The RhoGEF TEM4 Regulates Endothelial Cell Migration by Suppressing Actomyosin Contractility.

Persistent cellular migration requires efficient protrusion of the front of the cell, the leading edge where the actin cytoskeleton and cell-substrate adhesions undergo constant rearrangement. Rho family GTPases are essential regulators of the actin cytoskeleton and cell adhesion dynamics. Here, we examined the role of the RhoGEF TEM4, an activator of Rho family GTPases, in regulating cellular migration of endothelial cells.

Ischemic preconditioning of rat livers from non-heart-beating donors decreases parenchymal cell killing and increases graft survival after transplantation.

A critical shortage of donors exists for liver transplantation, which non-heart-beating cadaver donors could help ease. This study evaluated ischemic preconditioning to improve graft viability after non-heart-beating liver donation in rats. Ischemic preconditioning was performed by clamping the portal vein and hepatic artery for 10 min followed by unclamping for 5 min.

Icam-1 upregulation in ethanol-induced Fatty murine livers promotes injury and sinusoidal leukocyte adherence after transplantation.

Background. Transplantation of ethanol-induced steatotic livers causes increased graft injury. We hypothesized that upregulation of hepatic ICAM-1 after ethanol produces increased leukocyte adherence, resulting in increased generation of reactive oxygen species (ROS) and injury after liver transplantation (LT).

NIM811 prevents mitochondrial dysfunction, attenuates liver injury, and stimulates liver regeneration after massive hepatectomy.

Background: Massive hepatectomy (MHX) leads to failure of remnant livers. Excessive metabolic burden in remnant livers may cause mitochondrial dysfunction. This study investigated whether blockade of the mitochondrial permeability transition (MPT) with N-methyl-4-isoleucine cyclosporine (NIM811) improves the outcome of MHX.

Roles of mitophagy and the mitochondrial permeability transition in remodeling of cultured rat hepatocytes.

In primary culture, hepatocytes dedifferentiate, and their cytoplasm undergoes remodeling. Here, our aim was to characterize changes of mitochondria during remodeling. Hepatocytes were cultured one to five days in complete serumcontaining Waymouth's medium.

NIM811 (N-methyl-4-isoleucine cyclosporine), a mitochondrial permeability transition inhibitor, attenuates cholestatic liver injury but not fibrosis in mice.

Cholestasis causes hepatocyte death, possibly because of mitochondrial injury. This study investigated whether NIM811 (N-methyl-4-isoleucine cyclosporine), an inhibitor of the mitochondrial permeability transition (MPT), attenuates cholestatic liver injury in vivo. Cholestasis was induced in mice by bile duct ligation (BDL).

Activation of the oxygen-sensing signal cascade prevents mitochondrial injury after mouse liver ischemia-reperfusion.

The mitochondrial permeability transition (MPT) plays an important role in hepatocyte death caused by ischemia-reperfusion (IR). This study investigated whether activation of the cellular oxygen-sensing signal cascade by prolyl hydroxylase inhibitors (PHI) protects against the MPT after hepatic IR. Ethyl 3,4-dihyroxybenzoate (EDHB, 100 mg/kg ip), a PHI, increased mouse hepatic hypoxia-inducible factor-1alpha and heme oxygenase-1 (HO-1).

Minocycline and N-methyl-4-isoleucine cyclosporin (NIM811) mitigate storage/reperfusion injury after rat liver transplantation through suppression of the mitochondrial permeability transition.

Unlabelled: Graft failure after liver transplantation may involve mitochondrial dysfunction. We examined whether prevention of mitochondrial injury would improve graft function. Orthotopic rat liver transplantation was performed after 18 hours' cold storage in University of Wisconsin solution and treatment with vehicle, minocycline, tetracycline, or N-methyl-4-isoleucine cyclosporin (NIM811) of explants and recipients.

NIM811, a mitochondrial permeability transition inhibitor, prevents mitochondrial depolarization in small-for-size rat liver grafts.

ATP decreases markedly in small-for-size liver grafts. This study tested if the mitochondrial permeability transition (MPT) underlies dysfunction of small-for-size livers. Half-size livers were implanted into recipients of about twice the donor weight, resulting in quarter-size liver grafts.

Endothelial nitric oxide synthase protects transplanted mouse livers against storage/reperfusion injury: Role of vasodilatory and innate immunity pathways.

Endothelial nitric oxide synthase (eNOS) plays a role in microcirculatory and immunomodulatory responses after warm ischemia/reperfusion. We hypothesized that eNOS is essential to maintain microcirculation, attenuate macrophage infiltration and decrease graft injury after liver transplantation. Liver transplantation was performed after 18 hours of cold storage in University of Wisconsin (UW) solution from wildtype and eNOS-deficient (B6.

Tracker dyes to probe mitochondrial autophagy (mitophagy) in rat hepatocytes.

Mitochondria become targets for autophagic degradation after nutrient deprivation, a process also termed mitophagy. In this study, we used LysoTracker Red (LTR) and MitoTracker Green to characterize the kinetics of autophagosomal proliferation and mitophagy in cultured rat hepatocytes. Autophagy induced by nutrient deprivation plus glucagon increased LTR uptake assessed with a fluorescence plate reader and the number of LTR-labeled acidic organelles assessed with confocal microscopy in individual hepatocytes both by 4- to 6-fold.

Role of pH in protection by low sodium against hypoxic injury in isolated perfused rat livers.

Background/aims: The purpose of the present study was to characterize the role of Na+, pH and cellular swelling in the pathogenesis of hypoxic injury to rat livers.

