D-lactic acidosis

L- and D-Lactate: unveiling their hidden functions in disease and health

Lactate, once considered a mere byproduct of anaerobic metabolism, is now recognized as a critical signaling molecule with diverse roles in physiology and pathology. There are two stereoisomers of lactate: L- and D-lactate. Recent studies have shown that disruptions in these two lactate stereoisomers have distinct effects on health and disease. L-lactate is central to glycolysis and energy transfer through the Cori cycle but also acts as the dominant lactylation isomer induced by glycolysis, influencing metabolism and cell survival. Although less studied, D-lactate is linked to metabolic disorders and plays a role in mitochondrial dysfunction and oxidative stress. This review focuses on both L- and D-lactate and examines their biosynthesis, transport, and expanding roles in physiological and pathological processes, particularly their functions in cancer, immune regulation, inflammation, neurodegeneration and other diseases. Finally, we assess the therapeutic prospects of targeting lactate metabolism, highlighting emerging strategies for intervention in clinical settings. Our review synthesizes the current understanding of L- and D-lactate, offering insights into their potential as targets for therapeutic innovation.

Short bowel syndrome and d-lactic acidosis: A case report with supplemental home parenteral nutrition and teduglutide

d-Lactic acidosis is an uncommon cause of acidosis that occurs in patients with short bowel syndrome (SBS). Reduced intestinal absorption surface leads to carbohydrate malabsorption, fermented by abnormal colonic bacterial flora, resulting in elevated d-lactate levels. It should be suspected in SBS patients who exhibit typical neurological symptoms without other apparent causes, along with metabolic acidosis with normal l-lactate levels. Treatment involves correcting acidosis and managing bacterial overgrowth with non-absorbable antibiotics. This report presents a case of a patient on teduglutide for SBS who experienced an episode of d-lactic acidosis. To date, there are no documented cases in the literature of similar episodes in adult patients undergoing therapy with GLP2 analogs.

Prebiotics as modulators of colonic calcium and magnesium uptake

Ca2+ and Mg2+ are essential nutrients, and deficiency can cause serious health problems. Thus, lack of Ca2+ and Mg2+ can lead to osteoporosis, with incidence rising both in absolute and age-specific terms, while Mg2+ deficiency is associated with type II diabetes. Prevention via vitamin D or estrogen is controversial, and the bioavailability of Ca2+ and Mg2+ from supplements is significantly lower than that from milk products. Problems are likely to increase as populations age and the number of people on vegan diets surges. Developing new therapeutic strategies requires a better understanding of the molecular mechanisms involved in absorption by intestinal epithelia. The vitamin-D dependent, active pathway for the uptake of Ca2+ from the upper small intestine involving TRPV6 is highly efficient but only accounts for about 20% of total uptake. Instead, most Ca2+ uptake is thought to occur via passive paracellular diffusion across the ileum, although sufficiently high luminal concentrations are difficult to achieve.. Interestingly, colon and caecum also have a considerable capacity for the active absorption of Ca2+ and Mg2+, the molecular mechanisms of which are unclear. Intriguingly, stimulating fermentation by prebiotics enhances colonic absorption, which can rise from ~10% to ~30% of the total. Notably, fermentation releases protons, which inhibits channels highly selective for Ca2+ and Mg2+ (TRPV6 and TRPM6/TRPM7). Conversely, the non-selective cation channel TRPV3 is stimulated by both intracellular acidification and by numerous herbal compounds. Spicy, fiber-rich food, as traditionally consumed in many cultures, might enhance the uptake of Ca2+ and Mg2+ via this pathway.

Genome sequence and evaluation of safety and probiotic potential of Lacticaseibacillus paracasei LC86 and Lacticaseibacillus casei LC89

Aim

A comprehensive safety assessment of potential probiotic strains was essential for their application in the food industry. This article systematically evaluated the probiotic characteristics, whole-genome sequence analysis and safety of Lacticaseibacillus paracasei LC86 and Lacticaseibacillus casei LC89.

Methods

Firstly, the two strains of lactic acid bacteria selected were identified. Secondly, whole-genome sequencing was performed on LC86 and LC89, and their antibiotic resistance, pathogenicity, and virulence genes were analyzed. We tested various properties of the two strains, included tolerance, cell adhesion, hemolytic activity, catalase activity, gelatin hydrolysis, arginine hydrolysis ability, bile salt hydrolysis capacity, mucin degradation, bioamine, D-/L-lactic acid production and antibiotic susceptibility, to confirm the safety of LC86 and LC89 both in vitro and in vivo. Additionally, we studied the acute toxicity of LC86 and LC89 in mice through a 14-day oral gavage experiment.

Results

The two strains selected were identified as Lacticaseibacillus paracasei and Lacticaseibacillus casei. The genomes of both LC86 and LC89 were devoid of virulence, antibiotic resistance and pathogenicity genes. LC86 and LC89 exhibited good tolerance to temperature, artificial gastric fluid and artificial intestinal fluid; they were non-hemolytic, their catalase activity, gelatin hydrolysis, arginine hydrolysis and bile salt hydrolysis were all negative. They exhibited the capability to break down proteins and demonstrated sensitivity to a range of antibiotics. The oral LD50 for both LC86 and LC89 in mice was >2 × 1010 CFU/kg.

Conclusion

The experimental results above demonstrated the probiotic characteristics and safety of LC86 and LC89, indicating their potential as candidates for probiotics for human and animal applications.

Metabolic acidosis due to d-lactate in a patient with intestinal resection: Diagnostic challenges and nutritional strategies

INTRODUCTION

Metabolic acidosis, marked by decreased plasma bicarbonate and arterial pH, is a common complication following extensive abdominal surgeries. D-lactate acidosis presents additional diagnostic challenges due to nonspecific symptoms.

PRESENTATION OF CASE

A 65-year-old woman with hypertension and morbid obesity was admitted to the ICU for intestinal obstruction and peritonitis due to an incarcerated hernia. Extensive bowel resection required ileostomy and prolonged antibiotic therapy. She developed refractory metabolic acidosis, suspected to be D-lactate acidosis. Management included sodium bicarbonate for acid-base correction and carbohydrate restriction via enteral nutrition. Gradual carbohydrate reintroduction resolved the acidosis. After clinical stabilization, elevated D-lactate levels were confirmed, and she transitioned to an oral diet with protein supplementation.

DISCUSSION

Treatment focused on carbohydrate restriction to limit D-lactate production by reducing intestinal fermentation. Fructose was initially considered for its unique absorption properties that prevent fermentation, but limited formula availability led to complete carbohydrate elimination. Complex carbohydrates were gradually reintroduced to meet metabolic requirements without worsening acidosis. Intravenous bicarbonate, probiotics, and antibiotics were employed to manage severe acidosis. This case emphasizes the importance of individualized, multidisciplinary approaches in managing D-lactic acidosis and underscores the need for accessible, effective nutritional formulas.

CONCLUSION

Early diagnosis of D-lactate acidosis enables effective management through carbohydrate restriction, reducing bacterial fermentation and improving clinical outcomes.

Nanopore Identification of L-, D-Lactic Acids, D-Glucose and Gluconic Acid in the Serum of Human and Animals

DL-Lactic acid and D-glucose are important human health indicators. Their aberrant levels in body fluids may indicate a variety of human pathological conditions, suggesting an urgent need of daily monitoring. However, simultaneous and rapid analysis of DL-lactic acid and D-glucose using a sole but simple sensing system has never been reported. Here, an engineered Mycobacterium smegmatis porin A (MspA) nanopore is used to simultaneously identify DL-lactic acid and D-glucose. Highly distinguishable nanopore event features are reported. Assisted with a custom machine learning algorithm, direct identification of DL-lactic acid and D-glucose is performed with human serum, demonstrating its sensing reliability against complex and heterogeneous samples. This sensing strategy is further applied in the analysis of different animal serum samples, according to which gluconic acid is further identified. The serum samples from different animals report distinguishable levels of DL-lactic acid, D-glucose and gluconic acid, suggesting its potential applications in agricultural science and breeding industry. This sensing strategy is generally direct, rapid, economic and requires only ≈µL of input serum, suitable for point of care testing (POCT) applications.

