Identification of novel compound heterozygous variants in SLC19A2 and the genotype-phenotype associations in thiamine-responsive megaloblastic anemia.

BACKGROUND AND AIMS: Thiamine-responsive megaloblastic anemia (TRMA), caused by SLC19A2 loss-of-function variants, is characterized by the triad of megaloblastic anemia, progressive sensorineural deafness, and non-type 1 diabetes mellitus. Here, we present the case of a Chinese infant with two novel variants segregating in compound heterozygous form in SLC19A2 and reviewed genotype-phenotype associations (GPAs) in patients with TRMA. MATERIALS AND METHODS: Whole-exome sequencing was performed to establish a genetic diagnosis. The clinical manifestations and genetic variants were collected by performing a literature review. The bioinformatics software SIFT, PolyPhen2, and Mutation Taster was applied to predict variant effects and analyze GPAs. RESULTS: Two novel variants segregating in compound heterozygous form in SLC19A2 (NM_006996.2: exon2:c.336_363del:p.W112fs; exon2:c.358G>T:p.G120X) was identified. Thiamine supplementation corrected anemia and diabetes mellitus but did not improve the hearing defect. In the literature, 183 patients with TRMA with 74 variants in SLC19A2 have been reported, with high incidence in the Middle East, South Asia, and the northern Mediterranean. Patients with biallelic premature termination codon variants presented with more severe phenotypes, and truncating sites on extracellular domains was a protective factor for the hemoglobin level at diagnosis. CONCLUSION: Two novel compound heterozygous variants (NM_006996.2: exon2:c.336_363del:p.W112fs; exon2:c.358G>T:p.G120X) were identified, and GPAs in TRMA indicated the predictability of clinical manifestations.

Postimplant complications with transcatheter closure of congenital perimembranous ventricular septal defects: a single-center, longitudinal study from 2002 to 2011.

BACKGROUND: Whether or not to close perimembranous VSDs (pmVSDs) by transcatheter techniques is controversial because of a high rate of complications as compared with surgical alternatives. OBJECTIVE: We report the short- and long-term follow-up results of the use of several kinds of devices to close pmVSDs and the annual incidence of postimplant complications in our center. METHODS: From June 2002 to June 2011, 232 patients with pmVSD underwent attempted transcatheter closure; closure was successful in 209 cases (90.1%). Six types of occlusive devices were used. Patient age, defect size, device type, device size and its relation to defect size, and transcatheter and fluoroscopy time were analyzed for correlation with annual incidence of postimplant complications. RESULTS: There were no deaths during the follow-up period. Within 1 month after transcatheter closure, we found 91 adverse events (43.5%), but only 32 cases showed a trace amount of residual shunting. From 2002 to 2011, the annual incidence of postimplant complications gradually decreased, from 50% in 2002 to 17.6% in 2011. The use of Amplatzer occluder devices (r = 0.71, P = 0.033), double-disc symmetrical occluder devices (r = -0.68, P = 0.045), and transcatheter (r = 0.87, P = 0.003), and fluoroscopy time (r = 0.78, P = 0.02) were significantly correlated with the incidence of post-implant complications. CONCLUSIONS: Results of transcatheter closure of pmVSD in terms of postimplant complications are encouraging in our center. It seemed that eccentric Amplatzer and domestic occluder may be at rather higher risk for postimplant complications. The incidence of postimplant complications may be minimized by skilled maneuvers, excluding rather small patients, and selecting the appropriate kind of occlusive device.

[Myocardial matrix metalloproteinases activities in mice with viral myocarditis and their relationship with cardiac function and myocardial collagen amount].

