Are self-reported gastrointestinal symptoms among older adults associated with increased intestinal permeability and psychological distress?

Faecal intestinal permeability and intestinal inflammatory markers in older adults with age-related disorders: A systematic review and meta-analysis

This systematic review and meta-analysis appraised previous findings to uncover potential faecal intestinal permeability and intestinal inflammatory markers in older adults. A comprehensive literature search led to the identification of ten eligible studies with findings of potential faecal intestinal permeability (zonulin and alpha-1-antitrypsin) and intestinal inflammatory markers [calprotectin, lactoferrin and neutrophil gelatinase-associated lipocalin (NGAL)]. Most of the cases (n > 2) [Parkinson's disease (PD) and Alzheimer's disease (AD)] exhibited higher faecal alpha-1-antitrypsin, zonulin and calprotectin levels. The present meta-analysis confirmed significantly higher faecal alpha-1-antitrypsin in older persons with PD compared to non-PD [MD = 22.92 mg/dL; 95 % CI = 14.02-31.81, p < 0.00001; I2 = 0 % (p = 0.73)]. There was, however, no significant difference in faecal zonulin between PD and non-PD individuals [MD = 26.88 ng/mL; 95 % CI = -29.26-83.01, p = 0.35; I2 = 94 % (p < 0.0001)]. Meanwhile, faecal calprotectin was higher in older adults with GI symptoms, multiple system atrophy (MSA) or PD than the healthy controls [MD = 9.51 μg/g; 95 % CI = 0.07-18.95, p = 0.05; I2 = 84 % (p < 0.00001)]. Altogether, faecal calprotectin appears to be a potential intestinal inflammatory marker whereas previous findings on faecal alpha-1-antitrypsin as an intestinal permeability marker remain limited and require further validation.

Changes in Digestive Health, Satiety and Overall Well-Being after 14 Days of a Multi-Functional GI Primer Supplement

A recent review proposed a role for multi-functional food or supplement products in priming the gut to support both digestive and systemic health. Accordingly, we designed and eva-luated the effect of a multi-functional gastrointestinal (GI) primer supplement on participant-reported measures for digestive health, quality-of-life (e.g., energy/vitality and general health), and reasons for satiation (e.g., attitudes towards food and eating). In this single-arm clinical trial, 68 participants with mild digestive symptoms consumed the GI primer supplement daily for 14 days. Digestive symptoms were evaluated daily from baseline (Day 0) through Day 14. At baseline and Day 14, participants reported their stool consistency, reasons for satiation, and quality-of-life measures using validated questionnaires. At Day 14, participants reported significant improvements in all (13/13) digestive symptom parameters (p-values < 0.05) and an increase in % of stools with normal consistencies. There were significant improvements (p-values < 0.05) in energy/vitality and general health, and in specific attitudes towards food and eating (e.g., physical satisfaction, planned amount, decreased eating priority, decreased food appeal, and self-consciousness). Results suggest the GI primer supplement promotes digestive health, improves quality of life, and impacts attitudes towards food/eating. This study provides preliminary support for the gut priming hypothesis through which multi-functional digestive products may improve GI health.

Helicobacter pylori Eradication Treatment in Older Patients

Helicobacter pylori is the main etiopathogenetic factor of chronic gastritis, peptic ulcer disease and gastric cancer. The world's population is shifting towards older people, who have the highest prevalence of H. pylori. Aging-related peculiarities could have an impact on the treatment of H. pylori and there is still a lack of research data in the older population. The aim of this review was to summarize the findings of the most recent information, publications and studies on the issues relating to H. pylori infection in older patients. H. pylori eradication offers gastrointestinal and extra gastrointestinal benefits in older patients. Based on the main guidelines, H. pylori should be eradicated independent of the patient's age, only reconsidering cases with terminal illness and low life expectancy. Proton pump inhibitors are generally safe and well tolerated. Some antibiotics require dose adjustment only in advanced renal insufficiency and the risk of hepatotoxicity is very low. Special precautions should be taken in patients with polypharmacy and those taking aspirin or non-steroidal anti-inflammatory drugs. In older patients, H. pylori eradication treatment frequently causes only mild and short-term adverse events; however, treatment compliance is usually still very good. H. pylori treatment in older patients does not increase the risk of Clostridium difficile infection. Optimal eradication effectiveness (> 90%) is mostly achieved with bismuth- and non-bismuth-based quadruple therapies. Susceptibility-guided treatment of H. pylori can contribute to increasing the effectiveness of eradication regimens in older adults. To achieve optimal H. pylori eradication effectiveness in older patients, the same guidelines, which are applied to adults, also apply to this population: avoiding repetitive treatment prescriptions, choosing quadruple therapies, prescribing longer treatment duration and administering high-dose proton pump inhibitors twice daily.

