Studies on bacterial endotoxin and intestinal absorption function in patients with chronic heart failure

Disturbed intestinal integrity in patients with COPD: effects of activities of daily living

BACKGROUND

COPD is accepted to be a multicomponent disease with various comorbidities. To our knowledge, the contribution of the GI tract to the systemic manifestation of COPD has never been investigated. This metabolically active organ may experience recurring local oxygen deficits during daily life, leading to disturbed intestinal integrity in patients with COPD.

METHODS

Eighteen patients with moderate COPD (mean FEV₁, 55 ± 3% predicted) and 14 matched healthy control subjects were tested on two occasions: a baseline measurement at rest and, on another day, during the performance of activities of daily living (ADLs). To assess enterocyte damage, plasma intestinal fatty acid binding protein (IFABP) levels were determined, whereas urinary excretion of orally ingested sugar probes was measured using liquid chromatography and mass spectrometry to assess GI permeability.

RESULTS

Plasma IFABP concentrations were not different between patients with COPD and healthy control subjects at rest. In contrast, 0- to 3-h urinary lactulose to rhamnose and sucralose to erythritol ratios and 5- to 24-h urinary sucralose to erythritol ratios were significantly higher in patients with COPD compared with control subjects, indicating increased permeability of the small intestine and colon. Furthermore, the performance of ADLs led to significantly increased plasma IFABP concentrations in patients with COPD but not in control subjects. Similarly, the intestinal permeability difference between patients and control subjects was intensified.

CONCLUSIONS

Besides an altered intestinal permeability in patients with COPD when at rest, performing ADLs led to enterocyte damage in addition to intestinal hyperpermeability in patients with COPD but not in control subjects, indicating functional alteration in the GI tract. Hence, intestinal compromise should be considered as a new component of the multisystem disorder COPD.

TRIAL REGISTRY

ISRCTN Register; No.: ISRCTN33686980; URL: www.controlled-trials.com.

The role of micronutrients and macronutrients in patients hospitalized for heart failure

The detrimental pathophysiology of heart failure (HF) leaves room for physiologic and metabolomic concepts that include supplementation of micronutrients and macronutrients in these patients. Hence myocardial energetics and nutrient metabolism may represent relevant treatment targets in HF. This review focuses on the role of nutritive compounds such as lipids, amino acids, antioxidants, and other trace elements in the setting of HF. Supplementation of ferric carboxymaltose improves iron status, functional capacity, and quality of life in HF patients. To close the current gap in evidence further interventional studies investigating the role of micro- and macronutrients are needed in this setting.

Therapeutic effects of serelaxin in acute heart failure

Over the past few decades, research on the peptide hormone, relaxin, has significantly improved our understanding of its biological actions under physiological and diseased conditions. This has facilitated the conducting of clinical trials to explore the use of serelaxin (human recombinant relaxin). Acute heart failure (AHF) is a very difficult to treat clinical entity, with limited success so far in developing new drugs to combat it. A recent phase-III RELAX-AHF trial using serelaxin therapy given during hospitalization revealed acute (ameliorated dyspnea) and chronic (improved 180-day survival) effects. Although these findings support a substantial improvement by serelaxin therapy over currently available therapies for AHF, they also raise key questions and stimulate new hypotheses. To facilitate the development of serelaxin as a new drug for heart disease, joint efforts of clinicians, research scientists and pharmacological industries are necessary to study these questions and hypotheses. In this review, after providing a brief summary of clinical findings and the pathophysiology of AHF, we present a working hypothesis of the mechanisms responsible for the observed efficacy of serelaxin in AHF patients. The existing clinical and preclinical data supporting our hypotheses are summarized and discussed. The development of serelaxin as a drug provides an excellent example of the bilateral nature of translational research. 

Why cachexia kills: examining the causality of poor outcomes in wasting conditions

Weight loss is the hallmark of any progressive acute or chronic disease state. In its extreme form of significant lean body mass (including skeletal muscle) and fat loss, it is referred to as cachexia. It has been known for millennia that muscle and fat wasting leads to poor outcomes including death. On one hand, conditions and risk factors that lead to cachexia and inadequate nutrition may independently lead to increased mortality. Additionaly, cachexia per se, withdrawal of nutritional support in progressive cachexia, and advanced age may lead to death via cachexia-specific pathways. Despite the strong and consistent association of cachexia with mortality, no unifying mechanism has yet been suggested as to why wasting conditions are associated with an exceptionally high mortality risk. Hence, the causality of the cachexia-death association, even though it is biologically plausible, is widely unknown. This century-long uncertainty may have played a role as to why the field of cachexia treatment development has not shown major advances over the past decades. We suggest that cachexia-associated relative thrombocytosis and platelet activation may play a causal role in cachexia-related death, while other mechanisms may also contribute including arrhythmia-associated sudden deaths, endocrine disorders such as hypothyroidism, and immune system compromise leading to infectious events and deaths. Multidimensional research including examining biologically plausible models is urgently needed to investigate the causality of the cachexia-death association.

