Gastrointestinal Function

Using Bomb Calorimetry to Investigate Intestinal Energy Harvest in Anorexia Nervosa: Preliminary Findings on Stool Calorie Loss

OBJECTIVE

Renourishment and weight restoration are critical first steps in anorexia nervosa (AN) treatment. The ability of the gastrointestinal tract to harvest and utilize energy from food is essential for successful weight restoration, but the functional capacity of the intestine after prolonged caloric restriction remains unknown. In an exploratory study, we quantified the stool energy content of individuals with AN before and after renourishment.

METHOD

We used archived stool samples from a multisite cohort (NCT03119272) of 103 individuals with AN at admission and discharge from inpatient renourishment and 122 sex-matched non-eating disorder controls (non-ED). To determine whether bomb calorimetry may have utility in AN, we measured stool calorie loss as the number of kilocalories per gram of stool. Analyses included ANOVA, paired/unpaired t-tests, and Spearman rank correlations for associations between stool energy and clinical variables.

RESULTS

Following 25.10 ± 19.73 days of renourishment, patients gained an average of 5.67 ± 4.27 kg. Raw stool energy at discharge (AN-DIS: 5.72 ± 0.86 kcal/g) was significantly higher than admission (AN-AD: 5.41 ± 0.86 kcal/g; p < 0.01). Weight and BMI at admission and discharge were negatively correlated with raw stool energy at discharge.

DISCUSSION

Energy content in stool increases after inpatient refeeding, likely due to increased calorie consumption. Findings should be interpreted cautiously due to methodological limitations in this post hoc study design. Future studies should use a priori, gold-standard protocols to investigate stool calorie loss in AN, as prolonged restriction in AN may disrupt the gut and impede energy harvest.

TRIAL REGISTRATION

clinicaltrials.gov: NCT03119272.

Gastrointestinal involvement in neuromuscular disorders

Although not often discussed, many of the neuromuscular disorders (NMDs) affect the gastrointestinal tract (GIT). Depending on the type of NMD, the prevalence of GIT involvement ranges from <5% (e.g. hereditary neuropathies, myofibrillar myopathies) to 100% (e.g. MNGIE, OPMD). Particularly in NMDs with multisystem affection, involvement of the GIT can dominate the clinical presentation or at least make up a significant part of the clinical picture. The most prominent representatives of NMDs with multisystem involvement are the mitochondrial disorders (MIDs) and the myotonic dystrophies. The best known syndromic MIDs with GIT involvement are MNGIE, MELAS, Leigh, and Pearson syndromes. Among neuropathies, GIT involvement is most commonly found in ALS and GBS. GIT involvement may also be a feature of myasthenia. The clinical manifestations of GIT involvement are diverse and can affect the entire GIT, from the teeth to the rectum, including the liver and pancreas. The most well-known clinical manifestations of GIT involvement are dysphagia, nausea, vomiting, reflux, hollow organ dysmotility, hepatopathy, diabetes, diarrhea, constipation, and fecal incontinence. Even if treatment can usually only be symptomatic, the therapeutic options are diverse, are often effective, and can significantly and beneficially influence the course of the underlying NMD.

Single-cell transcriptome analysis reveals secretin as a hallmark of human enteroendocrine cell maturation

The traditional nomenclature of enteroendocrine cells (EECs), established in 1977, applied the "one cell - one hormone" dogma, which distinguishes subpopulations based on the secretion of a specific hormone. These hormone-specific subpopulations included S cells for secretin (SCT), K cells for glucose-dependent insulinotropic polypeptide (GIP), N cells producing neurotensin (NTS), I cells producing cholecystokinin (CCK), D cells producing somatostatin (SST), and others. In the past 15 years, reinvestigations into murine and human organoid-derived EECs, however, strongly questioned this dogma and established that certain EECs coexpress multiple hormones. Using the Gut Cell Atlas, the largest available single-cell transcriptome dataset of human intestinal cells, this study consolidates that the original dogma is outdated not only for murine and human organoid-derived EECs, but also for primary human EECs, showing that the expression of certain hormones is not restricted to their designated cell type. Moreover, specific analyses into SCT-expressing cells reject the presence of any cell population that exhibits significantly elevated secretin expression compared to other cell populations, previously referred to as S cells. Instead, this investigation indicates that secretin production is realized jointly by other enteroendocrine subpopulations, validating corresponding observations in murine EECs also for human EECs. Furthermore, our findings corroborate that SCT expression peaks in mature EECs, in contrast, progenitor EECs exhibit markedly lower expression levels, supporting the hypothesis that SCT expression is a hallmark of EEC maturation.

