[A prospective study on application of human umbilical cord mesenchymal stem cells combined with autologous Meek microskin transplantation in patients with extensive burns]

Objective: To investigate the effects of human umbilical cord mesenchymal stem cells (hUCMSCs) combined with autologous Meek microskin transplantation on patients with extensive burns. Methods: The prospective self-controlled study was conducted. From May 2019 to June 2022, 16 patients with extensive burns admitted to the 990th Hospital of PLA Joint Logistics Support Force met the inclusion criteria, while 3 patients were excluded according to the exclusion criteria, and 13 patients were finally selected, including 10 males and 3 females, aged 24-61 (42±13) years. A total of 20 trial areas (40 wounds, with area of 10 cm×10 cm in each wound) were selected. Two adjacent wounds in each trial area were divided into hUCMSC+gel group applied with hyaluronic acid gel containing hUCMSCs and gel only group applied with hyaluronic acid gel only according to the random number table, with 20 wounds in each group. Afterwards the wounds in two groups were transplanted with autologous Meek microskin grafts with an extension ratio of 1∶6. In 2, 3, and 4 weeks post operation, the wound healing was observed, the wound healing rate was calculated, and the wound healing time was recorded. The specimen of wound secretion was collected for microorganism culture if there was purulent secretion on the wound post operation. In 3, 6, and 12 months post operation, the scar hyperplasia in wound was assessed using the Vancouver scar scale (VSS). In 3 months post operation, the wound tissue was collected for hematoxylin-eosin (HE) staining to observe the morphological changes and for immunohistochemical staining to observe the positive expressions of Ki67 and vimentin and to count the number of positive cells. Data were statistically analyzed with paired samples t test and Bonferronni correction. Results: In 2, 3, and 4 weeks post operation, the wound healing rates in hUCMSC+gel group were (80±11)%, (84±12)%, and (92±9)%, respectively, which were significantly higher than (67±18)%, (74±21)%, and (84±16)% in gel only group (with t values of 4.01, 3.52, and 3.66, respectively, P<0.05). The wound healing time in hUCMSC+gel group was (31±11) d, which was significantly shorter than (36±13) d in gel only group (t=-3.68, P<0.05). The microbiological culture of the postoperative wound secretion specimens from the adjacent wounds in 2 groups was identical, with negative results in 4 trial areas and positive results in 16 trial areas. In 3, 6, and 12 months post operation, the VSS scores of wounds in gel only group were 7.8±1.9, 6.7±2.1, and 5.4±1.6, which were significantly higher than 6.8±1.8, 5.6±1.6, and 4.0±1.4 in hUCMSC+gel group, respectively (with t values of -4.79, -4.37, and -5.47, respectively, P<0.05). In 3 months post operation, HE staining showed an increase in epidermal layer thickness and epidermal crest in wound in hUCMSC+gel group compared with those in gel only group, and immunohistochemical staining showed a significant increase in the number of Ki67 positive cells in wound in hUCMSC+gel group compared with those in gel only group (t=4.39, P<0.05), with no statistically significant difference in the number of vimentin positive cells in wound between the 2 groups (P>0.05). Conclusions: The application of hyaluronic acid gel containing hUCMSCs to the wound is simple to perform and is therefore a preferable route. Topical application of hUCMSCs can promote healing of the autologous Meek microskin grafted area in patients with extensive burns, shorten wound healing time, and alleviate scar hyperplasia. The above effects may be related to the increased epidermal thickness and epidermal crest, and active cell proliferation.

Pharmacological treatment of inhalation injury after nuclear or radiological incidents: The Chinese and German approach

Inhalation injury is often associated with burns and significantly increases morbidity and mortality. The main toxic components of fire smoke are carbon monoxide, hydrogen cyanide, and irritants. In the case of an incident at a nuclear power plant or recycling facility associated with fire, smoke may also contain radioactive material. Medical treatments may vary in different countries, and in this paper, we discuss the similarities and differences in the treatments between China and Germany. Carbon monoxide poisoning is treated by 100% oxygen administration and, if available, hyperbaric oxygenation in China as well as in Germany. In addition, antidotes binding the cyanide ions and relieving the respiratory chain are important. Methemoglobin-forming agents (e.g., nitrites, dimethylaminophenol) or hydroxocobalamin (Vitamin B12) are options. The metabolic elimination of cyanide may be enhanced by sodium thiosulfate. In China, sodium nitrite with sodium thiosulfate is the most common combination. The use of dimethylaminophenol instead of sodium nitrite is typical for Germany, and hydroxocobalamin is considered the antidote of choice if available in cases of cyanide intoxications by fire smoke inhalation as it does not further reduce oxygen transport capacity. Systematic prophylactic use of corticosteroids to prevent toxic pulmonary edema is not recommended in China or Germany. Stable iodine is indicated in the case of radioiodine exposure and must be administered within several hours to be effective. The decorporation of metal radionuclides is possible with Ca (DTPA) or Prussian blue that should be given as soon as possible. These medications are used in both countries, but it seems that Ca (DTPA) is administered at lower dosages in China. Although the details of the treatment of inhalation injury and radionuclide(s) decorporation may vary, the general therapeutic strategy is very similar in China and Germany.