Gut-brain pathogenesis of post-acute COVID-19 neurocognitive symptoms

Approximately one third of non-hospitalized coronavirus disease of 2019 (COVID-19) patients report chronic symptoms after recovering from the acute stage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Some of the most persistent and common complaints of this post-acute COVID-19 syndrome (PACS) are cognitive in nature, described subjectively as "brain fog" and also objectively measured as deficits in executive function, working memory, attention, and processing speed. The mechanisms of these chronic cognitive sequelae are currently not understood. SARS-CoV-2 inflicts damage to cerebral blood vessels and the intestinal wall by binding to angiotensin-converting enzyme 2 (ACE2) receptors and also by evoking production of high levels of systemic cytokines, compromising the brain's neurovascular unit, degrading the intestinal barrier, and potentially increasing the permeability of both to harmful substances. Such substances are hypothesized to be produced in the gut by pathogenic microbiota that, given the profound effects COVID-19 has on the gastrointestinal system, may fourish as a result of intestinal post-COVID-19 dysbiosis. COVID-19 may therefore create a scenario in which neurotoxic and neuroinflammatory substances readily proliferate from the gut lumen and encounter a weakened neurovascular unit, gaining access to the brain and subsequently producing cognitive deficits. Here, we review this proposed PACS pathogenesis along the gut-brain axis, while also identifying specific methodologies that are currently available to experimentally measure each individual component of the model.

Gut Health and Its Association with Wellbeing and Nutrient Intake in Community-Dwelling Older Adults

Many of the increasing number of community-dwelling older adults will need increased healthcare in the future. By characterising gut health and its association with wellbeing and nutrient intake in this population, we aim to recognise areas along the gut–brain axis through which the health of community-dwelling older adults might be promoted. In this cross-sectional observational study, validated questionnaires were used to assess gut health, nutrient intake, and wellbeing in 241 community-dwelling older adults (≥65 years old). In total, 65% of the participants experienced at least one gastrointestinal symptom, of which females had more abdominal pain and constipation, while the oldest old (i.e., ≥80 years old) had more diarrhoea. Increased gastrointestinal symptoms correlated with more stress, anxiety, depression, and a decreased quality of life, in addition to dyspepsia which correlated with a lower E% of protein. Most of the participants did not reach the recommended intake for protein, fibre and polyunsaturated fats. Males had a lower intake of protein (E%) and fibre (g/MJ) than females, and the oldest old had a lower E% of protein than younger older adults. In conclusion, our results demonstrate that gastrointestinal symptoms are common, and most of the study participants had an imbalanced macronutrient intake, which could be a target for future possible dietary interventions to improve overall health.

Nutritional considerations to counteract gastrointestinal permeability during exertional heat stress

Intestinal barrier integrity and function are compromised during exertional heat stress (EHS) potentially leading to consequences that range from minor gastrointestinal (GI) disturbances to fatal outcomes in exertional heat stroke or septic shock. This mini-review provides a concise discussion of nutritional interventions that may protect against intestinal permeability during EHS and suggests physiological mechanisms responsible for this protection. Although diverse nutritional interventions have been suggested to be protective against EHS-induced GI permeability, the ingestion of certain amino acids, carbohydrates, and fluid per se is potentially effective strategy, whereas evidence for various polyphenols and pre/probiotics is developing. Plausible physiological mechanisms of protection include increased blood flow, epithelial cell proliferation, upregulation of intracellular heat shock proteins, modulation of inflammatory signaling, alteration of the GI microbiota, and increased expression of tight junction (TJ) proteins. Further clinical research is needed to propose specific nutritional candidates and recommendations for their application to prevent intestinal barrier disruption and elucidate mechanisms during EHS.

