Impact of alcohol intoxication on lymphatic contractile mechanisms

酒精中毒对淋巴收缩机制的影响

• 批准号: 8314893
• 负责人: Flavia Moreira Souza
• 金额: $ 5.22万
• 依托单位: LSU HEALTH SCIENCES CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-15 至 2015-03-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8314893
• 关键词: Acute; Affect; Alcohol abuse; Alcoholic Intoxication; Alcohols; Antigens; Area; Award; Binding; Biochemical; Blood Circulation; Blood alcohol level measurement; Cardiac; Cardiovascular Physiology; Clinical; Communication; Data; Development; Development Plans; Emergency Situation; Environment; Ethanol Metabolism; Faculty; Fluid Balance; Frequencies; Fura-2; Gastrointestinal tract structure; Heart; Homeostasis; Host Defense; Image; Immune; Immune response; Immune system; Immunity; Immunologic Monitoring; Immunologics; Impairment; Incidence; Infection; Infection prevention; Injury; Intervention; Intestines; Knowledge; Laboratories; Length of Stay; Lipids; Liquid substance; Lung; Lymph; Lymphatic; Lymphatic vessel; Measures; Mesentery; Methods; Modeling; Molecular; Morbidity - disease rate; Mucosal Immunity; Muscle Contraction; Nature; Organ; Pattern; Phase; Positioning Attribute; Prospective Studies; Proteins; Protocols documentation; Pump; Rattus; Recovery; Reporting; Research; Retrospective Studies; Role; Signaling Molecule; Smooth Muscle; Stretching; Stroke Volume; System; Testing; Therapeutic; Thinking; Tissues; Trauma; Work; Writing; alcohol effect; alcohol testing; base; constriction; cost; driving force; gastrointestinal; health care delivery; improved; indexing; injured; injury prevention; lymph flow; lymph nodes; lymphatic pump; mortality; myosin phosphatase; novel; pathogen; patient population; pressure; pulmonary function; response; rho; skills; therapeutic target

Alcohol intoxication complicates injury and infection by impairing cardiovascular function, fluid homeostasis, and host defense. The lymphatics of the gut are a multifunctional transport system that normally serves as a delivery and surveillance system for potentially harmfull antigens, optimizing mucosal innate and adaptative immunity. Alcohol increases mesenteric lymph flow, which could potentially be harmful if gut barrier function is compromised, such as after traumatic injury. In such cases increased lymph flow could facilitate delivery of an overwhelming number of pathogens to the lymph node barrier, allowing entry to the systemic circulation, and infection of the heart, lungs and other organs. We recently showed that alcohol modulates the intrinsic contractile cycle of mesenteric lymphatics that provides the driving force for lymph flow. We aim to discover the molecular mechanisms by which alcohol enhances intrinsic lymphatic pumping. Because of the known importance of Ca[2+] in smooth muscle contraction, we developed a novel method to measure cytosolic [Ca[2+]] in isolated rat collecting lymphatics. Our preliminary data indicate that alcohol modulates phasic contractions of lymphatic vessels by decreasing the frequency yet increasing the magnitude of cyclic mobilizations of Ca[2+] from internal stores. Alcohol also inhibits the lymphatic myogenic constriction in response to increases in luminal pressure. However, alcohol does not inhibit the associated gradual increase in cytosolic [Ca[2+]] during the diastolic phase of the contractile cycle, which suggests that the inhibition of myogenic constriction may instead be due to impaired sensitivity to Ca[2+]. We hypothesize that alcohol decreases the frequency and increases the magnitude of Ca[2+] mobilization in lymphatic smooth muscle to cause less frequent but larger contractions, and in addition decreases mesenteric lymphatic tone by inhibiting Ca[2+]-sensitizing mechanisms. We will test this hypothesis with two Specific Aims: 1) to test the prediction that acute alcohol intoxication induced-changes in the lymphatic phasic contraction pattern are caused by an altered cyclic mobilization of Ca[2+], and 2) to demonstrate that alcohol intoxication inhibits Ca[2+] sensitization in lymphatic smooth muscle, causing a decrease in tone and loss of myogenic responsiveness. We will utilize an established rat model of acute alcohol intoxication in combination with our novel method to simultaneously track changes in cytosolic [Ca[2+]] and intrinsic pump function in isolated mesenteric lymphatics. In addition, pharmacological interventions will be combined with biochemical analyses of key signaling molecules to determine the underlying Ca[2+]- dependent and Ca[2+]-sensitizing mechanisms impacted by alcohol intoxication. The successful completion of these studies will reveal the lymphatic contractile mechanisms impacted by alcohol intoxication, this will advance our knowledge on how alcohol intoxication disrupts immunity in the digestive tract. This information will also enable development of useful therapeutic strategies to prevent infections that hamper cardio- pulmonary function in alcohol-intoxicated trauma victims.

酒精中毒通过损害心血管功能、体液平衡和宿主防御使损伤和感染复杂化。肠道的免疫系统是一个多功能的运输系统，通常作为潜在有害抗原的递送和监测系统，优化粘膜先天性和适应性免疫。酒精会增加肠系膜淋巴流量，如果肠道屏障功能受损，如创伤后，这可能是有害的。在这种情况下，增加的淋巴流量可以促进大量病原体向淋巴结屏障的递送，从而允许进入体循环，以及心脏、肺和其他器官的感染。我们最近发现，酒精调节肠系膜血管的内在收缩周期，为淋巴液流动提供动力。我们的目标是发现酒精增强内在淋巴泵的分子机制。由于已知Ca[2+]在平滑肌收缩中的重要性，我们开发了一种新的方法来测量离体大鼠收集平滑肌细胞胞浆[Ca[2+]]。我们的初步数据表明，酒精通过降低频率但增加内部储存Ca[2+]循环动员的幅度来调节淋巴管的阶段性收缩。酒精也抑制淋巴肌收缩反应腔压力的增加。然而，在收缩周期的舒张期，酒精并不能抑制胞浆[Ca[2+]]的相关逐渐增加，这表明肌源性收缩的抑制可能是由于对Ca[2+]的敏感性受损。我们假设酒精降低频率并增加淋巴管平滑肌中Ca[2+]动员的幅度，从而导致频率较低但幅度较大的收缩，此外还通过抑制Ca[2+]敏感机制降低肠系膜淋巴管张力。我们将用两个特定目的检验这一假设：1）检验急性酒精中毒诱导的淋巴相收缩模式变化是由Ca[2+]循环动员改变引起的预测，2）证明酒精中毒抑制淋巴平滑肌中的Ca[2+]敏化，导致张力降低和肌源性反应丧失。我们将利用建立的急性酒精中毒大鼠模型，结合我们的新方法，同时跟踪细胞内[Ca[2+]]和固有泵功能在孤立的肠系膜动脉的变化。此外，药物干预将与关键信号分子的生化分析相结合，以确定受酒精中毒影响的潜在Ca[2+]依赖性和Ca[2+]致敏机制。这些研究的成功完成将揭示酒精中毒影响的淋巴收缩机制，这将促进我们对酒精中毒如何破坏消化道免疫力的认识。这一信息也将使有用的治疗策略，以防止感染，阻碍心肺功能的酒精中毒创伤受害者的发展。