HSV vector-mediated GAD67 suppresses neuropathic pain induced by perineural HIV gp120 in rats through inhibition of ROS and Wnt5a.

Human immunodeficiency virus (HIV)-related neuropathic pain is a debilitating chronic condition that is severe and unrelenting. Despite the extensive research, the exact neuropathological mechanisms remain unknown, which hinders our ability to develop effective treatments. Loss of GABAergic tone may have an important role in the neuropathic pain state. Glutamic acid decarboxylase 67 (GAD67) is one of the isoforms that catalyze GABA synthesis. Here, we used recombinant herpes simplex virus (HSV-1) vectors that encode gad1 gene to evaluate the therapeutic potential of GAD67 in peripheral HIV gp120-induced neuropathic pain in rats. We found that (1) subcutaneous inoculation of the HSV vectors expressing GAD67 attenuated mechanical allodynia in the model of HIV gp120-induced neuropathic pain, (2) the anti-allodynic effect of GAD67 was reduced by GABA-A and-B receptors antagonists, (3) HSV vectors expressing GAD67 reversed the lowered GABA-IR expression and (4) the HSV vectors expressing GAD67 suppressed the upregulated mitochondrial superoxide and Wnt5a in the spinal dorsal horn. Taken together, our studies support the concept that recovering GABAergic tone by the HSV vectors may reverse HIV-associated neuropathic pain through suppressing mitochondrial superoxide and Wnt5a. Our studies provide validation of HSV-mediated GAD67 gene therapy in the treatment of HIV-related neuropathic pain.

HSV-mediated p55TNFSR reduces neuropathic pain induced by HIV gp120 in rats through CXCR4 activity.

Human immunodeficiency virus (HIV)-related neuropathic pain is a debilitating chronic condition that is severe and unrelenting. Despite extensive research, the detailed neuropathological mechanisms remain unknown, which hinders our ability to develop effective treatments. In this study, we investigated the role of proinflammatory molecules, tumor necrosis factor-α (TNFα), CXCR4 and stromal-derived factor-1 α (SDF1α), in the L4/5 dorsal root ganglia (DRG) and the spinal dorsal horn in HIV gp120 protein-mediated neuropathic pain. Our results showed that the application of HIV gp120 to the sciatic nerve induced upregulation of TNFα, CXCR4 and SDF1α in both the DRG and the lumbar spinal dorsal horn. Non-replicating herpes simplex virus (HSV) vector encoding the p55TNFSR gene and producing a TNF-soluble receptor (TNFSR) to block bioactivity of TNFα reversed mechanical allodynia. Intrathecal AMD3100 (CXCR4 antagonist) increased mechanical threshold. The HSV vectors expressing p55TNFSR reversed upregulation of TNFα, CXCR4 and SDF1α induced by gp120 in the DRG and the spinal dorsal horn. These studies suggest that proinflammatory TNFα to the CXCR4/SDF1 pathway has an important role in the HIV-related neuropathic pain state and that blocking the proinflammatory cytokines or chemokines is able to reduce neuropathic pain. This work provides a novel gene therapy proof-of-concept for HIV-associated neuropathic pain.

The effect of octreotide on hepatic ischemia-reperfusion injury in a rabbit model.

BACKGROUND: Hepatic ischemic-reperfusion injury (HIRI) is a major cause of morbidity and mortality following liver surgery. Octreotide (Oct) has been reported to improve hepatocellular energy metabolism in a rat HIRI model. This study was designed to evaluate whether Oct could protect the liver of rabbits against ischemic-reperfusion (I/R) injury. METHODS: Twenty-four adult New Zealand rabbits were randomly divided into a sham operated group (Control), an ischemia/reperfusion group (I/R), and an ischemia/reperfusion + Oct pretreatment group (I/R + Oct). The hemodynamic (mean arterial pressure [MAP] and heart rate [HR]) changes, liver enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], and lactate dehydrogenase [LDH]) release, inflammatory cytokines (tumor necrosis factor [TNF]α and interleukin [IL]-1ß) levels, and endotoxin (ETX) levels were measured during I/R. RESULTS: Compared with the Control group, the MAP decreased and HR increased in I/R and I/R + Oct groups at ischemia 15 minutes (P < .05) but were less in the I/R + Oct group relative to the I/R group (P < .05). ALT, AST, LDH, IL-1ß, and ETX levels were increased in the I/R and I/R + Oct groups at ischemia 30 minutes (P < .05), however, the increase was lower in the I/R + Oct group relative to the I/R group (P < .05). Bcl-2 expression in the I/R + Oct group was higher compared with other groups (P < .05) and Bax expression in the I/R group was reduced compared with other groups (P < .05). Hepatocellular damage in the I/R + Oct group appeared to be less than in the I/R group by microscopy. CONCLUSIONS: Oct pretreatment attenuated hemodynamic changes and decreased liver enzyme changes induced by HIRI in a rabbit model. The protection mechanisms of Oct may be related to reduced ETX levels, down-regulation of the inflammatory cytokines TNFα and IL-1ß, and inhibition of hepatocellular apoptosis, as well as the modulation of the mitochondrion-mediated Bcl-2/Bax apoptosis pathway. Based on our study it appears that Oct may be useful in decreasing liver injury after liver surgery and/or transplantation and may serve as a promising agent against HIRI.

Adverse neurologic reactions to the sting of the imported fire ant.

While the cutaneous manifestations of the imported fire ant (IFA) sting are well known, neurologic sequelae are much more unusual. We report 2 cases of grand mal seizures associated with the sting of the IFA. The first patient suffered numerous stings without evidence of systemic reactions prior to the onset of the seizure. The second patient had manifestations of anaphylaxis prior to the occurrence of seizure. In both cases, the onset of seizures was delayed. As the geographic range of the IFA increases and more patients are stung, unusual reactions will be seen in greater frequency.