Resveratrol protects human endothelium from H(2)O(2)-induced oxidative stress and senescence via SirT1 activation

AIM

Silencing information regulator (SirT1), a NAD-dependent histone deacetylase, is an essential mediator of longevity in normal cells by calorie restriction. SirT1 has many biological functions, including transcription regulation, cell differentiation inhibition, cell cycle regulation, and anti-apoptosis. Resveratrol (RV)-induced SirT1 activation also improves endothelial dysfunction and suppresses vascular inflammation. In this study, we investigated the roles of RV-induced SirT1 activation in endothelial cells under oxidative stress.

METHODS

SirT1 mRNA expression levels were examined in the endothelium layer (endothelial cells) of cardiac coronary vessels from patients receiving coronary artery bypass graft surgery (CABG) surgery and aged rats using reverse transcriptase polymerase chain reaction (RT-PCR). To further explore the effect of SirT1 activation on oxidative stress-induced aging, senescence-associated β-galactosidase (SA-β-gal) expression in RV-treated human umbilical vein endothelial cells (HUVECs) with or without H(2)O(2) treatment was evaluated.

RESULTS

SirT1 expression was decreased in aged and atherosclerotic vessels in vivo, and significantly reduced in endothelial cells purified from vessel tissues. Furthermore, SirT1 levels were dose-dependently increased in RV-treated HUVECs. The SA-β gal assay showed that RV inhibited the senescent phenotype of H(2)O(2)-treated HUVECs. Reactive oxygen species (ROS) production and the percentage of cells positive for SA-β gal were significantly increased in siRNA-SirT1 (knockdown of SirT1 expression)-treated HUVEC cells. Importantly, the treatment effect of RV was significantly abolished in the oxidative effects of H(2)O(2)-treated HUVECs by siRNA-SirT1.

CONCLUSION

Our data suggested that SirT1 could be a crucial factor involved in the endothelial cells of atherosclerotic CAGB patients and aging rats. RV is a potential candidate for preventing oxidative stress-induced aging in endothelial cells. RV may also prevent ROS-induced damage via increased endothelial SirT1 expression.

Minimally invasive mitral valve surgery via submammary hidden incision

BACKGROUND

With the recent advancement in minimally invasive cardiac surgery based on the needs of decreasing costs, hospital stay, recovery time and improving cosmetic appearance, minimally invasive mitral valve surgery (MIMS) is being actively pursued. The objective of this study was to compare our submammary hidden incision method to two other more proven methods of MIMS with respect to length of operation, clinical outcome and cosmetic satisfaction.

METHODS

From July, 1996 to June, 1998, a total of 14 patients underwent MIMS in our hospital. Three different approaches were used: the limited right-side thoracotomy approach, the parasternal incision approach and our submammary hidden incision approach, of which, this is the first report. All relevant clinical results are reported, including general characteristics of the operations, morbidity and mortality, length of hospitalization, pain relief and patient satisfaction.

RESULTS

Five patients underwent MIMS via limited thoracotomy, four via parasternotomy and five with our submammary hidden incision method. There were six mitral valves repaired and eight replaced. Conversion to traditional sternotomy was not necessary in any of the three groups. The results from the three different approaches did not differ significantly across the different parameters measured. Nonetheless, the submammary hidden incision approach showed promise in the areas of length of stay for both intensive care patients (36.3 +/- 5.0 hours) and total hospitalization (10.7 +/- 0.6 days), pain relief and patient satisfaction.

CONCLUSIONS

The submammary hidden incision method does not result in any significant disadvantage in clinical outcome. The method resulted in more satisfied patients due to less pain, shorter hospital stay, and most importantly, cosmetic appearance of the resulting surgical scar. We will make the submammary hidden incision approach the MIMS approach of choice at our institution and continue to monitor the long-term results.

Surgical repair of Ebstein's anomaly

BACKGROUND

Ebstein's anomaly represents a congenital structural deformity of the tricuspid valve associated with a wide spectrum of morphologic and physiologic abnormalities. Valvuloplasty and tricuspid valve replacement are the main surgical treatments. Plication of the atrialized right ventricle and valvuloplasty of the tricuspid valve can achieve satisfactory clinical results. Two surgical techniques, known as Danielson's and Quaegebeur's methods, are often used clinically. This study was conducted to compare the postoperative results between both methods in treatment of Ebstein's anomaly.

METHODS

Valvuloplasty of tricuspid valve and the plication of atrialized right ventricle were performed in 8 out of 17 patients with Ebstein's anomaly in our hospital from January 1986 to August 1996. Danielson's method was used in six of eight patients, and Quaegebeur's method was used in the remaining two patients. There were three males and five females, aged from 8 months to 61 years (mean: 14.1 years).

