Neutrophil degranulation, endothelial and metabolic dysfunction in unvaccinated long COVID patients.

BACKGROUND: Long COVID symptoms are widely diffused and have a poorly understood pathophysiology, with possible involvement of inflammatory cytokines. MATERIALS AND METHODS: A prospective follow-up study involved 385 unvaccinated patients, started 1 month after SARS-CoV-2 infection and continued for up to 12 months. We compared circulating biomarkers of neutrophil degranulation, endothelial and metabolic dysfunction in subjects with long COVID symptoms and in asymptomatic post-COVID controls. RESULTS: The highest occurrence of symptoms (71%) was after 3 months from the infection, decreasing to 62.3% and 29.4% at 6 and 12 months, respectively. Compared to controls, long COVID patients had increased levels of the neutrophilic degranulation indices MMP-8 and MPO, of endothelial dysfunction indices L-selectin and P-selectin. Among indices of metabolic dysfunction, leptin levels were higher in long COVID patients than in controls. CONCLUSION: In unvaccinated patients, symptoms may persist up to 1 year after acute COVID infection, with increased indices of neutrophil degranulation, endothelial and metabolic dysfunction. The clinical implications of specific inflammatory biomarkers require further attention, especially in individuals with fatigue and long COVID-linked cognitive dysfunctions.

Effects of MBOAT7 polymorphism and steatosis on liver function assessed by methacetin breath test.

BACKGROUND: MBOAT7 rs641738 variant is a risk factor for nonalcoholic fatty liver disease (NAFLD) and liver fibrosis, but the relationship between this polymorphism and early liver dysfunction remains uncertain. METHODS: Eighty outpatients underwent blood analyses, liver imaging by ultrasound and acoustic radiation force impulse shear wave elastography and were genotyped for MBOAT7 (wild-type [WT], rs641738 heterozygous or homozygous) polymorphism using TaqMan assays. RESULTS: NAFLD was confirmed in 53 patients. Portal uptake and hepatocyte microsomal metabolization of (13 C)-methacetin were explored by measuring 13 CO2 appearance in exhaled air. The distribution of the MBOAT7 genotypes was comparable in subjects with or without NAFLD. The majority of subjects with or without NAFLD had fibrosis ≤ F1 but decreased portal extraction of (13 C)-methacetin, i.e. 78.6% in homozygous, 45.0% in heterozygous and 46.2% in WT for the MBOAT7 variant. Both substrate extraction and microsomal metabolization were mostly defective in the homozygous carriers. The extraction efficiency from portal blood flow was minimal in subjects with both homozygous rs641738 polymorphism and NAFLD, as compared to those with WT/heterozygous polymorphism, with or without NAFLD. CONCLUSIONS: The homozygous MBOAT7 rs641738 polymorphism per se is associated with a reduced extraction efficiency of (13 C)-methacetin from the portal flow pointing to subclinical liver dysfunction independently from liver fibrosis. Liver steatosis worsens (13 C)-methacetin extraction efficiency. We urge to better explore the mechanisms of interaction between external factors and multiple gene polymorphisms (including MBOAT7), paving the road to primary prevention and novel therapeutic strategies.

Ramadan intermittent fasting reduces visceral fat and improves gastrointestinal motility.

BACKGROUND: Ramadan is a model of intermittent fasting linked with possible beneficial effects. Scarce information, however, is available about the combined effects of Ramadan intermittent fasting (RIF) on anthropometric and metabolic indices, gastrointestinal symptoms, and motility. METHODS: In 21 healthy Muslims, we assessed the impact of RIF on caloric intake, physical activity, gastrointestinal symptoms and motility (gastric/gallbladder emptying by ultrasonography, orocaecal transit time by lactulose breath test), anthropometric indices, subcutaneous and visceral fat thickness (ultrasonography), glucose and lipid homeostasis. RESULTS: Mean caloric intake decreased from a median of 2069 kcal (range 1677-2641) before Ramadan to 1798 kcal (1289-3126) during Ramadan and increased again to 2000 kcal (1309-3485) after Ramadan. Although physical activity remained stable before, during, and after RIF, body weight, body mass index and waist circumference decreased in all subjects and in both genders, together with a significant decrease in subcutaneous and visceral fat thickness and insulin resistance. The postprandial gastric emptying speed was significantly faster after than before RIF. Fasting gallbladder volume was about 6% smaller after, than before Ramadan, with a stronger and faster postprandial gallbladder contraction. After RIF, lactulose breath test documented increased microbiota carbohydrate fermentation (postprandial H2 peak), and faster orocaecal transit time. RIF also significantly improved gastric fullness, epigastric pain and heartburn. CONCLUSIONS: RIF generates, in healthy subjects, multiple systemic beneficial effects in terms of fat burden, metabolic profile, gastrointestinal motility and symptoms. Further comprehensive studies should assess the potential beneficial effects of RIF in diseased people.

