IFN-gamma and Fas/FasL pathways cooperate to induce medial cell loss and neointimal lesion formation in allograft vasculopathy.

Using a clinically relevant, fully disparate, allogeneic aortic transplant mouse model of allograft vasculopathy, we have demonstrated that neointimal proliferation is dependent on CD8(+) T cell effector pathways in the presence of therapeutic doses of calcineurin inhibitor (CNI) immunosuppression. CD4(+) T cell pathways are ablated by CNI immunosuppression. In the current study, we examined the relationship between CD8(+) T cell activities, medial SMC loss and neointimal hyperplasia. We demonstrate that at 5-6wk post transplantation in a wild type/wild type transplant CD8(+) T cell infiltration, CD8(+) CTL effector cell mediator expression and medial SMC loss all occur within aortic interposition grafts in the face of CNI immunosuppression. Both IFN-gamma and CTL mediated effector function is required for SMC loss and lesion formation under these conditions. Using strain combinations and reconstitution models, we provide data that blockade of the perforin/granzyme pathway does not prevent lesion formation but that blockade of the Fas/FasL pathway of cytotoxicity dramatically reduces SMC loss and prevents neointimal lesion formation. Both of these blockade strategies are in the face of an active IFN-gamma pathway. These data suggest a cooperative role between Fas/FasL and IFN-gamma mediated effector functions in medial SMC loss and neointimal lesion formation.

Activation of innate immunity to reduce lung metastases in breast cancer.

Breast cancer continues to be one of the leading causes of cancer death in women. Mortality is primarily due to the development of metastases. Although therapies exist, they lack efficacy in preventing metastatic growth. As a result, novel agents are being investigated. In particular, treatments that target the immune system are being examined as potential anti-neoplastic agents. Cordyceps sinensis (Cs) is a fungus that has been used for over 2,000 years in China as a treatment for a variety of conditions including neoplasms. The available evidence suggests that efficacy of Cs as an anti-neoplastic therapeutic agent is related to a role as an activator of innate immune responses. The objectives of this study were: to investigate the ability of Cs to activate macrophages to produce factors that will induce protective responses against tumour growth; to study the ability of Cs to reduce primary tumour growth in vivo; and to examine the ability of Cs to reduce lung metastasis growth in vivo. We found that oral Cs does not reduce primary tumour growth but can reduce lung metastasis occurrence in a surgical excision model of metastatic mammary carcinoma. The evidence we have shown to date suggests that the reduction in metastases growth may be due to the effects of macrophage-derived factors on tumour cell cycle.

Use of a sulfated chitosan derivative to reduce bladder inflammation in the rat.

OBJECTIVES: Interstitial cystitis is a chronic, debilitating disease of the bladder. Treatments using intravesicular inoculation of long-chain polysaccharide formulations, such as hyaluronic acid or anti-inflammatory agents, have been used to some effect. The objective of this study was to test a long-chain polysaccharide derivative of chitosan as a vehicle for delivery of the anti-inflammatory agent 5-aminosalicylic acid (5-ASA) for treatment of inflammation in the bladder. METHODS: Bladder inflammation was induced in rats by intravesicular inoculation of protamine sulfate and lipopolysaccharide. Groups of rats were randomly assigned to the treated or control groups, which received either the treatment agents or saline 24 hours after induction. The animals were killed 5 days after inoculation, and the bladders harvested for histologic examination of inflammation by a blinded observer. Four parameters of inflammation were measured using a 6-point scale. In another experiment, urinary frequency was measured 4 days after inoculation. RESULTS: The most potent treatment agent was 3% N-sulphonato-N,O-carboxymethylchitosan plus 5-ASA, with a mean reduction in inflammation, as measured by histologic examination, of up to 75%. This level of reduction was significantly greater than that seen by treatment with the commercially available product Cystistat. In a separate experiment, 3% N-sulphonato-N,O-carboxymethylchitosan plus 5-ASA ameliorated the increase in urinary frequency seen in induced, untreated animals. CONCLUSIONS: The combination of 3% N-sulphonato-N,O-carboxymethylchitosan and 5-ASA reduced bladder inflammation as measured by histologic examination and by the lower urinary frequency.

Recipient cells form the proliferative lesion in the rat heterotopic tracheal allograft model of obliterative airway disease.

To determine the nature of the proliferative lesion in obliterative airway disease, heterotopic tracheal allograft transplantation was performed between fully disparate Brown Norway and Lewis rat strains. Four weeks after transplantation, the resulting lumenal occlusive lesion was stripped from the underlying tissue. The lesion was probed using immunohistochemical analysis with monoclonal antibodies and for DNA using strain-specific primers for Brown Norway or Lewis major histocompatibility complex Class I alleles. The lesions were alpha-actin positive, and polymerase chain reaction probing revealed only recipient DNA in the lesion tissue, regardless of the direction of transplantation, with no amplification of donor DNA. From this, we conclude that the proliferative lesion in the rat heterotopic tracheal model is of recipient origin a finding with important implications for the pathobiology of obliterative airway disease.