Molecular simplification of lipid A structure: TLR4-modulating cationic and anionic amphiphiles

A growing body of data suggests that therapies based on Toll-like receptors (TLR) targeting, in particular TLR4, holds promise in curing autoimmune and inflammatory pathologies still lacking specific treatment, included several rare diseases. While TLR4 activators (agonists) have already found successful clinical application as vaccine adjuvants, the use of TLR4 blockers (antagonists) as antisepsis agents or as agents against inflammatory diseases (including arthritis, multiple sclerosis, neuroinflammations) and cancer is still at a preclinical phase of development. This minireview focuses on recent achievements on the development of TLR4 modulators based on lipid A structure simplification, in particular on compounds having disaccharide or monosaccharide structures. As the TLR4 activity of natural TLR4 ligands (lipopolysaccharide, LPS and its biologically active part, the lipid A) depends on both the structure of endotoxin aggregates in solution and on single-molecule interaction with MD-2 and CD14 receptors, the rational design of TLR4 modulators should in principle take into account both these factors. In the light of the most recent advances in the field, in this minireview we discuss the structure–activity relationship in simplified lipid A analogs, with cationic or anionic amphiphilic structures.     

Variations in insulin requirements can be an early indicator of sepsis in burn patients

IntroductionA >25% increase in daily insulin dosing is suggestive of possible sepsis in burn patients, however, no conclusive evidence is available regarding the time point at which insulin dosing begins to increase. The purpose of this study is to determine the exact time point at which the insulin requirement increases among non-diabetic burn patients with sepsis.MethodsA retrospective chart review in non-diabetic burn patients with ≥20% total body surface area burned (TBSA) during 2010–2018 who received a blood culture for suspected sepsis. Absolute insulin dosing at intervals (0, 24, 48, 72, and 96 h prior to blood culture) were Box–Cox transformed and compared vs.?96 h reference using mixed-effects models accounting for within-patient dependencies.ResultsFifty-eight patients (84% males, age 44 ± 17 years, TBSA% 49 ± 17.5) were included. When cube root of daily insulin dosing was regressed on each time point in a mixed-effects model, statistically significant increase in insulin dosing compared to baseline was observed for ?48 (p = 0.018), ?24 (p = 0.011), and 0 h (p = 0.008).ConclusionDaily insulin dosing increases 48 h prior to development of other clinical signs of sepsis and can be used as a sensitive early marker.     

The vagal nerve as a link between the nervous and immune system in the instance of polymicrobial sepsis

Background The role of the vagal nerve in the autonomic nervous system is widely well known. Recently, an additional function was revealed serving as a connector between the nervous and immune system. This connection is called the “cholinergic inflammatory pathway.” Through stimulation of the acetylcholine receptors located upon the macrophages, the “unspecific” immune system can be directly influenced. Methods The vagal nerve was completely transected directly posterior to its passage through the diaphragm. The effect of complete vagotomy was analyzed using a murine model of polymicrobial peritonitis (colon ascendens stent peritonitis, CASP). Survival and clinical course of vagotomized or sham-operated mice were analyzed in the CASP model. Results After CASP surgery, vagotomy led to a significantly increased mortality (64.7%) in comparison to sham-vagotomized animals (34%). No difference in the bacterial load of various tissues (lung, liver, spleen, blood, lavage fluid, and kidney) from septic animals with or without vagotomy was observed. Vagotomized animals reveal elevated serum cytokine levels (TNF, IL-6, IL-10, and MCP-1) 20 h after the induction of polymicrobial peritonitis. Conclusion The vagal nerve is therefore an important modulator of the immune system. W. Kessler and T. Traeger contributed equally to this work Best of Forum Papers presented at the Annual Meeting of the German Society of Surgery, 2–5 May 2006, Berlin, Germany     

CD14+单核细胞人类白细胞抗原DR表达率与脓毒症关系的研究

目的了解烧伤延迟复苏时CDl4^＋单核细胞人类白细胞抗原DR（HLA—DR）表达率的变化，分析其与脓毒症的关系。方法选择烧伤面积大于30％TBSA的25例烧伤延迟复苏患者，于伤后1、3、7、14、28d取外周血，其中7例患者住院期间并发脓毒症，于脓毒症发生后连续2d亦取其外周血。另取20例健康体检者外周血作为对照。流式细胞仪检测CD14^＋单核细胞HLA．DR表达率，酶联免疫吸附测定法检测血浆中肿瘤坏死因子α（TNF—α）、白细胞介素10（IL-10）的浓度。结果非脓毒症患者伤后1、3、7、14、28dCD14^＋单核细胞HLA—DR表达率分别为（15±6）％、（74±5）％、（264±17）％、（284-16）％、（474-16）％，明显低于健康体检者[（924±10）％，P〈0．01]；脓毒症患者发生脓毒症后1、2d，该指标亦明显低于健康体检者及非脓毒症患者伤后1、7、14、28d（P〈0．01）。脓毒症患者TNF—d检出率及TNF—α、IL-10浓度，均高于非脓毒症患者和健康体检者（P〈0．05或P〈0．01）。伤后1、7、28d，外周血CD14^＋单核细胞HLA—DR表达率与IL—10浓度呈显著负相关（r分别为-0．9963、-0．7459、-0．8474，P〈0．01）。结论烧伤延迟复苏患者免疫功能低下，促炎性介质释放量增加，并发脓毒症时则更为严重。外周血CD14^＋单核细胞HLA—DR表达率可作为动态检测患者免疫功能状态的有效指标。     

