Host immune mechanisms were proposed to decline under microgravity conditions during spaceflights, which might result in severe infections in astronauts. Therefore, it was important to investigate the effects of microgravity on infecting organisms and their interaction with host cells. Data showed that simulated microgravity (SMG) conditions markedly increased production of the enterotoxigenic Escherichia coli (ETEC) heat-labile enterotoxin, which induced fluid secretory responses in a mouse model. SMG also enhanced production of tumor necrosis factor-alpha in murine macrophages infected with enteropathogenic E. coli (EPEC). In a similar fashion, simulated microgravity conditions augmented the invasive potential of Salmonella enterica serovar typhimurium and enhanced production of tumor necrosis-factor alpha in S. typhimurium-infected epithelial cells. Furthermore, coculturing of macrophages and S. typhimurium in a simulated microgravity environment resulted in activation of stress-associated mitogen-activated protein kinase kinase 4. Using the antiorthostatic tail suspension mouse model, which simulates some aspects of microgravity, oral inoculation of S. typhimurium markedly reduced the 50% lethal dose compared to mice infected under normal gravitational conditions. Microarray analysis revealed simulated microgravity-induced alterations in the expression of 22 genes in S. typhimurium, and protein expression profiles were altered in both EPEC and S. typhimurium, based on two-dimensional gel electrophoresis. These studies indicated alterations in the virulence potential of bacteria and in host responses to these pathogens under simulated microgravity conditions, which may represent an important environmental signal. Such studies are essential for better understanding bacterial-host cell interactions, particularly in the context of spaceflights and space habitations of long duration.

The treatment of keloids in black patients remains a medical dilemma. Previous studies have focused on primary alterations in the metabolism of fibroblasts as the key in the etiology of this condition. Yet alterations in the production of various cytokines which may alter fibroblast responses secondarily have received little attention. Twelve black patients with clinical and histological diagnosis of keloids and eight black control volunteers were studied. Peripheral blood mononuclear-cell (PBMC) fractions from both groups were assayed for production of interleukin-1 (IL-1), interleukin-2 (IL-2), interleukin-6 (IL-6), alpha-interferon (IFN-alpha), beta-interferon (IFN-beta), gamma-interferon (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and tumor necrosis factor-beta (TNF-beta). The production of IFN-alpha, IFN-gamma, and TNF-beta were markedly depressed in keloid patients compared to normal controls. However, IL-1 and IL-2 production was not significantly different between the two groups. In contradistinction, keloid patients produce greater amounts of IL-6, TNF-alpha, and IFN-beta. Altered levels of immunoregulatory cytokines may play a significant role in the net increase in collagen which characterizes keloid formation.

Progression of cervical cancer is associated with excessive circulating levels of cytokines, which are known to be modulators of tumor angiogenesis. The concentrations of cytokines and growth factors were assayed using enzyme-linked immunosorbant assays in the serum of 61 women in various stages of cancer [stage 0 (n = 6), stage I (n = 15), stage II (n = 15), stage III (n = 15), and stage IV (n = 10)] and of 20 healthy control subjects. Our results indicated that b-FGF and TNF-beta levels were significantly elevated in stage I, and serum levels of TGF-beta and IL-7 were elevated in stages II-IV of invasive carcinoma. Our experimental subjects had significantly increased serum levels of IL-6, GM-CSF, and angiogenin in stages I-IV of cervical cancer, and TNF-alpha serum levels were elevated in all stages of invasive carcinoma. The serum levels of IL-8 and IL-10 were elevated only in stages II-III, and the levels of IL-2 were elevated in stages III-IV. The serum levels of IL-1 alpha and IL-1 beta remained unaltered in all stages of cancer progression. Progression of cervical cancer is associated with increased serum levels of angiogenin, IL-2, IL-6, IL-7, IL-8, IL-10, b-FGF TNF-alpha, TGF-beta, TNF-beta, and GM-CSF during different stages, all of which have the potential to be angiogenic amplifiers.

The purpose of this study is to understand the multicellular interaction between tumor epithelial (TEC) and human umbilical vein endothelial cells (HUVEC). The development of in vitro systems in which to coculture these cells as multicellular aggregates is very critical. Cell lines were established from cervical tumor cells (n = 6) and two from HUVEC (n = 2) and they were cultured as three-dimensional (3-D) multicellular-cultures using Cytodex-3 microcarrier beads in the rotating wall vessel (RWV). After a 240-h incubation, TEC and HUVEC proliferated exponentially to 4.2 x 10(7) and 2.2 x 10(7) cells/ml, respectively, without requiring a feeder layer; in contrast to the two-dimensional (2-D) cultures that average about 8 x 10(5) cells/ml. Phase contrast microscopy indicated formation of 3-D aggregates that varied in size from 0.5 to 5 mm. The size of the aggregates (1-5 mm, 6-14 microcarriers) increased over time; however, the number of aggregates (0.5-1 mm, 2-5 microcarriers) decreased over a long-term incubation (240 h) because the cells merged to form large clumps. Maximum aggregation was observed with TEC at 120 h and HUVEC at 96 h. The culture of TEC in the absence of HUVEC produced minimal differentiation in contrast to cocultures. The TEC and HUVEC as cocultures in RWV proliferated at an accelerated rate (1.3 x 10(7) cells/ml, 96 h). The TEC-HUVEC coculture presented tubular structures penetrating the tumor cell masses, forming aggregates larger in size than the monocultures and typically with greater cell mass and number. The cells were viable (trypan blue exclusion) and metabolically active (glucose utilization) until 240 h. These data suggest that RWV provides a new model that allows us to investigate the regulatory factors that govern tumor angiogenesis.

High microvessel count in tumors may be used to predict recurrence in stage Ib squamous cell carcinoma of the cervix.

Peripheral blood mononuclear cells (PBMC) from patients with severe forms of inherited epidermolysis bullosa (EB) are deficient in functions governing cellular immunity. Very low levels of interferon-gamma (IFN-gamma), interleukin-1 (IL-1), and interleukin-2 (IL-2) were produced in vitro by PBMC from patients with severe forms of EB (recessive dystrophic and dominant dystrophic) as compared to sex- and age-matched controls. Lymphokine production by PBMC from patients with junctional EB was somewhat greater than that from patients with dystrophic forms of EB but was significantly less than that from controls. The production of interferon-alpha was not found to be altered in the severe forms of EB. The PBMC from dystrophic types of EB were also deficient in production of tumor necrosis factors (TNF-alpha and TNF-beta). The degree of the reduction in immune functions was directly related to the severity of skin involvement, with recessive dystrophic EB having the lowest level of cytokine production. This reduced production of monokines and lymphokines may be partially responsible for the progression of cutaneous infections to septicemia and for the metastasis of cutaneous squamous cell carcinomas in patients with severe forms of dystrophic EB.

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