TNF-α，IL-1β induce mechano growth factor expression in human fibroblast-like synoviocytes through the PKA pathway / 医用生物力学

Objective To investigate the effects of inflammatory factors TNF-α, IL-1β, IL-6 on expression of mechano growth factor (MGF). Methods In the experimental group, TNF-α and IL-6 at concentration of 25, 50, 100 ng/mL, or IL-1β at concentration of 2.5, 5.0, 10 ng/mL were applied to fibroblast-like synoviocytes (FLSs) for 12 hours. The inhibitor groups were pretreated with PKA pathway inhibitor KT5720 at concentration of 1.0 mmol for 1 hour. The control group remained under the same culture condition as the experimental group, but without any growth factor. Real-time PCR was used to measure the gene expression of MGF. Results Treated with TNF-α at concentration of 25 ng/mL and IL-1β at concentration of 10 ng/mL, the MGF expression in FLSs was significantly increased (P＜0.05). IL-6 had no effect on MGF expression. A specific inhibitor of cAMP-dependent protein kinase, at concentration of 1.0 mmol significantly decreased the activation of MGF synthesis by TNF-α and IL-1β in FLSs (P＜0.05). Conclusions TNF-α at concentration of 25 ng/mL and IL-1β at concentration of 10 ng/mL significantly induce the MGF expression in FLSs, which activate MGF synthesis via the PKA pathway. This study is of significance in improving the application of MGF used in tissue repair area to make up the insufficient stress stimulation.

Effects of oscillatory flow on shear stress distributions in perfusion bioreactor for bone tissue engineering / 医用生物力学

Objective To study the effects of oscillatory flow, as well as pore size and porosity of the 3D scaffold on distributions of flow rate and shear stress in perfusion bioreactor, and to propose optimization methods for preparing the 3D decellularized bone scaffold and perfusion bioreactor based on theoretical results. Methods Based on the previously established 3D decelluarized scaffold and perfusion bioreactor for bone tissue engineering in the laboratory, the decelluarized scaffold was simplified as an isotropic porous media. The velocity and shear stress distributions in the bioreactor were further simulated theoretically. Results Under the oscillatory flow, the Darcy shear stress and velocity in the 3D porous scaffold presented a consistently regular pattern. Compared with the unidirectional flow, the difference of velocity and Darcy shear stress decreased at different radius, which could contribute to the homogeneous 3D culture of seed cells in bone tissue engineering. Increasing the inlet perfusion velocity could improve the average Darcy shear stress. Increasing the pore diameter or porosity of the scaffold had no obvious effects on the peak value of velocity, but sharply reduced the average Darcy shear stress. Increasing inlet oscillation frequency could decrease the peak value of velocity and obviously decrease the difference of velocity at different radius. Conclusions Appropriate oscillatory flow was beneficial for generating required shear stress for stem cells in bone tissue engineering. The research findings in this study are expected to provide theoretical guidance to optimize the 3D culture method of seed cells for bone tissue engineering.

Necessity of defunctioning stoma in low anterior resection for rectal cancer: a meta-analysis / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To evaluate the necessity of defunctioning stoma in low anterior resection for rectal cancer below peritoneal reflection.</p><p><b>METHODS</b>The databases of Medline, Embase, Cochrane Library, Wanfang and CNKI were searched. The eligible studies were identified for pooled analyses.</p><p><b>RESULTS</b>Six randomized controlled trials with 648 cases(332 patients with defunctioning stoma and 316 without stoma) and 25 retrospective controlled trials with 10,722 cases(4,470 patients with defunctioning stoma and 6,252 without stoma) were included. Combined analyses showed that defunctioning stoma was effective for decreasing risk of postoperative anastomotic leakage (RR=0.33 and 95% CI:0.21-0.53 for RCTs, OR=0.60 and 95% CI:0.42-0.85 for retrospective studies), reoperation (RR=0.30, 95% CI:0.16-0.53 for RCTs, OR=0.26 and 95% CI:0.21-0.32 for retrospective studies) and mortality(OR=0.41, 95% CI:0.27-0.62 for retrospective studies).</p><p><b>CONCLUSION</b>Defunctioning stoma should be routinely performed in low anterior resection for high-risk patients.</p>