The effect of normovolemic modified ultrafiltration on inflammatory mediators, endotoxins, terminal complement complexes and clinical outcome in high-risk cardiac surgery patients

Objective:

The clinical benefit of normovolemic modified ultrafiltration (N-MUF) after cardiac surgery is still debated. As we have shown in a previous publication, there is a significant improvement in platelet function, so we were interested in whether ultrafiltration can reduce plasma levels of endotoxins, terminal complement complexes and cytokines after cardiopulmonary bypass (CPB) in adults with increased risk profiles.

Methods:

In this single-center, prospective, randomized trial, fifty high-risk patients (mean logistic EuroSCORE II: 17.5%) who underwent cardiac surgery were randomized. After CPB, Group 1 (n = 25) served as the control and in, Group 2 (n= 25), an N-MUF of 3000 ml was performed, using a BC140plus filter after weaning from CPB. Blood samples were taken after the induction of anesthesia, before CPB, before CPB weaning, 30 minutes after CPB and at 6, 24 and 48 hours postoperatively. Primary outcomes were plasma levels of lipopolysaccharide-binding protein (LBP), terminal complement complex (C5b9) and cytokines (IL-6, IL-10, IL-1beta, TNF-α). Secondary outcomes focused on differences in the clinical outcome.

Results:

A significant reduction in LBP concentration (preoperatively: 23.8±8.4 pg/ml, postoperatively: 14.2±12.9 pg/ml) and C5b9 (preoperatively: 4.18±2.6 pg/ml, postoperatively: 3.05±2.39 pg/ml) were detected 6 hours after N-MUF. In the N-MUF group, significantly lower concentrations of lactate could be detected in the early postoperative period. Furthermore, postoperative chest tube blood loss was significantly lower in the N-MUF group at 24 and 48 hours.

Conclusions:

N-MUF leads to a significant reduction of lipopolysaccharide-binding protein and terminal complement complex and was associated with reduced blood loss and postoperative lactate concentrations shortly after surgery.

Sickness behavior in community-dwelling elderly: associations with impaired cardiac function and inflammation

Sickness behavior is a cluster of symptoms that occur as a response to an infection and alterations in the inflammatory response. Under normal circumstances, sickness behavior is fully reversible once the pathogen has been cleared. Aging and chronic illness such as heart failure are associated with enhanced inflammatory activity that lasts for a long duration and no longer represents an adaptive response. The aim of this study was to explore whether inflammation mediates the relationship between impaired cardiac function and a symptom cluster including anhedonia, fatigue, and sleepiness, which might represent sickness behavior in community-dwelling elders. Structural equation modeling (SEM) showed that the factor impaired cardiac function (i.e., N-terminal fragment of pro-brain natriuretic peptide, left ventricular ejection fraction, and the heart failure medications angiotensin converting enzyme inhibitor, angiotensin receptor blockade, β-blocker, and diuretics) was associated with both inflammation (i.e., C-reactive protein; β = .26) and the symptom cluster (β = .31). Inflammation had a significant direct, but smaller, association with the symptom cluster (β = .21). By this pathway, inflammation also mediated an indirect association between impaired cardiac function and the symptom cluster (β = .05). Including creatinine, blood glucose, ischemic heart disease, previous and current tumor, respiratory disease, age, and body mass index in the SEM model did not change these associations. Our results imply that some aspects of the symptom panorama in elderly individuals with impaired cardiac function or heart failure could represent sickness behavior.

Disintegration of colonic epithelial tight junction in uremia: a likely cause of CKD-associated inflammation

BACKGROUND

Inflammation is a constant feature and a major mediator of the progression of chronic kidney disease (CKD) and its numerous complications. There is increasing evidence pointing to the impairment of intestinal barrier function and its contribution to the prevailing inflammation in advanced CKD. Under normal condition, the intestinal epithelium and its apical tight junction prevent entry of the luminal microorganisms, harmful microbial by-products and other noxious contents in the host's internal milieu. This study was designed to test the hypothesis that impaired intestinal barrier function in uremia must be due to disruption of the intestinal tight junction complex.

METHODS

Sprague-Dawley (SD) rats were randomized to undergo 5/6 nephrectomy (CKD) or sham-operation (control) and observed for 8 weeks. In a separate experiment, SD rats were rendered uremic by addition of 0.7% adenine to their food for 2 weeks and observed for an additional 2 weeks. Rats consuming a regular diet served as controls. The animals were then euthanized and their colons were removed and processed for expression of the key constituents of the tight junction complex using real-time polymerase chain reaction, western blot analysis and immunohistological examinations.

