Влияние пробиотиков на функциональную активность кишечной микробиоты беременных и микробиом новорожденных

Актуальность. Хронические воспалительные заболевания кишечника (ХВЗК), а именно неспецифический язвенный колит (НЯК) и болезнь Крона (БК), остаются одной из наиболее сложных и актуальных проблем гастроэнтерологии во всем мире. В настоящее время остается недостаточно изученным вопрос о влиянии микрофлоры кишечника и ее изменений на развитие и прогрессирование воспалительного процесса. Однако наиболее доминирующая этиологическая гипотеза говорит о том, что ХВЗК являются результатом аномального иммунного ответа на измененную микробиоту кишечника под воздействием факторов окружающей среды или патогенных микроорганизмов у генетически склонного хозяина. Изменения микробиоты при ХВЗК общепризнаны, но зависимость этих изменений от возраста пациентов еще нуждается в исследовании. Цель исследования: изучить особенности дисбиоза кишечника и частоты синдрома избыточного бактериального роста (СИБР) у пациентов с ХВЗК в зависимости от нозологии и возраста. Материалы и методы. Обследовано 120 пациентов с ХВЗК в возрасте от 19 до 79 лет, в среднем (43,90 ± 1,40) года; среди них 83 больных НЯК, 37 — БК. Все больные были разделены на группы в зависимости от нозологии и возраста. Больным были проведены водородный дыхательный тест для выявления СИБР, бактериологическое исследование кала и хроматография короткоцепочечных жирных кислот (КЖК) в копрофильтратах. Результаты. Установлены наличие глубоких изменений качественного и количественного состава микрофлоры толстой кишки и высокая частота выявления СИБР у пациентов с ХВЗК. Выявлена зависимость изменений состава микрофлоры тонкой и толстой кишки у больных от возраста и нозологии. Снижение концентрации бифидобактерий в содержимом толстого кишечника выявляли чаще всего у пациентов молодого возраста с БК, тогда как снижение количества лактобактерий чаще определялось у больных пожилого возраста в обеих нозологических группах. С возрастом росла частота выявления гемолитических биоваров кишечной палочки, условно-патогенных энтеробактерий и грибов рода Candida. Наблюдались изменения как суммарного общего содержания, так и показателей отдельных КЖК относительно здоровых лиц, что свидетельствовало об угнетении метаболической активности нормальной микрофлоры. Снижение уровней уксусной и масляной кислоты указывало на выраженное угнетение продуцентов этих метаболитов. Выводы. Выявлено, что больные пожилого возраста более склонны к развитию СИБР, снижению концентрации лактобактерий в содержимом толстой кишки, а также увеличению частоты выявления условно-патогенных энтеробактерий и грибов рода Candida. У больных молодого возраста преимущественно выявляется субкомпенсированная форма дисбиоза со снижением концентрации бифидобактерий. С возрастом также наблюдается угнетение продуцентов уксусной и масляной кислоты. Результаты данных исследований предоставят возможность клиницистам более тщательно подбирать терапевтическую тактику, а именно повлияют на выбор препаратов, которые модулируют микробиоту кишечника, с учетом не только нозологической формы, но и возраста пациента.

The aim is to determine the pathogenetic role of the metabolic activity of the intestinal microflora in the formation of the severity and duration of rotavirus diarrhea in early-aged children. Materials and methods. 60 children aged 1–24 months with RVI were included in the research group. The metabolic activity of the intestinal microflora was determined by detecting short-chain fatty acids (SCFAs) in feces in the dynamics of the disease (the absolute concentration (μmol/l) of acetate, propionate, butyrate, the total concentration of SCFAs and the value of the anaerobic index (AI) on the 3rd, 5th and 10th days of RVI) using high-performance liquid chromatography with LC-MS chromatography Agilent 1260 Infinity HPLC System, USA. Results. From the 5th day of RVI, with a minimally expressed diarrheal syndrome, a higher total pool of SCFA and higher AI values were observed than with moderate-severe and severe diarrhea (p ˂ 0.05 on the 5th and 10th days of RVI). A longer duration of the diarrheal syndrome in children was associated with a decrease in the metabolic activity of sucrolytic intestinal bacteria: patients with diarrhea ≤5 days had 2.4 times higher indicators of the total pool of SCFA, than patients with the duration of diarrhea ≥6 days (p ˂ 0.05). The degree of reduction in the concentration of C3 and the value of AI on the 2–3rd days of RVI was directly correlated with the duration of diarrhea, which increased by 1 day with a decrease in C3 by 20.6 μmol/l or a decrease in AI by 0.05. Conclusions. The influence of the intestinal microflora metabolic deficiency on the severity of diarrhea in early-aged children manifests itself from the 5th day of illness. A decrease in the concentration of propionate and the value of AI on the 2–3rd days of the disease is the earliest indicator of prolonged diarrhea in children with RVI.

