The environmental and socioeconomic effects of tuberculosis patients in the southwest of China: a population-based study.

OBJECTIVE: The objective of this study was to assess the incidence of tuberculosis (TB) and find the risk factors of TB patients with a high burden of TB in socioeconomic level, the high level of TB incidence and the great changes of economic and social factors, explore the possible factors, construct scientific and robust prediction model, and analyse whether the task of stopping TB can be accomplished by the expected global deadline. STUDY DESIGN: This was an ecological study. METHODS: Descriptive analysis, spatial and space-time scan, correlation analysis, and regression analysis were carried out, based on cases of TB in Sichuan Province and ecological data from 2006 to 2017, to explore the characters of TB and ecological factors, using the transfer function-noise model to forecast the trend of TB until 2035. RESULTS: Factors affecting the incidence of TB, increasing per capita green area, reporting status of TB among Tibetans and Yi minorities, comprehensive treatment management, total cost of TB per capita for urban residents, proportion of males with high school education, 20 to 20 h of 24-h accumulated precipitation, reducing HIV at the same time as AIDS deaths, the increase in the proportion of males in junior high school education, and the increase in the number of registered TB cases can reduce the incidence of TB. CONCLUSIONS: There was concentration mainly on enhanced control of the environment and society measures, helpful in guiding government planning to control TB. Reinforcement is required to reduce the TB of population aged 15-24 and aged 25-64 in socioeconomic level by 2035.

[Clinical features of patients with metastatic pheochromocytoma/paraganglioma].

Objective: To analyze the clinical features of patients with metastatic pheochromocytoma/paraganglioma (PPGL). Methods: A follow-up study. The clinical data of 250 patients with metastatic PPGL treated at Peking Union Medical College Hospital from January 2018 to August 2023 were retrospectively analyzed, including 124 males and 126 females. The clinical features and treatment status of patients with metastatic PPGL were summarized and analyzed. Kaplan-Meier survival curve was used to evaluate patients' prognosis. Results: The age of onset, age of diagnosis, and age of tumor metastasis in patients with metastatic PPGL were (33.1±14.2) years, (35.4±15.2) years, and (40.7±15.3) years, respectively. Metastasis occurred in 26.4%(66/250) of patients at the time of initial diagnosis. Among patients without metastases at the time of initial diagnosis, the time from primary tumor resection to metastasis[M(Q1, Q3)] was 5.0 (3.0, 9.0) years, among which 20.1%(37/184) of patients had metastases more than 10 years after surgery. Most patients showed increased 24-hour urinary norepinephrine and plasma normetanephrine, accounting for 78.2%(176/225) and 78.7%(85/108), respectively. 42.3%(69/163) of patients had increased neuron specific enolase (NSE)levels. Germline mutations were screened in 201 patients, of which 55.2%(111/201) had germline pathogenic mutations. In patients with gene mutations, 76.5%(85/111) had SDHB mutations. 52.0%(130/250) of metastatic PPGL patients had primary sites outside the adrenal gland, with the Ki-67 index of 5% (3%, 8%). There were 85.6%(214/250) patients had multisystem metastasis, with bone metastasis being the most common site of metastasis, accounting for 60.8%(152/250). In terms of treatment, 32.8%(75/229) of patients underwent two treatment regimens and 8.7%(20/229) of patients underwent three treatment regimens. Most patients had a good prognosis, with a 5-year and 10-year survival rate of 88.0% and 84.0%, respectively. However, some patients had rapid disease progression, and as of August 2023, 30 patients died, and the time from diagnosis to death in deceased patients was 2.0 (1.0, 4.0) years. Conclusions: Patients with metastatic PPGL have a high rate of germline mutations, especially those with SDHB mutations. The metastatic PPGL is usually multisystem metastasis with the characteristics of mostly paraganglioma, large lesion diameter and high Ki-67 index.

Association of radiotherapy for prostate cancer and second primary colorectal cancer: a US population-based analysis.