RESULTS

The CKD groups showed elevated plasma urea and creatinine, reduced creatinine clearance, thickened colonic wall and heavy infiltration of mononuclear leukocytes in the lamina propria. This was associated with marked reductions in protein expressions of claudin-1 (70-90%), occludin (50-70%) and ZO-1 (80-90%) in the colonic mucosa in both CKD models compared with the corresponding controls. The reduction in the abundance of the given proteins was confirmed by immunohistological examinations. In contrast, messenger RNA abundance of occludin, claudin-1 and ZO-1 was either unchanged or elevated pointing to the post-transcriptional/post-translational modification as a cause of the observed depletion of the tight junction proteins.

CONCLUSION

The study revealed, for the first time, that uremia results in depletion of the key protein constituents of the colonic tight junction, a phenomenon which can account for the impaired intestinal barrier function and contribute to the systemic inflammation in CKD.

Urine sugars for in vivo gut permeability: validation and comparisons in irritable bowel syndrome-diarrhea and controls

Mucosal barrier dysfunction contributes to gastrointestinal diseases. Our aims were to validate urine sugar excretion as an in vivo test of small bowel (SB) and colonic permeability and to compare permeability in patients with irritable bowel syndrome-diarrhea (IBS-D) to positive and negative controls. Oral lactulose (L) and mannitol (M) were administered with (99m)Tc-oral solution, (111)In-oral delayed-release capsule, or directly into the ascending colon (only in healthy controls). We compared L and M excretion in urine collections at specific times in 12 patients with IBS-D, 12 healthy controls, and 10 patients with inactive or treated ulcerative or microscopic colitis (UC/MC). Sugars were measured by high-performance liquid chromatography-tandem mass spectrometry. Primary endpoints were cumulative 0-2-h, 2-8-h, and 8-24-h urinary sugars. Radioisotopes in the colon at 2 h and 8 h were measured by scintigraphy. Kruskal-Wallis and Wilcoxon tests were used to assess the overall and pairwise associations, respectively, between group and urinary sugars. The liquid in the colon at 2 h and 8 h was as follows: health, 62 ± 9% and 89 ± 3%; IBS-D, 56 ± 11% and 90 ± 3%; and UC/MC, 35 ± 8% and 78 ± 6%, respectively. Liquid formulation was associated with higher M excretion compared with capsule formulation at 0-2 h (health P = 0.049; IBS-D P < 0.001) but not during 8-24 h. UC/MC was associated with increased urine L and M excretion compared with health (but not to IBS-D) at 8-24 h, not at 0-2 h. There were significant differences between IBS-D and health in urine M excretion at 0-2 h and 2-8 h and L excretion at 8-24 h. Urine sugars at 0-2 h and 8-24 h reflect SB and colonic permeability, respectively. IBS-D is associated with increased SB and colonic mucosal permeability.

Modulation of oxidative stress and microinflammatory status by colloids in refractory dialytic hypotension

Background

Intradialytic hypotension may adversely affect the outcome of chronic hemodialysis. Therapeutic albumin has powerful anti-oxidant and anti-inflammatory properties. We have recently shown that systematic colloid infusion during hemodialysis sessions improves hemodynamic parameters in most dialysis hypotension-prone patients unresponsive to usual of preventive measures.

We postulated that frequent hypotensive episodes may lead to a noxious inflammatory response mediated by oxidative stress induced by ischemia-reperfusion. The aim of this study was therefore to analyze the effect of 20% albumin and 4% gelatin infusions on oxidative stress and microinflammatory status in hypotension-prone patients unresponsive to usual preventive measures.

Methods

Prospective cross-over study (lasting 20 weeks) of routine infusion of 200 ml of 20% albumin versus 200 ml of 4% gelatin in 10 patients with refractory intradialytic hypotension. We analyzed the effect of 20% albumin and 4% gelatin on microinflammatory status, oxidative stress, serum nitrite and nitrate levels by analysis of variance.

Results

A significant decrease in serum ceruloplasmin and serum C3 was observed during the albumin period (p < 0.05, repeated measure ANOVA). A significant decrease in serum hydrogen peroxide was seen during albumin and gelatin administration (p < 0.01, repeated measure ANOVA) and a very large decrease in serum lipid peroxides was observed during the albumin period only (p < 0.01, Friedman test). Serum lactoferrin, serum proinflammatory cytokines and serum nitrite and nitrate levels remained stable during the different periods of this pilot trial.

Conclusions

We conclude that the improvement in microinflammatory status observed during colloid infusion in hypotension-prone dialysis patients may be related to a decrease in ischemia-reperfusion of noble organs, together with a specific reduction in oxidative stress by albumin.

Trial registration

ISRCTN 20957055