Identification of APOB variants in samples from the brazilian population with hypercholesterolemic phenotype

BACKGROUND AND AIMS: Apolipoprotein B plays a crucial role in regulating plasma cholesterol by mediating the interaction of low-density lipoprotein (LDL) with LDL receptors in the liver. Inherited mutations in this gene may increase the risk of developing premature atherosclerotic cardiovascular disease, especially in individuals with familial hypercholesterolemia type 2 (FH2). The aim of this study is to identify APOB variants that may indicate pathogenicity in a sample of the Brazilian population using a data bank exome sequencing study by NGS in a Brazilian population phenotypically diagnosed by clinical and laboratory profile. This finding is going to improve genetic hypercholesteremia diagnosis. METHODS: High-quality DNA samples (n»300) were sequenced using an exon-targeted gene sequencing (ETGS) strategy to identify variants in FHrelated genes. Pathogenicity classification was based on criteria established by the American College of Medical Genetics and Genomics (ACMG), also using information from ClinVar and pathogenicity scores from previous association studies. RESULTS: A total of 121 variants were identified in APOB, of which four are novel variants missense (p.Thr626Asn, p.Ile2750Thr, p.Gln2078Lys and p.Met4184Arg). After curating pathogenicity scores, variants were classified according to the ACMG criteria. Among them four as pathogenic or likely pathogenic (p.Pro2739Leu, p.His1923Arg, p.Pro994Leu and p.Pro877Leu), and 21 variants had uncertain significance. Additionally, 92 previously known variants with uncertain significance were classified as benign or likely benign. The results were submitted to Clinvar for actualization of pathogenicity. CONCLUSIONS: These results improve the molecular diagnosis associating APOB variants with the clinical phenotype of hypercholesterolemia.

Erythropoietin reduces the expression of myostatin in mdx dystrophic mice.

Erythropoietin (EPO) has been well characterized as a renal glycoprotein hormone regulating red blood cell production by inhibiting apoptosis of erythrocyte progenitors in hematopoietic tissues. EPO exerts regulatory effects in cardiac and skeletal muscles. Duchenne muscular dystrophy is a lethal degenerative disorder of skeletal and cardiac muscle. In this study, we tested the possible therapeutic beneficial effect of recombinant EPO (rhEPO) in dystrophic muscles in mdx mice. Total strength was measured using a force transducer coupled to a computer. Gene expression for myostatin, transforming growth factor-ß1 (TGF-ß1), and tumor necrosis factor-α (TNF-α) was determined by quantitative real time polymerase chain reaction. Myostatin expression was significantly decreased in quadriceps from mdx mice treated with rhEPO (rhEPO = 0.60 ± 0.11, control = 1.07 ± 0.11). On the other hand, rhEPO had no significant effect on the expression of TGF-ß1 (rhEPO = 0.95 ± 0.14, control = 1.05 ± 0.16) and TNF-α (rhEPO = 0.73 ± 0.20, control = 1.01 ± 0.09). These results may help to clarify some of the direct actions of EPO on skeletal muscle.

Overnight lowering of free fatty acids with Acipimox improves insulin resistance and glucose tolerance in obese diabetic and nondiabetic subjects.

Obesity is commonly associated with elevated plasma free fatty acid (FFA) levels, as well as with insulin resistance and hyperinsulinemia, two important cardiovascular risk factors. What causes insulin resistance and hyperinsulinemia in obesity remains uncertain. Here, we have tested the hypothesis that FFAs are the link between obesity and insulin resistance/hyperinsulinemia and that, therefore, lowering of chronically elevated plasma FFA levels would improve insulin resistance/hyperinsulinemia and glucose tolerance in obese nondiabetic and diabetic subjects. Acipimox (250 mg), a long-acting antilipolytic drug, or placebo was given overnight (at 7:00 P.M., 1:00 A.M., 7:00 A.M.) to 9 lean control subjects, 13 obese nondiabetic subjects, 10 obese subjects with impaired glucose tolerance, and 11 patients with type 2 diabetes. Euglycemic-hyperinsulinemic clamps and oral glucose tolerance tests (75 g) were performed on separate mornings after overnight Acipimox or placebo treatment. In the three obese study groups, Acipimox lowered fasting levels of plasma FFAs (by 60-70%) and plasma insulin (by approximately 50%). Insulin-stimulated glucose uptake during euglycemic-hyperinsulinemic clamping was more than twofold higher after Acipimox than after placebo. Areas under the glucose and insulin curves during oral glucose tolerance testing were both approximately 30% lower after Acipimox administration than after placebo. We conclude that lowering of elevated plasma FFA levels can reduce insulin resistance/hyperinsulinemia and improve oral glucose tolerance in lean and obese nondiabetic subjects and in obese patients with type 2 diabetes.