BACKGROUND: Radiotherapy (RT) is a common treatment for prostate cancer, yet the risk of second primary colorectal cancer (SPCRC) in patients with prostate cancer undergoing RT has not been adequately studied. METHODS: This study employed a population-based cohort design using the US Surveillance, Epidemiology, and End Results (SEER) database to identify individuals diagnosed between January 1975 and December 2015. The cumulative incidence of SPCRC was estimated using Fine-Gray competing risk regression. Poisson regression analysis was used to estimate the risk associated with RT. Survival outcomes of patients with SPCRC were evaluated using the Kaplan-Meier method. RESULTS: A total of 287,607 patients diagnosed with prostate cancer were identified. The cumulative incidences were higher in patients who did not receive RT (2.00%) compared to those who underwent RT (2.47%) after 25 years. After adjustment for multiple variables, RT was associated with an increased risk of developing combined SPCRC (adjusted HR 1.590). Additionally, the overall survival was significantly lower in patients who developed colorectal cancer after receiving RT as compared to those who did not receive RT. CONCLUSION: These findings underscore the need for diligent long-term monitoring and effective management strategies to detect SPCRC in patients treated with RT for prostate cancer.

Probing

The isomer depletion of ^{93m}Mo was recently reported [Chiara et al., Nature (London) 554, 216 (2018)NATUAS0028-083610.1038/nature25483] as the first direct observation of nuclear excitation by electron capture (NEEC). However, the measured excitation probability of 1.0(3)% is far beyond the theoretical expectation. In order to understand the inconsistency between theory and experiment, we produce the ^{93m}Mo nuclei using the ^{12}C(^{86}Kr,5n) reaction at a beam energy of 559 MeV and transport the reaction residues to a detection station far away from the target area employing a secondary beam line. The isomer depletion is expected to occur during the slowdown process of the ions in the stopping material. In such a low γ-ray background environment, the signature of isomer depletion is not observed, and an upper limit of 2×10^{-5} is estimated for the excitation probability. This is consistent with the theoretical expectation. Our findings shed doubt on the previously reported NEEC phenomenon and highlight the necessity and feasibility of further experimental investigations for reexamining the isomer depletion under low γ-ray background.

[Nonalcoholic fatty liver disease and liver transplantation].

The rising prevalence of nonalcoholic fatty liver disease (NAFLD) is now the second largest indication for liver transplantation in Western countries, but viral hepatitis B and end-stage alcohol-related liver disease are still the main indications in China. With the improvement of people's living standards, the prevalence of metabolic syndrome, and the number of NAFLD patients has also gradually increased. At the same time, with the hepatitis B vaccination popularization and the nucleos(t)ide analogues and other drugs uses, it is predicted that NAFLD-related end-stage liver disease may become one of the main indications for liver transplantation in our country in the future. This article reviews the research progress of NAFLD and liver transplantation.

[Complexity of Detecting CRISPR/Cas9-Mediated Homologous Recombination in Zebrafish].

Homology-directed (HD) genome modification offers an opportunity to precisely modify the genome. Despite reported successful cases, for many loci, precise genome editing remains challenging and inefficient in vivo. Here we report an effort to precisely knock-in a GFP reporter into gad locus mediated by CRISPR/Cas9 system in the zebrafish Danio rerio. PCR artifact was detected in testing for homologous recombination (HR), but was mitigated by optimizing PCR condition and decreasing the injected targeting plasmid concentration. Under this optimized condition, time course analysis revealed a decline of the HR-positive embryos at embryogenesis progressed. GFP signals also diminished at later developmental stages. The GFP signals were consistent with PCR detection, both of which suggested the loss of targeted insertion events at later stages. Such loss of insertion might be one underlying reason for the inability to obtain germ-line transgenic lines with GFP knocked into the gad locus. Our results suggest that the low HR efficiency associated with CRISPR-mediated knock-in is in part due to loss of insertion after targeted integration into the gad locus.

[The study on the detection method for mercury in blood with direct mercury analyzer].

Objective: To establish a method for determining mercury in blood with direct mercury analyzer. Methods: After the whole blood sample was extracted by solvent and removed by nitric acid, it was then measured by direct mercury analyzer. Results: After optimizing the conditions of the instrument, the linear range was 0.3-60.0 µg/L and the curve correlation coefficient was higher than 0.999. The lower limit of quantitations was 0.3 µg/L and the minimum quantitative concentration was 3.0 µg/L. The recovery and relative standard deviations (RSD) was 95.2%-97.6% and 1.4%-3.3%. Conclusion: The method is stable, reliable, easy to operate and has high sensitive. It can be used to determine mercury in blood.

