Martins Raquel Dos Santos, Hulscher Jan B F, Timmer Albert, Kooi Elisabeth M W, Poelstra Klaas
Division of Pediatric Surgery, Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, Netherlands.
Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands.
Front Pediatr. 2024 Apr 30;12:1401090. doi: 10.3389/fped.2024.1401090. eCollection 2024.
Necrotizing enterocolitis (NEC) is a life-threatening inflammatory disease. Its onset might be triggered by Toll-Like Receptor 4 (TLR4) activation via bacterial lipopolysaccharide (LPS). We hypothesize that a deficiency of intestinal alkaline phosphatase (IAP), an enzyme secreted by enterocytes that dephosphorylates LPS, may contribute to NEC development.
In this prospective pilot study, we analyzed intestinal resection specimens from surgical NEC patients, and from patients undergoing Roux-Y reconstruction for hepatobiliary disease as controls. We assessed IAP activity via enzymatic stainings and assays and explored IAP and TLR4 co-localization through immunofluorescence.
The study population consisted of five NEC patients (two Bell's stage IIb and three-stage IIIb, median (IQR) gestational age 25 (24-28) weeks, postmenstrual age at diagnosis 28 (26-31) weeks) and 11 controls (unknown age). There was significantly lower IAP staining in NEC resection specimens [49 (41-50) U/g of protein] compared to controls [115 (76-144), = 0.03]. LPS-dephosphorylating activity was also lower in NEC patients [0.06 (0-0.1)] than in controls [0.3 (0.2-0.5), = 0.003]. Furthermore, we observed colocalization of IAP and TLR4 in NEC resection specimens.
This study suggests a significantly lower IAP level in resection specimens of NEC patients compared to controls. This lower IAP activity suggests a potential role of IAP as a protective agent in the gut, which needs further confirmation in larger cohorts.
坏死性小肠结肠炎（NEC）是一种危及生命的炎症性疾病。其发病可能由细菌脂多糖（LPS）激活Toll样受体4（TLR4）引发。我们推测，肠碱性磷酸酶（IAP）缺乏可能会促使NEC的发展，IAP是一种由肠上皮细胞分泌的可使LPS去磷酸化的酶。
在这项前瞻性初步研究中，我们分析了外科NEC患者以及因肝胆疾病接受Roux-Y重建手术患者的肠切除标本，后者作为对照。我们通过酶染色和检测评估IAP活性，并通过免疫荧光探索IAP与TLR4的共定位。
研究人群包括5例NEC患者（2例Bell IIb期和3例IIIb期，胎龄中位数（IQR）为25（24 - 28）周，诊断时月经龄为28（26 - 31）周）和11例对照（年龄未知）。与对照[115（76 - 144），P = 0.03]相比，NEC切除标本中的IAP染色显著降低[49（41 - 50）U/g蛋白质]。NEC患者的LPS去磷酸化活性[0.06（0 - 0.1）]也低于对照[0.3（0.2 - 0.5），P = 0.003]。此外，我们在NEC切除标本中观察到IAP与TLR4的共定位。
本研究表明，与对照相比，NEC患者切除标本中的IAP水平显著降低。这种较低的IAP活性表明IAP在肠道中可能具有保护作用，这需要在更大的队列中进一步证实。