The use of probiotics as preventive agents in colorectal cancer is widely reported in the literature. However, the bioactivity of specific bacterial strains is only partially understood. Here, we identified Lactobacillus reuteri strains with anti-proliferative activity against colorectal cancer cells. We investigated the bioavailability and the efficacy of short chain fatty acids secreted by distinct Lactobacillus reuteri strains on the inhibition of colorectal cancer cells growth. Five L. reuteri strains were screened based on the short chain fatty acids bio-production and anti-proliferative effects on Caco-2 colon cancer cells. The composition of probiotic short chain fatty acids in cell culture conditioned medium was used to prepare short chain fatty acid synthetic formulations that were compared with the L. reuteri cell culture conditioned media. Later, the bio-stability of the bacteria in a simulated intestinal fluid was determined. Results showed that the production of short chain fatty acids was strain-dependent. L. reuteri NCIMB -11951, -701359 and -702656 were the most potent in producing total short chain fatty acids (402.2 ± 23. 5, p < 0.05 compared with the rest of strains) and inhibiting Caco-2 (by 56.7 ± 1.6 % compared to untreated cells at 72 h, p < 0.001). Comparing the inhibitory effect of the probiotic cell culture conditioned medium and the corresponding short chain fatty acid synthetic formulation showed that the role and relevance of short chain fatty acid production in colorectal cancer cell growth suppression was strain-dependent. L. reuteri NCIMB -702656 and -701359 showed resistance in simulated intestinal fluid (104.6 ± 0.6 % and 105.7 ± 4.1 % of viability at 4 h, respectively) and produced high amounts of total short chain fatty acids (1245.49 ± 0.49 - 1391.58 ± 4.84 mg/ L at 24 h, respectively). Depending partly on short chain fatty acid bio-production, specific L. reuteri strains demonstrated growth inhibitory activity and may be considered as a potential chemopreventive agent against colorectal cancer.

Short chain fatty acids (SCFAs) are primarily produced in the caecum and proximal colon via the bacterial fermentation of undigested carbohydrates that have avoided digestion in the small intestine. Increasing evidence supports the critical role that SCFAs play in health and homeostasis. Microbial SCFAs, namely butyric acid, serve as a principal energy source for colonocytes, and their production is essential for gut integrity. A direct link between SCFAs and some human pathological conditions, such as inflammatory bowel disease, irritable bowel syndrome, diarrhea, and cancer, has been proposed. The direct measurement of SCFAs in feces provides a non-invasive approach to demonstrating connections between SCFAs, microbiota, and metabolic diseases to estimate their potential applicability as meaningful biomarkers of intestinal health. This study aimed to adapt a robust analytical method (liquid–liquid extraction, followed by isobutyl chloroformate derivatization and GC–MS analysis), with comparable performances to methods from the literature, and to use this tool to tackle the question of pre-analytical conditions, namely stool processing. We focused on the methodology of managing stool samples before the analysis (fresh stool or dilution in either ethanol/methanol, lyophilized stool, or RNAlater®), as this is a significant issue to consider for standardizing results between clinical laboratories. The objective was to standardize methods for future applications as diagnostic tools. In this paper, we propose a validated GC–MS method for SCFA quantification in stool samples, including pre- and post-analytical comparison studies that could be easily used for clinical laboratory purposes. Our results show that using lyophilization as a stool-processing method would be the best method to achieve this goal.

