Kappa-opioid potentiation of tumor necrosis factor-alpha-induced anti-HIV-1 activity in acutely infected human brain cell cultures.

Opioids have been postulated to play an immunomodulatory role in the pathogenesis of HIV-1. Synthetic kappa-opioid receptor (KOR) ligands have been found to inhibit HIV-1 expression in acutely infected microglial cell cultures. We recently found that interleukin(IL)-1beta and tumor necrosis factor(TNF)-alpha have antiviral effects in acutely infected mixed glial/neuronal cell cultures. In the present study, we investigated whether selective KOR ligands would exert antiviral effects in acutely infected brain cell cultures. While the KOR ligand trans-3,4-dichloro-N-methyl-N[2-(1-pyrolidinyl)cyclohexyl]benze neaceamide methanesulfonate (U50,488) alone had little anti-HIV-1 activity, this opioid potentiated in a concentration-dependent manner the antiviral activity of TNF-alpha, but not of IL-1beta. The potentiating effect of U50,488 was detected after a 6-hr pretreatment and peaked at 24 hr. The KOR antagonist nor-binaltorphimine completely blocked the potentiating effect of U50,488, suggesting the involvement of a KOR-mediated mechanism. Antibodies to TNF-alpha completely blocked the potentiating effect of U50,488, suggesting a critical role for TNF-alpha. Antibodies to IL-1beta blocked the potentiating effect of U50,488, suggesting that IL-1beta was released following U50,488 treatment, which might contribute to the potentiating effect of U50,488. These in vitro findings support the notion that synthetic kappa-opioids could be considered as potential adjunctive therapeutic agents in HIV-1-related brain disease.

Thalidomide inhibits tumor necrosis factor-alpha production by lipopolysaccharide- and lipoarabinomannan-stimulated human microglial cells.

Tumor necrosis factor-alpha (TNF-alpha) is a pathogenic factor in bacterial meningitis. The effect of thalidomide on TNF-alpha production by microglia, the resident macrophages of the brain, was evaluated. In primary human fetal microglial cell cultures stimulated with lipopolysaccharide or lipoarabinomannan, thalidomide inhibited TNF-alpha release in a dose-dependent manner. The inhibitory effect of thalidomide was similar to that of dexamethasone, although expression of TNF-alpha mRNA in microglial cells was reduced only by thalidomide. The results of this in vitro study suggest that thalidomide could have therapeutic potential in gram-negative bacterial and tuberculous meningitis.

Tumor necrosis factor alpha upregulates human microglial cell production of interleukin-10 in vitro.

Interleukin (IL)-10 appears to play an important regulatory role in the systemic inflammatory response; however, production of IL-10 within the human central nervous system has not been described. Using cultures of human fetal microglial cells, the resident macrophages of the brain, we investigated the production and regulation of bioactive IL-10. Lipopolysaccharide stimulated acute release of tumor necrosis factor (TNF)-alpha (peak by 8 h) and delayed production of IL-10 (over a 48-h period) in microglial cell cultures. Treatment of microglial cell cultures with TNF-alpha and IL-6 resulted in a dose-dependent release of IL-10. These cytokines also induced expression of IL-10 mRNA. Treatment of microglial cell cultures with IL-10 markedly inhibited TNF-alpha and IL-6 production. These findings suggest that during inflammation within the brain, acute release of TNF-alpha and IL-6 by activated microglia could promote subsequent release of IL-10, which functions to minimize the potential neurotoxic effects of proinflammatory cytokines.

Transforming growth factor-beta protects human neurons against beta-amyloid-induced injury.

Deposition of amyloid fibrils in the brain is a histopathologic hallmark of Alzheimer disease (AD) and beta-amyloid protein (A beta), the principal component of amyloid fibrils, has been implicated in the neuropathogenesis of AD. In the present study, we first developed an in vitro model of A beta-induced neurodegeneration using human fetal brain-cell cultures and then tested the hypothesis that cytokines modulate A beta-induced neurodegeneration. When brain-cell cultures were exposed to A beta, marked neuronal loss (60% of neurons by microscopic assessment) and functional impairment (i.e., reduction in uptake of [3H]gamma-aminobutyric acid) were observed after 6 d of incubation. A beta-induced neurodegeneration was dose-dependent with maximal effect at 100 microM. Although interleukin (IL)-1, IL-6 and tumor necrosis factor (TNF)-alpha had a nominal effect, both the beta 1 and beta 2 isoforms of transforming growth factor-beta dose-dependently protected > 50% of neurons against A beta-induced injury. IL-4 also proved to be neuro-protective. A beta-induced neurodegeneration was accompanied by microglial cell proliferation and enhanced release of IL-1, IL-6, and TNF-alpha. These findings are consistent with the emerging concept that AD is an inflammatory disease and may lead to new therapeutic strategies aimed at reducing A beta-induced neurotoxicity.