OBJECTIVE: To investigate the dynamic changes of myocardial matrix metalloproteinases (MMPs) activities in mice with viral myocarditis (VM) and their relationships with cardiac function and myocardial collagen amount and to explore the role of MMPs in the pathologic lesion of VM. METHODS: Sixty-five six-week-old male DBA/2 mice were obtained from the Chinese Academy of Medical Sciences. They were divided into two groups randomly. Mice in infected group (n=50) were inoculated intraperitoneally with 0.14 ml of coxsackievirus B3 (CVB3, Nancy strain). Control mice (n=15) were inoculated intraperitoneally with 0.14 ml of Eagle's solution. Eight infected mice were sacrificed on day 3, 7, 10, 21 and 30, respectively and fifteen control mice were killed on day 30 after inoculation. Total protein concentration was determined according to the method of Bradford, while MMPs activities were measured with SDS-PAGE type substrate gels embedded with type I gelatin (zymography). Echocardiographic studies were performed under anesthesia with 3% chloralhydrate intraperitoneally (0.01-0.015 ml/g). Cardiac systolic function indexes, such as peak velocity of aorta (Vp) and flow velocity integral of aorta (Vi) were determined by echocardiography. Histological cross sections of hearts were stained with hematoxylin-eosin and myocardial histopathologic scores were counted under optical microscope. Myocardial collagen amount was measured by determination of hydroxyproline quantification. RESULTS: In virus-infected mice, both MMP-2 and MMP-9 activities were increased significantly compared with those in controls and reached the peak on day 10 (P < 0.01). On day 10, cardiac systolic function indexes (Vp and Vi) were all significantly lower than those at other stages after virus inoculation and in control group (P < 0.05). There was no obvious elevation in myocardial collagen amount in mice with VM at acute stage (P > 0.05). While the myocardial collagen amount in infected group at recovery stage (on day 21 and 30) increased significantly compared with controls. MMP-2 and MMP-9 activities positively correlated with myocardial histopathological scores, respectively (r =0.801, 0.821 P < 0.01), while they negatively correlated with Vp (r = -0.649, -0.683, P < 0.01) and Vi, respectively (r = -0.711, -0.755, P < 0.01). However, Vp and Vi negatively correlated with myocardial histopathological scores (r = -0.756, -0.584, P < 0.01). CONCLUSIONS: In mice with VM, the activities of myocardial MMP-2 and MMP-9 at acute stage increased significantly, then myocardial collagen amount elevated in recovery stage. These changes were associated with myocardial remodeling and cardiac dysfunction. Myocardial MMP activities are important markers of myocardial pathologic lesion. They are of value in the evaluation of the severity of myocardial damage and cardiac dysfunction in mice with VM.

Dynamic changes in myocardial matrix metalloproteinase activity in mice with viral myocarditis.

BACKGROUND: Matrix metalloproteinases (MMPs) are the major regulators of collagen degradation involved in the pathogenesis of several diseases of the heart. The purpose of this study was to investigate the dynamic changes in myocardial MMP activity in mice with viral myocarditis (VM), the relationship between MMP activity and both cardiac function and the quantity of myocardial collagen, and the role MMPs playing in the pathological lesions of VM. METHODS: Sixty-five six-week-old male DBA/2 mice were divided into two groups. Mice in the infected group (n = 50) were inoculated intraperitoneally with 0.14 ml of Coxsackievirus B3 (CVB3, Nancy strain). Control mice (n = 15) were inoculated intraperitoneally with 0.14 ml of Eagle's medium. Eight infected mice and three control mice were sacrificed on each of days 3, 7, 10, 21 and 30 after inoculation. MMP activity was measured on an SDS-PAGE substrate gel embedded with type I gelatin (zymography). Echocardiographic studies were performed under anesthesia with 3% chloralhydrate administered intraperitoneally (0.01 ml/g - 0.015 ml/g). Cardiac systolic function indices, such as peak velocity of the aorta (Vp), flow velocity integral of the aorta (Vi), ejection fraction (EF), and fractional shortening (FS) were determined by echocardiography. Histological cross sections of the hearts were stained with hematoxylin-eosin and myocardial histopathological scores were determined under an optical microscope. The amount of myocardial collagen was measured by means of hydroxyproline quantification. RESULTS: In virus-infected mice, both MMP-2 and MMP-9 activities were significantly higher than in control mice, reaching a peak on day 10 (P < 0.01). On day 10, cardiac systolic function indices (EF, FS, Vp, and Vi) were all significantly lower compared both to other stages following viral inoculation and to the control group (P < 0.05). In the acute stage, the amount of myocardial collagen in mice with VM was not significantly different from normal control mice (P > 0.05). However, the amount of myocardial collagen in infected mice at the recovery stage (on days 21 and 30) was significantly greater than those of the control mice. MMP-2 and MMP-9 activities positively correlated with myocardial histopathological scores (r = 0.801, 0.821, P < 0.01) and negatively correlated with Vp (r = -0.649, -0.683, P < 0.01) and Vi (r = -0.711, -0.755, P < 0.01). However, Vp negatively correlated with myocardial histopathological scores (r = -0.756, P < 0.01). CONCLUSIONS: In mice with VM, the activities of myocardial MMP-2 and MMP-9 increase significantly during the acute stage, and the total quantity of myocardial collagen increases by the time of recovery. These changes are associated with myocardial interstition remodeling and cardiac dysfunction. MMP activity is an important reference marker for myocardial pathological lesions and can be used to evaluate the severity of myocardial interstitial damage and cardiac dysfunction.