Dynamic changes in antibiotic resistance genes and gut microbiota after Helicobacter pylori eradication therapies.

BACKGROUND: Short-term antibiotics exposure is associated with alterations in microbiota and antibiotic resistance genes (ARGs) in the human gut. While antibiotics are critical in the successful eradication of Helicobacter pylori, the short-term and long-term impacts on the composition and quantity of antibiotics resistance genes after H. pylori eradication are unclear. This study used whole-genome shotgun metagenomic of stool samples to characterize the gut microbiota and ARGs, before and after H. pylori eradication therapy. RESULTS: Forty-four H. pylori-infected patients were recruited, including 21 treatment naïve patients who received clarithromycin-based triple therapy (CLA group) and 23 patients who failed previous therapies, in which 10 received levofloxacin-based quadruple therapy (LEVO group) and 13 received other combinations (OTHER group). Stool samples were collected at baseline (before current treatment), 6 week and 6 month after eradication therapy. At baseline, there was only a slight difference among the three groups on ARGs and gut microbiota. After eradication therapy, there was a transient but significant increase in gut ARGs 6 week post-therapy, among which the LEVO group had the most significant ARGs alteration compared to other two groups. For treatment naïve patients, those with higher ErmF abundance were prone to fail CLA eradication and gain more ARGs after treatment. For gut microbiota, the bacteria richness decreased at 6 week and there was a significant difference in microbiota community among the three groups at 6 week. CONCLUSIONS: Our findings demonstrated the dynamic alterations in gut microbiota and ARGs induced by different eradication therapies, which could influence the choices of antibiotics in eradication therapy.

Meta-analysis of genome-wide association studies identifies two loci associated with circulating osteoprotegerin levels.

Osteoprotegerin (OPG) is involved in bone homeostasis and tumor cell survival. Circulating OPG levels are also important biomarkers of various clinical traits, such as cancers and atherosclerosis. OPG levels were measured in serum or in plasma. In a meta-analysis of genome-wide association studies in up to 10 336 individuals from European and Asian origin, we discovered that variants >100 kb upstream of the TNFRSF11B gene encoding OPG and another new locus on chromosome 17q11.2 were significantly associated with OPG variation. We also identified a suggestive locus on chromosome 14q21.2 associated with the trait. Moreover, we estimated that over half of the heritability of OPG levels could be explained by all variants examined in our study. Our findings provide further insight into the genetic regulation of circulating OPG levels.

Post-genome wide association studies and functional analyses identify association of MPP7 gene variants with site-specific bone mineral density.

Our previous genome-wide association study (GWAS) in a Hong Kong Southern Chinese population with extreme bone mineral density (BMD) scores revealed suggestive association with MPP7, which ranked second after JAG1 as a candidate gene for BMD. To follow-up this suggestive signal, we replicated the top single-nucleotide polymorphism rs4317882 of MPP7 in three additional independent Asian-descent samples (n= 2684). The association of rs4317882 reached the genome-wide significance in the meta-analysis of all available subjects (P(meta)= 4.58 × 10(-8), n= 4204). Site heterogeneity was observed, with a larger effect on spine than hip BMD. Further functional studies in a zebrafish model revealed that vertebral bone mass was lower in an mpp7 knock-down model compared with the wide-type (P= 9.64 × 10(-4), n= 21). In addition, MPP7 was found to have constitutive expression in human bone-derived cells during osteogenesis. Immunostaining of murine MC3T3-E1 cells revealed that the Mpp7 protein is localized in the plasma membrane and intracytoplasmic compartment of osteoblasts. In an assessment of the function of identified variants, an electrophoretic mobility shift assay demonstrated the binding of transcriptional factor GATA2 to the risk allele 'A' but not the 'G' allele of rs4317882. An mRNA expression study in human peripheral blood mononuclear cells confirmed that the low BMD-related allele 'A' of rs4317882 was associated with lower MPP7 expression (P= 9.07 × 10(-3), n= 135). Our data suggest a genetic and functional association of MPP7 with BMD variation.

Genetic variant in vitamin D binding protein is associated with serum 25-hydroxyvitamin D and vitamin D insufficiency in southern Chinese.

