Search

Trimethylamine-N-Oxide (TMAO) is a proatherogenic and prothrombotic metabolite. Our study examined the association of plasma TMAO level with cardiovascular and all-cause mortality in hemodialysis (HD) patients. Patients who were at least 18 years-old and received HD for at least 6 months were enrolled within 6 months. Patients with coronary heart disease, congestive heart failure, arrhythmia, or stroke within 3 months before study onset were excluded. The primary endpoints were cardiovascular and all-cause death, and the secondary endpoint was cerebrovascular death. We recruited 252 patients and divided them into a high-TMAO group (>4.73 μg/mL) and a low-TMAO group (≤4.73 μg/mL). The median follow-up time was 73.4 months (interquartile range: 42.9, 108). A total of 123 patients died, 39 from cardiovascular disease, 19 from cerebrovascular disease, and 65 from other causes. Kaplan-Meier analysis indicated that the high-TMAO group had a greater incidence of cardiovascular death (Log-Rank: p = 0.006) and all-cause death (Log-Rank: p < 0.001). Cox regression analysis showed that high TMAO level was significantly associated with cardiovascular and all-cause mortality. After adjustment for confounding, this association remained significant for cardiovascular mortality (TMAO as a continuous variable: HR: 1.18, 95%CI: 1.07, 1.294, p < 0.001; TMAO as a dichotomous variable: HR: 3.44, 95%CI: 1.68, 7.08, p < 0.001) and all-cause mortality (TMAO as a continuous variable: HR: 1.14, 95%CI: 1.08, 1.21, p < 0.001; TMAO as a dichotomous variable: HR: 2.54, 95%CI: 1.71, 3.76, p < 0.001). High plasma TMAO level is significantly and independently associated with cardiovascular and all-cause mortality in HD patients. [ABSTRACT FROM AUTHOR]

Short-chain fatty acids (SCFAs) are a major group of endogenous metabolites generated by the gut microbiota and have been reported to play an important role in physical health, such as improving energy metabolism. Here, using 2-bromoacetophenone as the derivatization reagent (BP, 10 mg/mL, 40 °C for 20 min), a sensitive liquid chromatography–tandem mass spectrometric method was established for the quantitative determination of seven short-chain fatty acids in plasma and feces. The analyses were performed on a C18 column in positive multiple reaction monitoring mode. Specificity, linearity, accuracy, precision, recovery, and stability were observed within the quantitative limits of biological sample analysis. The established method has largely improved the sensitivity by 200- to 2000-fold than that in gas chromatography (GC). Especially for butyrate, the lower quantitative limit of 1 ng/mL, 1600-fold higher in sensitivity than that of GC (1.6 μg/mL), ensured the accurate determination of its low level in blood or feces (88 ± 29 ng/mL in blood, 176 ± 18 μg/g in feces). Then, the validated method was applied for therapeutic studies of berberine in hyperlipidemia hamsters in vivo and screening of 13 compounds (including five metabolites of berberine and eight typical isoquinoline alkaloids) in vitro. After berberine treatment (oral, 200 mg/kg, 2 weeks) to hyperlipidemia hamsters, the levels of butyrate were significantly upregulated in blood (77 ± 10 ng/mL vs. 117 ± 13 ng/mL, *P < 0.05) and feces (132 ± 11 μg/g vs. 547 ± 57 μg/g, ***P < 0.001), which further verified butyrate as an active endogenous metabolite in coordination with berberine to lower the blood lipids. Additionally, the berberine metabolites (M1, M2, M3), as well as two isoquinoline alkaloids (tetrandrine and dauricine), could also obviously induce the production of SCFAs (butyrate, etc.) in gut microbiota. In total, we have successfully established a new derivative LC-MS/MS method for the targeted quantitative determination of seven SCFAs in biological samples. [ABSTRACT FROM AUTHOR]