Insulin resistance in limb and trunk partial lipodystrophy (type 2 Köbberling-Dunnigan syndrome).

We studied insulin action in two patients with limb and trunk partial lipodystrophy with hirsutism and acanthosis nigricans. Glucose was normal in one of the patients and slightly above normal in the other during an oral glucose tolerance test (OGTT). An intravenous glucose tolerance test (IVGTT) was normal in both patients. Basal and glucose-stimulated insulin levels were elevated in both the OGTT and IVGTT in both patients. The response of plasma glucose to exogenously administered insulin was decreased. A euglycemic-hyperinsulinemic clamp performed in patient no. 2 indicated insulin resistance, which was not corrected by reducing the increased basal level of serum free fatty acids (FFAs). Binding of insulin to neck adipocytes was normal in both subjects, but glucose transport and oxidation in these cells was impaired. Insulin binding to abdominal adipocytes was increased in one patient whose adipocytes displayed higher glucose transport at low insulin concentrations. Glucose oxidation was decreased in abdominal adipocytes of both patients. We conclude that insulin resistance in Köbberling-Dunnigan type 2 partial lipodystrophy is not related to an alteration of the insulin molecule or to changes in insulin binding, but is more likely associated with a postreceptor defect, since glucose oxidation was impaired in adipocytes of the neck and abdomen.

Risk factors in obese women, with particular reference to visceral fat component.

Possible associations between increased visceral fat component and serum lipid concentrations, glucose tolerance and insulinaemia (specific radioimmunoassay) were studied as risk factors for cardiovascular disease in 50 adult obese women without known diabetes and 11 lean normal women. Visceral abdominal fat areas were evaluated by computed tomography and "true" insulin concentrations. Diabetes was observed in 6 obese women (12%) and impaired glucose tolerance in 13 (26%). In obese women, visceral fat area correlated significantly with VLDL-cholesterol, triglycerides, and systolic and diastolic blood pressure, whereas subcutaneous area correlated negatively with cholesterol and LDL-cholesterol. Insulinaemia was not increased in visceral obesity nor correlated with other risk factors. An association between increased visceral fat accumulation, dyslipidaemia and increased diastolic blood pressure was observed, but no significant correlations were noted between fasting "true" insulin or insulin response on an oral glucose tolerance test and intra-abdominal fat areas or dyslipidemia. The gender of the patients could have been an important factor in these last observations.

[Osteomyoarticular injuries in a physical conditioning program]. / Lesões osteomioarticulares no programa de condicionamento físico.

From the follow-up of one hundred and thirty patients in a physical conditioning program during the period of one year, partially disabling lesions with preliminary complaints were observed at the beginning of the program in thirteen patients, and lesions during the development of the program were observed in nineteen patients. Within the first group, four patients had to quit the program, two temporarily and two definitively. In the second group, five patients had to interrupt the program for periods varying from twenty days to two months. In both groups, treatment involving physical agents, kinesiotherapy and drugs was proposed. Interruptions in the physical conditioning program for periods longer than three weeks imply in considerable reduction of the cardiovascular benefits. The clinician must be aware of the fact that sedentary patients have not only cardiovascular, but also musculoskeletal deconditioning. These patients must be evaluated by the physiatrist in order that the disabling lesions be avoided and treated.

[Chronotropic and pressoric response in myocardiopathy in patients with heart failure during ergometric test. Correlation of spirometry variables with effort]. / Resposta cronotrópica e pressórica nas miocardiopatias em portadores de insuficiência cardíaca durante prova ergométrica. Correlação das variáveis espirométricas ao esforço.