What Are the Pearls and Pitfalls of the Dietary Management for Chronic Diarrhoea?

Chronic diarrhoea affects up to 14% of adults, it impacts on quality of life and its cause can be variable. Patients with chronic diarrhoea are presented with a plethora of dietary recommendations, often sought from the internet or provided by those who are untrained or inexperienced. In this review, we summarise the possible causes of chronic diarrhoea that can be managed by diet, the symptom improvement and quality of life benefits but also the potential risks of such dietary treatments. Clinicians need to consider both the benefits and risks of dietary treatments before making dietary recommendations to manage chronic diarrhoea. The pivotal role that dietitians have in ensuring optimal symptom improvement without jeopardising nutritional and overall health is discussed.

Colonic paracellular permeability and circulating zonulin-related proteins

OBJECTIVE

Irritable bowel syndrome (IBS) is a gut-brain disorder associated with increased gut permeability. Zonulin has been suggested to regulate the gut barrier and claimed to be pre-haptoglobin 2 (pre-HP2) and circulating zonulin is often used as a proxy for gastrointestinal permeability. This study investigated the correlation between colonic paracellular permeability and levels of circulating zonulin and pre-HP2.

MATERIALS AND METHODS

Colonic biopsies from 32 patients with IBS and 15 healthy controls (HC) were used to measure permeability in Ussing chambers and levels of zonulin (Cusabio ELISA). Zonulin was also measured in blood samples from 40 HC, 78 patients with IBS and 20 patients with celiac disease (CeD), before and after a gluten-free diet. In addition, we verified HP genotype and circulating pre-HP2 using a monoclonal pre-HP2 antibody (Bio-Rad) by ELISA.

RESULTS

Increased colonic paracellular permeability correlated positively with zonulin levels in IBS biopsies, but negatively with plasma zonulin. We found no agreement between circulating zonulin and pre-HP2. Genotyping revealed non-specificity of the zonulin kit, as all pre-HP2 non-producers presented detectable levels. Patients with CeD displayed higher pre-HP2 and zonulin levels compared to HC. A gluten-free diet in patients with CeD led to lower serum zonulin and pre-HP2 concentrations.

CONCLUSIONS

Our study suggests that neither circulating zonulin nor pre-HP2 mirror colonic permeability. Our data corroborate previous reports showing the inability of the Cusabio zonulin kit to target zonulin and highlights that the results of studies using this kit must be re-examined with caution.

Clinical Implications of Intestinal Barrier Damage in Psoriasis

Background

An increasing amount of evidence suggests an association between increased intestinal permeability and the pathogenesis of chronic inflammatory diseases. However, the clinical significance of gut barrier dysfunction in psoriasis remains to be established.

Objective

To evaluate whether there are differences in disease activity, the severity of gastrointestinal symptoms and the blood concentration of bacterial metabolites in psoriatic patients with a normal and altered intestinal barrier.

Patients and Methods

Gut barrier integrity was assessed with the serum concentrations of claudin-3, a modulator of intestinal tight junctions and an intestinal fatty acid-binding protein, a marker of enterocyte damage. Gastrointestinal symptoms were evaluated with a validated questionnaire. The concentration of trimethylamine N-oxide (TMAO), a gut microbiota-associated metabolite, was measured with high-performance liquid chromatography.