[Effects of cardiac support on delayed resuscitation in extensively burned patients with shock]

Objective: To explore the effects of cardiac support on delayed resuscitation in extensively burned patients with shock. Methods: Clinical data of 62 extensively burned patients with shock on admission, admitted to the 159th Hospital of PLA (hereinafter referred to as our hospital) from January 2012 to January 2017, were retrospectively analyzed. They were divided into cardiac support group (n=35) and control group (n=27) according to the use of deslanoside and ulinastatin. All patients were treated with routine fluid resuscitation based on the formula of the Third Military Medical University till post injury hour (PIH) 48. Patients in cardiac support group were given slow intravenous injection of deslanoside which was added in 20 mL 100 g/L glucose injection with first dose of 0.4 to 0.6 mg, 0.2 to 0.4 mg per 6 to 8 h, no more than 1.6 mg daily, and slow intravenous injection of 1×10(5)U ulinastatin which was added in 100 mL 50 g/L glucose injection, once per 12 h. Other treatments of patients in the two groups followed the same conventional procedures of our hospital. The following data of the two groups of patients were collected. (1) The data of urine volume per hour within PIH 48, heart rate, mean arterial pressure (MAP), central venous pressure (CVP), blood lactic acid, base excess, hematocrit, and albumin at PIH 48 were recorded. (2) The input volumes of electrolyte, colloid within the first and second 24 hours post burn and the total fluid input volumes within PIH 48 were recorded. (3) The data of creatine kinase, creatine kinase isoenzyme-MB, lactate dehydrogenase, total bile acid, alanine aminotransferase, aspartate aminotransferase, β(2)-microglobulin, urea nitrogen, and creatinine at PIH 48 were recorded. (4) The complications including cardiac failure, pulmonary edema, pleural effusion, seroperitoneum, renal failure, sepsis, and death were also recorded. Data were processed with independent sample ttest, Fisher's exact test, Pearson chi-square test, or continuous correction chi-square test. Results: (1) There were no statistically significant differences in urine volume within PIH 48, heart rate, MAP, CVP, hematocrit, or albumin at PIH 48 between the patients of two groups (t=0.150, 0.488, 0.805, 0.562, 1.742, 0.696, P>0.05). While the levels of blood lactic acid and base excess were respectively (4.2±2.2) and (-4.3±2.0) mmol/L in patients of cardiac support group, which were significantly better than (5.9±1.7) and (-6.0±3.1) mmol/L in patients of control group (t=3.249, 2.480, P<0.05 or P<0.01). (2) There was no statistically significant difference in input volume of colloid within the first 24 hours post burn between the patients of two groups (t=0.642, P>0.05). The input volume of electrolyte within the first 24 hours post burn, the input volumes of electrolyte and colloid within the second 24 hours post burn, and the total fluid input volume within PIH 48 of patients in cardiac support group were significantly less than those in control group (t=2.703, 4.223, 3.437, 2.515, P<0.05 or P<0.01). (3) The levels of creatine kinase, creatine kinase isoenzyme-MB, lactate dehydrogenase, total bile acid, alanine aminotransferase, aspartate aminotransferase, β(2)-microglobulin, urea nitrogen, and creatinine of patients in cardiac support group at PIH 48 were significantly lower than those in control group (t=3.066, 3.963, 3.225, 2.943, 2.431, 3.084, 4.052, 2.915, 3.353, P<0.05 or P<0.01). (4) The occurrences of pleural effusion and seroperitoneum and mortality of patients in cardiac support group were significantly lower than those in control group (χ(2)=5.514, 6.984, 4.798, P<0.05 or P<0.01). There were no statistically significant differences in cardiac failure, pulmonary edema, renal failure, and sepsis between the patients of two groups [χ(2)=1.314 (sepsis), P>0.05]. Conclusions: The cardiotonic and cardiac protection treatments in delayed resuscitation of extensively burned patients with shock contribute to improving the cellular anonic metabolism, reducing the volume of fluid resuscitation, and mitigating the ischemic and hypoxic damage to organs, so as to lay foundation for decreasing further complication incidences and mortality.

[Preliminary study on immunologic tolerance for hetero-skin graft induced by chimeric donors]

OBJECTIVE

To explore the feasibility of transplanting the skin from chimeric rats to rabbits.

METHODS

Chimeric rats were produced by transplanting the haematopoietic stem cells (HSCs) from rabbit marrows into fetal rats in uterus and followed by injecting the HSCs into the livers of the rats at newborn stage. After six weeks, the skin from chimeric rats was transplanted to the rabbits. In group A, the skin grafts from chimeric rat donors were transplanted to the HSCs donating rabbits, with the skin from non-chimeric rat to normal rabbits were used as control. In group B, the skin grafts from chimeric and non-chimeric rats were transplanted to the HSCs donating rabbits at the same time. Gross observation and the surviving time of heterogenic-skin graft were observed. The wound healing time was also recorded.

RESULTS

In group A, the surviving time and the wound healing time of non-chimeric grafts were (9.3 +/- 1.8) days and (20.9 +/- 2.1) days, respectively, while those in chimeric grafts were (15.1 +/- 2.6) and (18.5 +/-1.3) days, respectively. In group B, the surviving time and the wound healing time of non-chimeric grafts were similar to those of group A. Compared with those in non-chimeric grafts, the surviving time of chimeric grafts in both groups were prolonged (P < 0.01), and the wound healing time shortened (P < 0.05 or 0.01). Most of the wounds healed quickly after rejection of chimeric grafts, while the wounds with non-chimeric grafts were re-opened with exudation and some necrotic tissue.

CONCLUSION

Immunologic tolerance for skin graft can be induced by the skin from chimeric donors, which can prolong the surviving time of skin grafts and shorten the wound healing time.