PUFA-Induced Metabolic Enteritis as a Fuel for Crohn's Disease.

BACKGROUND & AIMS: Crohn's disease (CD) globally emerges with Westernization of lifestyle and nutritional habits. However, a specific dietary constituent that comprehensively evokes gut inflammation in human inflammatory bowel diseases remains elusive. We aimed to delineate how increased intake of polyunsaturated fatty acids (PUFAs) in a Western diet, known to impart risk for developing CD, affects gut inflammation and disease course. We hypothesized that the unfolded protein response and antioxidative activity of glutathione peroxidase 4 (GPX4), which are compromised in human CD epithelium, compensates for metabolic perturbation evoked by dietary PUFAs. METHODS: We phenotyped and mechanistically dissected enteritis evoked by a PUFA-enriched Western diet in 2 mouse models exhibiting endoplasmic reticulum (ER) stress consequent to intestinal epithelial cell (IEC)-specific deletion of X-box binding protein 1 (Xbp1) or Gpx4. We translated the findings to human CD epithelial organoids and correlated PUFA intake, as estimated by a dietary questionnaire or stool metabolomics, with clinical disease course in 2 independent CD cohorts. RESULTS: PUFA excess in a Western diet potently induced ER stress, driving enteritis in Xbp1-/-IEC and Gpx4+/-IEC mice. ω-3 and ω-6 PUFAs activated the epithelial endoplasmic reticulum sensor inositol-requiring enzyme 1α (IRE1α) by toll-like receptor 2 (TLR2) sensing of oxidation-specific epitopes. TLR2-controlled IRE1α activity governed PUFA-induced chemokine production and enteritis. In active human CD, ω-3 and ω-6 PUFAs instigated epithelial chemokine expression, and patients displayed a compatible inflammatory stress signature in the serum. Estimated PUFA intake correlated with clinical and biochemical disease activity in a cohort of 160 CD patients, which was similarly demonstrable in an independent metabolomic stool analysis from 199 CD patients. CONCLUSIONS: We provide evidence for the concept of PUFA-induced metabolic gut inflammation which may worsen the course of human CD. Our findings provide a basis for targeted nutritional therapy.

Discontinuation versus continuation of renin-angiotensin-system inhibitors in COVID-19 (ACEI-COVID): a prospective, parallel group, randomised, controlled, open-label trial.

BACKGROUND: SARS-CoV-2 entry in human cells depends on angiotensin-converting enzyme 2, which can be upregulated by inhibitors of the renin-angiotensin system (RAS). We aimed to test our hypothesis that discontinuation of chronic treatment with ACE-inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) mitigates the course o\f recent-onset COVID-19. METHODS: ACEI-COVID was a parallel group, randomised, controlled, open-label trial done at 35 centres in Austria and Germany. Patients aged 18 years and older were enrolled if they presented with recent symptomatic SARS-CoV-2 infection and were chronically treated with ACEIs or ARBs. Patients were randomly assigned 1:1 to discontinuation or continuation of RAS inhibition for 30 days. Primary outcome was the maximum sequential organ failure assessment (SOFA) score within 30 days, where death was scored with the maximum achievable SOFA score. Secondary endpoints were area under the death-adjusted SOFA score (AUCSOFA), mean SOFA score, admission to the intensive care unit, mechanical ventilation, and death. Analyses were done on a modified intention-to-treat basis. This trial is registered with ClinicalTrials.gov, NCT04353596. FINDINGS: Between April 20, 2020, and Jan 20, 2021, 204 patients (median age 75 years [IQR 66-80], 37% females) were randomly assigned to discontinue (n=104) or continue (n=100) RAS inhibition. Within 30 days, eight (8%) of 104 died in the discontinuation group and 12 (12%) of 100 patients died in the continuation group (p=0·42). There was no significant difference in the primary endpoint between the discontinuation and continuation group (median [IQR] maximum SOFA score 0·00 (0·00-2·00) vs 1·00 (0·00-3·00); p=0·12). Discontinuation was associated with a significantly lower AUCSOFA (0·00 [0·00-9·25] vs 3·50 [0·00-23·50]; p=0·040), mean SOFA score (0·00 [0·00-0·31] vs 0·12 [0·00-0·78]; p=0·040), and 30-day SOFA score (0·00 [10-90th percentile, 0·00-1·20] vs 0·00 [0·00-24·00]; p=0·023). At 30 days, 11 (11%) in the discontinuation group and 23 (23%) in the continuation group had signs of organ dysfunction (SOFA score ≥1) or were dead (p=0·017). There were no significant differences for mechanical ventilation (10 (10%) vs 8 (8%), p=0·87) and admission to intensive care unit (20 [19%] vs 18 [18%], p=0·96) between the discontinuation and continuation group. INTERPRETATION: Discontinuation of RAS-inhibition in COVID-19 had no significant effect on the maximum severity of COVID-19 but may lead to a faster and better recovery. The decision to continue or discontinue should be made on an individual basis, considering the risk profile, the indication for RAS inhibition, and the availability of alternative therapies and outpatient monitoring options. FUNDING: Austrian Science Fund and German Center for Cardiovascular Research.