Gastrointestinal discomfort is the most common adverse event in metformin treatment for type 2 diabetes. The mechanism of action of metformin is associated with gut microbiota. However, the gut microbial community structure related to metformin-induced gastrointestinal adverse events remains unclear. This study aimed to investigate it. 50 patients with newly diagnosed diabetes were treated with metformin 1500mg/d for 12 weeks. The patients were divided into two groups according to whether gastrointestinal adverse events occurred (group B) or did not occur (group A) after treatment. The fecal bacterial communities and short-chain fatty acids (SCFAs) were sequenced and compared. 70 diabetes mice were randomly divided into 8 groups and treated with metformin (Met), clindamycin (Clin) and/or SCFA, which were the Met+/Clin+, Met+/Clin-, Met-/Clin+, Met-/Clin-, Met+/SCFA+, Met+/SCFA-, Met-/SCFA+ and Met-/SCFA- group. After 4 weeks of metformin treatment, blood glucose, food intake, fecal SCFAs, gut microbiota and gut hormones were measured. Metformin increased the abundance of Phascolarctobacterium, Intestinimonas and Clostridium III. Functional prediction analysis showed that the propanoate metabolism pathway was significantly up-regulated. The concentrations of acetic acid and propanoic acid in feces were significantly increased. The abundance of Clostridium sensu stricto, Streptococcus and Akkermansia induced by metformin in group B was higher than that in group A. The propanoate metabolism pathway and propanoic acid in feces were significantly up-regulated in group B. In the animal experiments, the food intake decreased and glucose control increased in metformin groups compared with those in the control groups. The total GLP-1 level in the Met+/Clin- group was significantly higher than that in the Met-/Clin- group, while there was no statistical difference between the Met-/Clin- and Met+/Clin+ group. The total GLP-1 level in the Met-/SCFA+ group was significantly higher than that in the Met-/SCFA-group, while the levels of total GLP-1 and active GLP-1 in the Met+/SCFA- group and the Met+/SCFA+ group were significantly higher than those in the Met-/SCFA-group. Our data suggest that metformin promotes the secretion of intestinal hormones such as GLP-1 by increasing the abundance of SCFA-producing bacteria, which not only plays an anti-diabetic role, but also may causes gastrointestinal adverse events.