New Isotope

A new short-lived neutron-deficient isotope ^{220}Np was synthesized in the fusion-evaporation reaction ^{185}Re(^{40}Ar,5n)^{220}Np at the gas-filled recoil separator SHANS. Based on the measurement of the correlated α-decay chains, the decay properties of ^{220}Np with E_{α}=10040(18) keV and T_{1/2}=25_{-7}^{+14} µs were determined, which are in good agreement with theoretical predictions. From the new experimental results coupled with the recently reported α-decay data of ^{219,223}Np, the α-decay systematics for Np isotopes around N=126 was established, which allows us for the first time to test the robustness of the N=126 shell closure in Z=93 Np isotopes. The results also indicate that, in the region of nuclei with Z≥83, the proton drip line has been reached for all odd-Z isotopes up to Np.

[Hospitalization rates for influenza-associated severe acute respiratory illness in children younger than five years old in Suzhou of China, 2016-2018].

We analyzed the influenza surveillance data of Children's Hospital of Suzhou University from 2016 to 2018 and estimated the hospitalization burden of children under 5 years old due to influenza infection in Suzhou. The results showed that the influenza virus positive rate of 1 451 severe acute respiratory infection (SARI) cases in Children's Hospital of Suzhou University was 13.6% (95%CI: 11.8%-15.3%; 197 cases), among which the influenza pandemic intensity in 2017-2018 was relatively high, and A/H1N1 was the main pandemic virus. It was estimated that the hospitalization rate of influenza-related SARI in children under 5 years old in Suzhou was 6.9‰ (95%CI: 6.6‰-7.2‰), among which the hospitalization rate of children aged<6 months was higher, up to 11.4‰ (95%CI: 9.9‰-12.8‰).

Transcriptional regulation of the vitellogenin gene through a fecundity-related single nucleotide polymorphism within a GATA-1 binding motif in the brown planthopper, Nilaparvata lugens.

Identifying the Single Nucleotide Polymorphisms (SNPs) with functions in insect fecundity promises to provide novel insight into genetic mechanisms of adaptation and to aid in effective control of insect populations. We previously identified several SNPs within the vitellogenin (Vg) promoter region between a high-fecundity population (HFP) and a low-fecundity population (LFP) of the brown planthopper, Nilaparvata lugens Stål (Hemiptera: Delphacidae). Here, we found that an A-to-T (HFP allele to LFP allele) transversion at nucleotide -953 upstream of Vg in a Nilaparvata lugens GATA-1 (NlGATA-1) binding motif is associated with the level of Vg transcription. We also characterized NlGATA-1, containing a double CX2 CX17 CX2 C zinc finger, which has been implicated in the activation of Vg gene expression. Knockdown of the NlGATA-1 gene results in a reduced basal level of expression of the Vg gene and fewer offspring of N. lugens in vivo, whereas overexpression of NlGATA-1 in cells increased Vg promoter activity. Moreover, upon cotransfection with NlGATA-1 expression vector, the luciferase activities of Vg reporter vectors with the A allele were significantly higher than those with the T allele. These findings support a mechanism in which a SNP within the promoter of Vg is associated with the level of Vg transcription by altering the binding activity of NlGATA-1 and subsequently affecting fecundity in N. lugens.

Intra- and inter-specific variation in alarm pheromone produced by Solenopsis fire ants.

Some fire ants of the genus Solenopsis have become invasive species in the southern United States displacing native species by competition. Although the displacement pattern seems clear, the mechanisms underlying competitive advantage remain unclear. The ability of ant workers to produce relatively larger amount of alarm pheromone may correspond to relative greater fitness among sympatric fire ant species. Here we report on quantitative intra-specific (i.e. inter-caste) and inter-specific differences of alarm pheromone component, 2-ethyl-3,6-dimethylpyrazine (2E36DMP), for several fire ant species. The alarm pheromone component was extracted by soaking ants in hexane for 48 h and subsequently quantified by gas chromatography-mass spectrometry at single ion monitoring mode. Solenopsis invicta workers had more 2E36DMP than male or female alates by relative weight; individual workers, however, contained significantly less pyrazine. We thus believe that alarm pheromones may serve additional roles in alates. Workers of Solenopsis richteri, S. invicta, and hybrid (S. richteri × S. invicta) had significantly more 2E36DMP than a native fire ant species, Solenopsis geminata. The hybrid fire ant had significantly less 2E36DMP than the two parent species, S. richteri and S. invicta. It seems likely that higher alarm pheromone content may have favored invasion success of exotic fire ants over native species. We discuss the potential role of inter-specific variation in pyrazine content for the relationship between the observed shifts in the spatial distributions of the three exotic fire ant species in southern United States and the displacement of native fire ant species.

