Epidermal growth factor promotes mesenchymal stem cell-mediated wound healing and hair follicle regeneration.

BACKGROUND AND AIM: Bone marrow mesenchymal stem cells (MSC) are receiving increasing attention for skin wound repair. However, the specific mechanisms underlying MSC-mediated improvement in wound healing have not been fully elucidated. This study aims at testing whether epidermal growth factor (EGF) can promote MSC-mediated wound healing and hair follicle regeneration. METHODS: Excisional wounds in rats were transplanted with different collagen-chitosan scaffolds: control, MSC, and MSC + EGF. Regenerated tissues were harvested 1, 3, or 5 weeks following transplantation, stained with hematoxylin and eosin and evaluated microscopically. The formation of sebaceous glands was examined by Oil red staining and the regeneration of hair follicles by immunohistochemical staining and Western blot to test the expression of hair follicle-specific factors. RESULTS: Gross observations showed that the wounds were much smaller and the hairs grew faster in the MSC + EGF group. Histological analysis demonstrated that there were more hair follicles, sebaceous glands, and newly formed blood vessels in the MSC + EGF group compared with that in the MSC group. In addition, oil red staining showed that MSCs + EGF induced sebaceous gland regeneration. Finally, immunohistochemistry and western blot revealed that MSCs + EGF increased the expression of hair follicle-specific factors. CONCLUSION: MSCs alone cannot achieve the regeneration of hair follicles and EGF can promote MSC-mediated wound healing and hair follicle regeneration.

[Effects of fluid resuscitation programs on the levels of inflammatory mediators during burn shock stage].

OBJECTIVE: To explore the effects of different methods of fluid resuscitation on the levels of inflammatory mediators during burn shock stage. METHODS: Twenty-four miniature swine were numbered from 1 to 24 and randomly divided by EXCEL 2007 into 4 groups of succinylated gelatin, hydroxyethyl starch, Parkland and allogeneic plasma (n = 6 each). Severe burn shock model was established. Succinylated gelatin, hydroxyethyl starch (130/0.4), Ringer's lactate and swine allogenic plasma were used as resuscitation fluid (alternative colloid) according to the burn shock recovery principles (beginning at 2 h post-injury). The parameters of heart rate (HR), blood pressure (BP), urine volume and central venous pressure (CVP) before and within 48 h post-burn were recorded. And the levels of tumor necrosis factor alpha (TNF-α), interleukin (IL) -1ß and IL-8 were measured at the time of pre-injury as well as 4 h, 8 h, 24 h and 48 h post-injury. Statistical analyses were performed. RESULTS: All swine survived the shock stage. TNF-α in succinylated gelatin group was significantly higher at 48 h post-injury than that in allogeneic plasma group ((351 ± 74) vs (215 ± 44) ng/L, P < 0.05). TNF-α in hydroxyethyl starch group was significantly higher at 8 h post-injury than that in allogeneic plasma group ((327 ± 38) vs (249 ± 29) ng/L, P < 0.05). And they were both higher than the pre-burn levels (both P < 0.05). Compared with pre-injury ((508 ± 64) ng/L), the level of IL-1ß in succinylated gelatin group increased substantially at 4 h ((563 ± 76) ng/L), 8 h ((589 ± 76) ng/L) and 48 h ((736 ± 42) ng/L) post-injury (all P < 0.05). The hydroxyethyl starch group was higher at 48 h post-injury than that at pre-injury ((574 ± 72) vs (492 ± 41) ng/L, P < 0.05). Also in Parkland group, the levels were higher at 24 h and 48 h hours post-injury than that at pre-injury ((575 ± 31), (584 ± 65) vs (498 ± 33) ng/L, both P < 0.05). Only succinylated gelatin group was significantly higher (P < 0.01) at 48 h post-injury than allogeneic plasma group ((561 ± 48) ng/L). Compared with pre-injury ((561 ± 48) ng/L), the level of IL-8 in succinylated gelatin group increased significantly at 8 h ((1012 ± 100) ng/L), 24 h post-burn ((993 ± 87) ng/L), significantly higher than allogeneic plasma group ((866 ± 99) ng/L) at 24 h (all P < 0.05). Although hydroxyethyl starch and Parkland groups increased significantly at 4 h post-injury and 8 h, 48 h post-injury versus those at pre-injury (all P < 0.05). There was no significant difference at each time point compared with pre-burn (P > 0.05). CONCLUSIONS: The recovery regimens of hydroxyethyl starch and Parkland groups may restrain the levels of inflammatory mediators. And the effects are similar to those of allogeneic plasma group.

