Therapeutics of vein graft intimal hyperplasia: 100 years on.

Intimal hyperplasia is central to the pathology of vein graft re-stenosis, and despite considerable advances in our understanding of vascular biology since it was first described 100 years ago, it is still a significant clinical problem. Recent decades have seen the development of many new therapeutic agents aimed at treating this condition, but the successes of laboratory studies have not been replicated in the clinic yet. This review discusses these therapeutic agents, how their modes of action relate to the pathogenesis of vein graft intimal hyperplasia, and considerations of ways in which such therapy may be improved in the future.

Anti-LFA-1 monotherapy prevents neointimal formation in a murine model of transplant intimal hyperplasia.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is the pre-eminent cause of late cardiac allograft failure. It is characterized by a concentric intimal hyperplasia, which we designate transplant intimal hyperplasia (TIH). To date, blockade of the adhesion molecule lymphocyte function-associated antigen-1 (LFA-1) has been shown to be effective in preventing TIH in experimental models of transplantation, but only when combined with other immunosuppressants. In this study we explored the impact of monotherapy against LFA-1 in a carotid artery allograft model of TIH. METHODS: B10A(2R) (H-2(h2)) mice were used as donors and C57BL/6 (H-2(b)) mice used as recipients. The recipients were treated with a monoclonal antibody against LFA-1alpha (M17/4) or isotype-matched control immunoglobulin. Grafts were harvested after 35 days and analyzed by histomorphometry and immunohistochemistry. Blood samples were taken and analyzed by differential cell count and alloantibody levels. RESULTS: We found that treatment with M17/4 resulted in a significant reduction in TIH compared with controls. Immunostaining revealed that LFA-1alpha blockade inhibited CD45+ leukocyte infiltration, prevented intimal smooth muscle cell (SMC) proliferation, and preserved the medial SMC population. Finally, we demonstrated a reduction in the serum alloantibody titer in the group treated with anti-LFA-1alpha when compared with controls. CONCLUSIONS: We have demonstrated for the first time that LFA-1alpha blockade on its own can prevent development of TIH in an experimental model. The concept of modulating LFA-1alpha-mediated leukocyte migration and T-cell activation may therefore be of relevance to clinical cardiac transplantation and, as such, represents a potential target for therapeutic intervention against clinical CAV.

Postprandial ghrelin suppression is exaggerated following major surgery; implications for nutritional recovery.

Meeting patients' nutritional requirements and preventing malnutrition is a challenge following major surgical procedures. The role of ghrelin in nutritional recovery after non-gastrointestinal major surgery is unknown. We used coronary artery bypass grafting (CABG) as an example of anticipated good recovery post major surgery.Seventeen patients undergoing CABG (mean +/- SEM: 70.1 +/- 2.2 yrs, BMI 29.1 +/- 1.4 kg/m2, 15 male) underwent fasting and postprandial (45 mins after standard test breakfast) blood sampling pre-operatively (day 0), post-operatively (day 6) and at follow-up (day 40). Changes in food intake, biochemical and anthropometric markers of nutritional status were recorded. A comparison was made to 17 matched healthy controls (70.6 +/- 2.3 yrs, BMI 28.4 +/- 1.3 kg/m2).We observed significantly increased post-operative and follow-up fasting ghrelin concentrations compared with pre-operatively (pre-op. 402 +/- 42 pmol/L vs post-op. 642 +/- 97 pmol/L vs follow-up 603 +/- 94 pmol/L) (ANOVA p < 0.05). Significantly exaggerated postprandial suppression of ghrelin was seen postoperatively and continued until follow-up (Delta pre-op. 10 +/- 51 pmol/L vs Delta post-op. -152 +/- 43 pmol/L vs Delta follow-up -159 +/- 65 pmol/L, p < 0.05). This was associated with a 50% reduction in food intake {post-op. 4.5 +/- 0.5 MJ/D (1076 +/- 120 kcal/D) compared with estimated requirements 9.9 +/- 0.5 MJ/D (2366 +/- 120 kcal/D)}, leading to a 4% weight loss and a 5% reduction in muscle arm circumference loss over length of follow up.Our data support the hypothesis that prolonged changes in fasting and postprandial plasma ghrelin concentrations are associated with impaired nutritional recovery after CABG. These findings reinforce the need to investigate ghrelin in other patients groups undergoing major surgery.