Transcriptional response of Saccharomyces cerevisiae to lactic acid enantiomers

The model yeast, Saccharomyces cerevisiae, is a popular object for both fundamental and applied research, including the development of biosensors and industrial production of pharmaceutical compounds. However, despite multiple studies exploring S. cerevisiae transcriptional response to various substances, this response is unknown for some substances produced in yeast, such as D-lactic acid (DLA). Here, we explore the transcriptional response of the BY4742 strain to a wide range of DLA concentrations (from 0.05 to 45 mM), and compare it to the response to 45 mM L-lactic acid (LLA). We recorded a response to 5 and 45 mM DLA (125 and 113 differentially expressed genes (DEGs), respectively; > 50% shared) and a less pronounced response to 45 mM LLA (63 DEGs; > 30% shared with at least one DLA treatment). Our data did not reveal natural yeast promoters quantitatively sensing DLA but provide the first description of the transcriptome-wide response to DLA and enrich our understanding of the LLA response. Some DLA-activated genes were indeed related to lactate metabolism, as well as iron uptake and cell wall structure. Additional analyses showed that at least some of these genes were activated only by acidic form of DLA but not its salt, revealing the role of pH. The list of LLA-responsive genes was similar to those published previously and also included iron uptake and cell wall genes, as well as genes responding to other weak acids. These data might be instrumental for optimization of lactate production in yeast and yeast co-cultivation with lactic acid bacteria. KEY POINTS: • We present the first dataset on yeast transcriptional response to DLA. • Differential gene expression was correlated with yeast growth inhibition. • The transcriptome response to DLA was richer in comparison to LLA.

Dual Role of Probiotic Lactic Acid Bacteria Cultures for Fermentation and Control Pathogenic Bacteria in Fruit-Enriched Fermented Milk

The food industry has been developing new products with health benefits, extended shelf life, and without chemical preservation. Bacteriocin-producing lactic acid bacteria (LAB) strains have been evaluated for food fermentation to prevent contamination and increase shelf life. In this study, potentially probiotic LAB strains, Lactiplantibacillus (Lb.) plantarum ST8Sh, Lacticaseibacillus (Lb.) casei SJRP38, and commercial starter Streptococcus (St.) thermophilus ST080, were evaluated for their production of antimicrobial compounds, lactic acid and enzyme production, carbohydrate assimilation, and susceptibility to antibiotics. The characterization of antimicrobial compounds, the proteolytic activity, and its inhibitory property against Listeria (List.) monocytogenes and Staphylococcus (Staph.) spp. was evaluated in buriti and passion fruit-supplemented fermented milk formulations (FMF) produced with LAB strains. Lb. plantarum ST8Sh was found to inhibit List. monocytogenes through bacteriocin production and produced both L(+) and D(-) lactic acid isomers, while Lb. casei SJRP38 mainly produced L(+) lactic acid. The carbohydrate assimilation profiles were compatible with those usually found in LAB. The potentially probiotic strains were susceptible to streptomycin and tobramycin, while Lb. plantarum ST8Sh was also susceptible to ciprofloxacin. All FMF produced high amounts of L(+) lactic acid and the viability of total lactobacilli remained higher than 8.5 log CFU/mL during monitored storage period. Staph. aureus ATCC 43300 in fermented milk with passion fruit pulp (FMFP) and fermented milk with buriti pulp (FMB), and Staph. epidermidis KACC 13234 in all formulations were completely inhibited after 14 days of storage. The combination of Lb. plantarum ST8Sh and Lb. casei SJRP38 and fruit pulps can provide increased safety and shelf-life for fermented products, and natural food preservation meets the trends of the food market.

The Intersection of Ultra-Processed Foods, Neuropsychiatric Disorders, and Neurolaw: Implications for Criminal Justice

Over the last decade there has been increasing interest in the links between the consumption of ultra-processed foods and various neuropsychiatric disorders, aggression, and antisocial behavior. Neurolaw is an interdisciplinary field that seeks to translate the rapid and voluminous advances in brain science into legal decisions and policy. An enhanced understanding of biophysiological mechanisms by which ultra-processed foods influence brain and behavior allows for a historical reexamination of one of forensic neuropsychiatry's most famous cases-The People v. White and its associated 'Twinkie Defense'. Here in this Viewpoint article, we pair original court transcripts with emergent research in neurolaw, including nutritional neuroscience, microbiome sciences (legalome), pre-clinical mechanistic research, and clinical intervention trials. Advances in neuroscience, and related fields such as the microbiome, are challenging basic assumptions in the criminal justice system, including notions of universal free will. Recent dismissals of criminal charges related to auto-brewery syndrome demonstrate that courts are open to advances at the intersection of neuromicrobiology and nutritional neuroscience, including those that relate to criminal intent and diminished capacity. As such, it is our contention that experts in the neurosciences will play an increasing role in shaping research that underpins 21st-century courtroom discourse, policy, and decision-making.

Serum D-Lactate Concentrations in Dogs with Inflammatory Bowel Disease

The D-enantiomer of lactic acid (D-lactate) is normally produced from bacterial fermentation in the gastrointestinal tract in mammals. In humans, increased D-lactate concentrations are related to gastrointestinal disease, including short bowel syndrome and malabsorptive syndrome. Similarly, increased D-lactate concentrations have been described in calves affected by diarrhea, in cats with gastrointestinal diseases, and in dogs with parvoviral enteritis. The purpose of the present study was to measure the serum D-lactate concentrations in dogs with inflammatory bowel disease (IBD). We retrospectively reviewed data from the database of the VTH of Perugia University, and dogs affected by IBD with serum samples stored at -80 °C were considered eligible for inclusion. A total of 18 dogs with IBD and 10 healthy dogs were included in the study. The dogs with IBD were divided into three subcategories based on the severity of the disease. Serum D-lactate concentrations (μM) were determined using a commercially available colorimetric assay kit (D-Lactate Colorimetric Assay Kit; Catalog #K667-100, BioVision Inc., Milpitas, CA, USA). Our results showed no significant difference (p > 0.05) in the serum concentrations of D-lactate between dogs with various degrees of IBD and healthy dogs. However, the wide variability of the D-lactate concentrations in dogs with IBD and evidence of increased serum D-lactate concentrations in dogs with confirmed dysbiosis encourage further studies on this topic to understand potential factors influencing the serum D-lactate concentrations in dogs affected by IBD.

Fast, sensitive LC-MS resolution of α -hydroxy acid biomarkers via SPP-teicoplanin and an alternative UV detection approach

Enantioseparation of α -hydroxy acids is essential since specific enantiomers of these compounds can be used as disease biomarkers for diagnosis and prognosis of cancer, brain diseases, kidney diseases, diabetes, etc., as well as in the food industry to ensure quality. HPLC methods were developed for the enantioselective separation of 11 α -hydroxy acids using a superficially porous particle-based teicoplanin (TeicoShell) chiral stationary phase. The retention behaviors observed for the hydroxy acids were HILIC, reversed phase, and ion-exclusion. While both mass spectrometry and UV spectroscopy detection methods could be used, specific mobile phases containing ammonium formate and potassium dihydrogen phosphate, respectively, were necessary with each approach. The LC-MS mode was approximately two orders of magnitude more sensitive than UV detection. Mobile phase acidity and ionic strength significantly affected enantioresolution and enantioselectivity. Interestingly, higher ionic strength resulted in increased retention and enantioresolution. It was noticed that for formate-containing mobile phases, using acetonitrile as the organic modifier usually resulted in greater enantioresolution compared to methanol. However, sometimes using acetonitrile with high ammonium formate concentrations led to lengthy retention times which could be avoided by using methanol as the organic modifier. Additionally, the enantiomeric purities of single enantiomer standards were determined and it was shown that almost all standards contained some levels of enantiomeric impurities.