Contribution of the microbiome for better phenotyping of people living with obesity.

Obesity has reached epidemic proportion worldwide and in all ages. Available evidence points to a multifactorial pathogenesis involving gene predisposition and environmental factors. Gut microbiota plays a critical role as a major interface between external factors, i.e., diet, lifestyle, toxic chemicals, and internal mechanisms regulating energy and metabolic homeostasis, fat production and storage. A shift in microbiota composition is linked with overweight and obesity, with pathogenic mechanisms involving bacterial products and metabolites (mainly endocannabinoid-related mediators, short-chain fatty acids, bile acids, catabolites of tryptophan, lipopolysaccharides) and subsequent alterations in gut barrier, altered metabolic homeostasis, insulin resistance and chronic, low-grade inflammation. Although animal studies point to the links between an "obesogenic" microbiota and the development of different obesity phenotypes, the translational value of these results in humans is still limited by the heterogeneity among studies, the high variation of gut microbiota over time and the lack of robust longitudinal studies adequately considering inter-individual confounders. Nevertheless, available evidence underscores the existence of several genera predisposing to obesity or, conversely, to lean and metabolically health phenotype (e.g., Akkermansia muciniphila, species from genera Faecalibacterium, Alistipes, Roseburia). Further longitudinal studies using metagenomics, transcriptomics, proteomics, and metabolomics with exact characterization of confounders are needed in this field. Results must confirm that distinct genera and specific microbial-derived metabolites represent effective and precision interventions against overweight and obesity in the long-term.

The role of microbiota in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is the most frequent liver disease worldwide. Gut microbiota can play a role in the pathogenesis of NAFLD since dysbiosis is associated with reduced bacterial diversity, altered Firmicutes/Bacteroidetes ratio, a relative abundance of alcohol-producing bacteria, or other specific genera. Changes can promote disrupted intestinal barrier and hyperpermeability, filtration of bacterial products, activation of the immune system, and pro-inflammatory changes in the intestine, in the liver, and at a systemic level. Microbiota-derived molecules can contribute to the steatogenic effects. The link between gut dysbiosis and NAFLD, however, is confused by several factors which include age, BMI, comorbidities, dietary components, and lifestyle. The role of toxic chemicals in food and water requires further studies in both gut dysbiosis and NAFLD. We can anticipate that gut microbiota manipulation will represent a potential therapeutic tool to delay or reverse the progression of NAFLD, paving the way to primary prevention measures.

Novel insights into the pathogenic impact of diabetes on the gastrointestinal tract.

Type 2 and type 1 diabetes are common endocrine disorders with a progressively increasing incidence worldwide. These chronic, systemic diseases have multiorgan implications, and the whole gastrointestinal (GI) tract represents a frequent target in terms of symptom appearance and interdependent pathophysiological mechanisms. Metabolic alterations linked with diabetic complications, neuropathy and disrupted hormone homeostasis can lead to upper and/or lower GI symptoms in up to 75% of diabetic patients, with multifactorial involvement of the oesophagus, stomach, upper and lower intestine, and of the gallbladder. On the other hand, altered gastrointestinal motility and/or secretions are able to affect glucose and lipid homeostasis in the short and long term. Finally, diabetes has been linked with increased cancer risk at different levels of the GI tract. The presence of GI symptoms and a comprehensive assessment of GI function should be carefully considered in the management of diabetic patients to avoid further complications and to ameliorate the quality of life. Additionally, the presence of gastrointestinal dysfunction should be adequately managed to improve metabolic homeostasis, the efficacy of antidiabetic treatments and secondary prevention strategies.