Aim of investigation: to study the content and qualitative profile of shot-chain fatty acids in feces and blood serum in patients with NAFLD of different stages as indicators of intestinal microbiocenosis status and systemic lipid metabolism, and to evaluate the effectiveness of course antibacterial (rifaximin) and prebiotic (psyllium) therapy in the period of 6 months for the correction of gut microbiocenosis disorders. Material and methods: The survey included 115 patients (82 (71,3%) men, 33 (28,7%) women) with NAFLD of different stages (steatosis - 40 people, nonalcoholic steatohepatitis (NASH) of minimal activity - 30 people, NASH of moderate activity - 30 people, liver cirrhosis class A Child-Pugh - 15 people) at the average age of 51,83±8,48 years old. All the patients were examined by research of short-chain fatty acids (SCFA) using gas-liquid chromatographic analysis in various biological substrates (blood serum and feces). According to the management scheme, the patients with NAFLD were divided into 3 groups. The first group of 30 people (on the background of lifestyle modification) received a 6-month intake of psyllium. The second group of 35 people in addition to lifestyle modification received a 7-day course of rifaximin (7 - days/800 mg/d) and psyllium during the period of observation (6 months). The third group of 35 people received standard therapy of NAFLD without pharmacotherapy aimed to correction of gut microbiocenosis disorders. In the course of treatment the frequency and severity of clinical manifestations of intestinal bacterial overgrowth syndrome (SIBO) reduced in patients of groups 1 and 2 (in group 1 the complaints on abdominal pain and flatulence decreased by 11%, in group 2 - by 37%, the normalization of stool occurred in both groups), SIBO was not detected according to the results of the hydrogen breath test with lactulose, the level of total endotoxin was determined within normal values. Negative dynamics was noted in group 3: the increase in the number of complaints of abdominal pain by 16%, flatulence and unstable stool - by 10%, the frequency of registration of SIBO increased by 20%, increased level of total endotoxin was detected in 5.7% of patients. Results. The absolute concentration of SCFA in feces in patients with NAFLD (steatosis) is reduced, in patients with NASH of minimal activity, NASH of moderate activity and liver cirrhosis is increased, in the profile of C2-C4 acids there was the increase in the share of propionic and butyric acids and the decline in the share of acetic acid, the anaerobic index (AI) deflected in the region of strongly negative values, the total relative content of isoacids increased in all groups of patients, worsening with the severity of the pathological process (at normal Σ(C2-C6)=10.51±2.50 mg/g, C2=0.634±0.004, C3=0.189±0.001, C4=0.176±0.004, AI= -0.576(±0.012), Σ(isoCn)=0.068±0.004). The obtained results indicate marked changes in the qualitative and quantitative composition of the microflora, the decrease in the number and activity of obligate microorganisms and the increase in facultative and residual anaerobic bacteria. These changes in the microbial landscape lead to the marked disorders in the intestinal phase of lipid metabolism. The absolute concentration of SCFA in serum in patients with NAFLD (steatosis) is reduced, in patients with NASH of minimal activity, NASH of moderate activity is increased, in the profile of C2-C4 acids there is the decrease in the share of propionic acid and the increase in the share of butyric acid, most pronounced in steatosis and NASH of minimal activity. In patients with liver cirrhosis, the absolute concentration of SCFA in serum is increased, in the profile of C2-C4 acids, the share of acetic acid is sharply reduced with an increase in the share of propionic and butyric acids and the total relative content of isoacids. The content of caproic and isocaproic acids is increased in all groups (at normal Σ (C2-C6)=0.195±0.011 mg/g, C2=0.902±0.006, C3=0.071±0.004, C4 = 0.027±0.002, Σ (isoCn)=0.040±0.007, isoC6+C6=0.025±0.004). This fact can be explained by the changes in the functional state of hepatocytes, and, consequently, in the metabolic function of the liver (in particular with respect to lipid metabolism). The clinical efficacy of therapeutic management with the use of drugs aimed at the relief of the intestinal microflora disorders (course of rifaximin (if SIBO is identified) on the background of prolonged ingestion of psyllium) in patients with NAFLD of different stages, is supported by the normalization of the content and profile of SCFA in various biological substrates. In patients of group 3 there was noted the negative dynamics of estimated parameters SCFA. Thus, the results of the undertaken research of the parameters of SCFA in various biosubstrates indicate the marked changes in the intestinal microbiocenosis and their contribution to the development and enhancement of systemic metabolic processes. The inclusion of means aimed at correcting the microecological status disorders in the complex management of NAFLD is not only effective, but also pathogenetically necessary.

Relevance. The informative value of the content of volatile fatty acids (VFA) in the fistulous drainage from pancreas not been studied in the diagnosis of pancreonecrosis (PN). The informative value of the indices of the content of VFA in the blood has not been studied sufficiently in the diagnosis of PN.&#x0D; Aim of the study is to compare the content of VFA in the blood and in the fistulous drainage from pancreas in patients with pancreatic necrosis.&#x0D; Materials and methods. Samples of blood and fistulous drainage from pancreas isolated from patients with a confirmed diagnosis of PN were studied (n = 18). There was analysis of the concentrations of VFA: acetic, propionic, butyric and isovaleric acids by gas-liquid chromatography on an automated gas chromatograph "Crystallux-4000" with a capillary column "HP-FFAP" Agilent Technologies and a flame ionization detector. The anaerobic index and sum of VFA were calculated.&#x0D; Results. Higher values of the content of acetic, propionic and butyric acids, the sum of VFA and lower values of the content of isovaleric acid and anaerobic index were found in patients with PN in comparison with those of practically healthy donors. Higher values of the content of acetic, propionic and isovaleric acid, the sum of VFA and anaerobic index were noted in the fistulous drainage from pancreas in comparison with the same parameters in blood in patients with PN. The correlation of pairwise conjugated parameters of the content of propionic and isovaleric acids, anaerobic index and the sum of VFA in fistulous drainage from pancreas and blood are discovered in patients with PN.&#x0D; Conclusions. The concentration of acetic, propionic and isovaleric acids, the sum of VFA were higher in the fistulous drainage from pancreas than in the blood in patients with PN. The analysis of the parameters of the VFA can be used as additional criteria for the early diagnosis of PN.

