Indications and challenges of probiotics, prebiotics, and synbiotics in the management of arthralgias and spondyloarthropathies in inflammatory bowel disease

Engineered probiotics as live biotherapeutics for diagnosis and treatment of human diseases

The use of probiotics to regulate the intestinal microbiota to prevent and treat a large number of disorders and diseases has been an international research hotspot. Although conventional probiotics have a certain regulatory role in nutrient metabolism, inhibiting pathogens, inducing immune regulation, and maintaining intestinal epithelial barrier function, they are unable to treat certain diseases. In recent years, aided by the continuous development of synthetic biology, engineering probiotics with desired characteristics and functionalities to benefit human health has made significant progress. In this article, we summarise the mechanism of action of conventional probiotics and their limitations and highlight the latest developments in the design and construction of probiotics as living diagnostics and therapeutics for the detection and treatment of a series of diseases, including pathogen infections, cancer, intestinal inflammation, metabolic disorders, vaccine delivery, cognitive health, and fatty liver. Besides we discuss the concerns regarding engineered probiotics and corresponding countermeasures and outline the desired features in the future development of engineered live biotherapeutics.

Designer probiotics: Opening the new horizon in diagnosis and prevention of human diseases

Probiotic microorganisms have been used for therapeutic purposes for over a century, and recent advances in biotechnology and genetic engineering have opened up new possibilities for developing therapeutic approaches using indigenous probiotic microorganisms. Diseases are often related to metabolic and immunological factors, which play a critical role in their onset. With the help of advanced genetic tools, probiotics can be modified to produce or secrete important therapeutic peptides directly into mucosal sites, increasing their effectiveness. One potential approach to enhancing human health is through the use of designer probiotics, which possess immunogenic characteristics. These genetically engineered probiotics hold promise in providing novel therapeutic options. In addition to their immunogenic properties, designer probiotics can also be equipped with sensors and genetic circuits, enabling them to detect a range of diseases with remarkable precision. Such capabilities may significantly advance disease diagnosis and management. Furthermore, designer probiotics have the potential to be used in diagnostic applications, offering a less invasive and more cost-effective alternative to conventional diagnostic techniques. This review offers an overview of the different functional aspects of the designer probiotics and their effectiveness on different diseases and also, we have emphasized their limitations and future implications. A comprehensive understanding of these functional attributes may pave the way for new avenues of prevention and the development of effective therapies for a range of diseases.

Potential Application of Living Microorganisms in the Detoxification of Heavy Metals

Heavy metal (HM) exposure remains a global occupational and environmental problem that creates a hazard to general health. Even low-level exposure to toxic metals contributes to the pathogenesis of various metabolic and immunological diseases, whereas, in this process, the gut microbiota serves as a major target and mediator of HM bioavailability and toxicity. Specifically, a picture is emerging from recent investigations identifying specific probiotic species to counteract the noxious effect of HM within the intestinal tract via a series of HM-resistant mechanisms. More encouragingly, aided by genetic engineering techniques, novel HM-bioremediation strategies using recombinant microorganisms have been fruitful and may provide access to promising biological medicines for HM poisoning. In this review, we summarized the pivotal mutualistic relationship between HM exposure and the gut microbiota, the probiotic-based protective strategies against HM-induced gut dysbiosis, with reference to recent advancements in developing engineered microorganisms for medically alleviating HM toxicity.

Role of probiotics in prevention and treatment of enteric infections: a comprehensive review

Microorganisms that inhabits human digestive tract affect global health and enteric disorders. Previous studies have documented the effectiveness and mode of action of probiotics and classified as human-friendly biota and a competitor to enteric pathogens. Statistical studies reported more than 1.5 billion cases of gastrointestinal infections caused by enteric pathogens and their long-term exposure can lead to mental retardation, temporary or permanent physical weakness, and leaving the patient susceptible for opportunistic pathogens, which can cause fatality. We reviewed previous literature providing evidence about therapeutic approaches regarding probiotics to cure enteric infections efficiently by producing inhibitory substances, immune system modulation, improved barrier function. The therapeutic effects of probiotics have shown success against many foodborne pathogens and their therapeutic effectiveness has been exponentially increased using genetically engineered probiotics. The bioengineered probiotic strains are expected to provide a better and alternative approach than traditional antibiotic therapy against enteric pathogens, but the novelty of these strains also raise doubts about the possible untapped side effects, for which there is a need for further studies to eliminate the concerns relating to the use and safety of probiotics. Many such developments and optimization of the classical techniques will revolutionize the treatments for enteric infections.

