The impact of gut bacteria producing long chain homologs of vitamin K2 on colorectal carcinogenesis.

Colorectal cancer (CRC) is one of the foremost causes of cancer-related deaths. Lately, a close connection between the course of CRC and the intestinal microbiota has been revealed. Vitamin K2 (VK2) is a bacterially derived compound that plays a crucial role in the human body. Its significant anti-cancer properties may result, inter alia, from a quinone ring possessing a specific chemical structure found in many chemotherapeutics. VK2 can be supplied to our body exogenously, i.e., through dietary supplements or fermented food (e.g., yellow cheese, fermented soybeans -Natto), and endogenously, i.e., through the production of bacteria that constantly colonize the human microbiome of the large intestine.This paper focuses on endogenous K2 synthesized by the most active members of the human gut microbiome. This analysis tested 86 intestinally derived bacterial strains, among which the largest VK2 producers (Lactobacillus, Bifidobacterium, Bacillus) were selected. Moreover, based on the chosen VK2-MK4 homolog, the potential of VK2 penetration into Caco-2 cells in an aqueous environment without the coexistence of fats, pancreatic enzymes, or bile salts has been displayed. The influence of three VK2 homologs: VK2-MK4, VK2-MK7 and VK2-MK9 on apoptosis and necrosis of Caco-2 cells was tested proving the lack of their harmful effects on the tested cells. Moreover, the unique role of long-chain homologs (VK2-MK9 and VK2-MK7) in inhibiting the secretion of pro-inflammatory cytokines such as IL-8 (for Caco-2 tissue) and IL-6 and TNFα (for RAW 264.7) has been documented.

The Multi-Component Causes of Late Neonatal Sepsis-Can We Regulate Them?

Elucidating the mechanisms of bacterial translocation is crucial for the prevention and treatment of neonatal sepsis. In the present study, we aimed to evaluate the potential of lactoferrin to inhibit the development of late-onset blood infection in neonates. Our investigation evaluates the role of key stress factors leading to the translocation of intestinal bacteria into the bloodstream and, consequently, the development of life-threatening sepsis. Three stress factors, namely weaning, intraperitoneal administration of Gram-positive cocci and oral intake of Gram-negative rods, were found to act synergistically. We developed a novel model of rat pups sepsis induced by bacterial translocation and observed the inhibition of this process by supplementation of various forms of lactoferrin: iron-depleted (apolactoferrin), iron-saturated (hololactoferrin) and manganese-saturated lactoferrin. Additionally, lactoferrin saturated with manganese significantly increases the Lactobacillus bacterial population, which contributes to the fortification of the intestinal barrier and inhibits the translocation phenomenon. The acquired knowledge can be used to limit the development of sepsis in newborns in hospital neonatal intensive care units.

Effect of a Short-Time Probiotic Supplementation on the Abundance of the Main Constituents of the Gut Microbiota of Term Newborns Delivered by Cesarean Section-A Randomized, Prospective, Controlled Clinical Trial.

The gut microbiota plays a pivotal role in the maintenance of human health. Numerous factors, including the mode of delivery, impact early gut colonization in newborns. Recent research focuses on the use of probiotics in the prevention of gut dysbiosis in newborns delivered by cesarean section (CS). The objective of this study was to determine whether a probiotic supplement given to newborns delivered by CS during their stay in the maternity ward alters the pattern of early gut colonization by lactic acid bacteria versus potential pathogens. A prospective, randomized trial was conducted. In total, 150 newborns, born at 38-40 weeks gestational age and delivered by CS, were included in the study. They were randomized into the intervention group, supplemented orally with a probiotic containing Bifidobacterium breve PB04 and Lactobacillus rhamnosus KL53A, and the control group. Stool samples were obtained on days 5 and 6 of life and after one month of life and were analyzed for the presence and abundance of the main groups of bacteria. An application of two probiotic bacteria during the first days of life after CS resulted in quick and abundant colonization by days 5 and 6, with high populations of L. rhamnosus and B. breve. The applied bacterial strains were present in the majority of neonates one month after. The supplementation of term neonates delivered by cesarean section immediately after birth with a mixture of L. rhamnosus and B. breve enriched the gut microbiota composition with lactic acid bacteria.

Lactobacilli with superoxide dismutase-like or catalase activity are more effective in alleviating inflammation in an inflammatory bowel disease mouse model.

PURPOSE: Some lactobacilli, which possess superoxide dismutase-like activity and catalase activity naturally, have strong antioxidative properties. The aim of this study was to identify such strains and check which of them play a crucial role in alleviating intestinal inflammation. METHODS: We selected two Lactobacillus strains for use in animal studies: L. plantarum 30B (which has the highest catalase activity) and L. acidophilus 900 (which has the highest dismutase-like activity). Forty mice (C57B1/6J) were divided into four experimental groups with ten mice in each group. Group I (control group) was not supplemented with Lactobacillus, group II (catalase group) was orally supplemented with L. plantarum 30B, group III (dismutase-like group) was supplemented with L. acidophilus 900, and group IV (mixed group) was supplemented with both Lactobacillus strains. For 23 days, the temperature and body mass of each mouse were recorded and fecal samples for microbiological examination were collected. On day 23, the animals were sacrificed, and their intestines were removed for microbiological and histopathological studies. RESULTS: Compared to the control group, the highest drop in the body temperature was observed in groups II (P<0.05) and IV (P<0.05). Similarly, groups II (P<0.05) and IV (P<0.05) had the highest drop in body mass. Moreover, histopathological evaluation of colon fragments showed intracryptic abscesses in these groups. Group III mice showed most limited degree of inflammation. CONCLUSION: Lactobacillus strains with dismutase-like activity are more effective in alleviating intestinal inflammation than strains producing catalase, suggesting that superoxide anion radical decomposition is crucial in this process.

