The APOB rs693 polymorphism impacts the lipid profile of Brazilian older adults

The apolipoprotein B (APOB) gene contains several polymorphic sites described as risk modifiers for cardiovascular events. The objective of this study was to verify the association of the classic APOB Xba I polymorphism (rs693) with atherosclerotic risk factors in a segment of the Brazilian elderly population considering their usual dietary intake. Clinical and biochemical characteristics as well as total caloric and fat intake data were determined from 644 elderly individuals. Polymorphism analysis was performed by conventional polymerase chain reaction followed by enzyme restriction. Statistical analyses compared measures and proportions according to different APOB genotypic combinations. Statistically significant association was found between Xba I polymorphism and serum LDL, total cholesterol, and total lipid levels, with important elevations among T homozygotes compared to the other genotypes. There was homogeneity in all other parameters analyzed (including intake pattern), with a tendency for reduced levels of circulating apolipoprotein B among TT individuals. Our results pointed out that genetic variation in APOB affected the lipemic profile of elderly individuals in a context not biased by diet, generating a pattern suggestive of secretory disorder of lipoprotein particles, with possible implication in atherosclerotic risk.

Clinical and Metabolic Improvement after Bariatric Surgery in Older Adults: A 6-Year Follow-Up

AIM

Our aim in this study was to assess the clinical and metabolic impact of bariatric surgery in older adults.

METHODS

This analytical, observational, longitudinal study was carried out with individuals aged 60 years and older who underwent bariatric surgery after 55 years of age at a specialist center for obesity management located in the Federal District of Brazil. Post-surgery changes in the following parameters from baseline: total body weight, excess weight lost, body mass index (BMI), number of medications, number of comorbidities, and weight regain. Mean values of the variables of interest before and after surgery were compared using the nonparametric Wilcoxon test, Poisson regression and multiple linear regression to test the effect of different variables.

RESULTS

Overall, 74 subjects were assessed (78.3% female, mean age 65.8 ± 3.9 years). The mean time from bariatric surgery to assessment was 75.7 months. The mean weight and BMI in the overall sample at baseline was 101.9 ± 17.1 kg and 39.8 ± 4.9 kg/m², respectively. After the procedure, mean weight and BMI were reduced to 75.9 ± 12.9 kg and 29.4 ± 4.1 kg/m², respectively. Reductions were also achieved in mean number of medications used (P<0.001), number of comorbidities (P<0.001), triglyceride levels (P=0.007), and glycated hemoglobin (P=0.02). The mean HDL level increased significantly (P=0.008).

CONCLUSION

In this sample, bariatric surgery was not only useful to manage obesity, but also reduced the number of comorbidities and medications used, and was associated with improvement in clinical and laboratory parameters.

Dietary fat and apolipoprotein genotypes modulate plasma lipoprotein levels in Brazilian elderly women

Studies show that genetic polymorphisms in apolipoproteins, which are in charge of lipid transport, predispose to atherogenic dyslipidemia. This study aimed to investigate the impact of apolipoprotein E, A5, and B genotypes and dietary intake on lipid profile in a sample of elderly women in Brazil. Two hundred and fifty-two women (60 years or older) living in the outskirts of the Brazilian Federal District underwent clinical and laboratory assessments to characterize glycemic and lipidemic variables, and also to exclude confounding factors (smoking, drinking, hormone replacement, cognitive impairment, physical activity). Three-day food records were used to determine usual dietary intake, whereas genotypic evaluations were in accordance to established methodologies. Genotype frequencies were consistent with the Hardy-Weinberg equilibrium. Prior to adjustment, individuals carrying the epsilon2 allele showed higher serum levels of triglycerides (P<0.05) and VLDL (P<0.005) compared to epsilon4 carriers, whereas LDL levels were considerably elevated in epsilon4 compared to epsilon2 carriers. In the presence of high intake of total fat or a low ratio of polyunsaturated to saturated fatty acid, epsilon4 carriers lost protection against hypertriglyceridemia. There was no association of the apolipoprotein A5 and B genotypes with lipidemic levels independently of the fat intake regimen. Results are suggestive of a dysbetalipoproteinemic-like phenotype in postmenopausal women, with remarkable gene-diet interaction.

Chemotherapy of an experimental Trypanosoma cruzi infection with specific immunoglobulin-chlorambucil conjugate

Hybrid molecules were constructed with either polyclonal antibodies against Trypanosoma cruzi antigens or monoclonal antibody against Trypanosoma brucei brucei low-density lipoprotein (LDL)-receptor conjugated with chlorambucil. Physical-chemical analysis of the hybrid molecule showed four chlorambucil coupling sites in each IgG and a binding constant in the order of 10(4). Maintenance of IgG integrity was indicated by its circular dichroism pattern. Biologic activity of the hybrid molecule was shown by its inhibitory effect on the mobility and proliferation of the parasite. An IgG-chlorambucil conjugate, produced with monoclonal antibody anti-T. b. brucei LDL-receptor, led to the immobilization of the T. cruzi forms, albeit at a much lesser level than that obtained with a mouse polyclonal anti-T. cruzi IgG linked to the drug. Targeting experimental T. cruzi infection with a specific IgG-chlorambucil conjugate resulted in consistent reduction of parasitemia and mortality, thus showing its potential usefulness in controlling the acute form of the disease.

Characterisation of a Trypanosoma cruzi acidic 30 kDa cysteine protease

A novel proteolytic activity was identified in epimastigote, amastigote and trypomastigote forms of Trypanosoma cruzi using the fluorogenic substrate N-Succinyl-Leu-Leu-Val-Tyr-7-amido-4-methylcoumarin. Epimastigotes showed enzyme activity to be 2-fold higher than amastigotes and trypomastigotes. The protease that displays this activity was purified from epimastigote forms by a four step chromatographic procedure: Diethylaminoethyl-Sephacel, Phenyl-Sepharose, Phenyl-Superose, and Concanavalin A Sepharose columns. The purified enzyme is a glycoprotein that migrates as a 30 kDa protein in 12.5% SDS-polyacrylamide gel electrophoresis (PAGE), under reducing conditions. Its optimal enzymatic activity on both fluorogenic and protein substrates was found to occur at an acidic pH. The inhibition pattern of the purified 30 kDa protease showed that it belongs to the cysteine-protease class. In addition to the synthetic substrate, the purified protease hydrolysed bovine serum albumin (BSA) and human type I collagen. The N-terminal amino acid sequence of the protease shows similarity to the mammalian cathepsin B protease.