Severe Lactic Acidosis and Hypoglycemia Associated With Burkitt Lymphoma and the Warburg Effect

Type B lactic acidosis secondary to the Warburg effect is a rare metabolic complication associated with hematological malignancies. Type B lactic acidosis occurs without tissue dysoxia due to increased aerobic glycolysis and excess lactic acid formation, commonly known as the Warburg effect. Here, we present a case of Burkitt lymphoma in a 69-year-old female with severe type B lactic acidosis and hypoglycemia that was effectively treated by the prompt initiation of chemotherapy. Type B lactic acidosis has been mostly described with hematological malignancies and rarely with solid malignancies. It is considered one of the oncological emergencies, and initiation of chemotherapy as soon as possible has been beneficial compared to alkali therapy. Lactic acidosis associated with malignancies carries a poor prognosis and high mortality.

Ageratina adenophora causes intestinal integrity damage in goats via the activation of the MLCK/ROCK signaling pathway

As a global toxin invasive species, the whole herb of Ageratina adenophora (A. adenophora) contains various sesquiterpenes, which can cause various degrees of toxic reactions characterized by inflammatory damage when ingested by animals. Current studies on the toxicity of A. adenophora have focused on parenchymatous organs such as the liver and spleen, but few studies have been conducted on the intestine as the organ that is first exposed to A. adenophora and digests and absorbs its toxic components. In this study, after feeding goats with 40 % A. adenophora herb powder for 90 d, we found that the intestinal structure of goats showed pathological changes characterized, and the damage to the small intestinal segments was more severe than that of the large intestine. The MLCK/ROCK signaling pathway was activated, the cytoskeleton underwent centripetal contraction, the composition of tight junctions between intestinal epithelial cells was altered table, Occludin, Claudin-1 and Zonula occluden (ZO-1) amount was decreased, and the intestinal mechanical barrier was disrupted. The intestinal damage markers diamine oxidase (DAO) and D-lactate (D-LA) levels were elevated. In addition, we also found that intestinal bacteria translocate and enter the portal vein to colonize the liver and mesenteric lymph nodes. The expression of intestinal pro-inflammatory factors and anti-inflammatory factors was changed, the intestinal immune function was disrupted. The present study is the first to analyze the mechanism of poisoning of A. adenophora from the intestinal tract in compound-gastric animals.

Factors associated with D-lactic acidosis in pediatric intestinal failure: A case-control study

BACKGROUND

D-lactic acidosis (DLA) is a serious complication of short bowel syndrome (SBS) in children with intestinal failure (IF). Malabsorbed carbohydrates are metabolized by bacteria in the intestine to D-lactate which can lead to metabolic acidosis and neurologic symptoms.

METHODS

A retrospective chart review was performed in children ≤18 years old with SBS who had one of the following criteria: unexplained metabolic acidosis, neurologic signs or symptoms, history of antibiotic therapy for small bowel bacterial overgrowth, or high clinical suspicion of DLA. Cases had serum D-lactate concentration >0.25 mmol/L; controls with concentrations ≤0.25 mmol/L.

RESULTS

Of forty-six children, median age was 3.16 (interquartile range (IQR): 1.98, 5.82) years, and median residual bowel length was 40 (IQR: 25, 59) cm. There were 23 cases and 23 controls. Univariate analysis showed that cases had significantly lower median bicarbonate (19 vs. 24 mEq/L, p = 0.001), higher anion gap (17 vs. 14 mEq/L, p < 0.001) and were less likely to be receiving parenteral nutrition, compared with children without DLA. Multivariable analysis identified midgut volvulus, history of intestinal lengthening procedure, and anion gap as significant independent risk factors. Midgut volvulus was the strongest independent factor associated with DLA (adjusted odds ratio = 17.1, 95% CI: 2.21, 133, p = 0.007).

CONCLUSION

DLA is an important complication of pediatric IF due to SBS. Patients with IF, particularly those with history of midgut volvulus, having undergone intestinal lengthening, or with anion gap acidosis, should be closely monitored for DLA.

Isolation, Characterization, and Safety Evaluation of the Novel Probiotic Strain Lacticaseibacillus paracasei IDCC 3401 via Genomic and Phenotypic Approaches

This study aimed to explore the safety and properties of Lacticaseibacillus paracasei IDCC 3401 as a novel probiotic strain via genomic and phenotypic analyses. In whole-genome sequencing, the genes associated with antibiotic resistance and virulence were not detected in this strain. The minimum inhibitory concentration test revealed that L. paracasei IDCC 3401 was susceptible to all the antibiotics tested, except for kanamycin. Furthermore, the strain did not produce toxigenic compounds, such as biogenic amines and D-lactate, nor did it exhibit significant toxicity in a single-dose acute oral toxicity test in rats. Phenotypic characterization of carbohydrate utilization and enzymatic activities indicated that L. paracasei IDCC 3401 can utilize various nutrients, allowing it to grow in deficient conditions and produce health-promoting metabolites. The presence of L. paracasei IDCC 3401 supernatants significantly inhibited the growth of enteric pathogens (p < 0.05). In addition, the adhesion ability of L. paracasei IDCC 3401 to intestinal epithelial cells was found to be as superior as that of Lacticaseibacillus rhamnosus GG. These results suggest that L. paracasei IDCC 3401 is safe for consumption and provides health benefits to the host.

I am better than I look: genome based safety assessment of the probiotic Lactiplantibacillus plantarum IS-10506

BACKGROUND

Safety of probiotic strains that are used in human and animal trials is a prerequisite. Genome based safety assessment of probiotics has gained popularity due its cost efficiency and speed, and even became a part of national regulation on foods containing probiotics in Indonesia. However, reliability of the safety assessment based only on a full genome sequence is not clear. Here, for the first time, we sequenced, assembled, and analysed the genome of the probiotic strain Lactiplantibacillus plantarum IS-10506, that was isolated from dadih, a traditional fermented buffalo milk. The strain has already been used as a probiotic for more than a decade, and in several clinical trials proven to be completely safe.

METHODS

The genome of the probiotic strain L. plantarum IS-10506 was sequenced using Nanopore sequencing technology, assembled, annotated and screened for potential harmful (PH) and beneficial genomic features. The presence of the PH features was assessed from general annotation, as well as with the use of specialised tools. In addition, PH regions in the genome were compared to all other probiotic and non-probiotic L. plantarum strains available in the NCBI RefSeq database.

RESULTS

For the first time, a high-quality complete genome of L. plantarum IS-10506 was obtained, and an extensive search for PH and a beneficial signature was performed. We discovered a number of PH features within the genome of L. plantarum IS-10506 based on the general annotation, including various antibiotic resistant genes (AMR); however, with a few exceptions, bioinformatics tools specifically developed for AMR detection did not confirm their presence. We further demonstrated the presence of the detected PH genes across multiple L. plantarum strains, including probiotics, and overall high genetic similarities between strains.

CONCLUSION

The genome of L. plantarum IS-10506 is predicted to have several PH features. However, the strain has been utilized as a probiotic for over a decade in several clinical trials without any adverse effects, even in immunocompromised children with HIV infection and undernourished children. This implies the presence of PH feature signatures within the probiotic genome does not necessarily indicate their manifestation during administration. Importantly, specialized tools for the search of PH features were found more robust and should be preferred over manual searches in a general annotation.

Nutrition and Intestinal Rehabilitation of Children With Short Bowel Syndrome: A Position Paper of the ESPGHAN Committee on Nutrition. Part 2: Long-Term Follow-Up on Home Parenteral Nutrition

Short bowel syndrome (SBS) is the leading cause of intestinal failure (IF) in children. The preferred treatment for IF is parenteral nutrition which may be required until adulthood. The aim of this position paper is to review the available evidence on managing SBS and to provide practical guidance to clinicians dealing with this condition. All members of the Nutrition Committee of the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) contributed to this position paper. Some renowned experts in the field joined the team to guide with their expertise. A systematic literature search was performed from 2005 to May 2021 using PubMed, MEDLINE, and Cochrane Database of Systematic Reviews. In the absence of evidence, recommendations reflect the expert opinion of the authors. Literature on SBS mainly consists of retrospective single-center experience, thus most of the current papers and recommendations are based on expert opinion. All recommendations were voted on by the expert panel and reached >90% agreement. This second part of the position paper is dedicated to the long-term management of children with SBS-IF. The paper mainly focuses on how to achieve intestinal rehabilitation, treatment of complications, and on possible surgical and medical management to increase intestinal absorption.