Towards Full Thickness Small Intestinal Models: Incorporation of Stromal Cells

INTRODUCTION

Since small intestine is one of the major barriers of the human body, there is a need to develop reliable in vitro human small intestinal models. These models should incorporate both the epithelial and lamina propria compartments and have similar barrier properties compared to that of the human tissue. These properties are essential for various applications, such as studying cell-cell interaction, intestinal diseases and testing permeability and metabolism of drugs and other compounds. The small intestinal lamina propria contains multiple stromal cell populations with several important functions, such as secretion of extracellular matrix proteins and soluble mediators. In addition, stromal cells influence the intestinal epithelial barrier, support the intestinal stem cell niche and interact with immune cells.

METHODS

In this review, we provide an extensive overview on the different types of lamina propria stromal cells found in small intestine and describe a combination of molecular markers that can be used to distinguish each different stromal cell type. We focus on studies that incorporated stromal cells into human representative small intestine models cultured on transwells.

RESULTS AND CONCLUSION

These models display enhanced epithelial morphology, increased cell proliferation and human-like barrier properties, such as low transepithelial electrical resistance (TEER) and intermediate permeability, thus better mimicking the native human small intestine than models only consisting of an epithelium which generally show high TEER and low permeability.

Biofluid-Activated Biofuel Cells, Batteries, and Supercapacitors: A Comprehensive Review

Recent developments in wearable and implanted devices have resulted in numerous, unprecedented capabilities that generate increasingly detailed information about a user's health or provide targeted therapy. However, options for powering such systems remain limited to conventional batteries which are large and have toxic components and as such are not suitable for close integration with the human body. This work provides an in-depth overview of biofluid-activated electrochemical energy devices, an emerging class of energy sources judiciously designed for biomedical applications. These unconventional energy devices are composed of biocompatible materials that harness the inherent chemistries of various biofluids to produce useable electrical energy. This work covers examples of such biofluid-activated energy devices in the form of biofuel cells, batteries, and supercapacitors. Advances in materials, design engineering, and biotechnology that form the basis for high-performance, biofluid-activated energy devices are discussed. Innovations in hybrid manufacturing and heterogeneous integration of device components to maximize power output are also included. Finally, key challenges and future scopes of this nascent field are provided.

Iohexol is an intestinal permeability marker in broilers under coccidiosis challenge

Intestinal integrity losses have been identified as a main driver for poor performance in broilers. The oral administration of markers such as iohexol is a major asset for measuring intestinal permeability (IP) alterations. The aim of the current study was to evaluate oral iohexol administration and serum levels as a quantitative measure for IP in Ross 308 broilers and to identify possible associations with histologic measurements. A total of 40, day-old broiler chickens were randomly divided into 4 groups of 10 broilers and a coccidiosis model was used to induce IP. Three challenge groups received a mixture of different field strains and concentrations of Eimeria acervulina and Eimeria maxima at d 16, and 1 group operated as an uninfected control group. On d 20, 5 birds per group were orally administered the permeability marker iohexol at a dose of 64.7 mg/kg body weight and blood was taken 60 min after the oral gavage. On d 21 these 5 birds per group were euthanized. On d 21, 5 other birds per group were given iohexol where after blood was taken. These birds were euthanized on d 22. During necropsy, birds were scored for coccidiosis lesions and a duodenal segment was taken for histology. The Eimeria challenge had a significant impact on the villus length, crypt depth, villus-to-crypt ratio and CD3⁺ T-lymphocytes area percentage. Challenged birds had a significant higher concentration of serum iohexol on both sampling days, as compared to the uninfected controls. A significant correlation could be found between the serum iohexol concentration and the histologic parameters (villus length, crypt depth and villus-to-crypt ratio) on the first sampling day. This suggests that iohexol may be used as a gut permeability marker in broilers under Eimeria challenge.

