Fecal Microbial Transplantation for Diseases Beyond Recurrent Clostridium Difficile Infection

The Oral Microbiome and Cancer

There is mounting evidence that members of the human microbiome are highly associated with a wide variety of cancer types. Among oral cancers, oral squamous cell carcinoma (OSCC) is the most prevalent and most commonly studied, and it is the most common malignancy of the head and neck worldwide. However, there is a void regarding the role that the oral microbiome may play in OSCC. Previous studies have not consistently found a characteristic oral microbiome composition associated with OSCC. Although a direct causality has not been proven, individual members of the oral microbiome are capable of promoting various tumorigenic functions related to cancer development. Two prominent oral pathogens, Porphyromonas gingivalis, and Fusobacterium nucleatum can promote tumor progression in mice. P. gingivalis infection has been associated with oro-digestive cancer, increased oral cancer invasion, and proliferation of oral cancer stem cells. The microbiome can influence the evolution of the disease by directly interacting with the human body and significantly altering the response and toxicity to various forms of cancer therapy. Recent studies have shown an association of certain phylogenetic groups with the immunotherapy treatment outcomes of certain tumors. On the other side of the coin, recently it has been a resurgence in interest on the potential use of bacteria to cure cancer. These kinds of treatments were used in the late nineteenth and early twentieth centuries as the first line of defense against cancer in some hospitals but later displaced by other types of treatments such as radiotherapy. Currently, organisms such as Salmonella typhimurium and Clostridium spp. have been used for targeted strategies as potential vectors to treat cancer. In this review, we briefly summarize our current knowledge of the role of the oral microbiome, focusing on its bacterial fraction, in cancer in general and in OSCC more precisely, and a brief description of the potential use of bacteria to target tumors.

Fecal microbiota transplantation therapy for Parkinson's disease: A preliminary study

Imbalances in the gut microbiota mediate the progression of neurodegenerative diseases such as Parkinson's disease (PD). Fecal microbiota transplantation (FMT) is currently being explored as a potential therapy for PD. The objective of this study was to assess the efficacy and safety of FMT on PD. Fifteen PD patients were included, 10 of them received FMT via colonoscopy (colonic FMT group) and 5 received FMT via nasal-jejunal tube (nasointestinal FMT group). The score of PSQI, HAMD, HAMA, PDQ-39, NMSQ and UPDRS-III significantly decreased after FMT treatment (all P < .05). Colonic FMT group showed significant improvement and longer maintenance of efficacy compared with nasointestinal FMT (P = .002). Two patients achieved self-satisfying outcomes that last for more than 24 months. However, nasointestinal FMT group had no significant therapeutic effect, although UPDRS-III score slightly reduced. There were no patients were satisfied with nasointestinal FMT for more than 3 months. Among 15 PD patients, there were 5 cases had adverse events (AEs), including diarrhea (2 cases), abdominal pain (2 cases) and flatulence (1 case). These AEs were mild and self-limiting. We conclude that FMT can relieve the motor and non-motor symptoms with acceptable safety in PD. Compared with nasointestinal FMT, colonic FMT seems better and preferable.

Immunotherapy in Colorectal Cancer: Potential of Fecal Transplant and Microbiota-augmented Clinical Trials

PURPOSE OF REVIEW

This review summarizes the role of the microbiome in colorectal cancer (CRC) in the setting of immunotherapy and emphasizes the potential of microbiota-influencing strategies with a focus on the use of fecal microbiota transplant (FMT).

RECENT FINDINGS

Observations from preclinical and clinical studies suggest that the human gut microbiome is implicated in the CRC carcinogenesis and is integral in determining the clinical response and toxicity to immunotherapy. Among the therapeutic methods devised to exploit the microbiome, FMT is the most direct method and is backed by the highest level of evidence of efficacy in nonneoplastic disease settings. Furthermore, a favorable microbiome has the potential to overcome immunotherapy resistance and ameliorate immune-related adverse events (irAEs). To this end, clinical trials are underway to evaluate the potential of FMT and microbiota-augmented methods in the setting of immunotherapy in CRC.