Gut Microbial Changes Following Fecal Microbiota Transplantation for D-Lactic Acidosis in Two Children

D-lactic acidosis (D-LA) is an uncommon complication of short bowel syndrome characterized by elevated plasma D-lactate and encephalopathy. Treatments include rehydration, dietary carbohydrate restriction, and antibiotics to alter the gut microbiota. Fecal microbiota transplantation (FMT) has recently been used in children to successfully treat D-LA. We compared the clinical course and then utilized metagenomic shotgun sequencing to describe changes in the composition and function of the intestinal microbiome following FMT in 2 patients with recurrent D-LA. FMT altered the composition of the fecal microbiota in these 2 patients with recurrent D-LA, though not necessarily in a consistent manner. Importantly, microbial metabolic pathways were also impacted by FMT, which may be critical for achieving desired clinical outcomes. While sample size limits the generalizability of our results, these findings set the stage for further understanding of the role of microbes in the pathogenesis of recurrent D-LA.

Guar gum as galactomannan source induces dysbiosis and reduces performance in broiler chickens and dietary β-mannanase restores the gut homeostasis

Galactomannans are abundant nonstarch polysaccharides in broiler feed ingredients. In broilers, diets with high levels of galactomannans have been associated with innate immune response stimulation, poor zootechnical performance, nutrient and lipid absorption, and excessive digesta viscosity. However, data about its effects on the gut microbiome are scarce. β-Mannanases are enzymes that can hydrolyze β-mannans, resulting in better nutrient utilization. In the current study, we have evaluated the effect of guar gum, a source of galactomannans, supplemented to broiler diets, either with or without β-mannanase supplementation, on the microbiota composition, in an attempt to describe the potential role of the intestinal microbiota in β-mannanase-induced gut health and performance improvements. One-day-old broiler chickens (n = 756) were randomly divided into 3 treatments: control diet, guar gum-supplemented diet (1.7%), or guar gum-supplemented diet + β-mannanase (Hemicell 330 g/ton). The zootechnical performance, gut morphometry, ileal and cecal microbiome, and short-chain fatty acid concentrations were evaluated at different time points. The guar gum supplementation decreased the zootechnical performance, and the β-mannanase supplementation restored performance to control levels. The mannan-rich diet-induced dysbiosis, with marked effects on the cecal microbiota composition. The guar gum-supplemented diet increased the cecal abundance of the genera Lactobacillus, Roseburia, Clostridium sensu stricto 1, and Escherichia-Shigella, and decreased Intestinimonas, Alistipes, Butyricicoccus, and Faecalibacterium. In general, dietary β-mannanase supplementation restored the main microbial shifts induced by guar gum to levels of the control group. In addition, the β-mannanase supplementation reduced cecal isobutyric, isovaleric, valeric acid, and branched-chain fatty acid concentrations as compared to the guar gum-supplemented diet group, suggesting improved protein digestion and reduced cecal protein fermentation. In conclusion, a galactomannan-rich diet impairs zootechnical performance in broilers and results in a diet-induced dysbiosis. β-Mannanase supplementation restored the gut microbiota composition and zootechnical performance to control levels.

D-Lactate: Implications for Gastrointestinal Diseases

D-lactate is produced in very low amounts in human tissues. However, certain bacteria in the human intestine produce D-lactate. In some gastrointestinal diseases, increased bacterial D-lactate production and uptake from the gut into the bloodstream take place. In its extreme, excessive accumulation of D-lactate in humans can lead to potentially life-threatening D-lactic acidosis. This metabolic phenomenon is well described in pediatric patients with short bowel syndrome. Less is known about a subclinical rise in D-lactate. We discuss in this review the pathophysiology of D-lactate in the human body. We cover D-lactic acidosis in patients with short bowel syndrome as well as subclinical elevations of D-lactate in other diseases affecting the gastrointestinal tract. Furthermore, we argue for the potential of D-lactate as a marker of intestinal barrier integrity in the context of dysbiosis. Subsequently, we conclude that there is a research need to establish D-lactate as a minimally invasive biomarker in gastrointestinal diseases.

An Overview of Short-Bowel Syndrome in Pediatric Patients: Focus on Clinical Management and Prevention of Complications

Short-bowel syndrome (SBS) in pediatric age is defined as a malabsorptive state, resulting from congenital malformations, significant small intestine surgical resection or disease-associated loss of absorption. SBS is the leading cause of intestinal failure in children and the underlying cause in 50% of patients on home parental nutrition. It is a life-altering and life-threatening disease due to the inability of the residual intestinal function to maintain nutritional homeostasis of protein, fluid, electrolyte or micronutrient without parenteral or enteral supplementation. The use of parenteral nutrition (PN) has improved medical care in SBS, decreasing mortality and improving the overall prognosis. However, the long-term use of PN is associated with the incidence of many complications, including liver disease and catheter-associated malfunction and bloodstream infections (CRBSIs). This manuscript is a narrative review of the current available evidence on the management of SBS in the pediatric population, focusing on prognostic factors and outcome. The literature review showed that in recent years, the standardization of management has demonstrated to improve the quality of life in these complex patients. Moreover, the development of knowledge in clinical practice has led to a reduction in mortality and morbidity. Diagnostic and therapeutic decisions should be made by a multidisciplinary team that includes neonatologists, pediatric surgeons, gastroenterologists, pediatricians, nutritionists and nurses. A significant improvement in prognosis can occur through the careful monitoring of nutritional status, avoiding dependence on PN and favoring an early introduction of enteral nutrition, and through the prevention, diagnosis and aggressive treatment of CRSBIs and SIBO. Multicenter initiatives, such as research consortium or data registries, are mandatory in order to personalize the management of these patients, improve their quality of life and reduce the cost of care.

Short bowel syndrome: Complications and management

Short bowel syndrome (SBS) occurs when a patient loses bowel length or function significantly enough to cause malabsorption, oftentimes requiring lifelong parenteral support. In adults, this occurs most commonly in the setting of massive intestinal resection, whereas congenital anomalies and necrotizing enterocolitis predominate in children. Many patients with SBS develop long-term clinical complications over time related to their altered intestinal anatomy and physiology or to various treatment interventions such as parenteral nutrition and the central venous catheter through which it is administered. Identifying, preventing, and treating these complications can be challenging. This review will focus on the diagnosis, treatment, and prevention of several complications that can occur in this patient population, including diarrhea, fluid and electrolyte imbalance, vitamin and trace element derangements, metabolic bone disease, biliary disorders, small intestinal bacterial overgrowth, d-lactic acidosis, and complications of central venous catheters.

Neonatal intestinal failure: Growth pattern and nutrition intakes in accordance with weaning from parenteral nutrition

BACKGROUND

Short bowel syndrome is the most common cause of intestinal failure (IF) in infants. We aimed to evaluate growth, nutrition intakes, and predictors of weaning from parenteral nutrition (PN) of infants with IF.

METHODS

Clinical parameters, nutrition intakes, body weight and length z-scores were compared monthly from the 1st to 12th and at 18 and 24 months among infants receiving PN and those weaned. Logistic regression analysis was conducted to explore the predictors of weaning.

RESULTS

We included 23 infants (10/23 weaned). Median [range: minimum; maximum] birth weight and gestational age were 1620 [590; 3490] g and 31 [24; 39] weeks, respectively. All infants showed growth retardation with similar median delta weight z-score from birth to discharge: -1.48 [-1.92; -0.94] in not-weaned and -1.18 [-2.70; 0.31] in weaned infants (P = 0.833) and a subsequent regain after the discharge: 0.20 [-3.47; 3.25] and 0.84 [-0.03; 2.58], respectively (P = 0.518). No differences in length z-score were found. After the sixth month, infants weaned from PN received lower PN energy and protein intakes compared with those not-weaned. Infants weaned from PN showed lower PN dependency index (PNDI%) from 5 months onward (45% for weaned and 113% for not-weaned infants at 5 months: P < 0.001). The Belza score, a predictor of enteral autonomy computed at 6 months, is associated with being weaned from PN within 24 months (odds ratio: 1.906; P = 0.039).

CONCLUSION

Infants weaned and not-weaned showed similar growth patterns. Our findings support the clinical relevance of Belza score and PNDI% as predictors of weaning from PN.

