Effect of cyclo-oxygenase inhibition on in vitro B-cell function after burn injury

Skin tissue engineering--in vivo and in vitro applications

Significant progress has been made over the years in the development of in vitro-engineered substitutes that mimic human skin, either to be used as grafts for the replacement of lost skin or for the establishment of human-based in vitro skin models. This review summarizes these advances in in vivo and in vitro applications of tissue-engineered skin. We further highlight novel efforts in the design of complex disease-in-a-dish models for studies ranging from disease etiology to drug development and screening.

Skin tissue engineering--in vivo and in vitro applications

Significant progress has been made over the years in the development of in vitro-engineered substitutes that mimic human skin, either to be used as grafts for the replacement of lost skin or for the establishment of human-based in vitro skin models. This review summarizes these advances in in vivo and in vitro applications of tissue-engineered skin. We further highlight novel efforts in the design of complex disease-in-a-dish models for studies ranging from disease etiology to drug development and screening.

Modulation of prostaglandin activity, part 1: prostaglandin inhibition in the management of nonrheumatologic diseases: immunologic and hematologic aspects

Prostaglandins (PGs) are active biologic substances that are involved in a wide range of physiologic processes; when their production is out of balance, they are factors in the pathogenesis of illness. Modulation of PGs by inhibition or stimulation is promising for the management of various conditions. PG inhibitors are widely used to relieve pain and inflammation in patients with rheumatologic disease. Interest in the use of PG inhibitors to prevent cancer and cardiovascular events is growing. More than 27 y ago, investigators found that PG depresses antibody production in vivo; reduces serum iron, hemoglobin, and leukoid series in bone marrow during acute and chronic blood loss; reduces albumin during antigenic stimulation; suppresses hypercalcemia after bleeding; and reduces fasting blood sugar and hyperglycemia after ether anesthesia and bleeding. Chronic conditions that produce large quantities of PGs are associated with immunosuppression and secondary anemia. Investigators in the present study hypothesized (1) that the overproduction of PGs is responsible for immunosuppression and secondary anemia in conditions associated with increased PG synthesis, such as pathologic inflammation, malignancy, trauma, and injury, and (2) that PG inhibitors reverse immunosuppression and secondary anemia, thereby enhancing the immune response. This is supported by many reports that show the immunosuppressive effects of PGs and their role in the immunosuppression associated with pathologic inflammation, burns, trauma, and tumors. Inhibition of PGs can be achieved through the use of synthetic medicines and natural products. This article reviews the effects of PGs and inhibition of increased synthesis of PGs on the lymphoid system, hematologic indices, and bone marrow elements in trauma, injury, burns, and tumors. The Medline database (1966-2006) was used in this study. Investigators in the present study and others have provided evidence that shows the involvement of PGs in immunosuppression and secondary anemia, as well as the efficacy of inhibited overproduction of PGs in many pathologic conditions other than rheumatologic disease.

The effects of transforming growth factor-beta neutralization on postburn humoral immunity

BACKGROUND

Burn injury induces immunosuppression, which is associated with an increased susceptibility to infection. Our laboratory has demonstrated that burn injury also impairs humoral immunity. We reported that burn injury enhanced expression of transforming growth factor-beta (TGF-beta) mRNA and that exogenous TGF-beta further impaired humoral immunity. The objective of this study was to clarify the role of TGF-beta on humoral immunity after burn injury with a neutralizing experiment.

METHODS

Twelve BALB/c mice were randomly divided into two groups: sham and burn. Anesthetized mice received a 20% full-thickness burn or sham injury. The murine splenocytes containing 1.5 x 10 cells/mL were cultured with 2.5 microg/mL of lipopolysaccharide with or without 0.5 ng/mL of TGF-beta or 1 microg/mL of anti-TGF-beta neutralizing antibody, if necessary. Concentrations of immunoglobulin (Ig) M in the cell culture supernatant were determined by enzyme-linked immunosorbent assay and the number of IgM-secreting cells in the culture was measured by enzyme-linked immunospot assay.

RESULTS

After 2-day culture, neutralization of TGF-beta dramatically restored IgM synthesis after burn injury. After 5-day culture, however, it restored IgM concentration but failed to restore a number of IgM-secreting cells.

CONCLUSION

This neutralizing experiment demonstrated that TGF-beta is one of the inhibitors of IgM synthesis after burn injury. However, neutralization of TGF-beta was not enough to completely restore humoral immunity after burn injury. Investigation of the mechanism of impaired IgM synthesis after burn injury should be continued.

Influence of local anaesthetics on inflammatory activity postburn

Most studies investigating the pathophysiological processes taking place inside an experimental burn wound use in vitro techniques, which only allow for fragmented measurements of the actual and complex processes occurring inside a burn wound in vivo. In the present study, which used a recently developed in vivo technique in the rat, a full-thickness burn was induced and resulted in the formation of a subcutaneous gelatinous edema with distinct borders to the surrounding connective tissue and free communication with the systemic circulation allowing it to be easily separated for further analysis. In the present study, we investigated the effects of topical local anaesthetics (EMLA) on the inflammatory cascade of a burn wound in vivo. Results showed significantly higher myeloperoxidase (MPO) levels in EMLA-treated burned animals (P<0.01) versus placebo-treated burned controls. EMLA treatment induced a significant inhibition of the synthesis of leukotrien B(4) (LTB(4)) (P<0.001), prostaglandin E(1) (PGE(1)) (P<0.001), prostaglandin E(2) (PGE(2)) (P<0.001) and thromboxane B(2) (TXB(2)) (P<0.001) versus control, while free radical formation did not differ significantly between EMLA-treated and control animals. In conclusion, topical local anaesthetics significantly inhibit the release of several mediators known to take important part in the pathophysiological events ensuing a burn injury, such as activation of pain mechanisms (PGE), oedema formation (LTB), and postburn ischemia (TXB). The increased numbers of leukocytes (MPO) in the burn wound induced by topical local anaesthetic treatment could suggest increased influx and/or increased viability of leukocytes postburn.