To investigate the expression of short-chain fatty acids (SCFAs)-metabolites of intestinal flora-in gestational complications of gestational diabetes mellitus (GDM), preeclampsia (PE), and intrahepatic cholestasis of pregnancy (ICP), and its clinical significance. Targeted metabonomics was used to detect SCFAs in the serum of 28 GDM pregnant women, 28 PE pregnant women, 29 ICP pregnant women, and 27 healthy pregnant women (NP); their expression changes were observed; the correlation between SCFAs and clinical characteristics was studied; and their potential as biomarkers for clinical diagnosis was evaluated. There were significant differences in the SCFA metabolic spectrum between the GDM, PE, ICP, and NP groups. Quantitative analysis showed that the content of isobutyric acid in the three pregnancy complications groups (the GDM, PE, and ICP groups) was significantly higher than that in the NP group (p < 0.05), and other SCFAs also showed significant differences in the three pregnancy complications groups compared with the NP group (p < 0.05). Receiver operating characteristic (ROC) curve analysis of the generalized linear model showed that multiple SCFAs were highly sensitive and specific as diagnostic markers in the pregnancy complications groups, where isobutyric acid was highly predictive in GDM (area under the ROC curve (AUC) = 0.764) and PE (AUC = 1), and caproic acid was highly predictive in ICP (AUC = 0.968), with potential clinical application. The metabolic products of intestinal flora, SCFAs, during pregnancy are closely related to pregnancy complications (GDM, PE, and ICP), and SCFAs can be used as potential markers of pregnancy complications.

Previous studies have largely explored the microbial composition and pathogenesis of pregnancy gingivitis. However, the patterns of microbial colonization during pregnancy in the absence of pregnancy gingivitis have rarely been studied. Characterization of the oral microbiome in pregnant women with healthy gingiva is an important initial step in understanding the role of the microbiome in progression to pregnancy gingivitis. In this study, we compared the oral microbiome of pregnant women without gingivitis (healthy pregnancy) with pregnant women having gingivitis and nonpregnant healthy women to understand how pregnancy modifies the oral microbiome and induces progression to pregnancy gingivitis. Subgingival plaque samples were collected from Chinese pregnant women with gingivitis (n = 10), healthy pregnant women (n = 10), and nonpregnant healthy women (n = 10). The Illumina MiSeq platform was used to perform 16S rRNA gene sequencing targeting the V4 region. The alpha and beta diversity was significantly different between pregnant and nonpregnant women, but minimal differences were observed between pregnant women with and without gingivitis. Interestingly, the oral bacterial community showed higher abundance of pathogenic taxa during healthy pregnancy as compared with nonpregnant women despite similar gingival and plaque index scores. However, when compared with overt pregnancy gingivitis, pathogenic taxa were less abundant during healthy pregnancy. PICRUSt analysis (phylogenetic investigation of communities by reconstruction of unobserved states) also suggested no difference in the functional capabilities of the microbiome during pregnancy, irrespective of gingival disease status. However, metabolic pathways related to amino acid metabolism were significantly increased in healthy pregnant women as compared with nonpregnant women. The presence of pathogenic taxa in healthy pregnancy and pregnancy gingivitis suggests that bacteria may be necessary for initiating disease development but progression to gingivitis may be influenced by the host environmental factors. More efforts are required to plan interventions aimed at sustaining health before the appearance of overt gingivitis. The results of this study draw attention to the importance of oral health maintenance during pregnancy, as women without any prenatal oral conditions are predisposed to the risk of developing pregnancy gingivitis. Hence, it is important to incorporate comprehensive assessment of oral health in the prenatal health care schedules. Pregnant woman should be screened for oral risks, counseled on proper oral hygiene and expected oral changes, and referred for dental treatment, when necessary.