Show Me What You Have Inside-The Complex Interplay between SIBO and Multiple Medical Conditions-A Systematic Review

The microbiota, as a complex of microorganisms in a particular ecosystem, is part of the wider term-microbiome, which is defined as the set of all genetic content in the microbial community. Imbalanced gut microbiota has a great impact on the homeostasis of the organism. Dysbiosis, as a disturbance in bacterial balance, might trigger or exacerbate the course of different pathologies. Small intestinal bacterial overgrowth (SIBO) is a disorder characterized by differences in quantity, quality, and location of the small intestine microbiota. SIBO underlies symptoms associated with functional gastrointestinal disorders (FGD) as well as may alter the presentation of chronic diseases such as heart failure, diabetes, etc. In recent years there has been growing interest in the influence of SIBO and its impact on the whole human body as well as individual systems. Therefore, we aimed to investigate the co-existence of SIBO with different medical conditions. The PubMed database was searched up to July 2022 and we found 580 original studies; inclusion and exclusion criteria let us identify 112 eligible articles, which are quoted in this paper. The present SIBO diagnostic methods could be divided into two groups-invasive, the gold standard-small intestine aspirate culture, and non-invasive, breath tests (BT). Over the years scientists have explored SIBO and its associations with other diseases. Its role has been confirmed not only in gastroenterology but also in cardiology, endocrinology, neurology, rheumatology, and nephrology. Antibiotic therapy could reduce SIBO occurrence resulting not only in the relief of FGD symptoms but also manifestations of comorbid diseases. Although more research is needed, the link between SIBO and other diseases is an important pathway for scientists to follow.

Lactic Acidosis Related to Pharmacotherapy and Human Diseases

Lactic acidosis represents one of the most common conditions that can compromise the health of intensive care unit (ICU) patients, increasing the mortality of patients with high levels of Lactate who do not receive a proper treatment within the first 6 h of hospitalization. There are two enantiomers of lactic acid: L-lactic acid (when the concentration increases, it can lead to a state of severe acidemia risking cardiovascular collapse, causing an increase in mortality in ICU patients) and D lactic acid (produced in the human organism by microbiota and its production increases during some pathological status). Generally, increased levels of serum lactic acid could be due to numerous factors, including hypoxia (caused for example by septic/cardiogenic/hypovolemic or obstructive shock), specific pathologies (e.g., liver disease), use of some drugs (e.g., metformin), presence of toxins, and trauma. Since the underlying cause could be fatal for the ICU patient, it is important to understand the root of this clinical status with a view to correct it and prevent the risk of a poor clinical outcome. Prevention and early treatment are the keys to control the negative clinical consequences. The aim of this review is to revise the scientific literature for further confirmation about the importance of early identification of acidotic statuses and to underline how an early diagnosis can prevent the worst clinical outcome, especially for ICU patients who are more fragile compared to the general population.

Glucagon-like peptide-2 analogues for Crohn’s disease patients with short bowel syndrome and intestinal failure

Short bowel syndrome (SBS) with intestinal failure (IF) is a rare but severe complication of Crohn’s disease (CD), which is the most frequent benign condition that leads to SBS after repeated surgical resections, even in the era of biologics and small molecules. Glucagon-like peptide-2 analogues have been deeply studied recently for the treatment of SBS-IF. These drugs have a significant intestinotrophic effect and the potential to reduce the chronic dependence of SBS-IF patients on parenteral support or nutrition. Teduglutide has been approved for the treatment of SBS-IF, and apraglutide is currently in clinical development. The use of these drugs was examined with a focus on their use in CD patients.

Safety Evaluation by Phenotypic and Genomic Characterization of Four Lactobacilli Strains with Probiotic Properties

Probiotic Lactobacillus species are known to exert health benefits in hosts when administered in adequate quantities. A systematic safety assessment of the strains must be performed before the Lactobacillus strains can be designated as probiotics for human consumption. In this study, we selected Lactobacillus fermentum IDCC 3901, L. gasseri IDCC 3101, L. helveticus IDCC 3801, and L. salivarius IDCC 3551 as representative Lactobacilli probiotic strains and investigated their probiotic properties and potential risks through phenotypic and genomic characterization. Various assays including antimicrobial resistance, biogenic amine production, L-/D-lactate production, acute oral toxicity, and antipathogenic effect were performed to evaluate the safety of the four Lactobacillus strains. Genomic analysis using whole genome sequencing was performed to investigate virulence and antibiotic resistance genes in the genomes of the selected probiotic strains. The phenotypes of the strains such as enzymatic activity and carbohydrate utilization were also investigated. As a result, antibiotic resistances of the four Lactobacillus species were detected; however, neither antibiotic resistance-related genes nor virulence genes were found by genomic analysis. Moreover, the four Lactobacillus species did not exhibit hemolytic activity or β-glucuronidase activity. The biogenic amine production and oral acute toxicity were not shown in the four Lactobacillus species, whereas they produced D-lactate with minor ratio. The four Lactobacillus species exhibited antipathogenic effect to five pathogenic microorganisms. This study provides a way to assess the potential risks of four different Lactobacillus species and validates the safety of all four strains as probiotics for human consumption.

d-lactate-triggered extracellular trap formation in cattle polymorphonuclear leucocytes is glucose metabolism dependent

D-lactic acidosis is a metabolic disease of cattle caused by the digestive overgrowth of bacteria that are highly producers of d-lactate, a metabolite that then reaches and accumulates in the bloodstream. d-lactate is a proinflammatory agent in cattle that induces the formation of extracellular traps (ETs) in polymorphonuclear leucocytes (PMN), although information on PMN metabolic requirements for this response mechanism is insufficient. In the present study, metabolic pathways involved in ET formation induced by d-lactate were studied. We show that d-lactate but not l-lactate induced ET formation in cattle PMN. We analyzed the metabolomic changes induced by d-lactate in bovine PMN using gas chromatography-mass spectrometry (GC-MS). Several metabolic pathways were altered, including glycolysis/gluconeogenesis, amino sugar and nucleotide sugar metabolism, galactose metabolism, starch and sucrose metabolism, fructose and mannose metabolism, and pentose phosphate pathway. d-lactate increased intracellular levels of glucose and glucose-6-phosphate, and increased uptake of the fluorescent glucose analog 2-NBDG, suggesting improved glycolytic activity. In addition, using an enzymatic assay and transmission electron microscopy (TEM), we observed that d-lactate was able to decrease intracellular glycogen levels and the presence of glycogen granules. Relatedly, d-lactate increased the expression of enzymes of glycolysis, gluconeogenesis and glycogen metabolism. In addition, 2DG (a hexokinase inhibitor), 3PO (a 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 inhibitor), MB05032 (inhibitor of fructose-1,6-bisphosphatase) and CP-91149 (inhibitor of glycogen phosphorylase) reduced d-lactate-triggered ETosis. Taken together, these results suggest that d-lactate induces a metabolic rewiring that increases glycolysis, gluconeogenesis and glycogenolysis, all of which are required for d-lactate-induced ET release in cattle PMN.

In vitro assessment of histamine and lactate production by a multi-strain synbiotic

Recent studies suggest histamine and d-lactate may negatively impact host health. As excess histamine is deleterious to the host, the identification of bacterial producers has contributed to concerns over the consumption of probiotics or live microorganisms in fermented food items. Some probiotic products have been suspected of inducing d-lactic-acidosis; an illness associated with neurocognitive symptoms such as ataxia. The goals of the present study were to test the in vitro production of histamine and d-lactate by a 24-strain daily synbiotic and to outline methods that others can use to test for their production. Using enzymatic based assays, no significant production of histamine was observed compared to controls (P > 0.05), while d-lactate production was comparable to a commercially available probiotic with no associated health risk. These assays provide a means to add to the safety profile of synbiotic and probiotic products.