Non-alcoholic fatty liver disease: a multisystem disease requiring a multidisciplinary and holistic approach.

Non-alcoholic fatty liver disease (NAFLD) is a public health problem worldwide. This narrative Review provides an overview of the current literature to support the notion that NAFLD is a multisystem disease. Convincing evidence shows a strong association between NAFLD and the risk of developing multiple extrahepatic complications such as type 2 diabetes, cardiovascular disease (ie, the predominant cause of mortality in people with NAFLD), chronic kidney disease, and some types of extrahepatic malignancies. The magnitude of this risk parallels the severity of NAFLD (especially the stage of liver fibrosis). There are probably multiple underlying mechanisms by which NAFLD might increase the risk of cardiovascular disease, type 2 diabetes, and extrahepatic complications. Addressing the growing burden of NAFLD will require setting up a multidisciplinary working group and framework to progress and embrace novel collaborative ways of working to deliver holistic, person-centred care and management of people with NAFLD.

Dietary spermidine improves cognitive function.

Decreased cognitive performance is a hallmark of brain aging, but the underlying mechanisms and potential therapeutic avenues remain poorly understood. Recent studies have revealed health-protective and lifespan-extending effects of dietary spermidine, a natural autophagy-promoting polyamine. Here, we show that dietary spermidine passes the blood-brain barrier in mice and increases hippocampal eIF5A hypusination and mitochondrial function. Spermidine feeding in aged mice affects behavior in homecage environment tasks, improves spatial learning, and increases hippocampal respiratory competence. In a Drosophila aging model, spermidine boosts mitochondrial respiratory capacity, an effect that requires the autophagy regulator Atg7 and the mitophagy mediators Parkin and Pink1. Neuron-specific Pink1 knockdown abolishes spermidine-induced improvement of olfactory associative learning. This suggests that the maintenance of mitochondrial and autophagic function is essential for enhanced cognition by spermidine feeding. Finally, we show large-scale prospective data linking higher dietary spermidine intake with a reduced risk for cognitive impairment in humans.

Intravenous iron supplementation therapy.

Intravenous infusions of iron have evolved from a poorly effective and dangerous intervention to a safe cornerstone in the treatment of iron deficiency. Modern iron formulations are composite nanoparticles composed of carbohydrate ferric oxy-hydroxides. Iron dextran, iron derisomaltose (formely known as iron isomaltoside 1000), ferric carboxymaltose, ferrumoxytol, iron sucrose and sodium ferric gluconate can be infused at different doses and allow correction of total iron deficit with single or repeated doses in 1-2 weeks depending on the specific formulation. All iron preparations are associated with a risk of severe infusion reactions. In recent prospective clinical trials, the risk of moderate to severe infusion reactions was comparable among all modern preparations affecting <1% of patients. Hence, intravenous iron therapy is reserved for iron deficiency anemia patients with intolerance or unresponsiveness of oral iron. As per European drug label, intravenous iron may also be preferred when rapid correction of the iron deficit is required. In patients with inflammation, iron-deficiency should also be suspected as anemia cause when transferrin saturation is low because serum ferritin can be spuriously normal. The main treatment target for i.v. iron is an improvement of the quality of life, for which hemoglobin is a surrogate marker. An emerging complication affecting 50-74% of patients treated with ferric carboxymaltose in prospective clinical trials is hypophosphatemia - or more accurately the 6H syndrome (hyperphosphaturic hypophosphatemia triggered by high fibroblast growth factor 23 that causes hypovitaminosis D, hypocalcemia and secondary hyperparathyroidism). These biochemical changes can cause severe and potentially irreversible clinical complications, such a bone pain, osteomalacia and fractures. Individual selection of the appropriate iron therapy and evaluation of treatment response are mandatory to safely deliver improved outcome through intravenous iron therapies.

Dietary lipids fuel GPX4-restricted enteritis resembling Crohn's disease.

