Characterization and Preliminary Safety Evaluation of Akkermansia muciniphila PROBIO

In addition to providing certain health advantages to the host, a bacterial strain must possess a clearly defined safety profile to be regarded as a probiotic. In this study, we present a thorough and methodical assessment of the safety of a novel strain of bacteria, Akkermansia muciniphila PROBIO, which was isolated from human feces. Firstly, we examined the strain's overall features, such as its gastrointestinal tolerance and its physiological and biochemical traits. Next, we verified its genotoxic properties through bacterial reverse mutation and in vitro mammalian cell micronucleus assays. The drug sensitivity of A. muciniphila PROBIO was subsequently examined through an analysis of its antibiotic resistance genes. Additionally, the toxicological impact was verified through acute and sub-chronic toxicity studies. A genome-based safety assessment was conducted to gain further insights into gene function, including potential virulence factors and pathogenic properties. Finally, we assessed whether moxifloxacin resistance in A. muciniphila PROBIO is transferred using in vitro conjugation experiments. A. muciniphila PROBIO exhibited superior gastrointestinal tolerance, with no observed hematological or histopathological abnormalities. Moreover, the outcomes pertaining to mutagenic, clastogenic, or toxic impacts were found to be negative, even at exceedingly high dosages. Moreover, no adverse effects associated with the test substance were observed during the examination of acute and sub-chronic toxicity. Consequently, it was plausible to estimate the no-observed-adverse-effect level (NOAEL) to be 6.4 × 1011 viable bacteria for an average individual weighing 70 kg. Additionally, only three potential drug resistance genes and one virulence factor gene were annotated. A. muciniphila PROBIO is naturally resistant to moxifloxacin, and resistance does not transfer. Collectively, the data presented herein substantiate the presumed safety of A. muciniphila PROBIO for its application in food.

[Analysis of clinical phenotype and gene mutation characteristics of MYH9-related disorder]

Objective: To investigate the clinical phenotype and gene mutation characteristics of MYH9-related disorder (MYH9-RD). Methods: The clinical data of 66 patients with MYH9-RD in the First Affiliated Hospital of Soochow University from January 2010 to December 2022 were retrospectively analyzed. According to the bleeding symptom, the patients were divided into bleeding and non-bleeding group, and according to the mutation sites, the patients were divided into non-muscle myosin heavy chain ⅡA head region (MD) and tail region (TD) mutation group. Statistical analysis was made to explore the clinical features in different groups such as platelet counts, bleeding, renal function, cataracts and hearing as well as MYH9 gene mutations. Results: A total of 66 MYH9-RD patients were included, with 28 males and 38 females, diagnosis age of 1-63(26±2) years. And 41% (27/66) of the patients had no family history. All patients presented with macrothrombocytopenia and normal platelet aggregation(10/10), 92% (54/59) of the patients had visible blue inclusion bodies in neutrophils, 30% (20/66) had bleeding symptoms, 45% (22/49) had proteinuria or glomerulonephropathy, 20% (8/41) had bilateral hearing impairment, and 10% (4/42) had bilateral cataracts. 18 mutation sites were identified in total, including 15 missense, 1 splicing and 2 termination mutations. Among them, p.Asp1424Asn, p.Arg1933* and p.Arg702His/Cys mutations were identified in 56% (29/52) of the patients, and p.Ser96Leu, Arg1165Cys and p.Glu1841Lys mutations were recurrent mutations, while p.Ala44Thr, p.Asp1447Ala and c.3838-2A>G mutations were novel mutations. The average platelet count of patients in bleeding group was (19±3)×109/L, which was significantly less than (36±3)×109/L in non-bleeding group (P<0.001). Compared with TD mutation group, patients of MD mutation group were presented with lower platelet count and higher risk of bleeding, as well as more severe clinical presentations including renal and hearing impairment and cataracts (all P<0.05). Conclusion: Mutations of p.Asp1424Asn, p.Arg1933* and p.Arg702His/Cys in MYH9 gene are hotspot mutations for MYH9-RD patients, Compared with TD mutation group, patients of MD mutation group were presented with lower platelet count and higher risk of bleeding, as well as more severe clinical presentations including renal and hearing impairment and cataracts.