Paeoniflorin, the main component of Xiaoyao Wan, presents low oral bioavailability and unclear antidepressant mechanism. To elucidate the potential reasons for the low bioavailability of paeoniflorin and explore its antidepressant mechanism from the perspective of the gut microbiota, here, a chronic unpredictable depression model and forced swimming test were firstly performed to examine the antidepressant effects of paeoniflorin. Then the pharmacokinetic study of paeoniflorin in rats was performed based on the gut microbiota; meanwhile, the gut microbiota incubated with paeoniflorin in vitro was used to identify the possible metabolites of paeoniflorin. Molecular virtual docking experiments together with the specific inhibitor tests were applied to investigate the mechanism of paeoniflorin metabolism by the gut microbiota. Finally, the intestinal microbiota composition was analyzed by 16S rRNA gene sequencing technology. The pharmacodynamics tests showed that paeoniflorin had significant antidepressant activity, but its oral bioavailability was 2.32%. Interestingly, we found paeoniflorin was converted into benzoic acid by the gut microbiota, and was mainly excreted through the urine with the gut metabolite benzoic acid as the prominent excreted form. Moreover, paeoniflorin could also regulate the composition of the gut microbiota by increasing the abundance of probiotics. Therefore, the metabolism effect of gut microbiota may be one of the main reasons for the low oral bioavailability of paeoniflorin. Additionally, paeoniflorin can be metabolized into benzoic acid via gut microbiota enzymes, which might exert antidepressant effects through the blood–brain barrier into the brain. [ABSTRACT FROM AUTHOR]

Objective: X-linked dominant hypophosphatemia (XLH) is the most prevalent form of inherited rickets/osteomalacia in humans. The aim of this study was to identify PHEX gene mutations and describe the clinical features observed in 6 unrelated Chinese families and 3 sporadic patients with hypophosphatemic rickets/osteomalacia. Methods: For this study, 45 individuals from 9 unrelated families of Chinese Han ethnicity (including 16 patients and 29 normal phenotype subjects), and 250 healthy donors were recruited. All 22 exons and exon-intron boundaries of the PHEX gene were amplified by polymerase chain reaction (PCR) and directly sequenced. Results: The PHEX mutations were detected in 6 familial and 3 sporadic hypophosphatemic rickets/osteomalacia. Altogether, 2 novel mutations were detected: 1 missense mutation c.1183G>C in exon 11, resulting in p.Gly395Arg and 1 missense mutation c.1751A>C in exon 17, resulting in p.His584Pro. No mutations were found in the 250 healthy controls. Conclusions: Our study increases knowledge of the PHEX gene mutation types and clinical phenotypes found in Chinese patients with XLH, which is important for understanding the genetic basis of XLH. The molecular diagnosis of a PHEX genetic mutation is of great importance for confirming the clinical diagnosis of XLH, conducting genetic counseling, and facilitating prenatal intervention, especially in the case of sporadic patients. [ABSTRACT FROM AUTHOR]

Aim:Genetic variation in ALOX12, which encoded human 12-lipoxygenase, was found to be associated with fat mass in young Chinese men. The objective of this study was to investigate the relationship between single nucleotide polymorphisms (SNPs) and haplotypes in the ALOX15 gene and obesity-related phenotypes in Chinese nuclear families with male offspring.Methods:We recruited 1,296 subjects from 427 nuclear families with male offspring and genotyped five SNPs (rs9894225, rs748694, rs2619112, rs2619118, and rs916055) in the ALOX15 gene locus. The total fat mass (TFM), trunk fat mass (tFM), leg fat mass (LFM) and arm fat mass (AFM) were measured using dual-energy X-ray absorptiometry (DXA). The percentage of fat mass (PFM) was the ratio of TFM and body weight. The association between SNPs and haplotypes of ALOX15 and obesity-related phenotypic variation was measured using quantitative transmission disequilibrium test (QTDT).Results:Using QTDT to measure family-based genetic association, we found that rs916055 had a statistically significant association with PFM (P=0.038), whereas rs916055 had a marginal but statistically insignificant association with tFM (P=0.093). The multiple-parameter 1000 permutations test agreed with the family-based association results: both showed that rs916055 had a statistically significant association with PFM (P=0.033).Conclusion:rs916055 in ALOX15 gene was significantly associated with the percentage of fat mass in Chinese nuclear families with male offspring in the family-based association study using QTDT approach. [ABSTRACT FROM AUTHOR]

Dominant inheritance of osteogenesis imperfecta (OI) is caused by mutations in COL1A1 or COL1A2, the genes that encode type I collagen, and C RTAP, LEPRE1, PPIB, FKBP10, SERPINH1, and SP7 mutations were recently detected in a minority of patients with autosomal recessive OI. However, these findings have been mostly restricted to Western populations. The proportion of mutations and the correlations between genotype and phenotype in Chinese patients with OI are completely unknown. In this study, mutation analyses were performed for COL1A1, COL1A2, CRTAP, and LEPRE1 in a cohort of 58 unrelated Chinese patients with OI; the relationship between collagen type I mutations and clinical features was examined. A total of 56 heterozygous mutations were identified in COL1A1 and COL1A2, including 43 mutations in COL1A1 and 13 mutations in COL1A2. Among the 56 causative COL1A1 and COL1A2 mutations, 24 novel mutations were found, and 25 (44.6%) resulted in the substitution of a glycine within the Gly-X-Y triplet domain of the triple helix. Compared with COL1A1 haploinsufficiency ( n = 23), patients with mutations affecting glycine residues had a severe skeletal phenotype. In patients 18 years of age or older, on average patients with COL1A1 haploinsufficiency were taller and had higher femoral neck bone mineral density than with patients with helical mutations. Interestingly, we found two novel compound heterozygous mutations in the LEPRE1 gene in two unrelated families with autosomal recessive OI. Although the genotype-phenotype correlation is still unclear, our findings are useful to understand the genetic basis of Chinese patients with OI. [ABSTRACT FROM AUTHOR]