Previous large-scale genome-wide meta-analysis identified four loci affecting 25-hydroxyvitamin D (25(OH)D) concentrations. However, whether these loci are associated with 25(OH)D concentration in southern Chinese remain unknown. Our primary aim was to examine whether the four top hits (rs2282679, rs10741657, rs12785878 and rs6013897) could be replicated in 712 southern Chinese women. The associations between these single-nucleotide polymorphisms (SNPs), serum 25(OH)D concentration (continuous variable) and vitamin D insufficiency (dichotomized variable) were examined using multivariable linear regression and logistic regression, respectively. Age, body mass index and season were adjusted in the model. Among these four SNPs, rs2282679 was associated with serum 25(OH)D levels (ß=-0.066; P=9 × 10(-5)) and vitamin D insufficiency (odds ratio (OR)=1.51, 95% confidence interval (CI) 1.19-1.93; P=8.6 × 10(-4)), whereas rs12785878 was nominally associated with vitamin D insufficiency only (OR=0.79, 95% CI 0.63-0.99; P=0.042). Genotype risk score (GRS), by summing risk variants of these two SNPs, had more significant association with vitamin D insufficiency (OR=1.38; 95% CI 1.17-1.64; P(trend)=1.76 × 10(-4)) than the model that included only either SNP. The areas under receiver operating characteristic curves of rs2282679 and GRS were 0.561 (P=0.005) and 0.576 (P=5 × 10(-4)), respectively. Our study provides an independent evidence of the associations of rs2282679 and probably rs12785878 with 25(OH)D and vitamin D insufficiency in southern Chinese.

Identification of QTL genes for BMD variation using both linkage and gene-based association approaches.

Low bone mineral density (BMD) is a risk factor for osteoporotic fracture with a high heritability. Previous large scale linkage study in Northern Chinese has identified four significant quantitative trait loci (QTL) for BMD variation on chromosome 2q24, 5q21, 7p21 and 13q21. We performed a replication study of these four QTL in 1,459 Southern Chinese from 306 pedigrees. Successful replication was observed on chromosome 5q21 for femoral neck BMD with a LOD score of 1.38 (nominal p value = 0.006). We have previously identified this locus in a genome scan meta-analysis of BMD variation in a white population. Subsequent QTL-wide gene-based association analysis in 800 subjects with extreme BMD identified CAST and ERAP1 as novel BMD candidate genes (empirical p value of 0.032 and 0.014, respectively). The associations were independently replicated in a Northern European population (empirical p value of 0.01 and 0.004 for CAST and ERAP1, respectively). These findings provide further evidence that 5q21 is a BMD QTL, and CAST and ERAP1 may be associated with femoral neck BMD variation.

Combined Use of Common Fecal and Blood Markers for Detection of Endoscopically Active Inflammatory Bowel Disease.

INTRODUCTION: Monitoring of disease activity is essential in patients with inflammatory bowel disease. Although endoscopic remission is the ideal therapeutic goal, noninvasive biomarkers (blood and fecal) are more acceptable to patients and are less costly. We evaluated the performance of combinations of fecal and blood markers on the detection of endoscopically active disease. METHODS: Patients with ulcerative colitis (UC) or Crohn's disease (CD) on stable medications were recruited. Blood markers included C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), albumin, platelet count (PLT), and hemoglobin. Fecal biomarkers included fecal calprotectin (FCT) and fecal immunochemical test (FIT). These markers were compared with the endoscopic Mayo score for UC and the Simple Endoscopic Score for CD. RESULTS: One hundred thirteen patients (mean age 44.7 years, 63.7% men, 54.9% patients with UC and 45.1% patients with CD) were recruited. FCT correlated well with FIT (r = 0.58), CRP (r = 0.56), ESR (r = 0.40), albumin (r = -0.54), PLT (r = 0.61), and hemoglobin (r = -0.35; all Ps < 0.001). Among 66 patients with endoscopic evaluation, 39.4% with endoscopically active disease had higher FCT, FIT, CRP, ESR, PLT, lower albumin, and hemoglobin compared with those in endoscopic remission (all Ps < 0.01). All 7 markers demonstrated good area under receiver operating characteristics (>0.7), with FCT being the best (0.91) for endoscopically active disease. Combining FCT and FIT improved the specificity to 95%, but the sensitivity decreased to 65.4%. In the subgroup analysis of UC, adding PLT to FIT improved the sensitivity and specificity to 100% and 90.9%, respectively. DISCUSSION: The combined use of fecal biomarkers and blood indexes is superior to the use of fecal biomarkers alone in identifying endoscopically active disease.

Assessing quality of life of patients with advanced chronic obstructive pulmonary disease in the end of life.

Given the limitations of existing health-related quality-of-life (QOL) measures in capturing the end-of-life experience of patients with advanced chronic diseases, an empirically grounded instrument, the quality-of-life concerns in the end of life questionnaire (QOLC-E), was developed. Though it was built on the McGill quality of life questionnaire (MQOL), its sphere is more holistic and culturally specific for the Chinese patients in Hong Kong. One hundred and forty-nine patients with advanced chronic obstructive pulmonary disease (COPD) or metastatic cancer completed the questionnaire. Seven factors (28 items) which emerged from the factor analysis were grouped into four positive (support, value of life, food-related concerns, and healthcare concerns) and four negative (physical discomfort, negative emotions, sense of alienation, and existential distress) subscales. Good internal consistency and concurrent validity were shown. The results also revealed that these two groups of patients had similar QOL concerns. The validity of applying QOLC-E as an outcome measure to evaluate the effectiveness of palliative and psychoexistential interventions has yet to be tested.