[Performance of matrix assisted laser desorption ionization time of flight biotyper system in clinical bacteria identification].

Objective: To evaluate the performance of MALDI Biotyper system in identification of clinically isolated pathogens so as to provide a new rapid identification method. Methods: Total 21 270 pathogens strains, isolated from the First Affiliated Hospital of Fujian Medical Universityduring Nov. 2015 to Dec. 2016, were identified by VITEK-Ⅱ, API and MALDI Biotyper system, respectively.The isolated strains were confirmed by DNA sequencing. Results: The identification of common bacteria with MALDI Biotyper and phenotypic system is highly consistent (>95% and >90%). Among 43 strains of anaerobic bacteria, MALDI Biotyper could identify 90.7% bacteria to species level and 97.7% bacteria to genus level with the statistical significance(χ(2)=6.76, P<0.01), while phenotypic system only identified 65.1% bacteria to species and 69.8% bacteria to genus. Also, no statistical significance was shown for Trichosporon and Candida(P>0.05). MALDI Biotyper could identify 76% filamentous fungi and all of Actinomycetes, Nocardia, Mycobacterium and Legionella to genus level. Conclusions: MALDI Biotyper is an easy-performed, sensitive method for the identification of clinically isolated pathogens. Additionally, the pretreatment and reference database has the effect on identification.

[Clinical significance of centralized surveillance of hydatidiform mole].

Objective: To explore the clinical significance of centralized surveillance of hydatidiform mole. Methods: From Feb. 2013 to Feb. 2017 all patients with hydatidiform mole, who underwent suction curettage and were confirmed by histopathology in Dalian Maternal and Child Health Care Hospital, were registered centrally for serum hCG monitoring and treatment if necessary. Prophylactic chemotherapy was not administered regardless of risk factors for malignant transformation of hydatidiform mole. The risk factors included age of over 40 years, excessive uterine enlargement for presumed gestational age, a serum hCG level greater than 5 00 000 U/L, large theca lutein ovarian cysts (>6 cm), and a history of previous hydatidiform mole. The centralized surveillance of hydatidiform mole was based on the central pathology review, team cooperation and service improvement. Their treatments and outcomes were analyzed retrospectively. Results: A total of 407 women of hydatidiform mole were registered with histopathology confirmation, including 70 high-risk hydatidiform moles. The follow-up rate was 97.5% (397/407) . The incidence of post-mole neoplasia was 8.1% (32/397) , which was diagnosed in 22.9% (16/70) of high-risk and in 4.9% (16/327) of low-risk hydatidiform moles, showed statistically significant difference between high-risk and low-risk groups (χ(2)=25.108, P<0.01) . Thirty-two patients with post-mole neoplasia were all at low risk of International Federation of Gynecology and Obstetrics (FIGO) score (range, 0-6) and received complete remission with chemotherapy alone in 31 of them except one treated by hysterectomy. The primary cure rate of single-agent chemotherapy was 60.0% (18/30) . Patients with low-risk or high-risk post-mole neoplasia were both 16. There were no significant differences between the two groups in interval that was end of antecedent pregnancy to start of treatment, the serum level of hCG before treatment, clinical stage or risk factor score (all P>0.05) . Conclusions: The risk of malignant transformation is increased in high-risk hydatidiform mole, however, the high risk factor itself does not affect the prognosis in patients with timely diagnosis and treatment of post-mole neoplasia. Therefore, prophylactic chemotherapy is not recommended to high-risk hydatidiform mole patients. Centralized surveillance of hydatidiform mole is practical in a local hospital of China and could greatly improve the prognosis of post-mole neoplasia.

[Interactions between transforming growth factor beta and signal transducer and activator of transcription 3 in the development of liver fibrosis].