性别差异对脓毒症大鼠肝脏Toll样受体4和髓样分化蛋白-2基因表达的影响

目的探讨性别差异对脓毒症大鼠肝脏组织Toll样受体4(TLR4)和髓样分化蛋白- 2(MD-2)基因表达的影响。方法以脂多糖(LPS)按5 mg/kg体重由大鼠腹腔注射制作脓毒症动物模型,注射后2 h留取肝脏组织检测TLR4、MD-2和肿瘤坏死因子-α(TNF-α)基因表达,同时测定各组大鼠血浆中丙氨酸氨基转移酶(ALT)及雌二醇含量。结果正常雌雄性大鼠肝脏组织均可表达少量TLR4、MD-2、TNF-α基因,其中雌性组分别为0．175±0．034、0．211±0．044、0．201±0．068; 雄性组分别为0．205±0．061、0．243±0．049、0．243±0．063,两组数据差异无统计学意义(P> 0．05),但LPS刺激后雌性大鼠肝脏组织上述指标分别为0．615±0．089、0．708±0．181、0．730± 0．118,血浆中ALT含量为(81．07±10．72)U／L;雄性组分别为0．723±0．091、1．123±0．272、 0．881±0．156,ALT含量为(106．39±14．21)U／L,雌性组各项指标均明显低于雄性大鼠(P< 0．05)。相关分析表明雌性及雄性脓毒症大鼠肝脏组织TLR4及TNF-α基因表达与相应性别大鼠血浆中雌二醇含量呈显著负相关(P<0．05)。结论 LPS刺激后大鼠肝脏组织TLR4、MD-2及 TNF-α基因表达存在性别差异,内源性雌激素的作用可能导致雌性脓毒症大鼠肝脏组织损伤较雄性轻。     

Splanchnic metabolism associated with liver metastasis

Metastatic liver disease can modify the metabolic response to critical illness. Systemic lactic acidosis may arise from an increased production due to inadequate peripheral tissue oxygen transport, altered metabolic function such as depressed pyruvate oxidation or insufficient hepatic clearing capacity due to tumor replacement of functional liver mass. Hepatic venous catheterization in a patient with extensive metastatic melanoma to the liver and adult respiratory distress syndrome indicated a marked disparity between whole body and liver oxygenation which may arise due to a markedly stepped up splanchnic oxygen utilization unmatched by a proportionate rise in regional oxygen delivery. Since some neoplasms may exhibit increased metabolic activity, it is suspected that these metastatic lesions may have contributed to the observed regional hypermetabolism thereby worsening hepatic hypoxia and exacerbating lactic acidosis. This case also illustrates the difficulties in interpreting global indicators of metabolic function and oxygenation in critically ill patients.     

高迁移率族蛋白B1对大鼠脾脏树突状细胞表面共刺激分子表达的影响

目的观察高迁移率族蛋白B1(HMGB1)对树突状细胞(dendritic cells,DC)表面共刺激分子表达的影响,并对其机制进行初步探讨。方法分离正常Wistar大鼠脾脏DC后置于96孔培养板(1×10~5/孔),采用HMGB1刺激,观察HMGB1刺激与DC表面共刺激分子CD80、CD86和主要组织相容性复合物(MHC)Ⅱ表达的时间-效应关系及剂量-效应关系。结果HMGB1刺激后,DC表面共刺激分子CD80、CD86和MHCⅡ表达分别于24～72 h明显上调(P＜0．05,0．01),其中以作用48 h后DC表面共刺激分子表达上调尤为显著(P＜0．01)；0．1μg/ml、1μg/ml、10μg/ml的HMGB1刺激均可诱导DC表面共刺激分子CD80、CD86和MHCⅡ表达增强(P＜0．05,0．01),其中HMGB1的浓度在1μg/ml时,大鼠DC表面共刺激分子CD80、CD86和MHCⅡ的表达增强最明显(P＜0．01)。结论HMGB1能诱导DC表面共刺激分子表达增强,HMGB1可能是诱导DC成熟的免疫刺激信号。