PURPOSE: To correlate the variables heart rate (HR), blood pressure (BP) and double product (DP) during the ergometric test with the variables oxygen consumption (VO2) and pulmonary ventilation (VE) of spiroergometry. METHODS: A study was carried out with 40 male patients suffering from cardiomyopathy with heart failure (functional class II-IV of NYHA)-of ischemic (IS), Chagas' disease (CH) and idiopathic (ID) etiology. These three groups were compared to a group of 10 normal individuals (N). The 4 groups were evaluated under 4 different conditions: rest (RES), anaerobic threshold (LA), power peak of exercise (P) and in the fourth minute recovery (REC). The investigation was carried out with the data obtained through spiroergometry (using a treadmill and spiroergometric equipment specific for the effort), as well as data related to HR, BP, DP, VO2 and VE. RESULTS: There were significant differences observed in the ergometric evaluate of the HR, BP and DP responses in the IS, CH and ID groups as compared with the N group. There were significant difference observed in the spirometric evaluation to the VO2 and VE efforts in the IS, CH and ID groups as compared with the N group. CONCLUSION: The HR, BP and DP variables studies, obtained by means of classic ergometry, unaided by direct methodology (spiroergometry) enabled them to infer valuable data for the control and evaluation of cardiomyopathies with IC, taking into consideration the low chronotropic and pressoric responses in the various phases of evaluation during this study, corresponding to the concomitant low performance of O2 consumption and pulmonary ventilation.

Effect of a sulfonylurea (gliclazide) treatment on insulin sensitivity and glucose-mediated glucose disposal in patients with non-insulin-dependent diabetes mellitus (NIDDM).

Five male non-obese newly diagnosed NIDDM and 5 age-, sex- and body mass index (BMI) matched healthy controls without a family history of diabetes were submitted to a frequently sampled intravenous (i.v.) glucose tolerance test modified by exogenous insulin administration for estimation of insulin sensitivity (SI) and glucose-mediated glucose disposal (SG) with Bergman's minimal model computer analysis of glucose kinetics. The tests were repeated after 3 months treatment with a second generation sulfonylurea, gliclazide, in the diabetics subjects. SI and SG were markedly reduced before gliclazide therapy in the diabetics in comparison to the paired controls. After gliclazide, despite significantly lower (almost normal) plasma glucose, normalization of glycosylated hemoglobin and increased fasting insulin levels, there was a slight but significant increase in SI while SG showed a further reduction, the improvement in glucose control being also associated to the significant increased first and 2nd phase insulin release for the first 20 min after glucose infusion.

Evaluation of the physical fitness by the Bruno Balke protocol in sedentary and wheelchair trained paraplegic patients.

The Bruno Balke test is one of the methods available to measure the oxygen intake in wheelchair users. The equation of the test is:intake O2 = 33+ (speed average-133) x 0.17 ml/kg x min. (-1). The average speed represents the acceleration and may be used to measure the level of physical fitness. In order to verify the efficiency of this kind of evaluation, we selected ten male, sedentary paraplegic patients, level D5-D12 in an ordinary rehabilitation program and ten paraplegic athletes. All of them were submitted to the Bruno Balke test. The results demonstrated that the average speed, the covered distance and the oxygen intake were significantly greater in athletes than in sedentary individuals.

Short- and long-term gliclazide effects on pancreatic islet cell function and hepatic insulin extraction in non-insulin-dependent diabetes mellitus.

Nine non-obese males with non-insulin-dependent diabetes mellitus (NIDDM) were evaluated before and after 3 and 12 months (6 patients) treatment with the second generation hypoglycemic sulfonylurea: gliclazide. They underwent an oral glucose tolerance test, intravenous glucose and arginine tests measuring plasma insulin and C-peptide responses. Pre-hepatic insulin production and insulin delivery to peripheral tissues were calculated by deconvolution techniques and hepatic extraction of insulin estimated. An improvement was observed in the beta-cell function of the patients on gliclazide treatment: reduction of fasting plasma glucose associated with a progressive increase in C-peptide level but insulin levels decreased at 12 months, suggesting an increase in hepatic insulin extraction at this time. In the same way, while plasma glucose values after oral and i.v. glucose were greatly reduced at 3 and 12 months treatment, insulin did not change but C-peptide levels increased significantly at 12 month treatment. While the prehepatic insulin secretion rate increased progressively on gliclazide during all glucose challenges, the fractional hepatic insulin extraction fell after 3 and increased at 12 month treatment, with opposite changes in insulin delivered to peripheral tissues. Thus the insulinogenic effect of gliclazide could be masked during long-term administration by a concomitant effect of gliclazide which increases hepatic extraction of insulin. The maintenance of the responsiveness to the non-glucose secretagogue, arginine, as evaluated by the C-peptide levels, before and after correction of hyperglycemia, suggested improvement of beta-cell sensitivity to glucose after sulfonylurea treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Dissociated response of thyrotropin and prolactin to dopamine receptor blockade with domperidone in hypothyroid subjects.