Synergistic and Detrimental Effects of Alcohol Intake on Progression of Liver Steatosis.

Nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are the most common liver disorders worldwide and the major causes of non-viral liver cirrhosis in the general population. In NAFLD, metabolic abnormalities, obesity, and metabolic syndrome are the driving factors for liver damage with no or minimal alcohol consumption. ALD refers to liver damage caused by excess alcohol intake in individuals drinking more than 5 to 10 daily units for years. Although NAFLD and ALD are nosologically considered two distinct entities, they show a continuum and exert synergistic effects on the progression toward liver cirrhosis. The current view is that low alcohol use might also increase the risk of advanced clinical liver disease in NAFLD, whereas metabolic factors increase the risk of cirrhosis among alcohol risk drinkers. Therefore, special interest is now addressed to individuals with metabolic abnormalities who consume small amounts of alcohol or who binge drink, for the role of light-to-moderate alcohol use in fibrosis progression and clinical severity of the liver disease. Evidence shows that in the presence of NAFLD, there is no liver-safe limit of alcohol intake. We discuss the epidemiological and clinical features of NAFLD/ALD, aspects of alcohol metabolism, and mechanisms of damage concerning steatosis, fibrosis, cumulative effects, and deleterious consequences which include hepatocellular carcinoma.

Gut Microbiota and Short Chain Fatty Acids: Implications in Glucose Homeostasis.

Gut microbiota encompasses a wide variety of commensal microorganisms consisting of trillions of bacteria, fungi, and viruses. This microbial population coexists in symbiosis with the host, and related metabolites have profound effects on human health. In this respect, gut microbiota plays a pivotal role in the regulation of metabolic, endocrine, and immune functions. Bacterial metabolites include the short chain fatty acids (SCFAs) acetate (C2), propionate (C3), and butyrate (C4), which are the most abundant SCFAs in the human body and the most abundant anions in the colon. SCFAs are made from fermentation of dietary fiber and resistant starch in the gut. They modulate several metabolic pathways and are involved in obesity, insulin resistance, and type 2 diabetes. Thus, diet might influence gut microbiota composition and activity, SCFAs production, and metabolic effects. In this narrative review, we discuss the relevant research focusing on the relationship between gut microbiota, SCFAs, and glucose metabolism.

Noncommunicable diseases, climate change and iniquities: What COVID-19 has taught us about syndemic.

BACKGROUND: COVID-19 is generating clinical challenges, lifestyle changes, economic consequences. The pandemic imposes to familiarize with concepts as prevention, vulnerability and resilience. METHODS: We analysed and reviewed the most relevant papers in the MEDLINE database on syndemic, noncommunicable diseases, pandemic, climate changes, pollution, resilience, vulnerability, health costs, COVID-19. RESULTS: We discuss that comprehensive strategies must face multifactorial consequences since the pandemic becomes syndemic due to interactions with noncommunicable diseases, climate changes and iniquities. The lockdown experience, on the other hand, demonstrates that it is rapidly possible to reverse epidemiologic trends and to reduce pollution. The worst outcome is evident in eight highly industrialized nations, where 12% of the world population experienced about one-third of all COVID-19-deaths worldwide. Thus, a great economic power has not been fully protective, and a change of policy is obviously needed to avoid irreversible consequences. CONCLUSIONS: We are accumulating unhealthy populations living in unhealthy environments and generating unhealthy offspring. The winning policy should tackle structural inequities through a syndemic approach, to protect vulnerable populations from present and future harms.

Nonalcoholic Fatty Liver Disease (NAFLD). Mitochondria as Players and Targets of Therapies?

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and represents the hepatic expression of several metabolic abnormalities of high epidemiologic relevance. Fat accumulation in the hepatocytes results in cellular fragility and risk of progression toward necroinflammation, i.e., nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Several pathways contribute to fat accumulation and damage in the liver and can also involve the mitochondria, whose functional integrity is essential to maintain liver bioenergetics. In NAFLD/NASH, both structural and functional mitochondrial abnormalities occur and can involve mitochondrial electron transport chain, decreased mitochondrial ß-oxidation of free fatty acids, excessive generation of reactive oxygen species, and lipid peroxidation. NASH is a major target of therapy, but there is no established single or combined treatment so far. Notably, translational and clinical studies point to mitochondria as future therapeutic targets in NAFLD since the prevention of mitochondrial damage could improve liver bioenergetics.

