Dexamethasone inhibits vascular smooth muscle cell migration via modulation of matrix metalloproteinase activity.

BACKGROUND: Dexamethasone (DEX) has been shown to inhibit development of neointimal hyperplasia in rats. We hypothesize that DEX inhibits neointimal hyperplasia by altering matrix metalloproteinase (MMP) activity, resulting in inhibition of smooth muscle cell migration. METHODS: Rat aortic smooth muscle cells (RASMC) were harvested and cultured for two to four passages. A migration assay was performed in a Boyden chamber with chemoattractant (platelet-derived growth factor) and varying concentrations of DEX (10(-9) to 10(-5) M). The number of migrated cells was counted under light microscopy. Zymography was performed on culture media to assess MMP activity, and Western blotting was performed to assay MMP and levels of tissue inhibitors of MMPs (TIMPs). RESULTS: DEX progressively inhibited RASMC migration in a dose-dependent fashion. This effect was statistically significant for concentrations of 10(-7) to 10(-5) M (P < 0.0005). Zymography showed that DEX inhibits MMP-2 activity in a dose-dependent manner. Western blots indicated that total MMP-2 secretion was inhibited and that TIMP-2 secretion was increased by DEX. CONCLUSIONS: DEX inhibits platelet-derived growth factor-induced migration of RASMCs and MMP-2 activity in vitro. Our data suggest that DEX suppresses MMP activity and secretion, resulting in the inhibition of smooth muscle cell migration. This may explain the mechanism by which DEX inhibits neointimal hyperplasia.

Minimal incision abdominal aortic aneurysm repair.

PURPOSE: The use of a limited incision for abdominal aortic aneurysm (AAA) repair was evaluated, and its outcome was analyzed in comparison to laparoscopic-assisted and standard open repair. METHODS: Eleven patients who had an AAA that required a tube graft underwent minimal incision (MINI) repair. The procedure consisted of a standard endoaneurysmorrhaphy performed through an 8- to 10-cm minilaparotomy. Clinical characteristics, in-hospital outcomes, and total in-hospital charges for this procedure were then compared with those of comparative groups of patients who had undergone repair of AAA by means of a laparoscopic-assisted (LAP) approach or a standard open (OPEN) technique. RESULTS: MINI repair was successfully completed in all 11 patients. Patients in the three groups were comparable for age, sex, risk factors, and aortic dimensions. The mean values for operative time, blood loss, length of hospital stay, and total hospital charges for the three comparison groups were: 129. 7 minutes (MINI) vs. 244.8 minutes (LAP)*, 209.9 minutes (OPEN)*; 522.7 mL (MINI) vs. 1214.7 mL (LAP), 1795.8 mL (OPEN)*; 5.18 days (MINI) vs. 18.7 days (LAP), 17.4 days (OPEN); $22,692 (MINI) vs. $59, 922 (LAP)*, $62,324 (OPEN)* (*P <.05). Local complications occurred in 18.2% of patients who underwent MINI repair, 23.5% of patients who underwent LAP repair, and 29.7% of patients who underwent OPEN repair (P = not significant). Patients undergoing minilaparotomy demonstrated decreased compromise of gastrointestinal function, with a decreased need for postoperative fluid resuscitation (6799.7 mL [MINI], 7781.8 mL [LAP] vs. 11061.1 mL [OPEN]*) and shortened nasogastric tube decompression (1.6 days [MINI], 1.5 days [LAP] vs. 4.1 days [OPEN]*; *P <.05). CONCLUSION: MINI repair is a technically feasible technique that combines the benefits of minimally invasive surgery with those of conventional open repair with few, if any disadvantages. Facility of the procedure, combined with the potential cost benefits, encourages further study for consideration of this technique as a viable alternative for the management of AAAs.

Laparoscopically assisted abdominal aortic aneurysm repair.

Since the advent of laparoscopy, the sweeping changes seen in general surgery have not been paralleled in vascular surgery. However, the application of laparoscopic techniques to intraabdominal vascular procedures has now progressed from the animal laboratory to the clinical arena. Initial experience with laparoscopically assisted aortic bypasses for occlusive disease has led to the development of procedures for aneurysmal disease. This article reviews the current clinical experience in the evolving technique of laparoscopically assisted abdominal aortic aneurysm repair.

Laparoscopically assisted abdominal aortic aneurysm repair.

Since the first description of abdominal aortic aneurysms by sixteenth-century anatomist Vesalius, the history of this disease has reflected the remarkable progress of vascular surgery. From initial attempts of ligation and sclerosis to the recent advances of endovascular and laparoscopic repair, present-day vascular surgeons are supplied with a technically evolving choice of therapeutics. None of these procedures is mutually exclusive; currently, great interest lies in the use of laparoscopy to provide extraluminal control at the neck of aneurysms, to work with endoluminal grafts, and to control collateral vessel endoleaks. Laparoscopic vascular surgery must not be introduced into the clinical arena based only on the assumption that it is feasible. Clearly, it is a technically challenging procedure with a steep learning curve that requires specialized instrumentation and sophisticated laparoscopic suturing capability; however, with continued investigation, including prospective randomized trials, laparoscopic treatment of aortic aneurysms may become a standard option for high-risk patients.