The main objective of this cross-sectional study was to analyze the influence of lifestyle factors (diet, physical activity, sleep) that can affect the concentration of fecal short-chain fatty acids (SCFAs) and SCFAs' potential role in modulating cardiometabolic disease risk by interacting with biochemical and body composition parameters. The study comprised 77 healthy, non-obese individuals aged 30-45 years who were assessed for the concentration of SCFAs in stool, diet, physical activity level, and sleep duration. Moreover, body composition measurement and patients' biochemical parameters were included in the analysis. We have indicated a significant negative correlation between several SCFAs (especially acetic acid (AA), isobutyric acid (IBA), butyric acid (BA), propionic acid (PA), isovaleric acid (IVA) and valeric acid (VA)) with BMI, VAT/SAT ratio (visceral to subcutaneous fat ratio), and percentage of fat mass in a group of females enrolled in the study as well as with waist circumference (WC) in case of both sexes included in the study. Moreover, the results of our study acknowledged the importance of a diet in shaping the SCFA profile-we noticed significant negative associations between energy and fat intake and some SCFAs in males (IBA, IVA, VA, isocaproic acid (ICA)). Further, we indicated that a high intake of fiber (insoluble and soluble) in both males and females results in an elevated concentration of the vast majority of SCFAs and the amount of SCFAs in total. This effect was particularly noticeable in the case of the soluble fraction of fiber. These correlations reflect the fact that diet shapes the composition of the gut microbiota and SCFAs (main microbial metabolites) are synthesized from dietary fiber. In addition, we noticed that in a group of women, the concentration of AA, PA, and ICA as well as the total concentration of SCFAs showed a significant positive association with their sleep duration. We concluded that SCFAs can have a potential role in modulating cardiometabolic disease risk by interacting with adiposity parameters and diet. In addition, this potential direct link between diet and SCFAs may at least partly contribute to sleep improvement.

Short Chain Fatty Acids in Rats with Jejunal Blind Loops: I. Analysis of SCFA in small intestine, cecum, feces, and plasma

Short chain fatty acids (SCFAs) play important roles in periodontal diseases. However, the concentrations of SCFAs in gingival crevicular fluid of patients with aggressive periodontitis are not known. The aim of this intervention study was to investigate the influences of non-surgical periodontal therapy on levels of SCFAs in the gingival crevicular fluid of patients with generalized aggressive periodontitis (G-AgP), and analyze the concentrations of SCFAs in sites with or without the detected putative periodontal pathogens. Eighty gingival crevicular fluid samples (four per subject) were collected on filter paper strips from patients with G-AgP (n = 20; mean age 24.5 years), before and at 2 wk, 2, 4 and 6 mo after non-surgical periodontal treatment. Eighty gingival crevicular fluid samples (four per subject) were collected from periodontally healthy controls (n = 20; mean age 26.2 years). Concentrations of formic acid, succinic acid, acetic acid, lactic acid, propionic acid, butyric acid and isovaleric acid from the supernatant of gingival crevicular fluid samples were measured by high performance capillary electrophoresis. Porphyromonas gingivalis, Treponema denticola, Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Fusobacterium nucleatum from the precipitate of the same pretreatment samples of gingival crevicular fluids were analyzed by polymerase chain reaction amplification. The clinical parameters of patients with G-AgP during the 6 mo after non-surgical periodontal treatment were improved remarkably. The formic acid concentration increased significantly after treatment; the level of formic acid was lower in the P. gingivalis-, T. denticola-, P. intermedia- or F. nucleatum-positive sites compared with the negative sites. The concentrations of acetic acid, propionic acid and butyric acid reduced significantly after treatment and reached the lowest level at 2 wk post-treatment, although showed a tendency to increase after 2 mo post-treatment, and the three SCFA levels were significantly higher in P. gingivalis-, T. denticola-, P. intermedia- or F. nucleatum-positive sites compared with those in the negative sites. Non-surgical periodontal treatment resulted in a significant decrease of acetic acid, propionic acid, butyric acid levels and increase of formic acid level in gingival crevicular fluids in patients with G-AgP, accompanied by improvement in clinical parameters. A marked lower level of formic acid, as well as higher levels of acetic acid, propionic acid and butyric acid in gingival crevicular fluid of patients with G-AgP was consistent with periodontal pathogen infection.