The increased incidence of inflammatory bowel disease (IBD) has become a global phenomenon that could be related to adoption of a Western life-style. Westernization of dietary habits is partly characterized by enrichment with the ω-6 polyunsaturated fatty acid (PUFA) arachidonic acid (AA), which entails risk for developing IBD. Glutathione peroxidase 4 (GPX4) protects against lipid peroxidation (LPO) and cell death termed ferroptosis. We report that small intestinal epithelial cells (IECs) in Crohn's disease (CD) exhibit impaired GPX4 activity and signs of LPO. PUFAs and specifically AA trigger a cytokine response of IECs which is restricted by GPX4. While GPX4 does not control AA metabolism, cytokine production is governed by similar mechanisms as ferroptosis. A PUFA-enriched Western diet triggers focal granuloma-like neutrophilic enteritis in mice that lack one allele of Gpx4 in IECs. Our study identifies dietary PUFAs as a trigger of GPX4-restricted mucosal inflammation phenocopying aspects of human CD.

Choice of High-Dose Intravenous Iron Preparation Determines Hypophosphatemia Risk.

BACKGROUND: Ferric carboxymaltose (FCM) and iron isomaltoside 1000 (IIM) are increasingly used because they allow correction of severe iron deficiency in a single infusion. A transient decrease in serum phosphate concentrations is a frequent side effect of FCM. AIM: To characterize this adverse event and search for its predictors in a gastroenterology clinic patient cohort. METHODS: Electronic medical records of patients attending the University Hospital of Innsbruck were searched for the keywords ferric carboxymaltose or iron isomaltoside. Eighty-one patients with documented administration of FCM or IIM with plasma phosphate concentrations before and after treatment were included. RESULTS: The prevalence of hypophosphatemia (<0.8 mmol/L) increased from 11% to 32.1% after treatment with i.v. iron. The hypophosphatemia risk was greater after FCM (45.5%) compared with IIM (4%). Severe hypophosphatemia (<0.6 mmol/L) occurred exclusively after FCM (32.7%). The odds for hypophosphatemia after i.v. iron treatment were independently determined by baseline phosphate and the choice of i.v. iron preparation (FCM vs. IIM-OR = 20.8; 95% CI, 2.6-166; p = 0.004). The median time with hypophosphatemia was 41 days, but prolonged hypophosphatemia of ≥ 2 months was documented in 13 of 17 patients in whom follow-up was available. A significant increase in the phosphaturic hormone intact FGF-23 in hypophosphatemic patients shows that this adverse event is caused by FCM-induced hormone dysregulation. CONCLUSION: Treatment with FCM is associated with a high risk of developing severe and prolonged hypophosphatemia and should therefore be monitored. Hypophosphatemia risk appears to be substantially lower with IIM.

[Management of severe alcoholic hepatitis]. / Management bei schwerer alkoholischer Hepatitis.

Severe alcoholic hepatitis is still associated with high mortality and presence of liver failure manifested by jaundice, coagulopathy and encephalopathy is a poor prognostic indicator. The management of these patients includes at first hand several supportive measures as treatment of alcohol withdrawal, administration of fluid and vitamins and admission to an intensive care unit in the unstable patient. Glucocorticoids have been since decades the most intensively studied therapy in alcoholic hepatitis and are effective in certain subgroups. Indication for such a therapy is usually defined on a Maddrey Discriminant Function > 32. The Lille score at day 7 is used to decide whether corticosteroid therapy should be stopped or continued for a 1 month course. Nutritional supplementation is also likely to be beneficial. The main progress in better understanding its pathophysiology has come from cytokine studies. Various proinflammatory cytokines such as tumor necrosis factor-alpha (TNFα) or interleukin-1 (IL-1) have been proposed to play a role in this disease. This advancement has recently led to pilot studies investigating anti-TNF drugs such as pentoxifylline, infliximab (anti-TNF antibody) or etanercept in the treatment of this disease. These studies revealed besides for pentoxifylline rather negative results. Despite this fact, targeting of certain cytokines such as IL-1 remains an attractive treatment concept for this devastating disorder in the future.

Nutrition in pathophysiology and treatment of nonalcoholic fatty liver disease.

PURPOSE OF REVIEW: Overnutrition resulting in obesity plays a key role in nonalcoholic fatty liver disease, the major reason for abnormal liver function in many parts of the world. Currently, it is not clear which type of diet preferentially results in this common disease. RECENT FINDINGS: Excess nutrition leads to accumulation of various lipids in the liver, where fatty acids are considered the main driving force in the disease process. A liver loaded with fat is commonly associated with insulin resistance, the key pathophysiological phenomenon observed in nonalcoholic fatty liver disease. Not surprisingly, attempts to reduce body weight and thereby total liver fat are considered the key therapeutical steps in this disorder. Although voluntary weight loss is often not successful to reverse the disease process, various surgical procedures have proven effective in reducing overweight situations and liver steatosis. Weight loss not only reduces the amount of liver fat but also might improve inflammation and fibrosis in nonalcoholic steatohepatitis. SUMMARY: Although pharmacological approaches are eagerly awaited to achieve similar benefits; current available therapies have so far not fulfilled this expectation. Despite this frustration, such approaches are expected to be available in the near future.