To investigate the hypothesis of an altered hypothalamic dopaminergic activity in primary hypothyroidism, eight patients with hypothyroidism and seven normal subjects, all female, were studied. All of them were submitted to two tests: TRH stimulation and after the administration of dopamine receptor-blocking drug, Domperidone. The hypothyroid patients with basal TSH values less than or equal to 60 mU/L (4 cases--group 1) had lower PRL levels than the remaining 4 subjects with TSH greater than 60 mU/L (group 2) (p less than 0.001), despite all patients presenting the PRL levels within the normal range. A significant increase occurred for both TSH and PRL after the administration of TRH and Domperidone in normal as well as in the hypothyroid subjects, except for TSH in group 1 after the administration of Domperidone. The area under the curve for PRL response to THR was not different between the normal subjects and both hypothyroid groups, while that under the curve for TSH was greater in the hypothyroidism as a whole than in the normal subjects (p = 0.006) and between the hypothyroid groups, being greater in group 2 than in 1 (p less than 0.009). In relation to Domperidone, the area under the curve for TSH was significantly higher in group 2 when compared to the normal controls (p less than 0.001), while for PRL it was not different between hypothyroid groups in relation to normal controls and when groups I and II were compared. These results suggest that the hypothalamic dopamine activity is not altered in primary hypothyroidism and favor the small relevance of dopamine on the control of TSH secretion.

[Lymphocytic and serum magnesium in older healthy and hypertensive subjects]. / Magnésio linfocitário e sérico em idosos sadios e hipertensos.

PURPOSE: To study the lymphocyte and serum magnesium in older patients with and without arterial hypertension. PATIENTS AND METHODS: We studied the lymphocyte and serum Mg in 22 older patients, with diastolic blood pressure between 95 and 120 mmHg, not receiving drug treatment. A method of freezing produced total lysis of the cells. RESULTS: The mean lymphocyte Mg concentration in the older patients was 1.15 +/- 0.74 picomoles per 100 cells, significantly higher (p less than 0.05) than in the control group, that was 0.77 +/- 0.32 picomoles per 100 cells (lymphocyte Mg in older hypertensive patients/control = 1.49); there were no significant differences between groups with regard to serum Mg. Twelve older normotensive men studied also had lymphocyte Mg significantly higher than in the respective control group (lymphocyte Mg in older normotensive men/control = 1.70) and the serum Mg was also significantly higher than in the control group (1.63 +/- 0.12 versus 1.44 +/- 0.22 mEq/l. CONCLUSION: Since the high intracellular Mg concentration in the elderly patients may more accurately reflect the total body Mg status. We suggest to use Mg and Mg sparing diuretics in these patients, both hypertensive and normotensive, cautiously.

[Effect of beta blockers with intrinsic sympathomimetic activity on blood pressure and blood lipids in patients with essential hypertension]. / Influência de betabloqueadores com atividade simpaticomimética intrínseca sobre pressão arterial e lípides sangüíneos em portadores de hipertensão arterial essencial.

The aim of this study was to compare the effects of a beta-blocker (mepindolol) with intrinsic sympathomimetic activity (ISA) to a beta-blocker (metoprolol duriles) without ISA. Hypertensive patients with more than 50 years of age were selected and randomly allocated to receive either 5 mg/day mepindolol (Group A, 10 patients), or 200 mg/day metoprolol duriles (Group B, 9 patients), or placebo (Group C, 10 patients). They were submitted to clinical exam, stress testing and plasma lipids dosage before and after four weeks of treatment. At rest, there were a significant reduction of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) in all groups. The mean values for SBP, DBP and HR at rest after treatment were respectively: 154.0, 95.5, 73.7 (Group A); 148.8, 94.4, 70.1 (Group B); 153.0, 96.0, 77.8; (Group C). During stress testing, there were a significant reduction of SBP, HR and double product (DP). The DBP remained unchanged. The mean values for SBP, DBP, HR and DP during stress testing after treatment were respectively; 198.0, 115.5, 124.3, 246.9 (Group A); 198.8, 114.4, 144.6, 283.2 (Group B); 202.2, 119.0, 143.5, 283.4 (Group C). Total cholesterol, HDL-cholesterol, and LDL-cholesterol, have not changed with both beta-blockers. There were a significant increase in plasma triglycerides and VLDL-cholesterol levels after treatment with beta-blockers. In conclusion, both mepindolol and metoprolol were similarly effective in reducing arterial blood pressure of hypertensive patients. There were not significant differences between the beta-blocker with or without ISA in regard to their effects on plasma lipids.