoattractive action toward neutropils. Therefore, one of the strategies adopted to prevent this process is blocking the binding between IL-8 and its receptors. The aim of our study was to test the effect of meraxin, a new derivative from repertaxin, to protect the renal graft from ischemia and reperfusion injury.

MATERIALS AND METHODS

Eighty male syngenic rats were divided into four groups. The control group underwent only kidney transplantation, while the other groups were treated with meraxin at various dosages 2 hours before graft reperfusion. Blood and histological samples were taken at sacrifice 24 hours after transplantation.

RESULTS

Creatinine was significantly lower in the group treated with the high dosage of meraxin. Histological observation of the grafted tissue showed instead only a mild and not significant neutrophilic infiltration, equal in each group.

CONCLUSIONS

Graft function was improved by the administration of meraxin at high dosage, but this effect did not seem to be connected to a reduction in inflammatory infiltration in the parechymal tissue. Maybe the cause is in the mechanisms of clotting activation, due to alteration of adhesion molecules and endothelial cells.

Inhibition of laminin-8 in vivo using a novel poly(malic acid)-based carrier reduces glioma angiogenesis

We have previously shown that laminin-8, a vascular basement membrane component, was overexpressed in human glioblastomas multiforme and their adjacent tissues compared to normal brain. Increased laminin-8 correlated with shorter glioblastoma recurrence time and poor patient survival making it a potential marker for glioblastoma diagnostics and prediction of disease outcome. However, laminin-8 therapeutic potential was unknown because the technology of blocking the expression of multi-chain complex proteins was not yet developed. To inhibit the expression of laminin-8 constituents in glioblastoma in vitro and in vivo, we used Polycefin, a bioconjugate drug delivery system based on slime-mold Physarum polycephalum-derived poly(malic acid). It carries an attached transferrin receptor antibody to target tumor cells and to deliver two conjugated morpholino antisense oligonucleotides against laminin-8 alpha4 and beta1 chains. Polycefin efficiently inhibited the expression of both laminin-8 chains by cultured glioblastoma cells. Intracranial Polycefin treatment of human U87MG glioblastoma-bearing nude rats reduced incorporation of both tumor-derived laminin-8 chains into vascular basement membranes. Polycefin was thus able to simultaneously inhibit the expression of two different chains of a complex protein. The treatment also significantly reduced tumor microvessel density (p < 0.001) and area (p < 0.001) and increased animal survival (p < 0.0004). These data suggest that laminin-8 may be important for glioblastoma angiogenesis. Polycefin, a versatile nanoscale drug delivery system, was suitable for in vivo delivery of two antisense oligonucleotides to brain tumor cells causing a reduction of glioblastoma angiogenesis and an increase of animal survival. This system may hold promise for future clinical applications.

Lysophospholipid receptors: signalling, pharmacology and regulation by lysophospholipid metabolism

The lysophospholipids, sphingosine-1-phosphate (S1P), lysophosphatidic acid (LPA), sphingosylphosphorylcholine (SPC) and lysophosphatidylcholine (LPC), activate diverse groups of G-protein-coupled receptors that are widely expressed and regulate decisive cellular functions. Receptors of the endothelial differentiation gene family are activated by S1P (S1P(1-5)) or LPA (LPA(1-3)); two more distantly related receptors are activated by LPA (LPA(4/5)); the GPR(3/6/12) receptors have a high constitutive activity but are further activated by S1P and/or SPC; and receptors of the OGR1 cluster (OGR1, GPR4, G2A, TDAG8) appear to be activated by SPC, LPC, psychosine and/or protons. G-protein-coupled lysophospholipid receptors regulate cellular Ca(2+) homoeostasis and the cytoskeleton, proliferation and survival, migration and adhesion. They have been implicated in development, regulation of the cardiovascular, immune and nervous systems, inflammation, arteriosclerosis and cancer. The availability of S1P and LPA at their G-protein-coupled receptors is regulated by enzymes that generate or metabolize these lysophospholipids, and localization plays an important role in this process. Besides FTY720, which is phosphorylated by sphingosine kinase-2 and then acts on four of the five S1P receptors of the endothelial differentiation gene family, other compounds have been identified that interact with more ore less selectivity with lysophospholipid receptors.