Effects of temperature on intestinal microbiota and lipid metabolism in Rana chensinensis tadpoles

Climate change such as global warming is considered a major threat to amphibians. The guts of amphibians are home to trillions of microbes, which are key regulators of gastrointestinal digestion and play a crucial role in lipid metabolites. The aim of this study was to evaluate the effect of temperature change on intestinal microbiota and lipid metabolism in Rana chensinensis tadpoles. Morphological and intestinal microbiota data of R. chensinensis larvae exposed to different temperatures (15 °C, 21 °C, and 26 °C) were measured. The results show that the warm temperature causes histological damage to the intestinal epithelium. In addition, temperature treatments alter the diversity and composition of gut microbes in R. chensinensis tadpoles. At the phylum level of intestinal microbial community, Campilobacterota was detected only in the warm group. At the genera level, unclassified_f__Enterobacteriaceae was markedly declined in the warm group but was notably enriched in the cold group. For lipid metabolism-related genes, the expression levels of GPR109A, HDAC1, and APOA-I decreased significantly in both warm and cold treatment groups, while the expression levels of CLPS and LIPASE increased significantly. Collectively, these observations demonstrated that warm and cold temperatures may reduce the immune capacity of tadpoles by changing the composition of intestinal microorganisms and the expression of genes related to lipid metabolism, affecting the survival of tadpoles.

Gut-Liver Axis and Non-Alcoholic Fatty Liver Disease: A Vicious Circle of Dysfunctions Orchestrated by the Gut Microbiome

Non-alcoholic fatty liver disease (NAFLD) is a prevalent, multifactorial, and poorly understood liver disease with an increasing incidence worldwide. NAFLD is typically asymptomatic and coupled with other symptoms of metabolic syndrome. The prevalence of NAFLD is rising in tandem with the prevalence of obesity. In the Western hemisphere, NAFLD is one of the most prevalent causes of liver disease and liver transplantation. Recent research suggests that gut microbiome dysbiosis may play a significant role in the pathogenesis of NAFLD by dysregulating the gut-liver axis. The so-called "gut-liver axis" refers to the communication and feedback loop between the digestive system and the liver. Several pathological mechanisms characterized the alteration of the gut-liver axis, such as the impairment of the gut barrier and the increase of the intestinal permeability which result in endotoxemia and inflammation, and changes in bile acid profiles and metabolite levels produced by the gut microbiome. This review will explore the role of gut-liver axis disruption, mediated by gut microbiome dysbiosis, on NAFLD development.

Herbal therapies in gastrointestinal and hepatic disorders: An evidence-based clinical review

The gastrointestinal tract (GIT) and the liver constitute the major organs of the human body. Indeed, the very survival of the human body depends on their proper functioning. Because the GIT is a huge and complex organ system, the maintenance of proper GIT and liver health is an arduous task. GIT disturbances such as diarrhea, stomach ache, flatulence, constipation, nausea, and vomiting are very common, and they contribute to a significant burden on the healthcare system. Pharmacies are full of over-the-counter pharmacological drugs to alleviate its common conditions. However, these drugs do not always prove to be fully effective and patients have to keep on living with these ailments without a proper and long-term solution. The aim of this review article is to present a practical reference guide to the role of herbal medicines in dealing with gastrointestinal and hepatic disorders, which is supported by systematic reviews and evidence-based trials. People have depended on herbal medications for centuries for the treatment of various ailments of the GIT, liver, and other organ system problems. Recently, this trend of incorporating herbal medication for the treatment of various diseases in both developing and developed countries have surged. Many people continue to use herbal medications, even though substantial data about their efficacy, uses, and toxicological effects do not exist. In addition, while herbal medicines have enormous benefits in both the prevention and the treatment of medical ailments, they can also have toxicological effects. It is, therefore, of the utmost importance that appropriate time, energy, and resources are spent on the development of ethnopharmacology. In addition, herbal products should be classified in a pattern similar to pharmacological medications, including their uses, side effects, mechanism of action, efficacy, and so on.