Liver fibrosis is a common pathological response in chronic liver injury. In the pathological process of hepatic injury, signaling pathways associated with hepatic fibrosis, which mediates the repair, proliferation and fibrosis of the liver secrete different cytokines. In these pathways, transforming growth factor beta (TGFß) and signal transducer and activator of transcription 3 (STAT3) play key roles in the proliferation and activation of hepatic stellate cells (HSCs) and promote epithelial mesenchymal transition. In addition, it is also involved in the process of proliferation and transformation of collagen and extracellular matrix molecules into myofibroblasts. TGFß and STAT3 molecular-related signaling pathways mediate the loss of epithelial phenotype and gene expression in mature epithelial cells, transforming them into mesenchymal cells, and producing anti-apoptosis to hepatocytes and promoting the proliferation of HSCs. However, the mechanisms by which STAT3 and TGFß molecules are involved in the development and progression of liver fibrosis are not sound distinct. In this review, we attempt to know the mechanisms and interactions of TGFß and STAT3 molecules that mediate potential liver fibrosis, and promote their role in promoting HSCs production and epithelial mesenchymal transition.

[Incidence of postoperative venous thromboembolism after thoracic surgery and its characteristic: a single center, prospective cohort study].

Objective: To evaluate the incidence of postoperative venous thromboembolism (VTE) after thoracic surgery and its characteristic. Methods: This was a single-center, prospective cohort study. Patients undergoing major thoracic surgeries between July 2016 and March 2017 at Department of Thoracic Surgery, Beijing Chaoyang Hospital Affiliated to Capital Medical University were enrolled in this study. Besides the routine examination, all patients were screened for deep venous thrombosis (DVT) by using noninvasive duplex lower-extremity ultrasonography after surgery. CT pulmonary angiography (CTPA) was carried out if patients had one of the following conditions including typical symptoms of PE, high Caprini score (>9 points) or new diagnosed postoperative DVT. Caprini risk assessment model was used to detect high risk patients. No patients received any prophylaxis of VTE before surgery. Further data was analyzed for identifying the incidence of postoperative VTE. The t-test, χ2 test or Wilcoxon rank-sum test was used to analyze the quantitative data and classification data, respectively. Results: Totally 345 patients who undergoing major thoracic surgery were enrolled in this study including 145 benign diseases and 200 malignant diseases.There were 207 male and 138 female, aging from 15 to 85 years. Surgery procedures included 285 lung surgeries, 27 esophagectomies, 22 mediastinal surgeries and 11 other procedures. The overall incidence of VTE was 13.9% (48 of 345) after major thoracic surgery including 39 patients with newly diagnosed DVT (81.2%), 1 patient with PE (2.1%) and 8 patients with DVT+ PE (16.7%). The median time of VTE detected was 4.5 days postoperative. There were 89.6% (43/48) VTE cases diagnosed in 1 week. The incidence of VTE was 9.0% in patients with benign diseases, while 17.5% in malignant diseases (χ2=5.112, P<0.05). The incidence of VTE in patients with pulmonary diseases was 12.6%, among that, in patients with lung cancer and benign lung diseases was 16.4% and 7.5 % (χ2=4.946, P<0.05), respectively. Regarding to Caprini risk assessment model, the incidence of VTE in low risk patients, moderate risk patients (Caprini score 5 to 8 points)and high risk patients(≥9 points)were 0(0/77), 15.2%(33/217) and 29.4%(15/51), respectively(Z=-12.166, P<0.05). In patients with lung cancer, 98.2% of patients were moderate risk or high risk; only 3 cases scored low risk. The incidence of VTE in moderate risk and high risk patients was 13.4%(18/134) and 32.1%(9/28), respectively, while it was 0(0/3) in low risk patients. Conclusions: The overall incidence of VTE after major thoracic surgeries is 13.9%, and the incidence of VTE after lung cancer surgeries was 16.4%. Most of the VTE cases occurr within one week after the surgery. Caprini risk assessment model can identify high risk patients effectively.

Correlation of androgen receptor and SRD5A2 gene mutations with pediatric hypospadias in 46, XY DSD children.