Methods And Results: When livers were perfused with hypoxic Krebs-Henseleit bicarbonate buffer (KHB) containing 143 mM Na+, release of LDH began after 30 min and was maximal after 60 min. In livers perfused with choline-substituted low-Na+ KHB (25 mM Na+), LDH release began after 60 min and peaked after 120 min or longer.

c-Jun N-terminal kinase mediates hepatic injury after rat liver transplantation.

Background: Orthotopic liver transplantation (OLT) requires cold ischemic storage followed by warm reperfusion. Although c-Jun N-terminal kinase (JNK) is rapidly activated after OLT, the functional consequences of JNK activation are unknown. The aim of this study was to address the role of JNK after OLT using the selective JNK inhibitor CC-401.

Different patterns of renal cell killing after warm and cold ischemia.

Kidneys preserved for transplantation surgery sustain injuries caused by cold ischemia during storage. Additionally, kidneys harvested from non-heart-beating donors encounter the stress of warm ischemia. The aim of this study was to determine the specific cell types losing viability after warm and cold ischemia.

Carolina rinse solution minimizes kidney injury and improves graft function and survival after prolonged cold ischemia.

Background: Kidney damage caused by cold ischemia-reperfusion injury promotes adverse outcomes after renal transplantation. The purpose of this study was to determine whether Carolina rinse solution (CRS) used at the end of cold ischemic storage decreases kidney injury and improves graft function and survival.

Methods: Inbred male Lewis rats were used as donors and recipients.

Alteration in Kupffer cell function after mild hemorrhagic shock.

Functional changes in Kupffer cells occur after profound hemorrhagic shock. This study was performed to demonstrate if Kupffer cell changes also occur after mild hemorrhagic shock. Sprague-Dawley rats were bled to a systolic blood pressure of 60 to 70 mmHg and resuscitated with Lactated Ringers solution (twice the shed blood volume) after 30 min.

Kupffer cells mediate increased anoxic hepatocellular killing from hyperosmolarity by an oxygen- and prostaglandin-independent mechanism.

The purpose of this study was to evaluate the roles of Kupffer cells, prostaglandin biosynthesis, and glycolytic metabolism in accelerated anoxic cell killing by hyperosmolar stress. Isolated rat livers were perfused with anoxic normosmolar Krebs-Heinseleit bicarbonate buffer (KHB) or anoxic hyperosmolar KHB (+40 mM NaCl). Hyperosmolar KHB accelerated LDH release during anoxia in livers from both fed and fasted rats by as much as 3.

Protection of sinusoidal endothelial cells against storage/reperfusion injury by prostaglandin E2 derived from Kupffer cells.

Background: In clinical liver transplants, grafts are frequently exposed to endotoxin (lipopolysaccharide, LPS) before harvest and may be predisposed to dysfunction. Because graft failure is linked to sinusoidal endothelial cell injury after storage/reperfusion, we investigated the effect of donor exposure to LPS on graft survival in relation to sinusoidal endothelial cell injury after storage/reperfusion in rats.

Methods: Rats were injected with 0.

Protection by Carolina rinse solution, acidotic pH, and glycine against lethal reperfusion injury to sinusoidal endothelial cells of rat livers stored for transplantation.

The critical injury causing graft failure after prolonged liver storage involves reperfusion-induced killing of sinusoidal endothelial cells and activation of Kupffer cells. Treatment of stored livers with Carolina rinse solution (CRS) prevents endothelial cell killing, reduces Kupffer cell activation, and improves graft survival. Accordingly, our aim was to evaluate the components of CRS and other agents for protection against reperfusion injury to rat livers stored 24 hr in University of Wisconsin solution.

Protection by pentoxifylline against normothermic liver ischemia/reperfusion in rats.

Previously, pentoxifylline treatment of graft recipients was shown to protect against liver graft failure from storage/reperfusion injury after orthotopic rat liver transplantation. To determine whether pentoxifylline also protects against normothermic ischemia/reperfusion injury to liver, we induced lobar ischemia in rats followed by reflow and partial hepatectomy of the noninvolved liver. In rats receiving pentoxifylline 2 hr before surgery and then twice daily for 5 days, the 1-week survival rate more than doubled from 25% to 67% (P < 0.

Dual role of Kupffer cell activation and endothelial cell damage in reperfusion injury to livers stored for transplantation surgery.

In rat models of liver preservation, the primary event leading to liver graft failure after cold storage is a reperfusion injury causing damage to sinusoidal endothelial cells and activation of Kupffer cells (KC). After storage for longer than 16 h in University of Wisconsin solution, reperfusion induces rapid endothelial cell killing. Kupffer cell activation also occurs as indicated by cell surface ruffling, degranulation, release of hydrolytic enzymes, generation of oxygen radicals, and increased phagocytosis.

Reperfusion injury to endothelial cells after cold storage of rat livers: protection by mildly acidic pH and lack of protection by antioxidants.

Lethal reperfusion injury to sinusoidal endothelial cells occurs after cold ischemic storage of livers and may be responsible for liver graft failure from storage injury. Here, we evaluated potential mechanisms underlying this reperfusion injury. In rat livers stored in Euro-Collins solution for 24 h and reperfused with Krebs-Henseleit bicarbonate buffer, nonparenchymal cell killing showed periportal predominance as assessed by nuclear staining with trypan blue.

Activation of Kupffer cells in vivo following femur fracture.

Objective: To test the hypothesis that Kupffer cells are activated after blunt femur fracture leading to altered hepatic oxygen (O2) consumption.

Design: Prospective randomized experimental trials.

Setting: Laboratory.