A d,l-lactate biosensor based on allosteric transcription factor LldR and amplified luminescent proximity homogeneous assay

Lactate, a hydroxycarboxylic acid commercially produced by microbial fermentation, is widely applied in diverse industrial fields. Lactate exists in two stereoisomeric forms (d-lactate and l-lactate). d-Lactate and l-lactate are often simultaneously present in many biological samples. Therefore, a biosensor able to detect both d- and l-lactate is required but previously unavailable. Herein, an allosteric transcription factor LldR from Pseudomonas aeruginosa PAO1, which responds to both d-lactate and l-lactate, was combined with amplified luminescent proximity homogeneous assay technology to develop a d,l-lactate biosensor. The proposed biosensor was optimized by mutation of DNA sequence in binding site of LldR. The optimized biosensor B_Lac-6 can accurately detect the concentration of lactate independent on ratio of the two isomers in pending test samples. The biosensor was also tentatively used in quantitative analysis of d-lactate, l-lactate, or d,l-lactate in fermentation samples produced by three recombinant strains of Klebsiella oxytoca. With its desirable properties, the biosensor B_Lac-6 may be a potential choice for monitoring the concentration of lactate during industrial fermentation.

Evaluation of the safety and efficacy of lactic acid to reduce microbiological surface contamination on carcases from kangaroos, wild pigs, goats and sheep

Studies evaluating the safety and efficacy of lactic acid to reduce microbiological surface contamination from carcases of wild game (i.e. kangaroos and wild pigs) and small stock (i.e. goats and sheep) before chilling at the slaughterhouse were assessed. Wild pig and kangaroo hide-on carcases may have been chilled before they arrive at the slaughterhouse and are treated after removal of the hides. Lactic acid solutions (2-5%) are applied to the carcases at temperatures of up to 55°C by spraying or misting. The treatment lasts 6-7 s per carcass side. The Panel concluded that: [1] the treatment is of no safety concern, provided that the lactic acid complies with the European Union specifications for food additives; [2] based on the available evidence, it was not possible to conclude on the efficacy of spraying or misting lactic acid on kangaroo, wild pig, goats and sheep carcases; [3] treatment of the above-mentioned carcases with lactic acid may induce reduced susceptibility to the same substance, but this can be minimised; there is currently no evidence that prior exposure of food-borne pathogens to lactic acid leads to the occurrence of resistance levels that compromise antimicrobial therapy; and [4] the release of lactic acid is not of concern for the environment, assuming that wastewaters released by the slaughterhouses are treated on-site, if necessary, to counter the potentially low pH caused by lactic acid, in compliance with local rules.

Role of Lactate in Inflammatory Processes: Friend or Foe

During an inflammatory process, shift in the cellular metabolism associated with an increase in extracellular acidification are well-known features. This pH drop in the inflamed tissue is largely attributed to the presence of lactate by an increase in glycolysis. In recent years, evidence has accumulated describing the role of lactate in inflammatory processes; however, there are differences as to whether lactate can currently be considered a pro- or anti-inflammatory mediator. Herein, we review these recent advances on the pleiotropic effects of lactate on the inflammatory process. Taken together, the evidence suggests that lactate could exert differential effects depending on the metabolic status, cell type in which the effects of lactate are studied, and the pathological process analyzed. Additionally, various targets, including post-translational modifications, G-protein coupled receptor and transcription factor activation such as NF-κB and HIF-1, allow lactate to modulate signaling pathways that control the expression of cytokines, chemokines, adhesion molecules, and several enzymes associated with immune response and metabolism. Altogether, this would explain its varied effects on inflammatory processes beyond its well-known role as a waste product of metabolism.

Enantioselective metabolomics by liquid chromatography-mass spectrometry

Metabolomics strives to capture the entirety of the metabolites in a biological system by comprehensive analysis, often by liquid chromatography hyphenated to mass spectrometry. A particular challenge thereby is the differentiation of structural isomers. Common achiral targeted and untargeted assays do not distinguish between enantiomers. This may lead to information loss. An increasing number of publications demonstrate that the enantiomeric ratio of certain metabolites can be meaningful biomarkers of certain diseases emphasizing the importance of introducing enantioselective analytical procedures in metabolomics. In this work, the state-of-the-art in the field of LC-MS based metabolomics is summarized with focus on developments in the recent decade. Methodologies, tagging strategies, workflows and general concepts are outlined. Selected biological applications in which enantioselective metabolomics has documented its usefulness are briefly discussed. In general, targeted enantioselective metabolomics assays are often based on a direct approach using chiral stationary phases (CSP) with polysaccharide derivatives, macrocyclic antibiotics, chiral crown ethers, chiral ion exchangers, donor-acceptor phases as chiral selectors. Rarely, these targeted assays focus on more than 20 analytes and usually are restricted to a certain metabolite class. In a variety of cases, pre-column derivatization of metabolites has been performed, especially for amino acids, to improve separation and detection sensitivity. Triple quadrupole instruments are the detection methods of first choice in targeted assays. Here, issues like matrix effect, absence of blank matrix impair accuracy of results. In selected applications, multiple heart cutting 2D-LC (RP followed by chiral separation) has been pursued to overcome this problem and alleviate bias due to interferences. Non-targeted assays, on the other hand, are based on indirect approach involving tagging with a chiral derivatizing agent (CDA). Besides classical CDAs numerous innovative reagents and workflows have been proposed and are discussed. Thereby, a critical issue for the accuracy is often neglected, viz. the validation of the enantiomeric impurity in the CDA. The majority of applications focus on amino acids, hydroxy acids, oxidized fatty acids and oxylipins. Some potential clinical applications are highlighted.

Armillaria mellea fermentation liquor ameliorates p-chlorophenylalanine-induced insomnia associated with the modulation of serotonergic system and gut microbiota in rats

In China, Armillaria mellea (Vahl) P. Kumm. has been used as a folk medicine to treat insomnia for several hundred years. However, the underlying mechanisms involved are currently unknown. In this study, the anti-insomnia efficacy of A. mellea fermentation liquor (AFL) was evaluated in p-chlorophenylalanine-induced insomnia rats by measuring the serotonergic systems and gut microbiota. Our results demonstrate that all doses of AFL significantly reduced locomotor activity and alleviated decreasing weights in insomnia rats. Further, AFL exhibited better sedative effects by reducing sleep latency and increasing sleep duration in pentobarbital-treated rats. AFL treatment also elevated serum glutathione peroxidase and superoxide dismutase levels, while reducing serum interleukin-6, tumor necrosis factor-α, and interleukin-1β levels. Furthermore, AFL alleviated insomnia by enhancing 5-hydroxytryptamine content and the expression 5-HT_1A and 5-HT_2A receptor in the hippocampus. Meanwhile, AFL treatment normalized the composition of gut microbiota in insomnia-model rats, while increasing relative abundance of Lachnospiraceae, Ruminococcaceae, and Saccharimonadaceae restores the gut microbial ecosystem altered in insomnia rats. The experiments show that A. mellea alleviated insomnia by modulating serotonergic system and gut microbiota. PRACTICAL APPLICATIONS: Insomnia has become a serious health issue of global concern. As a well-known traditional Chinese medicine, Armillaria mellea has been clinically employed in the treatment of insomnia for centuries in Asia with significant efficacy. In the present study, we firstly reported A. mellea fermentation liquor potentially relieved insomnia rats by alteration of gut microbiota and serotonergic systems and could guide future clinical studies. As a popular edible and medicinal mushroom, A. mellea also can be potentially used in the development and production of novel food products in the future.

Safety evaluation of Lactococcus lactis IDCC 2301 isolated from homemade cheese

For applications of microorganisms as probiotics in the food industry, safety evaluation has increasingly become important to ensure the health of consumers. Although people have been using various lactic acid bacteria for different purposes, some studies have reported that certain lactic acid bacteria exhibit properties of virulence and produce toxic compounds. Thus, it is necessary to examine the characteristics associated with lactic acid bacteria that are safe for use as probiotics. This research aimed to assess the safety of Lactococcus lactis IDCC 2301 isolated from homemade cheese using in vitro and in vivo assays, including antibiotic resistance, hemolytic activity, toxin production, infectivity, and metabolic activity in immune-compromised animal species. The results demonstrated that the strain was susceptible to nine antibiotics suggested by the European Food Safety Authority (EFSA). Whole-genome analysis revealed that L. lactis IDCC 2301 neither has toxigenic genes nor harbors antibiotic resistance. Moreover, L. lactis IDCC 2301 showed neither hemolytic nor β-glucuronidase activity. Furthermore, none of the D-lactate and biogenic amines were produced by L. lactis IDCC 2301. Finally, it was demonstrated that there was no toxicity and mortality using single-dose oral toxicity tests in rats. These results indicate that L. lactis IDCC 2301 can be safely used as probiotics for human consumption.