Mitochondria Matter: Systemic Aspects of Nonalcoholic Fatty Liver Disease (NAFLD) and Diagnostic Assessment of Liver Function by Stable Isotope Dynamic Breath Tests.

The liver plays a key role in systemic metabolic processes, which include detoxification, synthesis, storage, and export of carbohydrates, lipids, and proteins. The raising trends of obesity and metabolic disorders worldwide is often associated with the nonalcoholic fatty liver disease (NAFLD), which has become the most frequent type of chronic liver disorder with risk of progression to cirrhosis and hepatocellular carcinoma. Liver mitochondria play a key role in degrading the pathways of carbohydrates, proteins, lipids, and xenobiotics, and to provide energy for the body cells. The morphological and functional integrity of mitochondria guarantee the proper functioning of ß-oxidation of free fatty acids and of the tricarboxylic acid cycle. Evaluation of the liver in clinical medicine needs to be accurate in NAFLD patients and includes history, physical exam, imaging, and laboratory assays. Evaluation of mitochondrial function in chronic liver disease and NAFLD is now possible by novel diagnostic tools. "Dynamic" liver function tests include the breath test (BT) based on the use of substrates marked with the non-radioactive, naturally occurring stable isotope 13C. Hepatocellular metabolization of the substrate will generate 13CO2, which is excreted in breath and measured by mass spectrometry or infrared spectroscopy. Breath levels of 13CO2 are biomarkers of specific metabolic processes occurring in the hepatocyte cytosol, microsomes, and mitochondria. 13C-BTs explore distinct chronic liver diseases including simple liver steatosis, non-alcoholic steatohepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma, drug, and alcohol effects. In NAFLD, 13C-BT use substrates such as α-ketoisocaproic acid, methionine, and octanoic acid to assess mitochondrial oxidation capacity which can be impaired at an early stage of disease. 13C-BTs represent an indirect, cost-effective, and easy method to evaluate dynamic liver function. Further applications are expected in clinical medicine. In this review, we discuss the involvement of liver mitochondria in the progression of NAFLD, together with the role of 13C-BT in assessing mitochondrial function and its potential use in the prevention and management of NAFLD.

Effects of Bifidobacterium longum BB536 and Lactobacillus rhamnosus HN001 in IBS patients.

BACKGROUND: Irritable bowel syndrome (IBS) is a common gastrointestinal disorder, which still lacks effective therapy. We aimed to investigate the effects of a novel formulation of Bifidobacterium longum BB536 and Lactobacillus rhamnosus HN001 with vitamin B6 (LBB) on symptoms, intestinal permeability, cultivable bacteria and metabolome in IBS subjects. MATERIALS AND METHODS: Twenty-five IBS patients (Rome IV criteria) (M:F = 8:17; age 48 years ± 11 SD) were randomized to treatment (LBB) or placebo (one month each) in a crossover randomized double-blind controlled trial. Symptoms, intestinal habits, disease severity, intestinal permeability and intestinal microbiota were analysed at 0, 30, 45 and 60 days. RESULTS: Percentage decrease from baseline of abdominal pain (-48.8% vs -3.5%), bloating (-36.35% vs +7.35%) and severity of disease (-30.1% vs -0.4%) was significantly (P < .0001) greater with LBB than placebo, respectively. In IBS-D patients, the improvement from baseline of Bristol score was more consistent with LBB (from 6 ± 0.4 to 4.3 ± 1.1, P < .00001) than placebo (from 6.2 ± 0.7 to 5.3 ± 1.1, P = .04). In IBS-C patients, Bristol score tended to improve from baseline after LBB (2.6 ± 1.1 vs 3.2 ± 0.5, P = .06). LBB significantly improved the percentage of sucralose recovery (colonic permeability) (1.86 ± 0.1 vs 1.1 ± 0.2, P = .01). During treatment, presumptive lactic acid bacteria and bifidobacteria, relative abundance of propanoic, butanoic, pentanoic acids and hydrocarbons increased, while phenol decreased. CONCLUSIONS: The novel formulation of B. longum BB536 and L. rhamnosus HN001 with B6 vitamin improves symptoms and severity of disease, restores intestinal permeability and gut microbiota in IBS patients.

