Influence of arterial hypertension treated with losartan on skin healing in rats

Losartan modifies mesh integration after abdominal wall repair: an experimental study

PURPOSE

Angiotensin II (AT II) receptor blockers have previously shown to reduce inflammatory response in many settings. We aimed to assess the effects of ATII receptor blocker (Losartan) on mesh integration after abdominal wall repair in a rat model.

METHODS

A total of 16 Wistar-Kyoto (WKY) and 16 previously hypertensive (SHRSP) rats were isolated. An acute ventral hernia followed by a bridged repair with heavyweight polypropylene mesh was performed. Subjects received either normal saline (WKY-C n = 8 and SHRPS-C n = 8) or 40 mg/kg losartan (WKY-L n = 8) and SHRPS-L n = 8) in the postoperative period. Blood pressure was recorded preoperatively and weekly after surgery. Necropsy with en-bloc resection of the abdominal wall was performed at postoperative day 30. Macroscopic and microscopic evaluations of the specimens were conducted. H&E and Masson's trichrome were used for histologic evaluation.

RESULTS

Both groups receiving Losartan showed a significant reduction of blood pressure after surgery (WKY-L: 130/85 vs 116/81 mmHg, SHRPS-L: 176/137 vs 122/101 mmHg, p < 0.01). A significant reduction in mesh incorporation and adherence scores were also observed on macroscopic analysis in Losartan groups (p < 0.01 and p   = 0.02, respectively). Microscopically, higher immature fibroplasia was observed after Losartan, with a significant reduction in scar plate formation and inflammatory response on the prosthetic surface (p = 0.04 and p  = 0.02, respectively).

CONCLUSION

Losartan modifies the interaction between the host tissue and the prosthesis. An impairment in mesh integration and immature fibroplasia in both normotensive and hypertensive rats detected in our model warrants further research.

Effects of antihypertensive drugs on surgical outcomes of breast reconstruction: a nationwide population-based claim study

Background

Experimental studies have reported that angiotensin receptor blockers (ARBs) increase the risk of surgical complications. However, clinical data on their effect on surgical outcomes are limited. The aim of this study was to investigate the impact of perioperative use of ARBs on the outcomes of breast reconstruction using population-based claim data.

Methods

Data of patients who underwent direct-to-implant or abdomen-based autologous breast reconstruction after total mastectomy from April 2015 to December 2018 were obtained from the Health Insurance Review and Assessment Service database. The patients were categorized as ARB, non-ARB, control, and non-hypertension groups. The effects of ARBs on surgical complications, length of hospital stay, and complication-related medical costs were evaluated.

Results

Of the 9,036 patients who met the inclusion criteria, 5,192 underwent direct-to-implant reconstruction, and 3,844 underwent abdomen-based autologous reconstruction. The length of hospital stay was the longest and the surgical complication rate and complication-related medical cost were the highest in the ARB group after both reconstruction methods. Compared with non-treatment with antihypertensive drugs, ARB use was found to be an independent risk factor for surgical complications in direct-to-implant reconstruction [odds ratio (OR), 1.96; 95% confidence interval (CI), 1.09-3.50; P=0.0237] and complication-related medical cost (OR, 1.93; 95% CI, 1.10-3.40; P=0.0221) in abdomen-based autologous reconstruction.

Conclusions

Perioperative ARB use was associated with adverse postoperative breast reconstruction outcomes. These findings might have a significant impact on perioperative antihypertensive management; nevertheless, further studies are warranted to confirm the study findings.

Effects of Antihypertensive Drugs on Outcomes of Breast Reconstruction

BACKGROUND

Angiotensin receptor blocker (ARB), a commonly used antihypertensive drug, is reported to affect wound healing and flap survival in animal models. However, this has not been elucidated in a clinical series. This study aimed to investigate the impact that perioperative use of ARB has on outcomes after breast reconstruction.

METHODS

Patients who underwent immediate breast reconstruction using a tissue expander or a deep inferior epigastric perforator (DIEP) flap were reviewed. The patients were categorized according to the types of antihypertensive medications as follows: the ARB group consisted of hypertensive patients treated with ARB alone or a combination of ARB and other drugs; the non-ARB group included those receiving drugs other than ARB; and the control group did not receive any medication. The effects of antihypertensive drugs on the development of complications were evaluated.

RESULTS

The study analyzed 1390 cases including 999 cases of tissue-expander insertion and 391 cases of DIEP flap reconstruction. With regard to tissue-expander reconstruction, the rates of seroma, reoperation, reconstruction failure, and overall complications were significantly higher in the ARB group than in the other two groups. Compared with no medication, ARB use was an independent risk factor for these complications. With regard to DIEP flap reconstruction, the ARB group showed a significantly higher rate of fat necrosis and significantly greater odds for the development of overall perfusion-related complications and fat necrosis than the control group after adjustment for other variables.

CONCLUSIONS

Perioperative administration of ARB might be associated with adverse outcomes after breast reconstruction.

Influence of arterial hypertension on colonic healing in rats

PURPOSE

Evaluation of colonic healing in spontaneously hypertensive rats.

METHODS

Fifty male, young and inbred rats were used. Twenty-five Wistar Kyoto rats (WKY) as control and twenty-five spontaneously hypertensive rats (SHR) as an experimental group. Colotomy and bowel suture at 2.5 cm from the peritoneal reflection were performed. All animals were allocated randomly into sub-groups for review at the third, seventh and fourteenth days after surgery. We evaluated the concentration of angiotensin II, the burst pressure, epithelialization, the organization of the tunics of the bowel wall, inflammatory response and collagen deposition.

RESULTS

The burst pressure, epithelialization, organization of the tunics and collagen deposition was not significant between groups. The inflammatory reaction was more intense in the control group on the third postoperative day (p=0.023) as the experimental group on the remaining time.

CONCLUSION

Systemic arterial hypertension in rats did not influence significantly the healing process of colonic anastomoses.

Impact of hypertension in liver regeneration in rats

PURPOSE

To determine the impact of hypertension in liver regeneration, in rats by examining gain in liver mass and the replication of hepatocytes and stellate cells.

METHODS

Forty Wistar rats were allocated into two groups of twenty, the control and experiment group. The experiment group animals were submitted to induction of renovascular hypertension. A week later, all the animals underwent a partial hepatectomy. Measurements were taken after 24 hours and seven days, when ten animals in each group were euthanized. Thus, four subgroups were obtained. The livers were excised and sent for histopathological analysis.

RESULTS

The control group had a greater gain in liver mass than the experiment group seven days after partial hepatectomy (p=0.0051). The difference in the activate stellate cell count was not statistically significant following analysis after both 24 hours and seven days (p=1.0). A higher number of dividing hepatocytes was observed in the control group seven days after partial hepatectomy (p=0.0014).

CONCLUSION

In rats, hypertension had no direct influence on stellate cell replication, but led to a delay in liver mass gain and were shown to be a reduction factor on hepatocyte replication seven days after partial hepatectomy.