Anti-proliferative effect of two lactic acid bacteria strains of human origin on the growth of a myeloma cell line

Anticancer effect of bacteria on cervical cancer: Molecular aspects and therapeutic implications

Cervical cancer is the second common cancer and the third leading cause of cancer deaths among women in less developed countries. It has been indicated that changes in vaginal microbiome play an important role in the occurrence and development of cervical cancer. However, studies have shown that probiotics play an effective role in fighting cancer by affecting pathogenic bacteria, inducing cancer cells apoptosis, and other anticancer activities. Therefore, the purpose of the present study is reviewing the anticancer effect of cervicovaginal bacteria and their potential for cervical cancer treatment.

The controversial role of Enterococcus faecalis in colorectal cancer

Colorectal cancer (CRC) is a complex and widespread disease, currently ranked as the third most frequent cancer worldwide. It is well known that the gut microbiota has an essential role in the initiation and promotion of different cancer types, particularly gastrointestinal tumors. In fact, bacteria can trigger chronic inflammation of the gastric mucosal, which can induce irreversible changes to intestinal epithelial cells, thus predisposing individuals to cancer. Some bacterial strains, such as Helicobacter pylori, Streptococcus bovis, Bacteroides fragilis, Clostridium septicum and Fusobacterium spp. have a well established role in CRC development. However, the role of Enterococcus faecalis still remains controversial. While part of the literature suggests a harmful role, other papers reported E. faecalis as an important probiotic microorganism, with great applicability in food products. In this review we have examined the vast majority of published data about E. faecalis either in CRC development or concerning its protective role. Our analysis should provide some answers regarding the controversial role of E. faecalis in CRC.

Surfacing role of probiotics in cancer prophylaxis and therapy: A systematic review

Cancers figure among the most important causes of morbidity and mortality worldwide. Cancer and its associated infections are always complicated even when specific cancer regimens are available. It is well proved that Lactobacillus and other probiotic bacteria can modulate-ameliorate specific mechanisms against various infections including cancers. The present systematic review is intended to focus on the 'cellular and molecular mechanisms' of probiotic bacteria in the prevention and treatment of various cancers. The clinical and experimental findings of various studies explain the mechanisms such as apoptosis, antioxidant activity, immune response and epigenetics and illustrate the role of probiotics in cancer management and prophylaxis. In addition, the present review also discusses the safety aspects of probiotics when they are used in therapeutic and nutritional diet management. However, further investigations are required to reveal the effectiveness of probiotics in cancer treatment in clinical settings.

Protective Effect of a Lactobacillus salivarius Strain of Human Origin

The protective effect of a Lactobacillus salivariusstrain from human faeces (HA8) was evaluated against the cytotoxicity of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosodibutylamine (NDBA) and N-nitrosopiperidine (NPIP) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. L. salivariusHA8 strain showed a moderate protective effect against NPYR and weak against NDBA and NPIP. No protective effect against cytotoxicity of NDMA was observed at the bacterial population used. To test the effect of L. salivariusHA8 on cytokine production (interleukin-1 ± (IL-1 ±), interleukin-8 (IL-8) and tumour necrosis factor alpha (TNF-≥)), the human macrophage cell line (THP-1) was cultured in the presence and absence of lipopolysaccharide (LPS). L. salivariusHA8 induced IL-1 ±, IL-8 and TNF-≥ releases when cells were stimulating with and without LPS.

The Potential Role of Probiotics in Cancer Prevention and Treatment

The human gut microbiota has a significant effect on many aspects of human physiology such as metabolism, nutrient absorption, and immune function. Imbalance of the microbiota has been implicated in many disorders including inflammatory bowel disease, obesity, asthma, psychiatric illnesses, and cancers. As a kind of functional foods, probiotics have been shown to play a protective role against cancer development in animal models. Clinical application of probiotics indicated that some probiotic strains could diminish the incidence of postoperative inflammation in cancer patients. Chemotherapy or radiotherapy-related diarrhea was relieved in patients who were administered oral probiotics. The present review summarizes the up-to-date studies on probiotic effects and the underlying mechanisms related to cancer. At present, it is commonly accepted that most commercial probiotic products are generally safe and can improve the health of the host. By modulating intestinal microbiota and immune response, some strains of probiotics can be used as an adjuvant for cancer prevention or/and treatment.