Gastroesophageal reflux disease (GERD) is a condition characterized by persistent symptoms and complications resulting from reflux of gastric contents into the esophagus. Short-chain fatty acids (SCFAs) are fermentation products of dietary fibres by the gut microbiota and are often studied for their anti-inflammatory and anticancer effects. The presence of SCFAs in the upper gastrointestinal tract, including in patients with GERD, has not been previously studied. The aim of this study was to investigate the relationship between the concentrations of SCFAs in the saliva of different age groups of patients with GERD. The study included 86 patients diagnosed with GERD, divided into two groups according to age: under and over 60 years of age, treated in the Gastroenterology and Hepatology Outpatient Clinic of the University Hospital in Cracow and 39 patients without gastrointestinal tract diseases. After clinical examination, blood was drawn to determine complete blood count, haemoglobin, and CRP. The oral cavity was examined, and unstimulated mixed saliva was collected. The SCFAs analysis was made by liquid chromatography-tandem mass spectrometry after facile derivatization coupled with liquid-liquid extraction. Of the six SCAFs studied, the highest median concentrations of acetic acid and propionic acid were observed in the saliva of patients with GERD and in the control group, in both the younger and older groups of patients. The concentrations of acetic acid and propionic acid were also higher compared with the four other fatty acids in the saliva of patients with GERD and in the control subjects. There were no correlations between salivary SCFAs levels and selected clinical and endoscopic parameters, including chronic inflammatory changes of the esophagus and stomach. In conclusions: SCFAs are present in the saliva of patients with GERD and in the control healthy persons. With the exception of valeric and isovaleric acids, salivary levels of SCFAs were significantly higher in patients with GERD compared to the control group. The highest concentrations of acetic acid and propionic acid were observed in patients with GERD and in both the younger and older patient groups. There were no differences in the concentrations of SCFAs in the saliva of female and male groups. We found no correlations between salivary SCFAs levels and selected clinical, laboratory and endoscopic changes of the oesophagus and stomach.

Probiotics are helpful microorganisms that are resistant to biliary, gastric, and pancreatic secretions and can attach to the epithelial cells and colonize the surface of the intestinal cells. These capabilities are the main mechanisms of probiotics that allow them the adaptation to gut conditions. Probiotic cells attach to the intestinal cells and inhibit the attachment of enteric pathogenic germs to the intestinal mucosa by producing growth-inhibitory elements such as short-chain fatty acids, bacteriocin, and toxic oxygen metabolites. Attaching to the mucosal layer is essential for their functions, but it can increase the possibility of translocation and pathogenicity. On the other hand, there are also concerns about the possible transmission of antimicrobial resistance properties from probiotic strains to pathogenic bacteria in the gut environment. Consequently, the use of probiotics is entirely safe only in healthy people, and also it should be used with caution in children, the elderly, pregnant women, and immunocompromised patients. In recent years, scientists take a new approach to using probiotics in a non-viable form (currently known as postbiotics) to overcome the technological, economic, and clinical problems regarding the application of live probiotics. Hence, this chapter provides an overview of the nutritional and clinical concerns caused by probiotic intake in vulnerable patients, with emphasis on the application of a non-viable form of probiotics as a promising alternative.

Multiple system atrophy (MSA) and Parkinson's disease (PD) have overlapping symptoms, making diagnosis challenging. Short-chain fatty acids (SCFAs) are produced exclusively by gut microbiota and were reduced in feces of MSA patients. However, plasma SCFA concentrations in MSA patients have not been investigated. We aimed to investigate the plasma SCFAs in MSA patients and to identify the potential differential diagnostic ability. Plasma SCFA were measured in 25 MSA patients, 46 healthy controls, and 46 PD patients using gas chromatography-mass spectrometry. Demographic and clinical characteristics of the participants were evaluated. Acetic acid concentration was lower in MSA patients than in healthy controls. Acetic acid and propionic acid concentrations were lower in MSA and MSA with predominant parkinsonism (MSA-P) patients than in PD patients. A receiver operating characteristic curve (ROC) analysis revealed reduced acetic acid concentration discriminated MSA patients from healthy controls with 76% specificity but only 57% sensitivity and an area under the curve (AUC) of 0.68 (95% confidence interval (CI): 0.55-0.81). Combined acetic acid and propionic acid concentrations discriminated MSA patients from PD patients with an AUC of 0.82 (95% CI: 0.71-0.93), 84% specificity and 76% sensitivity. Especially, with combined acetic acid and propionic acid concentrations, MSA-P patients were separated from PD patients with an AUC of 0.89 (95% CI: 0.80-0.97), 91% specificity and 80% sensitivity. Plasma SCFAs were decreased in MSA patients. The combined acetic acid and propionic acid concentrations may be a potential biomarker for differentiating MSA patients from PD patients.