Here we report the identification of two different mutations in chloride channel 7 gene in two unrelated patients with autosomal dominant osteopetrosis type II. We determined that one patient (a 32-year-old woman) carried a heterozygous gene for a R767W mutation in exon 24, and another patient (a 17-year-old boy) carried a heterozygous gene for a novel frameshift mutation (Glu798FS) in exon 25. Recent studies have reported loss-of-function mutations in the chloride channel 7 (CLCN7) gene as a cause of autosomal dominant osteopetrosis type II (ADO-II). The identification of gene mutations in Chinese with ADO has not been reported previously. In this study, we identified mutations of the CLCN7 gene in two unrelated Chinese families with ADO-II. Two probands with ADO-II were diagnosed based on their bone characteristics on X-rays and their laboratory results. All 25 exons of the CLCN7 gene, including the exon-intron boundaries, were sequenced. We found in family 1 that the proband (a 32-year-old woman) was heterozygous for a CLCN7 mutation. The nonsynonymous mutation consisted of a heterozygous C/T transition at codon 2327 in exon 24, which resulted in an arginine (CGG)-to tryptophan (TGG) substitution at position 767 (R767W). The same heterozygous mutation (C/T) was determined in her father and son, who were asymptomatic with normal skeleton radiography. In family 2, we found that the proband (a 17-year-old boy) carried a novel frameshift mutation (Glu798FS) resulting from a G insertion between codon 60 and codon 61 in exon 25. The heterozygous -/G insertion is predicted to elongate the peptide of CLCN7 by 120 amino acids after position 797 amino acids. Similarly, some individuals of this family carried the same heterozygous mutation, but they are all asymptomatic. Furthermore, the R767W and Glu798FS mutations were not found in 100 unrelated controls. Our present findings suggest that the novel Glu798FS mutation in exon 25 and R767W in exon 24 in the CLCN7 gene were responsible for ADO-II in these Chinese patients. [ABSTRACT FROM AUTHOR]

It has been reported that monoamine neurotransmitters can be produced by gut microbiota, and that several related metabolites of amino acids in these pathways are associated with nervous system (NVS) diseases. Herein, we focused on three pathways, namely, phenylalanine (Phe), tryptophan (Trp), and glutamic acid (Glu), and established an underivatized liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for the quantification of nineteen monoamine neurotransmitters and related metabolites in the gut microbiota. The neurotransmitters and related metabolites included Phe, tyrosine (Tyr), l-dopa (Dopa), dopamine (DA), 3-methoxytyramine, Trp, hydroxytryptophan, 5-hydroxytryptamine (5-HT), 5-hydroxyindole-3-acetic acid (5-HIAA), kynurenine (KN), kynurenic acid (KYNA), melatonin, tryptamine (TA), indole-3-lactic acid (ILA), indole-3-acetic acid (IAA), indolyl-3-propionic acid (IPA), Glu, gamma-aminobutyric acid (GABA), and acetylcholine (Ach). A fluoro-phenyl bonded column was used for separation, and the mobile phase consisted of methanol:acetonitrile (1:1) and water, with 0.2% formic acid in both phases. The compounds exhibited symmetric peak shapes and sufficient sensitivity under a total analysis time of 8.5 min. The method was fully validated with acceptable linearity, accuracy, precision, matrix effect, extraction recovery, and stability. The results showed that neurotransmitters, such as Dopa, DA, 5-HT, GABA, and Ach, were present in the gut microbiota. The metabolic pathway of Trp was disordered under depression, with lower levels of 5-HT, 5-HIAA, KN, KYNA, TA, ILA, IAA, IPA, and Glu, and a higher ratio of KYNA/KN. In addition, some first-line NVS drugs, such as sertraline, imipramine, and chlorpromazine, showed regulatory potential on these pathways in the gut microbiota. [ABSTRACT FROM AUTHOR]