Surface display of p75, a Lactobacillus rhamnosus GG derived protein, on Bacillus subtilis spores and its antibacterial activity against Listeria monocytogenes

Lactobacillus rhamnosus p75 protein with peptidoglycan hydrolase (PGH) activity is one of the key molecules exhibiting anti-apoptotic and cell-protective activity for human intestinal epithelial cells. In this study, with the goal of developing new probiotics, the p75 protein was displayed on the surface of Bacillus subtilis spores using spore coat protein CotG as an anchoring motif. The PGH activity, stability, and the antibacterial activity of the spore-displayed p75 (CotG-p75) protein were also investigated. The PGH activity of the CotG-p75 against peptidoglycan extracted from B. subtilis was confirmed by the ninhydrin test. Under various harsh conditions, compared to the control groups, the PGH activities of CotG-p75 were very stable in the range of pH 3–7 and maintained at 70% at 50 °C. In addition, the antibacterial activity of CotG-p75 against Listeria monocytogenes was evaluated by a time-kill assay. After 6 h incubation in phosphate-buffered saline, CotG-p75 reduced the number of viable cells of L. monocytogenes by up to 2.0 log. Scanning electron microscopy analysis showed that the cell wall of L. monocytogenes was partially damaged by the treatment with CotG-p75. Our preliminary results show that CotG-p75 could be a good candidate for further research to develop new genetically engineered probiotics.

Terminal Ileitis due to Yersinia Infection: An Underdiagnosed Situation

Endoscopy is currently the gold standard for the diagnosis of inflammatory bowel disease (IBD). The presence of macroscopic lesions along with the microscopic detection of inflammatory infiltration in the terminal ileum often leads the gastroenterologist to the diagnosis of Crohn's disease (CD). However, some of these cases could be, in fact, an infection caused by Yersinia spp., accompanied or not with CD, which could be easily diagnosed with the identification of serum antibodies against Yersinia outer protein antigens (YOP antigens). Since Yersiniosis is considered to be an uncommon situation, food and water are not usually checked for the possibility of contamination by Yersinia. Therefore, it is reasonable to assume that the true prevalence of Yersinia infection in patients with terminal ileitis is probably underestimated. In this article, we review the most important data regarding the various aspects of Yersinia infection with special focus on its pathophysiology and diagnosis. We recommend testing for serum antibodies against YOP antigens in all patients with an endoscopic and histological image of terminal ileitis in order to identify Yersiniosis in conjunction or not with terminal ileum CD.

The Prospects for the Therapeutic Implications of Genetically Engineered Probiotics

The interest in the therapeutic use of probiotic microorganisms has been increased during the last decade although the doubts have ascended about the probiotics mainly because their beneficial effects are not fully understood, and, in many cases, their usefulness has not been validated in clinical trials. Consequently, the notion got a considerable interest in those strains having proven probiotic potential to be engineered for improvement in their beneficial features. The process of genetic engineering can also be used for probiotic strains for the reversion of antimicrobial resistance and other modifications for their safer and effective human applications. The lactic acid bacilli are predominantly opposite as they already have gained attention owing to their health-promoting benefits and their safety for human consumption; therefore, their use, especially as a delivery agent of vaccines and drugs, is gaining attention. The tailoring of probiotic strains will not only improve the data regarding the probiotic potential of these strains but also clinch the doubts concerning these probiotics. This article focuses on the approaches of bioengineered probiotics and discusses the potential prospects for their therapeutic applications including immunomodulation, cognitive health, and anticancer therapeutics.

Biotechnology of health-promoting bacteria

Over the last decade, there has been an increasing scientific and public interest in bacteria that may positively contribute to human gut health and well-being. This interest is reflected by the ever-increasing number of developed functional food products containing health-promoting bacteria and reaching the market place as well as by the growing revenue and profits of notably bacterial supplements worldwide. Traditionally, the origin of probiotic-marketed bacteria was limited to a rather small number of bacterial species that mostly belong to lactic acid bacteria and bifidobacteria. Intensifying research efforts on the human gut microbiome offered novel insights into the role of human gut microbiota in health and disease, while also providing a deep and increasingly comprehensive understanding of the bacterial communities present in this complex ecosystem and their interactions with the gut-liver-brain axis. This resulted in rational and systematic approaches to select novel health-promoting bacteria or to engineer existing bacteria with enhanced probiotic properties. In parallel, the field of gut microbiomics developed into a fertile framework for the identification, isolation and characterization of a phylogenetically diverse array of health-promoting bacterial species, also called next-generation therapeutic bacteria. The present review will address these developments with specific attention for the selection and improvement of a selected number of health-promoting bacterial species and strains that are extensively studied or hold promise for future food or pharma product development.

