Research advances on stem cell therapy for diabetic foot wounds / 中华烧伤杂志

Diabetic foot wound repair is a challenging issue in clinical practice. Due to the influence of multiple factors including the damage and regeneration failure of local tissue, the impaired pathways of wound repairing through blood vessels and nerve nutrition, and disorders of a variety of cellular factors, traditional treatment methods are often difficult to achieve good therapeutic effects. Stem cells are a type of cells with potentials of multidirectional differentiation, which also possess functions such as regulating immunity and paracrine to facilitate the comprehensive wound repair, so they have promising application prospect at present for the treatment of diabetic foot wounds. Because the relevant parameters of stem cell treatment are in the exploratory phase, there were no standardized data. This paper reviews the application of stem cells in the research of diabetic foot wound treatment over the past 6 years, analyzing and summarizing the contents in focused aspects including the types and sources of stem cells, effects of donor age and gender on stem cells, mode of administration, transplantation survival rate and safety, which may provide a reference for further application of stem cells in the clinical treatment of diabetic foot wound.

Restitution of atrial repolarization and atrial fibrillation in canine atrium / 中华心血管病杂志

<p><b>OBJECTIVE</b>Electrical restitution was believed to be a determinant responsible for the stability of heart rhythm. Although numerous studies focused on the role of action potential duration restitution (APDR) in the initiation and maintenance of ventricular fibrillation (VF), the relationship between atrial APDR and atrial fibrillation (AF) has not been fully understood. This study aims to investigate the characteristics of APDR of left atrium (LA) and right atrium (Rs) in canines and the relevance to induction of AF.</p><p><b>METHODS</b>Monophasic action potential (MAP) was recorded from LA and RA in 14 canines using the MAP recording-pacing combination catheter. APDR, plotted as action potential duration (APD) on the preceding diastolic interval (DI), was assessed by use of programmed stimulation with a single extrastimulus (S1S2) at LA and RA. Episodes of AF were recorded and analyzed.</p><p><b>RESULTS</b>APD90 was significantly shorter in the LA than that in the RA [(157.4 +/- 43.5) ms vs. (170.9 +/- 37.9) ms, P < 0.05]. The mean slope of the APDR curve by S1S2 in the LA was significantly greater than that in the RA (1.3 +/- 0.4 vs. 0.9 +/- 0.3, P < 0.05). The incidence of induced AF was significantly higher in the LA than in the RA (11/18 vs. 7/18, P < 0.05).</p><p><b>CONCLUSIONS</b>The APDR and MAP characteristics are not uniform between atrium, which may be one of the important mechanisms responsible for the initiation of AF. Heterogeneity of APDR between LA and RA might create critical gradients or a dispersion of repolarization and substrate for re-entrant arrhythmias and vulnerability to AF.</p>

Impact of right upper pulmonary vein isolation on atrial vagal innervation and vulnerability to atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Based on the hypothesis that pulmonary vein isolation could result in the damage of the epicardial fat pads, this study aimed to investigated the impact of right upper pulmonary vein (RUPV) isolation on vagal innervation to atria.</p><p><b>METHODS</b>Bilateral cervical sympathovagal trunks were decentralized in 6 dogs. Metoprolol was given to block sympathetic effects. Multipolar catheters were placed into the right atrium (RA) and coronary sinus (CS). RUPV isolation was performed via transseptal procedure. Atrial effective refractory period (ERP), vulnerability window (VW) of atrial fibrillation (AF), and sinus rhythm cycle length (SCL) were measured at RA and distal coronary sinus (CSd) at baseline and vagal stimulation before and after RUPV isolation. Serial sections of underlying tissues before and after ablation were stained with haematoxylin and eosin.</p><p><b>RESULTS</b>SCL decreased significantly during vagal stimulation before RUPV isolation (197 +/- 21 vs 13 +/- 32 beats per minute, P < 0.001), but remained unchanged after RUPV isolation (162 +/- 29 vs 140 +/- 39 beats per minute, P > 0.05). ERP increased significantly before RUPV isolation compared with that during vagal stimulation [(85.00 +/- 24.29) ms vs (21.67 +/- 9.83) ms at RA, P < 0.001; (90.00 +/- 15.49) ms vs (33.33 +/- 25.03) ms at CSd P < 0.005], but ERP at baseline hardly changed after RUPV isolation compared with that during vagal stimulation [(103.33 +/- 22.50) vs (95.00 +/- 16.43) ms at RA, P = 0.09; (98.33 +/- 24.83) vs (75.00 +/- 29.50) ms at CSd, P = 0.009]. The ERP shortening during vagal stimulation after RUPV isolation decreased significantly [(63.33 +/- 22.51) ms vs (8.33 +/- 9.83) ms at RA, P < 0.005; (56.67 +/- 20.66) ms vs (23.33 +/- 13.66) ms at CSd, P < 0.05]. AF was rarely induced at baseline before and after RUPV isolation (VW close to 0), while VW of AF to vagal stimulation significantly decreased after RUPV isolation [(40.00 +/- 10.95) vs 0 ms at RA, P < 0.001; (45.00 +/- 32.09) vs (15.00 +/- 23.45) ms at CS, P < 0.05]. The architecture of individual ganglia was significantly altered after ablation.</p><p><b>CONCLUSIONS</b>The less ERP shortening to vagal stimulation and altered architecture of individual ganglia after right upper pulmonary vein isolation indicate that isolation may result in damage of the epicardial fat pads, thereby attenuating the vagal innervation to atria. The decreased vulnerability window of atrial fibrillation indicates that vagal denervation may contribute to its suppression.</p>