Results

One hundred and fourteen patients with psoriasis were finally enrolled in the study – 68 with an altered gut barrier and 46 with a properly functioning intestinal barrier. Patients with an altered gut barrier showed a significantly higher score in the Gastrointestinal Symptom Rating Scale (3.20 vs 1.46, p<0.001). Moreover, patients with psoriasis and a disrupted intestinal barrier demonstrated a higher disease activity (PASI: 19.7 vs 10.3, p<0.001) and systemic inflammatory parameters (neutrophil-to-lymphocyte ratio: 2.86 vs 1.71, p<0.001; C-reactive protein 3.76 vs 1.92; p<0.05). The marker of bacterial translocation was significantly higher in psoriatic patients with damaged gut integrity (TMAO: 375.7±51.9 vs 119.4±27.5 ng/mL; p<0.05).

Conclusion

The altered gut barrier in psoriasis is associated with gastrointestinal symptoms, systemic inflammatory profile and the increased blood concentration of gut microbiota-derived metabolite – TMAO. Intestinal barrier modulation represents a new promising therapeutic approach.

A polyphenol-rich dietary pattern improves intestinal permeability, evaluated as serum zonulin levels, in older subjects: The MaPLE randomised controlled trial

BACKGROUND & AIM

Increased intestinal permeability (IP) can occur in older people and contribute to the activation of the immune system and inflammation. Dietary interventions may represent a potential strategy to reduce IP. In this regard, specific food bioactives such as polyphenols have been proposed as potential IP modulator due to their ability to affect several critical targets and pathways that control IP. The trial aimed to test the hypothesis that a polyphenol-rich dietary pattern can decrease serum zonulin levels, an IP surrogate marker involved in tight junction modulation, and can beneficially alter the intestinal microbiota, and IP-associated biochemical and clinical markers in older subjects.

METHODS

A randomised, controlled, cross-over intervention trial was performed. Sixty-six subjects (aged ≥ 60 y) with increased IP based on serum zonulin levels, were randomly allocated to one of the two arms of the intervention consisting of a control diet (C-diet) vs. a polyphenol-rich diet (PR-diet). Each intervention was 8-week long and separated by an 8-week wash out period. At the beginning and at the end of each intervention period, serum samples were collected for the quantification of zonulin and other biological markers. Faecal samples were also collected to investigate the intestinal microbial ecosystem. In addition, anthropometrical/physical/biochemical parameters and food intake were evaluated.

RESULTS

Fifty-one subjects successfully completed the intervention and a high compliance to the dietary protocols was demonstrated. Overall, polyphenol intake significantly increased from a mean of 812 mg/day in the C diet to 1391 mg/day in the PR-diet. Two-way analysis of variance showed a significant effect of treatment (p = 0.008) and treatment × time interaction (p = 0.025) on serum zonulin levels, which decreased after the 8-week PR-diet. In addition, a treatment × time interaction was observed showing a reduction of diastolic blood pressure (p = 0.028) following the PR-diet, which was strongest in those not using antihypertensive drugs. A decrease in both diastolic (p = 0.043) and systolic blood pressure (p = 0.042) was observed in women. Interestingly, a significant increase in fibre-fermenting and butyrate-producing bacteria such as the family Ruminococcaceae and members of the genus Faecalibacterium was observed following the PR intervention. The efficacy of this dietary intervention was greater in subjects with higher serum zonulin at baseline, who showed more pronounced alterations in the markers under study. Furthermore, zonulin reduction was also stronger among subjects with higher body mass index and with insulin resistance at baseline, thus demonstrating the close interplay between IP and metabolic features.

CONCLUSIONS

These data show, for the first time, that a PR-diet can reduce serum zonulin levels, an indirect marker of IP. In addition, PR-diet reduced blood pressure and increased fibre-fermenting and butyrate-producing bacteria. These findings may represent an initial breakthrough for further intervention studies evaluating possible dietary treatments for the management of IP, inflammation and gut function in different target populations. THIS STUDY WAS REGISTERED AT WWW.ISRCTN.

ORG AS

ISRCTN10214981.