Gastrointestinal defects in gallstone and cholecystectomized patients.

BACKGROUND AND AIM: Several gallstone patients complain of dyspeptic symptoms, irrespective of the presence of typical colicky pain. Symptoms often persist after a cholecystectomy. Systematic studies on dyspepsia and dynamic gastrointestinal motor function are missing in gallstone patients with preserved gallbladder or after a cholecystectomy. MATERIALS AND METHODS: Forty-six gallstone patients (age 55 ± 2 years; 15M, 31F) and 24 cholecystectomized patients (age 57 ± 2 years; 6M, 18F) (no difference in type and volume of gallstones between the two groups) were compared against a group of 65 healthy controls (age 51 ± 2 years; 30M, 35F). Dyspepsia occurring in the prior months was assessed by a questionnaire, gastric and gallbladder emptying by functional ultrasonography and orocecal transit time by a hydrogen breath test using a lactulose-enriched standard liquid meal. RESULTS: Gallstone patients had significantly greater dyspepsia, fasting and residual gallbladder volumes, and slower gallbladder emptying, gastric emptying and small intestinal transit time than controls. In cholecystectomized patients, gastric emptying further delayed, compared to gallstone patients and controls. CONCLUSION: Gallstone patients with the gallbladder "in situ" or after a cholecystectomy display dyspeptic symptoms. Symptoms are associated with multiple gastrointestinal motility defects involving the gallbladder, stomach and small intestine. After cholecystectomy, gastric emptying worsens.

A novel cluster of patients with Familial Mediterranean Fever (FMF) in southern Italy.

BACKGROUND: Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disorder characterised by recurrent attacks of fever and serositis (peritonitis, pleuritic or synovitis) affecting mainly populations of Mediterranean origin. AIM: To describe a relatively new cluster of FMF subjects from Apulia and Basilicata regions (southern Italy). PATIENTS AND METHODS: Subjects were screened for FMF using the Tel-Hashomer criteria and genetic analysis. Demographic data were taken from patients' files and direct interviews. Patients were investigated about attack duration, intensity and site, body temperature, skin manifestations and overall quality of life before and after treatment with colchicine. Inflammatory parameters were also measured between these periods. RESULTS: Forty-nine subjects had FMF (M : F = 26 : 23, age 38 years ± 2 SE) and followed-up up to 8 years. The age at disease onset was 22·1 years ± 1·2SE and the diagnostic delay was 15·5 years ± 1·9SE. The majority of patients (82%) suffered from abdominal pain, and 35% had undergone prior abdominal surgery or laparotomy. Severity score (ISSF) was mild in 43% of patients and intermediate in 57% of patients. Serum amyloid A (SAA) was increased in 20% of patients (16·9 ± 3·7, normal range < 6·4 mg/dL). In over 95% of patients, inflammation markers, duration and intensity of febrile painful attacks, quality of life and ISSF score improved dramatically following colchicine treatment. CONCLUSION: The Apulia region represents a new endemic area for FMF. Clinical presentation of FMF can be misleading and requires a complete and early workup to recognise the disease and avoid unjustified surgery. Colchicine remains the gold standard therapy to prevent FMF attacks and fatal long-term complications.

Bile Acid Physiology.

The primary bile acids (BAs) are synthetized from colesterol in the liver, conjugated to glycine or taurine to increase their solubility, secreted into bile, concentrated in the gallbladder during fasting, and expelled in the intestine in response to dietary fat, as well as bio-transformed in the colon to the secondary BAs by the gut microbiota, reabsorbed in the ileum and colon back to the liver, and minimally lost in the feces. BAs in the intestine not only regulate the digestion and absorption of cholesterol, triglycerides, and fat-soluble vitamins, but also play a key role as signaling molecules in modulating epithelial cell proliferation, gene expression, and lipid and glucose metabolism by activating farnesoid X receptor (FXR) and G-protein-coupled bile acid receptor-1 (GPBAR-1, also known as TGR5) in the liver, intestine, muscle and brown adipose tissue. Recent studies have revealed the metabolic pathways of FXR and GPBAR-1 involved in the biosynthesis and enterohepatic circulation of BAs and their functions as signaling molecules on lipid and glucose metabolism.

