Role of cimetidine in the prevention of intimal hyperplasia in rat carotid artery

Appraisal of the extent of chronic allograft vasculopathy in animal models: Proposition of a standardized micromorphometric method

Arterial obstruction due to intimal myproliferation is an outcome used for investigating chronic allograft vasculopathy in animal models. Since harvested tissue may be distorted while processing, discrepancy may happen in the measure of the obstruction. We propose a standardized micromorphometric method for calculating the percentage of obstruction with eliminating the variability in the shape of the vessel cross-section. The mathematical adjustment avoids the overestimation of the percentage of obstruction and improves accuracy.

Repair of groin hernia with synthetic mesh: meta-analysis of randomized controlled trials

OBJECTIVE

To measure the effects of laparoscopic and open placement of synthetic mesh on recurrence and persisting pain following groin hernia repair.

SUMMARY BACKGROUND DATA

Synthetic mesh techniques are claimed to reduce the risk of recurrence but there are concerns about costs and possible long-term complications, particularly pain.

METHODS

Electronic databases were searched and experts consulted to identify randomized or quasi-randomized trials that compared mesh with non-mesh methods, or laparoscopic with open mesh placement. Individual patient data were sought for each trial. Aggregated data were used where individual patient data were not available. Meta-analyses of hernia recurrence and persisting pain were based on intention to treat.

RESULTS

There were 62 relevant comparisons in 58 trials. These included 11,174 participants: individual patient data were available for 6,901 patients, supplementary aggregated data for 2,390 patients, and published data for 1883 patients. Recurrence and persisting pain were less after mesh repair (overall recurrences: 88 in 4,426 vs. 187 in 3,795; OR 0.43, 95% CI 0.34-0.55; P <.001) (overall persistent pain: 120 in 2,368 vs. 215 in 1,998; OR 0.36, 95% CI 0.29-0.46; P <.001), regardless of the non-mesh comparator. Whereas the reduction in recurrence was similar after laparoscopic and open mesh placement (OR 1.26, 95% CI 0.76-2.08; P =.36), persistent pain was less common after laparoscopic than open mesh placement (OR 0.64; 95% CI 0.52-0.78; P <.001).

CONCLUSIONS

The use of synthetic mesh substantially reduces the risk of hernia recurrence irrespective of placement method. Mesh repair appears to reduce the chance of persisting pain rather than increase it.

Role of histamine H1 and H2 receptor antagonists in the prevention of intimal thickening

Vascular smooth muscle cell migration to the intima from the media and proliferation in the intima play key roles in atherosclerosis and restenosis after coronary angioplasty. Histamine released from adherent platelets at the injured artery and from mast cells in atheromas has stimulant actions on both smooth muscle cell migration and proliferation, and histamine receptor antagonists abolish the effect of histamine in vitro. The aim of this study was to examine the effect of histamine receptor antagonists on intimal thickening. Endothelial injury in the mouse femoral artery was induced by a photochemical reaction between localized irradiation by green light and intravenously administered rose bengal. The histamine H1 receptor antagonist, diphenhydramine, at a dose of 30 mg/kg or the histamine H2 receptor antagonist, cimetidine, at a dose of 200 mg/kg was intraperitoneally administered to mice for 21 days after endothelial injury. Twenty-one days after endothelial injury, morphometric analysis was performed to measure the cross-sectional areas of the intima and media. Diphenhydramine significantly reduced the intimal area to 1.1 +/- 0.3 (x 10(-3) mm2) compared with the value in the control group, which was 6.2 +/- 1.4 (x 10(-3) mm2), but cimetidine (5.5 +/- 1.9, x 10(-3) mm2) did not. Similarly, the ratio of intimal area to medial area in the diphenhydramine-treated group but not in the cimetidine-treated group was significantly reduced (83%). In the in vitro study, cimetidine inhibited neither proliferation nor migration of mouse vascular smooth muscle cells stimulated by platelet-derived growth factor (PDGF). In contrast, diphenhydramine significantly (P < 0.05) inhibited proliferation in a dose-dependent manner, but did not inhibit migration. These results suggest that diphenhydramine, a histamine H1 receptor antagonist, reduced the formation of intimal hyperplasia, at least in part due to inhibition of cell proliferation. However, cimetidine, a histamine H2 receptor antagonist, was ineffective. Histamine may play a key role in intimal thickening, in part via histamine H1 receptors in this model.