Increased Intestinal Permeability in Older Subjects Impacts the Beneficial Effects of Dietary Polyphenols by Modulating Their Bioavailability

Polyphenols have great potential in regulating intestinal health and ameliorating pathological conditions related to increased intestinal permeability (IP). However, the efficacy of dietary interventions with these phytochemicals may significantly be influenced by interindividual variability factors affecting their bioavailability and consequent biological activity. In the present study, urine samples collected from older subjects undergoing a crossover intervention trial with polyphenol-rich foods were subjected to metabolomics analysis for investigating the impact of increased IP on the bioavailability of polyphenols. Interestingly, urinary levels of phase II and microbiota-derived metabolites were significantly different between subjects with healthier intestinal barrier integrity and those with increased IP disruption. Our results support that this IP-dependent impaired bioavailability of polyphenols could be attributed to disturbances in the gut microbial metabolism and phase II methylation processes. Furthermore, we also observed that microbiota-derived metabolites could be largely responsible for the biological activity elicited by dietary polyphenols against age-related disrupted IP.

Differences in Gut Microbiome Composition between Senior Orienteering Athletes and Community-Dwelling Older Adults

Background: Gastrointestinal (GI) health is an important aspect of general health. Gastrointestinal symptoms are of specific importance for the elderly, an increasing group globally. Hence, promoting the elderly’s health and especially gastrointestinal health is important. Gut microbiota can influence gastrointestinal health by modulation of the immune system and the gut–brain axis. Diverse gut microbiota have been shown to be beneficial; however, for the elderly, the gut microbiota is often less diverse. Nutrition and physical activity, in particular, are two components that have been suggested to influence composition or diversity. Materials and Methods: In this study, we compared gut microbiota between two groups of elderly individuals: community-dwelling older adults and physically active senior orienteering athletes, where the latter group has less gastrointestinal symptoms and a reported better well-being. With this approach, we explored if certain gut microbiota were related to healthy ageing. The participant data and faecal samples were collected from these two groups and the microbiota was whole-genome sequenced and taxonomically classified with MetaPhlAn. Results: The physically active senior orienteers had a more homogeneous microbiota within the group and a higher abundance of Faecalibacterium prausnitzii compared to the community-dwelling older adults. Faecalibacterium prausnitzii has previously shown to have beneficial properties. Senior orienteers also had a lower abundance of Parasutterella excrementihominis and Bilophila unclassified, which have been associated with impaired GI health. We could not observe any difference between the groups in terms of Shannon diversity index. Interestingly, a subgroup of community-dwelling older adults showed an atypical microbiota profile as well as the parameters for gastrointestinal symptoms and well-being closer to senior orienteers. Conclusions: Our results suggest specific composition characteristics of healthy microbiota in the elderly, and show that certain components of nutrition as well as psychological distress are not as tightly connected with composition or diversity variation in faecal microbiota samples.

The Intestinal Barrier and Current Techniques for the Assessment of Gut Permeability

The intestinal barrier is essential in human health and constitutes the interface between the outside and the internal milieu of the body. A functional intestinal barrier allows absorption of nutrients and fluids but simultaneously prevents harmful substances like toxins and bacteria from crossing the intestinal epithelium and reaching the body. An altered intestinal permeability, a sign of a perturbed barrier function, has during the last decade been associated with several chronic conditions, including diseases originating in the gastrointestinal tract but also diseases such as Alzheimer and Parkinson disease. This has led to an intensified interest from researchers with diverse backgrounds to perform functional studies of the intestinal barrier in different conditions. Intestinal permeability is defined as the passage of a solute through a simple membrane and can be measured by recording the passage of permeability markers over the epithelium via the paracellular or the transcellular route. The methodological tools to investigate the gut barrier function are rapidly expanding and new methodological approaches are being developed. Here we outline and discuss, in vivo, in vitro and ex vivo techniques and how these methods can be utilized for thorough investigation of the intestinal barrier.