A novel therapeutic effect of statins on nephrogenic diabetes insipidus.

Statins competitively inhibit hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase, resulting in reduced plasma total and low-density lipoprotein cholesterol levels. Recently, it has been shown that statins exert additional 'pleiotropic' effects by increasing expression levels of the membrane water channels aquaporin 2 (AQP2). AQP2 is localized mainly in the kidney and plays a critical role in determining cellular water content. This additional effect is independent of cholesterol homoeostasis, and depends on depletion of mevalonate-derived intermediates of sterol synthetic pathways, i.e. farnesylpyrophosphate and geranylgeranylpyrophosphate. By up-regulating the expression levels of AQP2, statins increase water reabsorption by the kidney, thus opening up a new avenue in treating patients with nephrogenic diabetes insipidus (NDI), a hereditary disease that yet lacks high-powered and limited side effects therapy. Aspects related to water balance determined by AQP2 in the kidney, as well as standard and novel therapeutic strategies of NDI are discussed.

The inulin hydrogen breath test predicts the quality of colonic preparation.

BACKGROUND: Successful bowel preparation is essential to an adequate performance of colonoscopy. Polyethylene glycol (PEG) with electrolyte solutions induces diarrhea with depletion of substrates fermentable by hydrogen (H2)-producing colonic microbiota. Inulin has recently been suggested as a prebiotic substrate for the H2 breath test because it is resistant to intestinal hydrolysis and is fermented mostly by the colonic bacteria. This study aimed to assess time-dependent changes in H2 breath levels in order to predict the colonic preparation of patients scheduled for colonoscopy with or without oral supplementation of inulin. METHODS: In this prospective nonrandomized trial, 127 subjects drank 4 l of PEG 280-mg solution as bowel preparation for colonoscopy. A subgroup of 31 patients also ingested inulin (10 g in 200 ml of water) at breakfast as an additional substrate to increase colonic H2 production. Measurements of H2 breath levels were performed immediately before and after colonic preparation. As the main outcome measure, the quality of the colonic preparation was scored as excellent to fair (i.e., clean bowel allowing successful pan-colonoscopy, including the terminal ileum) or poor (incomplete colonoscopy due to fecal debris). RESULTS: The H2 breath levels decreased from 11.0 ± 1.8 ppm before PEG to 1.8 ± 0.3 ppm after PEG (n = 18; P < 0.001). The H2 concentrations after PEG ingestion were significantly lower (P < 0.001) in the patients with excellent-to-fair preparation than in the 19 patients with poor preparation. Ingestion of inulin induced an overall increase in H2 breath levels and improved discrimination between the patients with excellent-to-fair colonic preparation and those with poor preparation, leading to the sensitivity and specificity of such a test reaching 100 %. CONCLUSIONS: The H2 breath test with inulin ingestion can be a simple, noninvasive, reliable method for predicting successful colonic preparation that leads to cost savings and less patient discomfort/stress or need to repeat colonoscopy.

Gut microbes in metabolic disturbances. Promising role for therapeutic manipulations?

The prevalence of overweight, obesity, type 2 diabetes, metabolic syndrome and steatotic liver disease is rapidly increasing worldwide with a huge economic burden in terms of morbidity and mortality. Several genetic and environmental factors are involved in the onset and development of metabolic disorders and related complications. A critical role also exists for the gut microbiota, a complex polymicrobial ecology at the interface of the internal and external environment. The gut microbiota contributes to food digestion and transformation, caloric intake, and immune response of the host, keeping the homeostatic control in health. Mechanisms of disease include enhanced energy extraction from the non-digestible dietary carbohydrates, increased gut permeability and translocation of bacterial metabolites which activate a chronic low-grade systemic inflammation and insulin resistance, as precursors of tangible metabolic disorders involving glucose and lipid homeostasis. The ultimate causative role of gut microbiota in this respect remains to be elucidated, as well as the therapeutic value of manipulating the gut microbiota by diet, pre- and pro- synbiotics, or fecal microbial transplantation.