Probiotic engineering: towards development of robust probiotic strains with enhanced functional properties and for targeted control of enteric pathogens

There is a growing concern about the increase in human morbidity and mortality caused by foodborne pathogens. Antibiotics were and still are used as the first line of defense against these pathogens, but an increase in the development of bacterial antibiotic resistance has led to a need for alternative effective interventions. Probiotics are used as dietary supplements to promote gut health and for prevention or alleviation of enteric infections. They are currently used as generics, thus making them non-specific for different pathogens. A good understanding of the infection cycle of the foodborne pathogens as well as the virulence factors involved in causing an infection can offer an alternative treatment with specificity. This specificity is attained through the bioengineering of probiotics, a process by which the specific gene of a pathogen is incorporated into the probiotic. Such a process will subsequently result in the inhibition of the pathogen and hence its infection. Recombinant probiotics offer an alternative novel therapeutic approach in the treatment of foodborne infections. This review article focuses on various strategies of bioengineered probiotics, their successes, failures and potential future prospects for their applications.

Bioengineered probiotics, a strategic approach to control enteric infections

Enteric infections account for high morbidity and mortality and are considered to be the fifth leading cause of death at all ages worldwide. Seventy percent of all enteric infections are foodborne. Thus significant efforts have been directed toward the detection, control and prevention of foodborne diseases. Many antimicrobials including antibiotics have been used for their control and prevention. However, probiotics offer a potential alternative intervention strategy owing to their general health beneficial properties and inhibitory effects against foodborne pathogens. Often, antimicrobial probiotic action is non-specific and non-discriminatory or may be ineffective. In such cases, bioengineered probiotics expressing foreign gene products to achieve specific function is highly desirable. In this review we summarize the strategic development of recombinant bioengineered probiotics to control enteric infections, and to examine how scientific advancements in the human microbiome and their immunomodulatory effects help develop such novel and safe bioengineered probiotics.

The joint-gut axis in inflammatory bowel diseases

Inflammatory bowel diseases, Crohn's disease and ulcerative colitis, are associated with a variety of extraintestinal manifestations. The most common extraintestinal manifestation, articular involvement, occurs in 16% to 33% of inflammatory bowel disease patients. These arthropathies may increase morbidity, resulting in a worse quality of life compared with inflammatory bowel disease patients without arthropathies. Thus, arthropathies in inflammatory bowel diseases represent a major medical problem in these patients. Arthritis associated with inflammatory bowel diseases is one of the diseases captured under the umbrella of spondyloarthritis. Spondyloarthritis is a group of inflammatory diseases with overlapping features and is linked to Human Leukocyte Antigen-B27. Arthropathy in inflammatory bowel diseases is clinically divided into peripheral and axial involvement. Peripheral arthritis often flares with relapses of bowel disease resulting in a different treatment approach than axial arthritis in which the course is independent of inflammatory bowel disease activity. Definitions, prevalence, pathophysiology and treatment of the arthropathies commonly seen in inflammatory bowel diseases such as peripheral arthritis, dactylitis, enthesitis, arthralgia, sacroiliitis, inflammatory back pain and ankylosing spondylitis are summarized.

Rheumatic manifestations of inflammatory bowel disease

This article reviews the literature concerning rheumatic manifestations of inflammatory bowel disease (IBD), including common immune-mediated pathways, frequency, clinical course and therapy. Musculoskeletal complications are frequent and well-recognized manifestations in IBD, and affect up to 33% of patients with IBD. The strong link between the bowel and the osteo-articular system is suggested by many clinical and experimental observations, notably in HLA-B27 transgenic rats. The autoimmune pathogenic mechanisms shared by IBD and spondyloarthropathies include genetic susceptibility to abnormal antigen presentation, aberrant recognition of self, the presence of autoantibodies against specific antigens shared by the colon and other extra-colonic tissues, and increased intestinal permeability. The response against microorganisms may have an important role through molecular mimicry and other mechanisms. Rheumatic manifestations of IBD have been divided into peripheral arthritis, and axial involvement, including sacroiliitis, with or without spondylitis, similar to idiopathic ankylosing spondylitis. Other periarticular features can occur, including enthesopathy, tendonitis, clubbing, periostitis, and granulomatous lesions of joints and bones. Osteoporosis and osteomalacia secondary to IBD and iatrogenic complications can also occur. The management of the rheumatic manifestations of IBD consists of physical therapy in combination with local injection of corticosteroids and nonsteroidal anti-inflammatory drugs; caution is in order however, because of their possible harmful effects on intestinal integrity, permeability, and even on gut inflammation. Sulfasalazine, methotrexate, azathioprine, cyclosporine and leflunomide should be used for selected indications. In some cases, tumor necrosis factor-α blocking agents should be considered as first-line therapy.