The impact of lactoferrin with different levels of metal saturation on the intestinal epithelial barrier function and mucosal inflammation.

Translocation of bacteria, primarily Gram-negative pathogenic flora, from the intestinal lumen into the circulatory system leads to sepsis. In newborns, and especially very low birth weight infants, sepsis is a major cause of morbidity and mortality. The results of recently conducted clinical trials suggest that lactoferrin, an iron-binding protein that is abundant in mammalian colostrum and milk, may be an effective agent in preventing sepsis in newborns. However, despite numerous basic studies on lactoferrin, very little is known about how metal saturation of this protein affects a host's health. Therefore, the main objective of this study was to elucidate how iron-depleted, iron-saturated, and manganese-saturated forms of lactoferrin regulate intestinal barrier function via interactions with epithelial cells and macrophages. For these studies, a human intestinal epithelial cell line, Caco-2, was used. In this model, none of the tested lactoferrin forms induced higher levels of apoptosis or necrosis. There was also no change in the production of tight junction proteins regardless of lactoferrin metal saturation status. None of the tested forms induced a pro-inflammatory response in Caco-2 cells or in macrophages either. However, the various lactoferrin forms did effectively inhibit the pro-inflammatory response in macrophages that were activated with lipopolysaccharide with the most potent effect observed for apolactoferrin. Lactoferrin that was not bound to its cognate receptor was able to bind and neutralize lipopolysaccharide. Lactoferrin was also able to neutralize microbial-derived antigens, thereby potentially reducing their pro-inflammatory effect. Therefore, we hypothesize that lactoferrin supplementation is a relevant strategy for preventing sepsis.

Supplementation of standard antibiotic therapy with oral probiotics for bacterial vaginosis and aerobic vaginitis: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: This multicentre, randomised, double-blind, placebo-controlled trial was performed to determine whether the use of oral probiotic preparation (prOVag®) containing three Lactobacillus strains together with standard metronidazole treatment and also targeted antibiotic treatment (following the failure of metronidazole therapy) could reduce the recurrence rates of bacterial vaginosis (BV) and aerobic vaginitis (AV). METHODS: Patients at private gynaecological clinics in Poland with histories of recurrent BV/AV and current symptoms were randomly allocated to receive metronidazole and probiotic or placebo, and assessed monthly on visits II and III-V. The total number of study visits was 5-6 (I, II, II bis - if applicable, III, IV, V). One probiotic or placebo capsule was administered with metronidazole/targeted antibiotic twice daily for 10 days; during follow up, patients took one capsule daily for 10 days perimenstrually. Clinical examination and vaginal swabbing were performed at each visit. Primary outcomes were clinical or microbiological BV/AV recurrence and probiotic safety. Secondary outcomes were vaginal pH, Nugent score, and Lactobacillus counts in the vaginal microbiota. Safety analysis was performed in 578 (probiotic, n = 285; placebo, n = 293) 18-50-year-old women who were randomised. RESULTS: BV/AV was confirmed microbiologically in 241 (probiotic, n = 118; placebo, n = 123) participants, who continued the trial. Data from 154 (probiotic, n = 73; placebo, n = 81) participants who completed the study were analysed to determine the efficacy of prOVag. Additional analyses included 37 (probiotic, n = 22; placebo, n = 15) participants who received targeted antibiotics and probiotics or placebo. prOVag lengthened the time to clinical relapse of BV/AV symptoms up to 51 % (p < 0.05) compared with placebo; AV relapse was delayed by up to 76 % (p < 0.05). Probiotic use also reduced and maintained low vaginal pH and Nugent score, and increased vaginal Lactobacillus counts following standard treatment. CONCLUSION: This study demonstrated that oral probiotics lengthened remission in patients with recurrent BV/AV and improved clinical and microbiological parameters. TRIAL REGISTRATION: NCT01993524 ; 20 November 2013.

A high-throughput method for the quantification of iron saturation in lactoferrin preparations.

Lactoferrin is considered as a part of the innate immune system that plays a crucial role in preventing bacterial growth, mostly via an iron sequestration mechanism. Recent data show that bovine lactoferrin prevents late-onset sepsis in preterm very low birth weight neonates by serving as an iron chelator for some bacterial strains; thus, it is very important to control the iron saturation level during diet supplementation. An accurate estimation of lactoferrin iron saturation is essential not only because of its clinical applications but also for a wide range of biochemical experiments. A comprehensive method for the quantification of iron saturation in lactoferrin preparations was developed to obtain a calibration curve enabling the determination of iron saturation levels relying exclusively on the defined ratio of absorbances at 280 and 466 nm (A(280/466)). To achieve this goal, selected techniques such as spectrophotometry, ELISA, and ICP-MS were combined. The ability to obtain samples of lactoferrin with determination of its iron content in a simple and fast way has been proven to be very useful. Furthermore, a similar approach could easily be implemented to facilitate the determination of iron saturation level for other metalloproteins in which metal binding results in the appearance of a distinct band in the visible part of the spectrum.