The Auto-Brewery Syndrome: A Perfect Metabolic "Storm" with Clinical and Forensic Implications

Auto-brewery syndrome (ABS) is a rare, unstudied, unknown, and underreported phenomenon in modern medicine. Patients with this syndrome become inebriated and may suffer the medical and social implications of alcoholism, including arrest for inebriated driving. The pathophysiology of ABS is reportedly due to a fungal type dysbiosis of the gut that ferments some carbohydrates into ethanol and may mimic a food allergy or intolerance. This syndrome should be considered in patients with chronic obstruction or hypomotility presenting with elevated breath and blood alcohol concentrations, especially after a high carbohydrate intake. A glucose challenge test should be performed as the confirmatory test. Treatment typically includes antifungal drugs combined with changes in lifestyle and nutrition. Additional studies are particularly needed on the human microbiome to shed light on how imbalances of commensal bacteria in the gut allow yeast to colonize on a pathological level.

Lactate cross-talk in host-pathogen interactions

Lactate is the main product generated at the end of anaerobic glycolysis or during the Warburg effect and its role as an active signalling molecule is increasingly recognised. Lactate can be released and used by host cells, by pathogens and commensal organisms, thus being essential for the homeostasis of host-microbe interactions. Infection can alter this intricate balance, and the presence of lactate transporters in most human cells including immune cells, as well as in a variety of pathogens (including bacteria, fungi and complex parasites) demonstrates the importance of this metabolite in regulating host-pathogen interactions. This review will cover lactate secretion and sensing in humans and microbes, and will discuss the existing evidence supporting a role for lactate in pathogen growth and persistence, together with lactate's ability to impact the orchestration of effective immune responses. The ubiquitous presence of lactate in the context of infection and the ability of both host cells and pathogens to sense and respond to it, makes manipulation of lactate a potential novel therapeutic strategy. Here, we will discuss the preliminary research that has been carried out in the context of cancer, autoimmunity and inflammation.

Chronic intestinal failure and short bowel syndrome in Crohn’s disease

Chronic intestinal failure (CIF) is a rare but feared complication of Crohn’s disease. Depending on the remaining length of the small intestine, the affected intestinal segment, and the residual bowel function, CIF can result in a wide spectrum of symptoms, from single micronutrient malabsorption to complete intestinal failure. Management of CIF has improved significantly in recent years. Advances in home-based parenteral nutrition, in particular, have translated into increased survival and improved quality of life. Nevertheless, 60% of patients are permanently reliant on parenteral nutrition. Encouraging results with new drugs such as teduglutide have added a new dimension to CIF therapy. The outcomes of patients with CIF could be greatly improved by more effective prevention, understanding, and treatment. In complex cases, the care of patients with CIF requires a multidisciplinary approach involving not only physicians but also dietitians and nurses to provide optimal intestinal rehabilitation, nutritional support, and an improved quality of life. Here, we summarize current literature on CIF and short bowel syndrome, encompassing epidemiology, pathophysiology, and advances in surgical and medical management, and elucidate advances in the understanding and therapy of CIF-related complications such as catheter-related bloodstream infections and intestinal failure-associated liver disease.

D-lactic acidosis presenting as metabolic encephalopathy in a patient with short bowel syndrome

We present a case of D-lactic acidosis presenting as a metabolic encephalopathy secondary to small intestinal bacterial overgrowth. This patient had a known history of short bowel syndrome. Of note, this case required the alteration of treatment to promote a sustained clinical and biochemical improvement. We discuss the pathophysiological mechanisms thought to be involved. We also review the current therapies as well as potential future strategies. This case highlights the importance of the prompt clinical recognition of signs and symptoms as well as the rapid initiation of management strategies to ameliorate this condition.

Safety assessment of Lactobacillus reuteri IDCC 3701 based on phenotypic and genomic analysis

Purpose

Lactobacillus reuteri is one of the most largely studied human-commensal bacteria and widely used as a form of probiotics. Safety of probiotics has become increasingly important for human consumption due to increasing health-concerns in food industry. In this study, the safety of L. reuteri IDCC 3701 isolated from human breast milk was thoroughly investigated.

Methods

Whole-genome sequence analysis was performed to identify antibiotic resistance and toxigenicity of L. reuteri IDCC 3701. Phenotypic analysis such as minimal inhibitory concentration, β-hemolysis, extracellular enzyme activity, and the production of biological amines and L/D-lactate, was investigated. Finally, acute oral toxicity test was performed to access L. reuteri IDCC 3701 safety.

Results

Although multiple resistances to gentamicin and kanamycin were observed in L. reuteri IDCC 3701, it was revealed that these resistances are intrinsic and not transferable through whole-genome analysis. In addition, various phenotypic analysis concerning hemolysis, enzyme activity, and D-lactate production did not show any negative results. Although L. reuteri IDCC 3701 harbors a histidine decarboxylase gene, no biogenic amines were detected. Finally, L. reuteri IDCC 3701 exhibited no evidence of acute toxicity according to an in vivo study.

Conclusion

Our findings demonstrate that L. reuteri IDCC 3701 is considered to be safe for human consumption as probiotics based on the in silico, in vitro and in vivo studies.

Safety assessment of Streptococcus thermophilus IDCC 2201 used for product manufacturing in Korea

Safety evaluation of probiotics has become increasingly important for human consumption in food industry. The aims of this study were to assess safety of Streptococcus thermophilus IDCC 2201 through in vitro and in vivo tests. In results, this strain was found to be negative for hemolytic and β-glucuronidase activity. In addition, thermophilus IDCC 2201 was susceptible to nine antibiotics suggested by EFSA. In accordance with MIC tests, whole-genome analysis indicated that S. thermophilus IDCC 2201 neither harbors antibiotic resistance nor toxigenic genes. Furthermore, none of the biogenic amines including tyramine and histamine was produced and negligible amounts of D-lactate were produced by S. thermophilus IDCC 2201. Finally, it was confirmed that there was no mortality and toxicity throughout single-dose oral toxicity tests in rats. Therefore, we report that S. thermophilus IDCC 2201 is considered to be safe for human consumption as probiotics.

Quantitative Evaluation of D-Lactate Pathophysiology: New Insights into the Mechanisms Involved and the Many Areas in Need of Further Investigation

In contrast to L-lactate, D-lactate is produced in minimal quantities by human cells, and the plasma D-lactate concentration normally is maintained at a concentration of only about 0.01 mM. However, in short bowel syndrome, colonic bacterial production of D-lactate may lead to plasma concentrations >3mM with accompanying acidosis and neurological symptoms - a syndrome known as D-lactic acidosis. Minor increases in plasma D-lactate have been observed in various gastrointestinal conditions such as ischemia, appendicitis and Crohn's disease, a finding touted to have diagnostic utility. The novel aspect of this review paper is the application of numerical values to the processes involved in D-lactate homeostasis that previously have been described only in qualitative terms. This approach provides a number of new insights into normal and disordered production, catabolism and excretion of D-lactate, and identifies multiple gaps in our understanding of D-lactate physiology that should be amenable to relatively simple investigative study.

Gut microbiome-derived lactate promotes to anxiety-like behaviors through GPR81 receptor-mediated lipid metabolism pathway

Accumulating evidence suggests that chronic stress could perturb the composition of the gut microbiota and induce host anxiety- and depression-like behaviors. In particular, microorganism-derived products that can directly or indirectly signal to the nervous system. This study sought to investigate whether high levels of Lactobacillus and lactate in the gut of rats under chronic unpredictable stress (CUS) were the factors leading to anxiety behavior. We collected faeces and blood samples in a sterile laboratory bench to study the microbiome and plasma metabolome from adult male rats age and environment matched healthy individuals. We sequenced the V3 and V4 regions of the 16S rRNA gene from faeces samples. UPLC-MS metabolomics were used to examine plasma samples. Search for potential biomarkers by combining the different data types. Finally, we found a regulated signaling pathway through the relative expression of protein and mRNA. Both lactate feeding and fecal microbiota transplantation caused behavioral abnormalities such as psychomotor malaise, impaired learning and memory in the recipient animals. These rats also showed inhibition of the adenylate cyclase (AC)-protein kinase A (PKA) pathway of lipolysis after activation of G protein-coupled receptor 81 (GPR81) by lactate in the liver, as well as increased tumor necrosis factor α (TNF-α), compared with healthy controls. Furthermore, we showed that sphingosine-1-phosphate receptor 2 (S1PR2) protein expression in hippocampus was reduced in chronic unpredictable stress compared to control group and its expression negatively correlates with symptom severity. Our study suggest that the gut microbiome-derived lactate promotes to anxiety-like behaviors through GPR81 receptor-mediated lipid metabolism pathway.