Genetic variants in GREM2 are associated with bone mineral density in a southern Chinese population.

CONTEXT: Gremlin 2 (GREM2) is a regulator of osteoblast differentiation and osteogenesis. A recent genome-wide association study identified GREM2 as a novel susceptibility gene for trabecular volumetric bone mineral density (BMD). OBJECTIVE: We investigated whether GREM2 gene variants were associated with areal BMD in southern Chinese people. RESEARCH DESIGN AND METHODS: We genotyped 108 single-nucleotide polymorphisms (SNPs) in 417 cases (defined as BMD Z-score ≤-1.28) and 359 controls (defined as BMD Z-score ≥+1). Multivariable logistic regression using an additive model was used to evaluate the association. The most associated SNPs of BMD at the spine, femoral neck, and total hip was then replicated in an additional 454 cases and 401 controls. RESULTS: Twelve, 13, and 14 SNPs showed nominal association with BMD at the spine, femoral neck, and total hip, respectively. The minor alleles of rs9728351 (odds ratio [OR] = 2.56; 95% confidence interval [CI] = 1.33-4.92), rs11588607 (OR = 1.65; 95% CI = 1.14-2.4), and rs4454537 (OR = 1.87; 95% CI = 1.22-2.86) were associated with the low BMD at the spine, femoral neck, and total hip, respectively. Among these SNPs most associated with BMD, rs4454537 was successfully replicated in an independent cohort (OR = 1.59; 95% CI = 1.05-2.4). Meta-analysis showed that the minor allele of rs4454537 was associated with low total hip BMD with an OR of 1.72 (95% CI = 1.28-2.31) (P = 3.2 × 10(-4); P(corrected) = .043). CONCLUSIONS: The minor allele of rs4454537 is significantly associated with low BMD at the total hip of southern Chinese people. Our study further suggests GREM2 as a novel susceptibility gene for osteoporosis.

Genome-wide association study identifies a susceptibility locus for thyrotoxic periodic paralysis at 17q24.3.

Thyrotoxic periodic paralysis (TPP) is a potentially life-threatening complication of thyrotoxicosis. We conducted a genome-wide association study (GWAS) and a replication study with a total of 123 southern Chinese with TPP (cases) and 1,170 healthy controls and identified a susceptibility locus on chromosome 17q24.3 near KCNJ2 (rs312691: odds ratio (OR) = 3.3; P(meta-analysis) = 1.8 × 10(-14)). All subjects with TPP also had Graves' disease, and subsequent TPP versus Graves' disease comparison confirmed that the association at 17q24.3 was specific to TPP. The area under the curve (AUC) of rs312691 genotype for risk prediction of TPP in subjects with Graves' disease was 0.73. Expression quantitative trait locus (eQTL) analysis identified SNPs in the region flanking rs312691 (±10 kb) that could potentially affect KCNJ2 expression (P = 0.0001). Our study has identified a susceptibility locus associated with TPP and provides insight into the causes of TPP.

Cutaneous and pulmonary sarcoidosis in a Hong Kong Chinese woman with silicone breast prostheses.

Sarcoidosis is rarely reported in Hong Kong. We report cutaneous and pulmonary sarcoidosis in a 54-year-old Chinese woman, who presented with papular lesions over the face and neck. She had silicone breast augmentation surgery 4 years earlier. Skin biopsy revealed granulomatous inflammation and anti-tuberculosis treatment was started empirically but stopped 2 months later owing to a poor response. A right supraclavicular lymph node was aspirated and revealed granulomatous inflammation. The CXR was normal initially but subsequently showed diffuse reticulonodular opacities and a small right-sided pleural effusion. High-resolution CT of the thorax showed mediastinal lymphadenopathy and diffuse perilymphatic nodular opacities consistent with sarcoidosis. Sputum mycobacterial culture was negative. Fibreoptic bronchoscopy showed no endobronchial lesion but the transbronchial biopsy showed granulomatous inflammation with no evidence of infection, malignancy or foreign body. Pulmonary function tests were normal except for impairment of transfer factor. One year later, most of the cutaneous lesions had healed spontaneously. The CXR showed partial improvement of the right pleural opacification but little change in the lung field. The features of sarcoidosis and its association with silicone are reviewed.