We performed an exploratory study by analyzing the correlation of 46, XY disorders of sex development (46, XY DSD) with androgen receptor (AR) and steroid 5α-reductase-2 (SRD5A2) gene mutations and a safety analysis of dihydrotestosterone (DHT) gel treatment for pediatric micropenis. We collected samples from 76 pediatric patients with 46, XY DSD and 50 healthy adult men with normal fertility as the control group. The pediatric patients were treated with DHT gel (0.1-0.3 mg/kg/day) for three to six months. The extended penis length, testicular volume, and multiple blood parameters were collected before treatment and one, three, and six months after treatment. Of the 76 cases with 46, XY DSD, 31.58% had hypospadias with micropenis and 6.58% had male pseudohermaphroditism. Through AR gene screening, it was found that 14 patients had AR point mutations and 22 patients had SRD5A2 mutations. After treatment with DHT, the penis length of the patients significantly improved after one, three, and six months of treatment, with longer treatment times resulting in greater improvement. Before treatment with DHT, the average serum DHT value of patients with 46, XY DSD was 24.29 pg/mL. After one, three, and six months of treatment, this value increased to 430.71, 328.9, and 323.6 pg/mL, respectively. We conclude that for pediatric patients who have male hermaphroditism or hypospadias with micropenis, AR and SRD5A2 gene mutation detection should be performed. Local application of DHT gel can promote penis growth effectively without systemic adverse reactions.

Relationship between EPHX2 gene polymorphisms and essential hypertension in Uygur, Kazakh, and Han.

We investigated the association between rs751141 polymorphisms in the EPHX2 gene and essential hypertension in Uygur, Kazakh, and Han subjects in Xinjiang, China. A total of 302 essential hypertensive patients in Uygur, 267 in Kazakh, and 368 in Han, as well as 323 normotensive controls in Uygur, 284 in Kazakh, and 348 in Han were enrolled in this study. The TaqMan assay was used to detect the rs751141 G/A gene polymorphism in EPHX2. The rs751141 G/A genotype frequencies for the GA+AA genotypes were 40.2% in essential hypertensive subjects and 52.0% in control subjects in the Han population. The frequencies were significantly different between the 2 Han groups (P < 0.01). The rs751141G/A gene polymorphism showed no significant difference between essential hypertensive patients and normotensive controls in Kazakh and Uygur (all P > 0.05). Essential hypertension in Xinjiang was associated with the rs751141 G/A allele gene polymorphism in EPHX2 in Han subjects but not in Kazakh and Uygur subjects. The rs751141 allele gene polymorphism may be an independent protective factor against essential hypertension in the Han population.

Clostridium sporogenes delivers interleukin-12 to hypoxic tumours, producing antitumour activity without significant toxicity.

UNLABELLED: Clostridium sporogenes ATCC 3584 is an obligate anaerobe that has been reported to possess excellent tumour-targeting capacity. Here, we use Cl. sporogenes as a vector to deliver IL-12, a potent antitumour cytokine that bears numerous antitumour properties but that has limited clinical applications due to its strong toxicity when delivered systemically. In this study, Cl. sporogenes was genetically engineered to secrete murine IL-12, and its antitumour efficacy and toxicity were investigated in a murine EMT6 mammary carcinoma model. After intravenous injection, Cl. sporogenes was able to selectively settle and reproduce in the tumours without encroaching on normal tissues, resulting in a clear delay of tumour growth and a 14·3% cure rate. Importantly, the mice showed no obvious toxicity-associated side effects, such as diarrhoea and weight loss, during the treatment process. The significant antitumour efficacy and low toxicity of this treatment may be explained by the selective tumour-targeting properties of Cl. sporogenes and by the sustained release of IL-12 accompanying bacterial proliferation. This moderate local IL-12 concentration would not induce the severe response in the entire body, that is inevitable when IL-12 is administered directly. SIGNIFICANCE AND IMPACT OF THE STUDY: Interleukin-12 (IL-12) is a potent antitumour cytokine, but it is toxic when administrated systemically. This study demonstrates that murine IL-12 can be systemically delivered to hypoxic sites in solid tumours by Clostridium sporogenes, producing a clear delay in tumour growth and a 14·3% cure rate in a mouse tumour model. Importantly, there is no obvious toxicity associated with IL-12 during the treatment process. This result may be accounted for by the excellent tumour-targeting capacity of Cl. sporogenes, targeting IL-12 directly to the tumour site instead of to the entire body.