The effects of microencapsulated Lactobacillus casei on tumour cell growth: In vitro and in vivo studies

It has been known for some time that the micro-milieu of solid tumours provides an ideal environment for growth of facultative and strictly anaerobic bacteria, and it has been shown that certain species including Lactobacillus and Clostridium can colonise those environments leading to regression of tumour growth. Such observations have given rise to the concept of bacteriolytic therapy where live microorganisms might be employed to colonise the tumour and exert a tumorolytic effect. In choosing such an approach, it would be advantageous to exploit a relatively non-pathogenic strain and provide some form of containment that would enable site-specific injection and minimise dispersion of the microorganism throughout the host. In testing the feasibility of such an approach, we prepared microencapsulated formulations of Lactobacillus casei NCDO 161 and demonstrated that conditioned extra-capsular culture media were toxic to tumour cells in vitro. We further investigated the effects of the microencapsulated formulations on tumour growth in vivo following direct intra-tumoural injection. The study demonstrates significant inhibition of tumour growth in vivo by these formulations and suggests potential therapeutic benefit of this approach in the treatment of solid tumours.

Preparation of selenium/zinc-enriched probiotics and their effect on blood selenium and zinc concentrations, antioxidant capacities, and intestinal microflora in canine

The aim of this study was to prepare Se/Zn-enriched probiotics and investigate their effect on blood Se and Zn concentrations, blood antioxidant capacities, and intestinal microflora in canine. The preparation was performed in a single-factor experiment. The optimal culture conditions were as follows: the initial concentrations of Se(4+) and Zn(2+) were 5 and 150 µg/ml, respectively; the inoculation volume was 5%; and the liquid volume of the medium was 50 ml in a 250-ml flask. The medium was then cultured at 32°C for 36 h. The biomass of the final product was 26.83 g/l, organic Se concentration was 173.35 µg/g, organic Zn concentration was 4.38 mg/g, Candida utilis biomass was 8.69 lg colony-forming units (CFU)/ml, and Lactobacillus biomass was 9.61 lg CFU/ml. In vivo, 20 indigenous dogs were randomly assigned to two dietary treatment groups for a 35-day study and fed a basal diet or a diet supplemented with 2.0 g of Se/Zn-enriched probiotics. Blood and fecal samples were collected on days 0, 15, and 30 of the experiment. Compared with the control group, the blood Se concentration; the blood Zn concentration; the activities of glutathione peroxidase, superoxide dismutase, and total antioxidant capacity in the blood; and the amount of Lactobacillus and Bifidobacterium in the feces increased in the supplemented group during the period of supplementation (P < 0.01), while malondialdehyde level in the blood and the amounts of Escherichia coli, Staphylococcus, and Enterococcus in the feces decreased in the supplemented group (P < 0.01).

Immune modulation and expression of cytokine genes in rainbow trout Oncorhynchus mykiss upon probiotic feeding

This study elucidates the immune modulation including the expression of cytokine genes following dietary administration of three selected probiotic bacteria--Lactobacillus rhamnosus, Enterococcus faecium and Bacillus subtilis to fish, rainbow trout Oncorhynchus mykiss. They were fed for 45 days on either a basal control diet or one of the three probiotic diets containing the specific bacteria in freeze-dried form at a density of 10(9)CFUgfeed-1. The non-specific immune parameters examined--superoxide anion production by the head kidney leukocytes and the alternate complement activity of serum was improved by probiotic feeding. Besides this, the relative gene expressions of interleukin-1beta1, tumor necrosis factor 1 and 2 and transforming growth factor-beta were up regulated in the spleen and the head kidney. The comparatively better performance of E. faecium could possibly be linked to their suitable ambient temperature conditions. Thus, probiotic bacteria delivered in feed exerts its influence on the immune system of fish, both at cellular and molecular levels.