SUMMARY

Evidence from animal studies, retrospective studies, and smaller-scale prospective human studies have led to initiation of a number of microbiota-augmented clinical trials in CRC. Given the intimate relationship between the gut microbiota and the immune system as well as antitumor immune responses, potentiating immunotherapy and managing its toxicity are major areas of research in microbiota-augmented therapies in cancer. Therefore, evaluation of the patient microbiome as a routine part of clinical outcome analysis is warranted in future clinical trials.

Bibliometric analysis of subject trends and knowledge structures of gut microbiota

BACKGROUND

Gut microbiota is an emerging field of research, with related research having breakthrough development in the past 15 years. Bibliometric analysis can be applied to analyze the evolutionary trends and emerging hotspots in this field.

AIM

To study the subject trends and knowledge structures of gut microbiota related research fields from 2004 to 2018.

METHODS

The literature data on gut microbiota were identified and downloaded from the PubMed database. Through biclustering analysis, strategic diagrams, and social network analysis diagrams, the main trend and knowledge structure of research fields concerning gut microbiota were analyzed to obtain and compare the research hotspots in each period.

RESULTS

According to the strategic coordinates and social relationship network map, Clostridium Infections/microbiology, Clostridium Infections/therapy, RNA, Ribosomal, 16S/genetics, Microbiota/genetics, Microbiota/immunology, Dysbiosis/immunology, Infla-mmation/immunology, Fecal Microbiota Transplantation/methods, Fecal Microbiota Transplantation can be used as an emerging research hotspot in the past 5 years (2014-2018).

CONCLUSION

Some subjects were not yet fully studied according to the strategic coordinates; and the emerging hotspots in the social network map can be considered as directions of future research.

Fecal transplants as a microbiome-based therapeutic

Impaired microbiome diversity and composition can develop into a potent etiological agent of disease and increase susceptibility to infection. Given this, interventions targeting the microbiome have developed rapidly, with healthy donor feces being a de facto source of beneficial communities employed to rebalance patients' microbiomes. Recent evidence has demonstrated that bacterial and viral richness, short chain fatty acid production, bile acid conversion as well as presence of bacterial and fungal pathobionts are associated with therapy efficacy; however, little is known of the influence of host factors such as genetics, medications, and diet. Here, current knowledge on factors associated with fecal transplant efficacy, as well as efforts to transition to other forms of therapy are reviewed.

Intestinal microbiota: a new force in cancer immunotherapy

Cancer displays high levels of heterogeneity and mutation potential, and curing cancer remains a challenge that clinicians and researchers are eager to overcome. In recent years, the emergence of cancer immunotherapy has brought hope to many patients with cancer. Cancer immunotherapy reactivates the immune function of immune cells by blocking immune checkpoints, thereby restoring the anti-tumor activity of immune cells. However, immune-related adverse events are a common complication of checkpoint blockade, which might be caused by the physiological role of checkpoint pathways in regulating adaptive immunity and preventing autoimmunity. In this context, the intestinal microbiota has shown great potential in the immunotherapy of cancer. The intestinal microbiota not only regulates the immune function of the body, but also optimizes the therapeutic effect of immune checkpoint inhibitors, thus reducing the occurrence of complications. Therefore, manipulating the intestinal microbiota is expected to enhance the effectiveness of immune checkpoint inhibitors and reduce adverse reactions, which will lead to new breakthroughs in immunotherapy and cancer management. Video abstract.

Harnessing the microbiota for therapeutic purposes

The myriads of microorganisms colonizing the human host (microbiome) affect virtually every aspect of its physiology in health and disease. The past decade witnessed unprecedented advances in microbiome research. The field rapidly transitioned from descriptive studies to deep mechanistic insights into host-microbiome interactions. This offers the opportunity for microbiome-targeted therapeutic manipulation. Currently, several strategies of microbiome-targeted interventions are intensively explored. Best evidence from human randomized clinical trials is available for fecal microbiota transplantation (FMT). However, patient eligibility as well as long-term efficacy and safety are not sufficiently defined. Therefore, there is currently no officially approved indication for FMT. Probiotics (live microorganisms) have long been discussed as a means to aid human health but have yielded varying results. Emerging techniques utilizing microbiota-targeted diets, small microbial molecules, recombinant bacteriophages, and precise control of strain abundance recently yielded promising results but require further investigation. The rapid technological progress of "omics" tools spurs advances in personalized medicine. Understanding and integration of interindividual microbiome variability holds potential to promote personalized preventive and therapeutic approaches. Emerging evidence points towards the microbiome as an important player having an impact on transplantation outcomes. Microbiome-targeted interventions have potential to aid against the many challenges faced by transplant recipients.

