School of Pharmacy, School of Medicine, Changzhou University, Changzhou, Jiangsu 213164, China; Affiliated Changzhou Children's Hospital of Nantong University, Changzhou, Jiangsu 213003, China.
School of Pharmacy, School of Medicine, Changzhou University, Changzhou, Jiangsu 213164, China.
Int Immunopharmacol. 2021 Jul;96:107597. doi: 10.1016/j.intimp.2021.107597. Epub 2021 Mar 31.
Necrotizing enterocolitis (NEC) remains a fatal gastrointestinal disorder in neonates. Disialyllacto-N-tetraose (DSLNT), a function-unclear human milk-derived hexasaccharide, shows anti-NEC potential in previous animal studies. This study is aimed to explore the role of mast cell (MC), a fundamental cell type of mucosal immune system and protective DSLNT in regulating pathological process of NEC. For this purpose, infantile intestinal-tissues were collected from NEC neonates for examination of MCs and its proteases-positive cells. MC accumulation and MC-specific proteases (chymase, tryptase and dipeptidyl peptidase I) were firstly found in lesioned area of NEC infants in-vivo. Subsequent in-situ experiments on neonatal ileum segments showed that purified MC-chymase induced a destructive epithelial layer shedding from basement and microvascular endothelium damage in infantile intestinal segments. Human foreskin MC-activation model was established and DSLNT were applied; MC products (histamine and MC-proteases) were used as MC activation/degranulation indicators. In this in-vitro model, DSLNT pretreatment suppressed release of histamine, chymase and tryptase by MC to the tissue supernatants during lipopolysaccharide or complement C5a stimulation. Newborn rats were formula-hand-fed with or without DSLNT supplement and exposed to hypoxia/cold-stress to induce experimental-NEC-model. In NEC rats, DSLNT supplementation reduced the incidence and pathological scores of NEC, inhibited local accumulation of MC and reduced cytokines (IL-1β, IL-6 and TNF-α) levels in the ileum of rats. In conclusion, MC was causally implicated in epithelium barrier failure in pathogenesis of NEC. DSLNT favorably modulated MC homeostasis by regulating MC degranulation/accumulation, contributing to attenuated NEC. This indicated novel pathomechanisms and potential targets of NEC.
坏死性小肠结肠炎（NEC）仍然是新生儿致命的胃肠道疾病。二唾液酸乳糖-N-四糖（DSLNT）是一种功能不明的人乳来源的六糖，在之前的动物研究中显示出抗 NEC 的潜力。本研究旨在探索肥大细胞（MC）作为黏膜免疫系统的基本细胞类型和保护性 DSLNT 在调节 NEC 病理过程中的作用。为此，从 NEC 新生儿中收集婴儿肠道组织，以检查 MC 及其蛋白酶阳性细胞。MC 聚集和 MC 特异性蛋白酶（糜蛋白酶、胰蛋白酶和二肽基肽酶 I）首先在 NEC 婴儿的病变区域中被发现。随后在新生儿回肠段的原位实验表明，纯化的 MC-糜蛋白酶诱导上皮层从基底脱落，并破坏婴儿肠道段的微血管内皮细胞。建立了人包皮 MC 激活模型，并应用了 DSLNT；MC 产物（组胺和 MC 蛋白酶）被用作 MC 激活/脱颗粒的指标。在这个体外模型中，DSLNT 预处理抑制了 LPS 或补体 C5a 刺激时 MC 向组织上清液中释放组胺、糜蛋白酶和胰蛋白酶。新生大鼠用或不用 DSLNT 补充配方奶喂养，并暴露于缺氧/冷应激下，以诱导实验性 NEC 模型。在 NEC 大鼠中，DSLNT 补充减少了 NEC 的发生率和病理评分，抑制了 MC 的局部积累，并降低了大鼠回肠中的细胞因子（IL-1β、IL-6 和 TNF-α）水平。总之，MC 在 NEC 的发病机制中与上皮屏障功能障碍有关。DSLNT 通过调节 MC 脱颗粒/聚集来有利地调节 MC 稳态，有助于减轻 NEC。这表明了 NEC 的新发病机制和潜在靶点。