Effects of cyclic mechanical stretch on BMP-2 expression in RA and OA fibroblast-like synoviocytes / 医用生物力学

Objective To explore the role of mechanical stimulation in synovium under different pathological conditions through studying the effects of cyclic mechanical stretch on the expression of bone morphogenetic protein 2 (BMP-2) in rheumatoid arthritis (RA) and osteoarthritis (OA) fibroblast-like synoviocytes (FLS). Method 6% and 0.5 Hz stretch generated by Flex cell 4000 tension systems was applied on normal, RA and OA FLS of human knee joint source under normal and inflammatory conditions for 2 h or 6 h, respectively. Results Cyclic mechanical stretch of 6%, 0.5 Hz had no significant effects on the expression of BMP-2 in normal, RA and OA FLS at 2 h, while in RA FLS it increased significantly at 6 h. Inflammatory cytokines (IL-1β) didn’t influence normal FLS at 2 h, but made BMP-2 mRNA significantly increased at 6 h. IL-1β increased BMP-2 mRNA of RA FLS significantly both at 2 h and 6 h. IL-1β increased BMP-2 mRNA of OA FLS significantly only at 2 h, but had no significant effect at 6 h. The co-effect of IL-1β and cyclic mechanical stretch induced the ascension of BMP-2 expression significantly in normal and RA FLS at 2 h, and in normal, RA and OA FLS at 6 h. Conclusions Response of BMP-2 mRNA to mechanic stimulation and IL-1β in normal, RA and OA FLS were different. Inflammation may play a more important role than mechanical stimulation in the pathogenesis of RA and OA. Synergetic effect in inflammation and mechanical stimulation were found in OA FLS at 6 h, which reveals that they may co-act in the occurrence and development of OA.

Association of peripheral and central blood pressure with the alpha-adducin Gly460Trp polymorphism in a Chinese population / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the association of peripheral and central blood pressure with the alpha-adducin Gly460Trp polymorphism in Chinese.</p><p><b>METHODS</b>We randomly selected 6 villages from JingNing County, ZheJiang Province. We invited nuclear families to take part in our study. We measured each participant's blood pressure at the non-dominant arm by means of a standard mercury sphygmomanometer at subjects' homes. Five consecutive readings were averaged for analysis. Central blood pressures were obtained by use of SphigmoCor pulse wave analysis system. The observers administered a standardized questionnaire to collect information on smoking habits, alcohol consumption and use of antihypertensive drugs. Venous blood was sampled and the adducin genotype was determined by restrictive fragment length polymorphism (RFLP).</p><p><b>RESULTS</b>Four hundred and forty-two subjects included 230 (52.0%) women, and 116 (26.2%) hypertensive patients, of whom 49 (11.1%) took antihypertensive drugs. The frequencies of alpha -adducin GlyGly, GlyTrp and TrpTrp genotypes were 21.3%, 54.5% and 24.2%, respectively. There was no association between the alpha-adducin Gly460Trp polymorphism and peripheral systolic and diastolic blood pressure and pulse pressure. However, both before and after adjustment for sex, age, age(2), body-mass index, current smoking, alcohol intake, and antihypertensive treatment, the alpha-adducin polymorphism was significantly (P < 0.02) associated with central systolic blood pressure and central pulse pressure. After adjustment, central systolic blood pressure (+/- SE) averaged 122.5 +/- 3.5, 114.1 +/- 1.5 and 109.1 +/- 1.8 mm Hg (P = 0.01) in the GlyGly, GlyTrp and TrpTrp subjects, respectively. The corresponding values for central pulse pressure were 39.4 +/- 1.3, 36.4 +/- 1.0 and 32.9 +/- 0.9 mm Hg (P = 0.002), respectively.</p><p><b>CONCLUSIONS</b>In the JingNing population, the adducin 460Trp allele was associated with lower levels of central systolic pressure and pulse pressure.</p>