The gut microbiome in psoriasis and psoriatic arthritis

This review summarizes existing research on the gut microbiome composition and function in psoriasis and psoriatic arthritis, exploring potential roles in disease pathogenesis, progression, and management. A strong relationship between skin, joint, and gastrointestinal inflammation exists, as demonstrated by an increased prevalence of psoriasis, psoriatic arthritis, and inflammatory bowel disease co-occurring together; however, the link between them has not been fully elucidated. Studies analyzing the gut microbiome in psoriasis and psoriatic arthritis reveal a unique pattern of dysbiosis. With regard to the gut microbiome's role in psoriasis and psoriatic arthritis pathogenesis, we discuss several theories including intestinal permeability, altered immune homeostasis, and imbalance of short- and medium-chain fatty acid-producing bacteria. We also discuss how the gut microbiome affects patient risk of psoriatic arthritis and other serious comorbidities, and how fecal microbes could be used clinically as therapeutic targets or markers of disease.

New Therapeutic Targets in Autoimmune Cholangiopathies

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are autoimmune cholangiopathies characterized by limited treatment options. A more accurate understanding of the several pathways involved in these diseases has fostered the development of novel and promising targeted drugs. For PBC, the characterization of the role of farnesoid X receptor (FXR) and perixosome-proliferator activated receptor (PPAR) has paved the way to several clinical trials including different molecules with choleretic and antinflammatory action. Conversely, different pathogenetic models have been proposed in PSC such as the “leaky gut” hypothesis, a dysbiotic microbiota or a defect in mechanisms protecting against bile acid toxicity. Along these theories, new treatment approaches have been developed, ranging from drugs interfering with trafficking of lymphocytes from the gut to the liver, fecal microbiota transplantation or new biliary acids with possible immunomodulatory potential. Finally, for both diseases, antifibrotic agents are under investigation. In this review, we will illustrate current understanding of molecular mechanisms in PBC and PSC, focusing on actionable biological pathways for which novel treatments are being developed.

Fecal microbiota transplantation ameliorates active ulcerative colitis

Ulcerative colitis (UC) is a complex chronic pathological condition of the gut in which microbiota targeted treatment, such as fecal microbiota transplantation (FMT), has shown an encouraging effect. The aim of the present study was to investigate the efficacy and safety of FMT in patients with mild or moderate UC. A single-center, open-label study was designed, including 47 patients with mild or moderate active UC who received three treatments of fresh FMT via colonic transendoscopic enteral tubing within 1 week. The inflammatory bowel disease questionnaire, partial Mayo scores, colonoscopy, erythrocyte sedimentation rate, C-reactive protein level and procalcitoin values were used to assess the efficacy of FMT and alteration in gut microbiota was detected by 16S ribosomal RNA-sequencing. Before FMT, microbiota Faecalibacterium prausnitzii (F. prausnitzii) levels were significantly decreased in patients with UC compared with healthy donors (P<0.01). At 4 weeks post-FMT, F. prausnitzii levels were significantly increased (P<0.05), and the Mayo score was significantly decreased (1.91±1.07 at baseline vs. 4.02±1.47 at week 4; P<0.001) in patients with UC compared with healthy donors. Steroid-free clinical responses were reported in 37 patients (84.1%), and steroid-free clinical remission was achieved in 31 patients (70.5%) at week 4 post-FMT, however, steroid-free remission was not achieved in any patient. No adverse events were reported in 41 (93.2%) patients after FMT or during the 12-week follow-up. Shannon's diversity index and Chao1 estimator were also improved in patients with UC receiving FMT. In conclusion, the results of the present study suggested that FMT resulted in clinical remission in patients with mild to moderate UC, and that the remission may be associated with significant alterations to the intestinal microbiota of patients with UC. Furthermore, F. prausnitzii may serve as a diagnostic and therapeutic biomarker for the use of FMT in UC.