Enhancement in ex vivo phagocytic capacity of peritoneal leukocytes in mice by oral delivery of various lactic-acid-producing bacteria

Lactic-acid-producing bacteria (LABs) are known to have immunomodulating activity. In the current study, various LABs were tested for their immunity-enhancing activity, especially the phagocytic activity of leukocytes. Viable but not heat-killed cells of Weissella kimchii strain PL9001, Lactobacillus fermentum strain PL9005, and L. plantarum strain PL9011 significantly increased the ex vivo phagocytic capacity of mouse peritoneal leukocytes to ingest fluorescein isothiocyanate (FITC)-labeled Escherichia coli in a strain-dependent manner. Results of this and previous studies suggest these LABs as candidates for new probiotics. This is the first report of the enhancement of peritoneal leukocyte activity of these species.

Differentiation of Enterococcus faecium from Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains by PCR and dot-blot hybridisation

Variations in length and sequence of the 16S/23S spacer region of Enterococcus faecium provided the basis for development of simple PCR and dot-blot hybridisation assays that enabled the differentiation of potentially probiotic Enterococcus faecium strains from Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Such assays may be useful for differentiation of yoghurt starter cultures and enterococcal strains when they are simultaneously present in probiotic food products.

Probiotics, infection and immunity

PURPOSE OF REVIEW

Taking live bacteria by mouth to improve health (probiotics) is not intuitively rational yet it is a practice with a long history. As interest in the effects on health of the intestinal flora has developed, along with major advances in the technology for studying it, so has come a new interest in establishing the true benefits of probiotic therapy. This review summarizes the most recent contributions to this rapidly developing area.

RECENT FINDINGS

Probiotic bacteria, mainly bifidobacteria and lactobacilli for historical reasons, can prevent or ameliorate some diseases. Many empirical studies have been done, but work to develop the ideal characteristics of probiotics lags behind. Current literature covers survival of probiotics in the gut, mucosal adherence, antibacterial/pathogen mechanisms, effects on immune function and clinical studies.

SUMMARY

Probiotic bacteria are effective in preventing and reducing the severity of acute diarrhoea in children. They are also useful in antibiotic associated diarrhoea but not for elimination of Helicobacter pylori. In inflammatory bowel disease, especially ulcerative colitis, probiotics offer a safe alternative to current therapy. Probiotics have been used to prevent urogenital tract infection with benefit and, perhaps more intriguingly, to reduce atopy in children. Probiotics do not invariably work and study of mechanisms is urgently needed.

Probiotics: potential pharmaceutical applications

Realisation of the importance of human gut microbiota in health restoration and maintenance has kindled an interest in probiotics. Probiotics are defined as the microbial food supplements, which beneficially affect the host by improving its intestinal microbial balance. Probiotics are the health enhancing functional food ingredients used therapeutically to prevent diarrhea, improve lactose tolerance and modulate immunity. They may also have potential to prevent cancer and lower serum cholesterol levels. Lactobacillus, Bifidobacterium and several other microbial species are perceived to exert such effects by changing the composition of the gut microbiota. However, it is important that exogenously administered bacteria reach and establish themselves in the large intestine in an intact form. The use of non-digestible oligosaccharides ('prebiotics') can fortify intestinal microflora and stimulate their growth. The present review encompasses information regarding the probiotics and their proposed uses. It addresses the concepts of prebiotics and synbiotics, the application of genetic engineering to produce newer probiotics. Finally, the list of commercially available products are reviewed with discussion of questions regarding the reliability, utility and the safety of these products.