Recently, the risk of viral infection has dramatically increased owing to changes in human ecology such as global warming and an increased geographical movement of people and goods. However, the efficacy of vaccines and remedies for infectious diseases is limited by the high mutation rates of viruses, especially, RNA viruses. Here, we comprehensively review the effectiveness of several probiotics and paraprobiotics (sterilized probiotics) for the prevention or treatment of virally-induced infectious diseases. We discuss the unique roles of these agents in modulating the cross-talk between commensal bacteria and the mucosal immune system. In addition, we provide an overview of the unique mechanism by which viruses are eliminated through the stimulation of type 1 interferon production by probiotics and paraprobiotics via the activation of dendritic cells. Although further detailed research is necessary in the future, probiotics and/or paraprobiotics are expected to be among the rational adjunctive options for the treatment of various viral diseases.

Abstract  A germinated barley foodstuff (GBF) containing glutamine‐rich protein and hemicellulose‐rich fiber was made from brewer's spent grain, by physical isolation. Our previous studies demonstrated that GBF supported maintenance of epithelial cell populations, facilitated epithelial repair, and suppressed epithelial nuclear factor κB‐DNA‐binding activity through generating increased short‐chain fatty acid (especially butyrate) production by luminal microflora, which includes Bifidobacterium and Eubacterium, thereby preventing experimental colonic injury. The fiber fraction also modulates stool water content because of its high water‐holding capacity. The patients with mild to moderate active ulcerative colitis who had been unresponsive to or intolerant of standard treatment received 20–30 g GBF, feeding daily in a non‐randomized, open‐label fashion. At 4 weeks, this treatment resulted in a significant clinical and endoscopic improvement. The improvement was associated with an increase in stool butyrate concentrations. These results indicate that GBF feeding is a potentially new, attractive prebiotic treatment in patients with ulcerative colitis. The potency of GBF on modulating microflora, as well as the high water‐holding capacity, may play an important role in treatment and prolongation of remission in ulcerative colitis.

Eubacterium limosum ameliorates experimental colitis and metabolite of microbe attenuates colonic inflammatory action with increase of mucosal integrity

Because the intestinal microflora play an important role in the development of inflammatory bowel disease (IBD), there is currently some interest in the manipulation of the composition of the microflora towards a potentially more remedial community. This review summarizes the clinical and experimental efficacy of the manipulation of microflora by the use of prebiotics, probiotics, synbiotics, and antibiotics in IBD. Prebiotics, defined as nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth or activity of one or a limited number of bacterial species already resident in the colon, can modulate the colonic microbiota by increasing the number of specific bacteria and thus changing the composition of the microbiota. Prebiotics for IBD include lactosucrose, oligofructose, inulin, bran, psyllium, and germinated barley foodstuff (GBF). GBF, which mainly consists of dietary fiber and glutamine-rich protein, is a prebiotic foodstuff for ulcerative colitis. GBF has shown to be converted into a preferential nutrient for colonocytes through Eubacterium and Bifidobacterium and also inactivate nuclear factor kappa B (NFkB). Moreover, it exhibits a potent waterholding capacity and bile-acid binding capacity. Probiotics, which are microbial food supplements that beneficially affect the host by improving the intestinal microbial balance, have been used to change the composition of colonic microbiota. The approaches for IBD include VSL No.3, Nissle1917, Clostridium butyricum and Bifidobacterium-fermented milk. Use of Lactococci secreting IL-10 provides excellent results. The combination of prebiotics and probiotics in a synbiotic has not been studied in IBD but is promising. The use of antibiotics continues to be of interest. Although these strategies hold great promise and appear to be useful in some settings, more clinical study is needed to firmly establish the relevance of these therapies.

Because intestinal microflora play a pivotal role in the development of inflammatory bowel disease (IBD), there is currently some interest in alternating the composition of the microflora toward a potentially more remedial community. This paper summarizes the clinical and experimental efficacy of the manipulation of microflora by the use of antibiotics, probiotics, and prebiotics in IBD. Germinated barley foodstuff (GBF) is a prebiotic whose unique characteristics make it highly suitable for applications in IBD. It also helps prolong remission in remissive ulcerative colitis (UC) patients and also attenuates clinical activity in non-remissive UC patients. GBF has shown to be converted into a preferential nutrient, butyrate, for colonocytes through the action of Eubacterium and Bifidobacterium, and this bacterial butyrate can provide anti-inflammatory effects. The probiotic approaches for IBD include VSL, Nissle1917, Clostridium butyricum, and Bifidobacterium-fermented milk. In this paper, we summarize the distinctive role of another probiotic, Eubacterium limosum (E. limosum), which is a commensal microorganism that is promoted by GBF administration. The metabolites of E. limosum included butyrate, which can accelerate intestinal epithelial growth and inhibit IL-6 production. This new probiotic approach may be useful as an adjunctive IBD treatment in the future. Although these strategies hold great promise and appear to be useful in some settings, more experimental and clinical studies are needed to firmly establish their relevance.

Germinated barley foodstuff (GBF), which mainly consists of dietary fiber and glutamine-rich protein, is a prebiotic for ulcerative colitis (UC). In our previous study, we carried out a clinical trial of GBF with mildly to moderately active UC patients and showed that GBF treatment was able to attenuate the symptoms of UC in a relatively short-term. The aim of this study was to investigate the efficacy of long-term administration of GBF in the treatment of UC in a multi-center open trial. Twenty-one patients with mildly to moderately active UC received 20-30 g of GBF for 24 weeks in an open-label protocol while baseline treatments (5-amino-salicyrate compounds and/or steroids) were continued. The response to the GBF treatment was evaluated using a clinical scoring and after 24 weeks of observation, the GBF group showed a significant decrease in clinical activity index (especially, the degree of visible blood in stools and the presence of nocturnal diarrhea) compared with the control group (p<0.05). No side effects related to GBF were observed. In conclusion, GBF can reduce the clinical activity of UC over long-term as well as short-term administration. Nutraceutical GBF therapy may have a place in long-term management of UC, but controlled studies are needed to demonstrate its efficacy in the treatment of this disorder.