The Oral Microbiome and Cancer

There is mounting evidence that members of the human microbiome are highly associated with a wide variety of cancer types. Among oral cancers, oral squamous cell carcinoma (OSCC) is the most prevalent and most commonly studied, and it is the most common malignancy of the head and neck worldwide. However, there is a void regarding the role that the oral microbiome may play in OSCC. Previous studies have not consistently found a characteristic oral microbiome composition associated with OSCC. Although a direct causality has not been proven, individual members of the oral microbiome are capable of promoting various tumorigenic functions related to cancer development. Two prominent oral pathogens, Porphyromonas gingivalis, and Fusobacterium nucleatum can promote tumor progression in mice. P. gingivalis infection has been associated with oro-digestive cancer, increased oral cancer invasion, and proliferation of oral cancer stem cells. The microbiome can influence the evolution of the disease by directly interacting with the human body and significantly altering the response and toxicity to various forms of cancer therapy. Recent studies have shown an association of certain phylogenetic groups with the immunotherapy treatment outcomes of certain tumors. On the other side of the coin, recently it has been a resurgence in interest on the potential use of bacteria to cure cancer. These kinds of treatments were used in the late nineteenth and early twentieth centuries as the first line of defense against cancer in some hospitals but later displaced by other types of treatments such as radiotherapy. Currently, organisms such as Salmonella typhimurium and Clostridium spp. have been used for targeted strategies as potential vectors to treat cancer. In this review, we briefly summarize our current knowledge of the role of the oral microbiome, focusing on its bacterial fraction, in cancer in general and in OSCC more precisely, and a brief description of the potential use of bacteria to target tumors.

Emerging therapies in primary sclerosing cholangitis: pathophysiological basis and clinical opportunities

Primary sclerosing cholangitis (PSC) is a progressive liver disease, histologically characterized by inflammation and fibrosis of the bile ducts, and clinically leading to multi-focal biliary strictures and with time cirrhosis and liver failure. Patients bear a significant risk of cholangiocarcinoma and colorectal cancer, and frequently have concomitant inflammatory bowel disease and autoimmune disease manifestations. To date, no medical therapy has proven significant impact on clinical outcomes and most patients ultimately need liver transplantation. Several treatment strategies have failed in the past and whilst prescription of ursodeoxycholic acid (UDCA) prevails, controversy regarding benefits remains. Lack of statistical power, slow and variable disease progression, lack of surrogate biomarkers for disease severity and other challenges in trial design serve as critical obstacles in the development of effective therapy. Advances in our understanding of PSC pathogenesis and biliary physiology over recent years has however led to a surge of clinical trials targeting various mechanistic compartments and currently raising hopes for imminent changes in patient management. Here, in light of pathophysiology, we outline and critically evaluate emerging treatment strategies in PSC, as tested in recent or ongoing phase II and III trials, stratified per a triad of targets of nuclear and membrane receptors regulating bile acid metabolism, immune modulators, and effects on the gut microbiome. Furthermore, we revisit the UDCA trials of the past and critically discuss relevant aspects of clinical trial design, including how the choice of endpoints, alkaline phosphatase in particular, may affect the future path to novel, effective PSC therapeutics.

Gut microbiota in colorectal cancer: mechanisms of action and clinical applications

Colorectal cancer (CRC) accounts for about 10% of all new cancer cases globally. Located at close proximity to the colorectal epithelium, the gut microbiota comprises a large population of microorganisms that interact with host cells to regulate many physiological processes, such as energy harvest, metabolism and immune response. Sequencing studies have revealed microbial compositional and ecological changes in patients with CRC, whereas functional studies in animal models have pinpointed the roles of several bacteria in colorectal carcinogenesis, including Fusobacterium nucleatum and certain strains of Escherichia coli and Bacteroides fragilis. These findings give new opportunities to take advantage of our knowledge on the gut microbiota for clinical applications, such as gut microbiota analysis as screening, prognostic or predictive biomarkers, or modulating microorganisms to prevent cancer, augment therapies and reduce adverse effects of treatment. This Review aims to provide an overview and discussion of the gut microbiota in colorectal neoplasia, including relevant mechanisms in microbiota-related carcinogenesis, the potential of utilizing the microbiota as CRC biomarkers, and the prospect for modulating the microbiota for CRC prevention or treatment. These scientific findings will pave the way to clinically translate the use of gut microbiota for CRC in the near future.