RESULTS

All patients achieved clinical improvement in cardiothoracic ratio and heart functional class. Cardiac arrhythmia was the likely cause of death in two patients treated by Danielson's method, and one patient developed complete atrioventricular (A-V) block postoperatively. By Quaegebeur's method, all patients survived, but a permanent pacemaker was implanted for both patients due to their preoperative complete A-V block.

CONCLUSIONS

Both methods achieved satisfactory postoperative results. However, Quaegebeur's method seems to be more effective because it provided a simultaneous reconstruction of both tricuspid valve and right ventricle without the need for additional excision of the right atrium.

Improved postoperative pain relief via preemptive analgesia in relation to heart rate variability for coronary artery bypass grafting: a preliminary report

BACKGROUND

Sudden cardiac death remains to be the most devastating outcome for patients who undergo cardiac surgery. Surgical stress in combination with postoperative pain are key factors of such tragedy. Preemptive analgesia (PA) is supposed to provide optimal postoperative pain management, and epidural morphine infusion to provide effective pain relief and stress reduction after cardiac surgery. Heart rate (HR) variability seems to correlate to the survival of acute myocardial infarction (AMI) patients. This study was conducted to evaluate the benefits of PA for coronary artery bypass grafting (CABG) patients in the sense of improvement in postoperative respiratory and cardiovascular functions, and its correlation to HR and HR variability.

METHODS

A total of 40 patients who underwent CABG from June 1995 to December 1995 were randomly selected and divided into two groups (Group A and Group B). Group A (n = 20) was treated with conventional postoperative analgesia of intravenous (i.v.) meperidine HCl (Demerol). Group B (n = 20) was treated with PA using epidural infusion of local anesthetics plus ketamine and morphine during surgery and then using intermittent epidural morphine infusion for postoperative pain control when necessary, and Demerol was given intravenously as in group A. Postoperative pain intensity was measured by a modified visual analogue pain scale from 0 to 10 (0 = no pain, 10 = severe pain). Perioperative HR and HR variability data based on 24-hour electrocardiograph (ECG) Holter monitoring along with data on respiratory and cardiovascular functions were gathered, analyzed, and compared between Group A and Group B.

RESULTS

Effective analgesia (mean pain score of 0-2) was achieved in 50% of Group A patients and 75% of Group B patients. Group B with the reduced dosage of demerol also had the benefits of smaller degree of respiratory insufficiency, earlier extubation, and less incidence of re-intubation as compared with Group A. For HR comparison between Group A and Group B, statistically significant differences (p < 0.05) were observed in 3 out of the 16 postoperative time segments. For HR variability comparison between Group A and Group B, statistically significant difference (p < 0.05) was observed in one of the time segments while another segment showed marginal significance (p = 0.061). Group B patients also maintained better overall respiratory and cardiovascular functions.

CONCLUSIONS

PA method through the use of epidural anesthesia along with morphine infusion provided better postoperative pain relief and more stable respiratory and cardiovascular functions in our patients with cardiac surgery. Although the differences in HR and HR variability between the control and the PA groups were not statistically significant throughout the period studied, the potential benefits of better understanding the relationship between postoperative pain control and HR variability justify further studies to be conducted.

Effect of energy balance and somatotropin on insulin-like growth factor I in serum and on weight and progesterone of corpus luteum in heifers

Holstein heifers (approximately 1 yr old) were fed to be in negative energy balance (n = 14; NEB) or positive energy balance (n = 15; PEB) during four estrous cycles. Each heifer was given PGF2 alpha to control the timing of fourth estrus. From 1 d after PGF2 alpha injection until 10 d after estrus, half of the heifers were injected daily with 14 mg of somatotropin (bST), and the corpus luteum (CL) was collected on d 10. Heifers in NEB had less IGF-I in serum (P < .01), smaller CL (P < .01), and less progesterone in CL (P < .01) than heifers in PEB. Exogenous bST increased (P < .01) IGF-I in serum, but this increase was greater in heifers in PEB than those in NEB (P < .01 for interaction of energy balance and bST). Nonetheless, bST did not alter weight or progesterone content of the CL in either energy balance group. In addition, serum IGF-I during the first 10 d after estrus was not correlated to luteal weight and only weakly correlated (r = .3) with luteal progesterone content. We conclude that exogenous bST given during luteal development does not alter growth or progesterone content of the CL in heifers. Reduced concentration of IGF-I in serum during luteal development does not account for suppressed luteal growth and progesterone synthesis of heifers in NEB.