Mowry Katie C, Bonvallet Paul P, Bellis Susan L
Wounds. 2017 Sep;29(9):277-285.
Chronic and recalcitrant wounds present a significant therapeutic challenge. Amniotic tissues contain many regenerative cytokines, growth factors, and extracellular matrix molecules including proteoglycans, hyaluronic acid, and collagens I, III, and IV. Dehydrated amnion/chorion grafts are currently used to treat a variety of wounds such as diabetic foot ulcers and burns.
The investigators hypothesized that processing methodologies, dehydration, and hypothermic processing and storage of amniotic tissues would affect overall quality of wound healing; they compared dehydrated amnion/chorion (dHACM) grafts to a novel hypothermically stored amniotic membrane (HSAM) graft in a full-thickness rat wound model.
Sprague-Dawley rats were anesthetized and prepped for surgery; four 1.5-cm diameter full-thickness wounds were created and treated with either: (1) dHACM, (2) dHACM meshed, (3) HSAM, or (4) wound left ungrafted (sham). After 9 or 21 days, wounds and surrounding areas were collected and stained with hematoxylin and eosin. Blinded quantitative analysis of quality of wound healing was completed by evaluating hair follicle/gland formation, dense/scar-like matrix, and basket-weave matrix.
At varying time points following placement of the grafts into full-thickness defects, the authors found that all amniotic-derived tissue grafts appeared to stimulate improved healing over sham wounds, evidenced by more normal-appearing dermal matrix architecture, epidermal structure, and maturity. In addition, the HSAM grafts promoted greater tissue regeneration than the dHACM meshed grafts, as measured by the presence of basket-weave collagen matrix and formation of follicles and glands.
In sum, this study builds on the amassing literature supporting amniotic tissues for wound repair and demonstrates the importance of tissue processing on the quality of wound healing.
慢性难愈性伤口带来了重大的治疗挑战。羊膜组织含有许多再生细胞因子、生长因子以及细胞外基质分子,包括蛋白聚糖、透明质酸、Ⅰ型、Ⅲ型和Ⅳ型胶原蛋白。脱水羊膜/绒毛膜移植物目前用于治疗多种伤口,如糖尿病足溃疡和烧伤。
研究人员推测,羊膜组织的处理方法、脱水、低温处理和储存会影响伤口愈合的整体质量;他们在大鼠全层伤口模型中,将脱水羊膜/绒毛膜(dHACM)移植物与一种新型低温储存羊膜(HSAM)移植物进行了比较。
将Sprague-Dawley大鼠麻醉并准备手术;制造四个直径1.5厘米的全层伤口,并用以下方法处理:(1)dHACM,(2)网状dHACM,(3)HSAM,或(4)不进行移植(假手术)。9天或21天后,收集伤口及周围区域,并用苏木精和伊红染色。通过评估毛囊/腺体形成、致密/瘢痕样基质和篮状编织基质,对伤口愈合质量进行盲法定量分析。
在将移植物植入全层缺损后的不同时间点,作者发现,所有羊膜来源的组织移植物似乎都比假手术伤口能促进更好的愈合,表现为真皮基质结构、表皮结构和成熟度更接近正常。此外,通过篮状编织胶原基质的存在以及毛囊和腺体的形成来衡量,HSAM移植物比网状dHACM移植物能促进更大程度的组织再生。
总之,本研究以大量支持羊膜组织用于伤口修复的文献为基础,证明了组织处理对伤口愈合质量的重要性。