The role of colonic mast cells and myenteric plexitis in patients with diverticular disease.

BACKGROUND: Gut mast cells represent an important cell population involved in intestinal homeostasis and inflammatory processes. However, their possible role has not to date been investigated in colonic diverticular disease. AIMS: This study aims to evaluate colonic mast cells in patients undergoing surgery for diverticular disease. METHODS: Surgical resection samples from 27 patients undergoing surgery for diverticular disease (12 emergency procedures for severe disease and 15 elective procedures) were evaluated. The number of mast cells was assessed in the various layers by means of a specific antibody (tryptase) and compared with those evaluated in ten controls. In patients with mast cells degranulation, double immunohistochemistry, also assessing nerve fibres, was carried out. In addition, the presence of myenteric plexitis was sought. RESULTS: Compared with controls, the number of mast cells in diverticular patients was significantly increased, both as an overall figure and in the various layers of the large bowel. In patients in whom mast cells degranulation was present, these were always closed to nerve fibres. No differences were found between the two subgroups of patients with respect to the number and distribution of mast cells; however, all patients undergoing emergency surgery (but none of those undergoing elective procedures) had myenteric plexitis, represented by lymphocytic infiltration in 67 % and eosinophilic infiltration in 33 % of cases. CONCLUSIONS: Patients with diverticular disease display an increase of mast cells in the large bowel. The presence of myenteric plexitis in those with complicated, severe disease, suggest that this could represent a histopathologic marker of more aggressive disease.

Decreased circulating T regulatory lymphocytes in obese patients undergoing bariatric surgery.

OBJECTIVE: It has been previously demonstrated that T lymphocytes may be involved in the development of hypertension and microvascular remodeling, and that circulating T effector lymphocytes may be increased in hypertension. In particular, Th1 and Th 17 lymphocytes may contribute to the progression of hypertension and microvascular damage while T-regulatory (Treg) lymphocytes seem to be protective in this regard. However, no data is available about patients with severe obesity, in which pronounced microvascular alterations were observed. DESIGN AND METHODS: We have investigated 32 severely obese patients undergoing bariatric surgery, as well as 24 normotensive lean subjects and 12 hypertensive lean subjects undergoing an elective surgical intervention. A peripheral blood sample was obtained before surgery for assessment of CD4+ T lymphocyte subpopulations. Lymphocyte phenotype was evaluated by flow cytometry in order to assess T-effector and Treg lymphocytes. RESULTS: A marked reduction of several Treg subpopulations was observed in obese patients compared with controls, together with an increased in CD4+ effector memory T-effector cells. CONCLUSION: In severely obese patients, Treg lymphocytes are clearly reduced and CD4+ effector memory cells are increased. It may be hypothesized that they might contribute to the development of marked microvascular alterations previously observed in these patients.

High incidence of appendix carcinoid tumors among candidates for bariatric surgery: diagnostic and therapeutic implications.

Although the appendix has been recognized as a preferential site for carcinoid tumors in obese patients, no definitive guidelines are so far available regarding the management of these patients when candidates for bariatric surgery. This study was designed to fill that gap. Between 2000-2008, 558 patients underwent bariatric procedures. Appendectomy was routinely performed in 477 cases. Their charts were retrospectively retrieved and histopathology responses on surgical specimens were recorded. We aimed to assess: incidence of appendix carcinoid tumors (ACTs) and any possible risk-factor; modality of diagnosis (pre-, intra- or post-operatively); impact on the planned bariatric procedure; treatment reserved to such cases. Typical ACTs were diagnosed in 7 patients (1.4%) (median age: 33 years; median BMI: 49 kg/m²; males/females: 1/6). Four were diagnosed intra-operatively. Because of dimensions (<2 cm) and absence of mesoappendiceal or serosal involvement, simple appendectomy was performed during bariatric procedure, as planned. Three were diagnosed post-operatively (all <2 cm). In 1 case right hemicolectomy was performed 1 month later due to mesoappendiceal involvement. No appendectomy-related complication was encountered. All patients remained tumor-free during follow-up (mean: 64 months; range, 25-92). Young age, female sex, high BMI and diabetes mellitus resulted significantly associated with ACT. Our study sustains routine appendectomy or at least careful investigation of the appendix during bariatric surgery. For tumors <2 cm without mesoappendiceal or serosal involvement, simple appendectomy proved sufficient. Bariatric surgery did not have a negative effect on the treatment of malignancies that are discovered intra- or post-operatively.

Laparoscopic versus open left lateral hepatectomy.

Laparoscopic liver surgery is becoming more popular, and many high-volume liver centers are now gaining expertise in this area. Laparoscopic left lateral hepatectomy (LLLH) is a standardized and anatomically well-defined resection and may transform into a primarily laparoscopic procedure for cancer surgery or living donor hepatectomy for transplantation. Five case-control series were identified comparing a total of 167 cases (86 cases of LLLH plus 81 cases of open left lateral hepatectomy). Groups were matched by age and sex, with broadly similar indications for surgery and resection techniques. LLLH is associated with shorter hospital stays and less blood loss without compromising the margin status or increasing complication rates. Donors of LLLH grafts did not have higher graft-related morbidity. Prospective studies are required to define the safety in terms of disease-free and overall survival in this new avenue in laparoscopic liver surgery.