[Effects of resuscitation with different kinds of colloids on pulmonary edema in swine in shock stage of severe burn injury].

OBJECTIVE: To observe and compare the effects of natural colloid and artificial colloid on pulmonary edema of swine during shock stage of severe burn injury. METHODS: Twelve Guangxi Bama miniature swine were inflicted with 40% TBSA full-thickness burn on the back, and then they were divided into natural colloid group (N) and artificial colloid group (A) according to the random number table, with six swine in each group. At post injury hour (PIH) 2, fluid resuscitation was begun. The main part of electrolyte was lactic acid Ringer's solution. The colloids included swine plasma and hydroxyethyl starch 130/0.4. Before injury and at every hour within PIH 48, heart rate, blood pressure, urine volume, central venous pressure (CVP), and pulmonary arterial wedge pressure (PAWP) were recorded. The mean heart rate, blood pressure, urine volume per hour per kg of body weight, CVP, PAWP, resuscitation liquid volume, and the ratio of fluid intake to output during the first and second PIH 24 were calculated. At PIH 48, lung tissue was harvested for histopathological observation and calculation of lung water ratio. Data were processed with one-way analysis of variance, analysis of variance of repeated measurement, LSD test and independent sample t test. RESULTS: (1) There were no statistically significant differences between two groups in heart rate, blood pressure, and urine volume before injury and during the first and second PIH 24 (P values all above 0.05); during the first PIH 24, the CVP and PAWP of group A were significantly higher than those of group N (P values all below 0.05). Compared with those before injury, the heart rate, CVP and PAWP of two groups during the first and second PIH 24 were significantly higher (P < 0.05 or P < 0.01); the urine volume of group N was decreased during the first PIH 24 (P < 0.05), while there was no significant change in group A (P > 0.05); the urine volumes of two groups during the second PIH 24 were increased, while no statistically significant differences were observed (P values all above 0.05). There were no statistically significant differences in blood pressure of two groups between the first, second PIH 24 and before injury (P values all above 0.05). (2) There were no statistically significant differences in the resuscitation liquid volume and fluid intake to output ratio between two groups during the first and second PIH 24 (P values all above 0.05). (3) The alveolar septum was found widened in varying degrees, and there were edema fluid accumulating and inflammatory cell infiltrating within the pulmonary interstitial of lung tissue sections in both two groups. (4) The lung water ratio of group N [(71 ± 10)%] was not statistically significant different from that of group A [(79 ± 4)%, t = -1.753, P > 0.05]. CONCLUSIONS: The natural colloid or artificial colloid (hydroxyethyl starch 130/0.4) applied during shock stage had similar effects on pulmonary edema in swine with severe burn.

[Retrospective survey of nutritional support therapy in adult patients after severe burn].

OBJECTIVE: To investigate the status of nutritional support therapy in moderate and severe burn patients. METHODS: The burn patients with age over 16 y and burn area larger than 20% TBSA were enrolled in the retrospective study. According to length of stay, all patients were divided into the first period (271 cases, was from 1994 to 2001 year), and second period (273 cases, from 2002 to 2007 year), and they were subdivided into a (20% - 30% TBSA), b (31% - 50% TBSA), c (51% - 70% TBSA), d (larger than 70% TBSA) groups. The death rate and ratio of nutritional support therapy were compared. The change in albumin and other indices (including side-effects, complication, etc) were analyzed in each group in second period. RESULTS: There were similar in general conditions in both groups, however, some were obvious difference in two periods between nutritional support therapy rate (74.17% in first period vs 85.35% in second period, P < 0.01), and the ratio of parenteral nutrition to enteral nutrition (1.5:1.0 in first period, 1.0:1.5 in second period, P < 0.01). There were also significant differences in albumin levels among each group in second period on 4, 7, 14 days after burn (P < 0.05). In the second period, parenteral nutrition preparation was mostly delivered through central vein in the form of "all-in-one", among them 62 cases of positive catheter cultures were found. Enteral nutrition was delivered by oral route in 108 cases, naso-gastric or naso-enteric tubes with pump in 165 cases. 27 cases with severe gastrointestinal complications and 2 cases with inhalation pneumonia occurred. CONCLUSION: The ratio of parenteral nutrition and enteral nutrition in burn patients was higher in our ward than average level in China. There is still a long way ahead to optimize nutritional therapy.