[Exploring the causality between intestinal flora and hyperplastic scars of human based on two-sample Mendelian randomization analysis].

Objective: To investigate the causality between intestinal flora and hypertrophic scars (HS) of human. Methods: This study was a study based on two-sample Mendelian randomization (TSMR) analysis. The data on intestinal flora (n=18 473) and HS (n=208 248) of human were obtained from the genome-wide association study database. Genetically variable genes at five levels (phylum, class, order, family, and genus) of known intestinal flora, i.e., single nucleotide polymorphisms (SNPs), were extracted as instrumental variables for linkage disequilibrium (LD) analysis. Human genotype-phenotype association analysis was performed using PhenoScanner V2 database to exclude SNPs unrelated to HS in intestinal flora and analyze whether the selected SNPs were weak instrumental variables. The causal relationship between intestinal flora SNPs and HS was analyzed through four methods of TSMR analysis, namely inverse variance weighted (IVW), MR-Egger regression, weighted median, and weighted mode. Scatter plots of significant results from the four aforementioned analysis methods were plotted to analyze the correlation between intestinal flora SNPs and HS. Both IVW test and MR-Egger regression test were used to assess the heterogeneity of intestinal flora SNPs, MR-Egger regression test and MR-PRESSO outlier test were used to assess the horizontal multiplicity of intestinal flora SNPs, and leave-one-out sensitivity analysis was used to determine whether HS was caused by a single SNP in the intestinal flora. Reverse TSMR analyses were performed for HS SNPs and genus Intestinimonas or genus Ruminococcus2, respectively, to detect whether there was reverse causality between them. Results: A total of 196 known intestinal flora, belonging to 9 phyla, 16 classes, 20 orders, 32 families, and 119 genera, were obtained, and multiple SNPs were obtained from each flora as instrumental variables. LD analysis showed that the SNPs of the intestinal flora were consistent with the hypothesis that genetic variation was strongly associated with exposure factors, except for rs1000888, rs12566247, and rs994794. Human genotype-phenotype association analysis showed that none of the selected SNPs after LD analysis was excluded and there were no weak instrumental variables. IVW, MR-Egger regression, weighted median, and weighted mode of TSMR analysis showed that both genus Intestinimonas and genus Ruminococcus2 were causally associated with HS. Among them, forest plots of IVW and MR-Egger regression analyses also showed that 16 SNPs (the same SNPs number of this genus below) of genus Intestinimonas and 15 SNPs (the same SNPs number of this genus below) of genus Ruminococcus2 were protective factors for HS. Further, IVW analysis showed that genus Intestinimonas SNPs (with odds ratio of 0.62, 95% confidence interval of 0.41-0.93, P<0.05) and genus Ruminococcus2 SNPs (with odds ratio of 0.62, 95% confidence interval of 0.40-0.97, P<0.05) were negatively correlated with the risk of HS. Scatter plots showed that SNPs of genus Intestinimonas and genus Ruminococcus2 were protective factors of HS. Both IVW test and MR-Egger regression test showed that SNPs of genus Intestinimonas (with Q values of 5.73 and 5.76, respectively, P>0.05) and genus Ruminococcus2 (with Q values of 13.67 and 15.61, respectively, P>0.05) were not heterogeneous. MR-Egger regression test showed that the SNPs of genus Intestinimonas and genus Ruminococcus2 had no horizontal multiplicity (with intercepts of 0.01 and 0.06, respectively, P>0.05); MR-PRESSO outlier test showed that the SNPs of genus Intestinimonas and genus Ruminococcus2 had no horizontal multiplicity (P>0.05). Leave-one-out sensitivity analysis showed that no single intestinal flora SNP drove the occurrence of HS. Reverse TSMR analysis showed no reverse causality between HS SNPs and genus Intestinimonas or genus Ruminococcus2 (with odds ratios of 1.01 and 0.99, respectively, 95% confidence intervals of 0.97-1.06 and 0.96-1.04, respectively, P>0.05). Conclusions: There is a causal relationship between intestinal flora and HS of human, in which genus Intestinimonas and genus Ruminococcus2 have a certain effect on inhibiting HS.