Bitter Peptides YFYPEL, VAPFPEVF, and YQEPVLGPVRGPFPIIV, Released during Gastric Digestion of Casein, Stimulate Mechanisms of Gastric Acid Secretion via Bitter Taste Receptors TAS2R16 and TAS2R38

Eating satiating, protein-rich foods is one of the key aspects of modern diet, although a bitter off-taste often limits the application of some proteins and protein hydrolysates, especially in processed foods. Previous studies of our group demonstrated that bitter-tasting food constituents, such as caffeine, stimulate mechanisms of gastric acid secretion as a signal of gastric satiation and a key process of gastric protein digestion via activation of bitter taste receptors (TAS2Rs). Here, we tried to elucidate whether dietary non-bitter-tasting casein is intra-gastrically degraded into bitter peptides that stimulate mechanisms of gastric acid secretion in physiologically achievable concentrations. An in vitro model of gastric digestion was verified by casein-fed pigs, and the peptides resulting from gastric digestion were identified by liquid chromatography-time-of-flight-mass spectrometry. The bitterness of five selected casein-derived peptides was validated by sensory analyses and by an in vitro screening approach based on human gastric parietal cells (HGT-1). For three of these peptides (YFYPEL, VAPFPEVF, and YQEPVLGPVRGPFPIIV), an upregulation of gene expression of TAS2R16 and TAS2R38 was observed. The functional involvement of these TAS2Rs was verified by siRNA knock-down (kd) experiments in HGT-1 cells. This resulted in a reduction of the mean proton secretion promoted by the peptides by up to 86.3 ± 9.9% for TAS2R16kd (p < 0.0001) cells and by up to 62.8 ± 7.0% for TAS2R38kd (p < 0.0001) cells compared with mock-transfected cells.

Riboflavin intake, MTRR genetic polymorphism (rs1532268) and gastric cancer risk in a Korean population: a case-control study

The vitamin B group, including riboflavin, plays paramount roles in one-carbon metabolism (OCM), and disorders related to this pathway have been linked to cancer development. The variants of genes encoding OCM enzymes and the insufficiency of B vitamins could contribute to carcinogenesis. Very few observational studies have revealed a relationship between riboflavin and gastric cancer (GC), especially under conditions of modified genetic factors. We carried out a study examining the association of riboflavin intake and its interaction with MTRR (rs1532268) genetic variants with GC risk among 756 controls and 377 cases. The OR and 95 % CI were evaluated using unconditional logistic regression models. We observed protective effects of riboflavin intake against GC, particularly in the female subgroup (OR = 0·52, 95 % CI 0·28, 0·97, Ptrend = 0·031). In the MTRR (rs1532268) genotypes analysis, the dominant model showed that the effects of riboflavin differed between the CC and CT + TT genotypes. Compared with CC carriers, low riboflavin intake in T+ carriers was significantly associated with a 93 % higher GC risk (OR = 1·93, 95 % CI 1·09, 3·42, Pinteraction = 0·037). In general, higher riboflavin intake might help reduce the risk of GC in both CC and TC + TT carriers, particularly the T+ carriers, with marginal significance (OR = 0·54, 95 % CI 0·28, 1·02, Pinteraction = 0·037). Our study indicates a protective effect of riboflavin intake against GC. Those who carry at least one minor allele and have low riboflavin intake could modify this association to increase GC risk in the Korean population.