Effects of Dietary Fibres on Acute Indomethacin-Induced Intestinal Hyperpermeability in the Elderly: A Randomised Placebo Controlled Parallel Clinical Trial

The effect of dietary fibres on intestinal barrier function has not been well studied, especially in the elderly. We aimed to investigate the potential of the dietary fibres oat β-glucan and wheat arabinoxylan to strengthen the intestinal barrier function and counteract acute non-steroid anti-inflammatory drug (indomethacin)-induced hyperpermeability in the elderly. A general population of elderly subjects (≥65 years, n = 49) was randomised to a daily supplementation (12g/day) of oat β-glucan, arabinoxylan or placebo (maltodextrin) for six weeks. The primary outcome was change in acute indomethacin-induced intestinal permeability from baseline, assessed by an in vivo multi-sugar permeability test. Secondary outcomes were changes from baseline in: gut microbiota composition, systemic inflammatory status and self-reported health. Despite a majority of the study population (85%) showing a habitual fibre intake below the recommendation, no significant effects on acute indomethacin-induced intestinal hyperpermeability in vivo or gut microbiota composition were observed after six weeks intervention with either dietary fibre, compared to placebo.

High Prevalence and Gender-Related Differences of Gastrointestinal Manifestations in a Cohort of DM1 Patients: A Perspective, Cross-Sectional Study

Myotonic dystrophy type 1 (DM1, MIM #160900), the most common muscular dystrophy among adults, is a multisystem disorder, which affects, besides the skeletal muscle, several other tissues and/or organs, including the gastrointestinal apparatus, with manifestations that frequently affect the quality of life of DM1 patients. So far, only few, mainly retrospective studies evaluated this specific topic in DM1, so we performed a perspective study, enrolling 61 DM1 patients who underwent an extensive diagnostic protocol, including administration of the Gastrointestinal Symptom Rating Scale (GSRS), a validated patient-reported questionnaire about GI symptoms, laboratory tests, liver US scan, and an intestinal permeability assay, in order to characterize frequency and assess correlations regarding specific gastrointestinal manifestations with demographic or other DM1-related features. Our results in our DM1 cohort confirm the high frequency of various gastrointestinal manifestations, with the most frequent being constipation (45.9%). γGT levels were pathologically increased in 65% of DM1 patients and GPT in 29.82%; liver ultrasound studies showed steatosis in 34.4% of patients. Significantly, 91.22% of DM1 patients showed signs of altered intestinal permeability at the specific assay. We documented a gender-related prevalence and severity of gastrointestinal manifestations in DM1 females compared to DM1 males, while males showed higher serum GPT and γGT levels than females. Correlation studies documented a direct correlation between severity of muscle weakness estimated by MIRS score and γGT and alkaline phosphatase levels, suggesting their potential use as biomarkers of muscle disease severity in DM1.

Differential effects of dietary fibres on colonic barrier function in elderly individuals with gastrointestinal symptoms

Gastrointestinal problems are common in elderly and often associated with psychological distress and increased levels of corticotrophin-releasing hormone, a hormone known to cause mast cell (MC) degranulation and perturbed intestinal barrier function. We investigated if dietary fibres (non-digestible polysaccharides [NPS]) could attenuate MC-induced colonic hyperpermeability in elderly with gastrointestinal (GI) symptoms. Colonic biopsies from elderly with diarrhoea and/or constipation (n = 18) and healthy controls (n = 19) were mounted in Ussing chambers and pre-stimulated with a yeast-derived beta (β)-glucan (0.5 mg/ml) or wheat-derived arabinoxylan (0.1 mg/ml) before the addition of the MC-degranulator Compound (C) 48/80 (10 ng/ml). Permeability markers were compared pre and post exposure to C48/80 in both groups and revealed higher baseline permeability in elderly with GI symptoms. β-glucan significantly attenuated C48/80-induced hyperpermeability in elderly with GI symptoms but not in healthy controls. Arabinoxylan reduced MC-induced paracellular and transcellular hyperpermeability across the colonic mucosa of healthy controls, but did only attenuate transcellular permeability in elderly with GI symptoms. Our novel findings indicate that NPS affect the intestinal barrier differently depending on the presence of GI symptoms and could be important in the treatment of moderate constipation and/or diarrhoea in elderly.