D-Lactic Acid as a Metabolite: Toxicology, Diagnosis, and Detection

Two enantiomers of lactic acid exist. While L-lactic acid is a common compound of human metabolism, D-lactic acid is produced by some strains of microorganism or by some less relevant metabolic pathways. While L-lactic acid is an endogenous compound, D-lactic acid is a harmful enantiomer. Exposure to D-lactic acid can happen by various ways including contaminated food and beverages and by microbiota during some pathological states like short bowel syndrome. The exposure to D-lactic acid cannot be diagnosed because the common analytical methods are not suitable for distinguishing between the two enantiomers. In this review, pathways for D-lactic acid, pathological processes, and diagnostical and analytical methods are introduced followed by figures and tables. The current literature is summarized and discussed.

High anion gap metabolic acidosis caused by D-lactate: mind the time of blood collection

Introduction

D-lactic acidosis is an uncommon cause of high anion gap acidosis.

Materials and methods

A 35-year old woman was admitted to the emergency room with somnolence, drowsiness, dizziness, incoherent speech and drunk appearance. Her past medical history included a Roux-en-Y bypass. Point-of-care venous blood analysis revealed a high anion gap acidosis. Based on the clinical presentation, routine laboratory results and negative toxicology screening, D-lactate and 5-oxoprolinuria were considered as the most likely causes of the high anion gap acidosis. Urine organic acid analysis revealed increased lactate, but no 5-oxoproline. Plasma D-lactate was < 1.0 mmol/L and could not confirm D-lactic acidosis.

What happened

Further investigation revealed that the blood sample for D-lactate was drawn 12 hours after admission, which might explain the false-negative result. Data regarding the half-life of D-lactate are, however, scarce. During a second admission, one month later, D-lactic acidosis could be confirmed with an anion gap of 40.7 mmol/L and a D-lactate of 21.0 mmol/L measured in a sample collected at the time of admission.

Main lesson

The time of blood collection is of utmost importance to establish the diagnosis of D-lactic acidosis due to the fast clearance of D-lactate in the human body.

From methylglyoxal to pyruvate: a genome-wide study for the identification of glyoxalases and D-lactate dehydrogenases in Sorghum bicolor

Background

The glyoxalase pathway is evolutionarily conserved and involved in the glutathione-dependent detoxification of methylglyoxal (MG), a cytotoxic by-product of glycolysis. It acts via two metallo-enzymes, glyoxalase I (GLYI) and glyoxalase II (GLYII), to convert MG into D-lactate, which is further metabolized to pyruvate by D-lactate dehydrogenases (D-LDH). Since D-lactate formation occurs solely by the action of glyoxalase enzymes, its metabolism may be considered as the ultimate step of MG detoxification. By maintaining steady state levels of MG and other reactive dicarbonyl compounds, the glyoxalase pathway serves as an important line of defence against glycation and oxidative stress in living organisms. Therefore, considering the general role of glyoxalases in stress adaptation and the ability of Sorghum bicolor to withstand prolonged drought, the sorghum glyoxalase pathway warrants an in-depth investigation with regard to the presence, regulation and distribution of glyoxalase and D-LDH genes.

Result

Through this study, we have identified 15 GLYI and 6 GLYII genes in sorghum. In addition, 4 D-LDH genes were also identified, forming the first ever report on genome-wide identification of any plant D-LDH family. Our in silico analysis indicates homology of putatively active SbGLYI, SbGLYII and SbDLDH proteins to several functionally characterised glyoxalases and D-LDHs from Arabidopsis and rice. Further, these three gene families exhibit development and tissue-specific variations in their expression patterns. Importantly, we could predict the distribution of putatively active SbGLYI, SbGLYII and SbDLDH proteins in at least four different sub-cellular compartments namely, cytoplasm, chloroplast, nucleus and mitochondria. Most of the members of the sorghum glyoxalase and D-LDH gene families are indeed found to be highly stress responsive.

Conclusion

This study emphasizes the role of glyoxalases as well as that of D-LDH in the complete detoxification of MG in sorghum. In particular, we propose that D-LDH which metabolizes the specific end product of glyoxalases pathway is essential for complete MG detoxification. By proposing a cellular model for detoxification of MG via glyoxalase pathway in sorghum, we suggest that different sub-cellular organelles are actively involved in MG metabolism in plants.

Serum D-lactate concentrations in dogs with parvoviral enteritis

BACKGROUND

Dogs infected with canine parvovirus (CPV) have compromised intestinal epithelial barrier integrity. Production of D-lactate by enteric bacteria may directly reflect disease severity or contribute to metabolic acid-base status in these dogs.

HYPOTHESIS

Serum D-lactate concentration will be increased in CPV dogs compared to healthy controls and correlate with markers of disease severity and acid-base status.

ANIMALS

Dogs with CPV undergoing treatment (n = 40) and healthy control dogs (n = 9).

METHODS

Prospective observational study. Dogs with CPV had a baseline and daily CBC, venous blood gas with serum electrolyte concentrations, composite clinical severity score, and serum D-lactate concentration performed. A single serum D-lactate measurement was obtained from healthy control dogs.

RESULTS

The CPV dogs had a higher D-lactate concentration (mean ± SD) of 469 ± 173 μM compared to controls, 306 ± 45 μM (P < .001). There was no difference in baseline D-lactate concentrations for CPV survivors (474 ± 28 μM), versus nonsurvivors (424 ± 116 μM; P = .70). D-lactate concentration decreased over the first 4 days of treatment (-9.6 μM/d; P = .46). Dogs hospitalized for <4 days had lower baseline D-lactate concentrations compared to those hospitalized ≥4 days (400 ± 178 μM versus 520 ± 152 μM; P = .03). No sustained correlation over time between serum D-lactate concentration and clinical severity score or recorded acid-base results.

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum D-lactate concentrations are higher in dogs with CPV compared to healthy controls but do not appear to be clinically relevant. No relationship identified between serum D-lactate concentrations and markers of CPV disease severity, acid-base status, or outcome.

Short Bowel Syndrome as the Leading Cause of Intestinal Failure in Early Life: Some Insights into the Management

Intestinal failure (IF) is the critical reduction of the gut mass or its function below the minimum needed to absorb nutrients and fluids required for adequate growth in children. Severe IF requires parenteral nutrition (PN). Pediatric IF is most commonly due to congenital or neonatal intestinal diseases or malformations divided into 3 groups: 1) reduced intestinal length and consequently reduced absorptive surface, such as in short bowel syndrome (SBS) or extensive aganglionosis; 2) abnormal development of the intestinal mucosa such as congenital diseases of enterocyte development; 3) extensive motility dysfunction such as chronic intestinal pseudo-obstruction syndromes. The leading cause of IF in childhood is the SBS. In clinical practice the degree of IF may be indirectly measured by the level of PN required for normal or catch up growth. Other indicators such as serum citrulline have not proven to be highly reliable prognostic factors in children. The last decades have allowed the development of highly sophisticated nutrient solutions consisting of optimal combinations of macronutrients and micronutrients as well as guidelines, promoting PN as a safe and efficient feeding technique. However, IF that requires long-term PN may be associated with various complications including infections, growth failure, metabolic disorders, and bone disease. IF Associated Liver Disease may be a limiting factor. However, changes in the global management of IF pediatric patients, especially since the setup of intestinal rehabilitation centres did change the prognosis thus limiting "nutritional failure" which is considered as a major indication for intestinal transplantation (ITx) or combined liver-ITx.