Morphological, molecularbiological and functional characterization of neuromuscular alteratoins in diverticular disease

憩室病是最常见的胃肠道疾病之一。尽管发病率很高，但DD的发病机制在很大程度上仍然是个谜。最近的证据表明，DD是由神经肌肉改变引起的，这种改变引发了憩室的形成和症状。在以前的资助期间，我们能够通过分析从憩室炎患者和肠神经细胞培养获得的样本表明，DD(1)与肠神经细胞丢失(寡神经元性神经节细胞减少症)有关；(2)显示神经营养因子GDNF及其相应的受体(RET，GFRa1/2)表达缺陷，这反过来可能是神经细胞丢失的原因；(3)以5-羟色胺和毒扁豆碱能神经递质系统紊乱为特征，这有助于解释伴随DD的肠道运动模式改变；(4)进一步显示结构和功能肌肉变化，表明DD潜在的神经病和肌病。基于这些数据，目前的建议旨在解决以下几个方面：(1)评估憩室炎患者最重要的抑制性神经递质系统(NO、VIP)的可能变化，以及其他神经营养因子(GDNF家族成员、内皮素、神经调节蛋白)是否表现出表达缺陷。由于神经营养因子显著影响突触可塑性，突触可塑性的标记物(突触素、SNAP25)将提示憩室炎是否与突触有关。(2)目前在憩室炎患者身上进行的一系列实验也将在憩室病患者身上进行。如果这一集体发现类似的发现(例如神经节细胞减少、神经递质紊乱、神经营养因子缺乏、突触)，这些数据将支持潜在的神经肌肉改变最初参与DD发病机制的假说。(3)在人体病理学中检测到的神经肌肉变化的潜在病理机制将在体外模型中进一步研究。为此，除肠神经细胞培养外，我们还建立了培养肠平滑肌细胞的模型。这些体外模型将能够评估神经营养因子在DD中改变对肠神经细胞的增殖、分化和突触可塑性的影响，以及对肠平滑肌细胞结构和功能分化的影响。这些实验所获得的数据可以修正传统的DD的发病概念，并确定肠道神经/肌肉病变是DD的病因，这可能为预防和(药物)治疗方法开发创新的概念。

Diverticular disease (DD) represents one of the most common gastrointestinal diseases. Despite the high prevalence, the pathogenesis of DD, however, remains largely enigmatic. Recent evidences indicate that DD is caused by neuromuscular alterations which trigger formation of diverticula as well as symptoms. During previous funding periods, we were able to show by analyzing samples obtained from patients with diverticulitis and enteric nerve cell cultures that DD (1) is associated with a loss of enteric nerve cells (oligoneuronal hypoganglionosis); (2) displays expression deficits of the neurotrophic factor GDNF and its corresponding receptors (RET, GFRa1/2) which in turn might account for the nerve cell loss; (3) is characterized by disturbances of the serotonergic and muscarinic neurotransmitter systems which helps to explain the altered intestinal motility patterns accompanying DD, (4) displays structural and functional muscular changes further indicating an underlying neuropathy and myopathy in DD. Based on these data, the current proposal is aimed to address the following aspects: (1) To assess in patients with diverticulitis putative changes in the most important inhibitory neurotransmitter systems (NO, VIP) and whether other neurotrophic factors (GDNF family members, endothelin, neuregulin) display expression deficits. As neurotrophic factors significantly influence synaptic plasticity, markers of synaptic plasticity (synaptophysin, synaptobrevin, synaptotagmin, SNAP25) will indicate whether diverticulitis is associated with a synaptopathy. (2) The set of experiments so far carried out in patients with diverticulitis will also be conducted in patients with diverticulosis. If this collective reveals similar findings (e.g. hypoganglionosis, neurotransmitter disturbances, deficits of neurotrophic factors, synaptopathy), these data would support the hypothesis of underlying neuromuscular alterations being initially involved in the pathogenesis of DD. (3) The underlying pathomechanisms of neuromuscular changes detected in the human pathology will be further investigated in in vitro models. For this purpose, besides enteric nerve cell cultures we have established a model of cultured enteric smooth muscle cells. These in vitro models will allow to assess the influence of neurotrophic factors shown to be altered in DD on proliferation, differentiation and synaptic plasticity of enteric nerve cells as well as on structural and functional differentiation of enteric smooth muscle cells. The data obtained in the experiments proposed could revise traditional pathogenetic concepts of DD and identify enteric neuro-/myopathies as etiologic factors in DD which may allow to develop innovative concepts for prophylactic and (pharmaco-)therapeutic approaches.