Evolution of digestive enzymes and dietary diversification in birds

As the most species-rich class of tetrapod vertebrates, Aves possesses diverse feeding habits, with multiple origins of insectivory, carnivory, frugivory, nectarivory, granivory and omnivory. Since digestive enzymes mediate and limit energy and nutrient uptake, we hypothesized that genes encoding digestive enzymes have undergone adaptive evolution in birds. To test this general hypothesis, we identified 16 digestive enzyme genes (including seven carbohydrase genes (hepatic amy, pancreatic amy, salivary amy, agl, g6pc, gaa and gck), three lipase genes (cyp7a1, lipf and pnlip), two protease genes (ctrc and pgc), two lysozyme genes (lyz and lyg) and two chitinase genes (chia and chit1)) from the available genomes of 48 bird species. Among these 16 genes, three (salivary amy, lipf and chit1) were not found in all 48 avian genomes, which was further supported by our synteny analysis. Of the remaining 13 genes, eight were single-copy and five (chia, gaa, lyz, lyg and pgc) were multi-copy. Moreover, the multi-copy genes gaa, lyg and pgc were predicted to exhibit functional divergence among copies. Positively selected sites were detected in all of the analyzed digestive enzyme genes, except agl, g6pc, gaa and gck, suggesting that different diets may have favored differences in catalytic capacities of these enzymes. Furthermore, the analysis also revealed that the pancreatic amylase gene and one of the lipase genes (cyp7a1) have higher ω (the ratio of nonsynonymous to the synonymous substitution rates) values in species consuming a larger amount of seeds and meat, respectively, indicating an intense selection. In addition, the gck carbohydrase gene in species consuming a smaller amount of seeds, fruits or nectar, and a lipase gene (pnlip) in species consuming less meat were found to be under relaxed selection. Thus, gene loss, gene duplication, functional divergence, positive selection and relaxed selection have collectively shaped the evolution of digestive enzymes in birds, and the evolutionary flexibility of these enzymes may have facilitated their dietary diversification.

[Unusual case of struvite urolithiasis in a dog. A case report]

A dog was referred for nutrition consultation after surgical removal of struvite uroliths from the bladder. Inspection of the dog's current ration revealed a pronounced vitamin-A deficiency together with a marked deficiency of protein, phosphorus and magnesium. Therefore, a supersaturation of the urine with ammonium, magnesium and phosphate, the three constituents of struvite, as a cause of struvite calculi formation appears rather unlikely. Vitamin-A deficiency can promote urinary infections and consequently struvite stone formation because of the lack of the protective effect of vitamin A on the epithelia of the urinary tract. Not only common causes for struvite urolith formation, including urinary supersaturation with stone-forming constituents and urinary tract infection, but also less common causes, including vitamin-A deficiency, which was the presumed trigger in the present case study, have to be taken into consideration. Dietetic measures appear to be a useful tool in such cases to prevent uroliths from reoccurring.

Serum cobalamin concentrations in cats with gastrointestinal signs: correlation with histopathological findings and duration of clinical signs

The aims of this study were to investigate the prevalence of hypocobalaminaemia in UK cats presented for referral investigation of gastrointestinal signs and to ascertain whether the duration of clinical signs or severity of disease (based on WSAVA Gastrointestinal Standardization histopathological grading) related to cobalamin concentration. The study population comprised 39 cats, of which 11 (28.2%) had hypocobalaminaemia. Eight of these cats were diagnosed with a single cause of gastrointestinal signs: intestinal inflammation (five); alimentary lymphoma (two); and cholangitis (one). Two or more concurrent diseases were diagnosed in the three remaining cases. Alimentary lymphoma and the most severe grade of histological intestinal inflammation were associated most commonly with concurrent hypocobalaminaemia, but there was no statistically significant correlation between serum cobalamin concentrations and histopathological score or duration of clinical signs.