Morphine amplifies HIV-1 expression in chronically infected promonocytes cocultured with human brain cells.

Previous studies have shown that morphine promotes the replication of human immunodeficiency virus (HIV)-1 in peripheral blood mononuclear cell cocultures. In the present study, we tested the hypothesis that morphine would amplify HIV-1 expression in the chronically infected promonocytic clone U1 when cocultured with lipopolysaccharide-stimulated human fetal brain cells. Marked upregulation of HIV-1 expression was observed in these cocultures (quantified by measurement of HIV-1 p24 antigen levels in supernatants), and treatment of brain cells with morphine resulted in a bell-shaped dose-dependent enhancement of viral expression. The mechanism of morphine's amplifying effect appears to be opioid receptor-mediated and to involve enhanced production of tumor necrosis factor-alpha by microglial cells.

Dilatation and evacuation procedures and second-trimester abortions. The role of physician skill and hospital setting.

Some clinicians have hesitated to perform dilatation and evacuation (D & E) procedures at 13 weeks' gestation or later because D & Es are more difficult to perform safely than suction-curettage procedures. Moreover, many clinicians still believe all second-trimester abortion procedures should be performed in a hospital. To evaluate these concerns, we analyzed 24,664 abortion performed between 1973 and 1978 by four physicians associated with a large outpatient abortion facility; 3,711 (15%) of the abortions were second-trimester procedures. Dilatation and evacuation was associated with a lower rate of serious complications per 100 procedures (0.23) than instillation of either dinoprost (prostaglandin F2 alpha) (1.28) or hypertonic saline (2.26). In addition, D & E had lower rates for most other specific complications. We conclude that D & E, while requiring more operator skill than earlier suction-curettage procedures, can be learned by gynecologists familiar with suction-curettage, can be performed more safely than the alternative instillation procedures, and can be safely practiced in selected ambulatory settings.

PIP: Continuing controversies have surrounded the emergence of dilatation and evacuation procedures as a method of performing 2nd trimester abortions. To evaluate concerns relating to 2nd trimester abortions, the 6 year experience between 1973-1978 of a labor abortion facility in the midwest, staffed by 4 physicians, was analyzed. Due to the fact that focus was on 1 specific practice, the situation of comparing different case series results among different institutions was avoided. Additionally, the facility served women from the same locality and socioeconomic stratum throughout the study interval. By restricting analysis to 1 group of physicians, variations in operator technique were controlled for, thus reducing the potential biases resulting from clinicians with different levels of training, experience, and innate skill. Excluding abortions performed concurrnetly with sterilization, the Meadowbrook Women's Clinic (MWC) in Minneapolis performed 24,664 abortion procedures during the 6-year study interval. At 12 week's gestation or earlier, 20,953 (84% of the total) were performed by suction curettage. At 13 weeks' gestation or later, 2204 (9%) were by dilatation and evacuation, 884 (4%) by saline instillation, and 623 (3%) by dinoprost instillation accounted for almost all abortions at 13 week's gestation or later. The overall serious complication rate for procedures at MWC was low. Approximately 1 in 400 dilatation and evacuation procedures, 1 in 80 dinoprost instillation procedures, and 1 in 40 saline instillation procedures led to temperature greater than 38 degrees Centigrade for more than 3 days, hemorrhage requiring transfusion, or unintended abdominal surgery. Fewer than 1 in 1000 women undergoing a suction curettage procedure suffered serious complications. Of those procedures available at 13 weeks' gestation or later, dilatation and evacuation was the safest. Compared with dinoprost instillation, dilatation and evacuation was associated with significantly lower rates of serious complications, hemorrhage, retained products of conception, re-evacuation, endometritis, and febrile morbidity. Even when performed at 17 weeks' gestation or later, dilatation and evacuation had a lower rate of serious complications than either dinoprost or saline instillation, although only significantly so for the latter. Dilatation and evacuation had a slightly higher rate of cervical injury, although this was not statistically significant. At MWC, neither gestational age, the physician, nor the type of facility had a great effect on the relatively low risks of dilatation and evacuation.