HIV-1 genetic diversity and transmitted drug resistance to integrase strand transfer inhibitors among recently diagnosed adults in Porto Alegre, South Brazil

OBJECTIVES

The HIV-1 genetic diversity and the presence of transmitted drug resistance mutations (TDRMs) against integrase strand transfer inhibitors (INSTIs) were assessed sequencing samples of antiretroviral (ARV)-naive HIV-1-infected individuals from South Brazil.

METHODS

Viral RNA from 42 ART-naive individuals was submitted to complete HIV-1 integrase gene amplification by RT-PCR and sequencing.

RESULTS

Viral strains carrying TDRMs against INSTIs were not detected in the present study. However, the polymorphisms L74M and L74I were each observed in 4.8% of the individuals. These accessory mutations have been reported as putative causes of TDRMs in ART with raltegravir, but only when associated with additional major mutations. When submitted to HIV-1 subtyping, 50% were classified as subtype C, 21% as recombinant BC, 19% as subtype B, 4.8% as subtype F1 and 4.8% as recombinant CF1.

CONCLUSIONS

All 42 ARV-naive individuals were apparently susceptible to INSTIs, included in the Brazilian therapeutic guideline since 2009. To the best of our knowledge, this is the first study to evaluate TDRMs against INSTIs in Brazil. The most prevalent HIV-1 subtypes were subtype C, followed by the recombinant BC and subtype B, which is in agreement with previous studies. However, the presence of subtype F1 and recombinant CF1 reported herein was not observed in previous studies.

The influence of HIV-1 subtypes C, CRF31_BC and B on disease progression and initial virologic response to HAART in a Southern Brazilian cohort

BACKGROUND

Although most HIV-1 infections in Brazil are due to subtype B, Southern Brazil has a high prevalence of subtype C and recombinant forms, such as CRF31_BC. This study assessed the impact of viral diversity on clinical progression in a cohort of newly diagnosed HIV-positive patients.

METHODS

From July/2004 to December/2005, 135 HIV-infected patients were recruited. The partial pol region was subtyped by phylogeny. A generalized estimating equation (GEE) model was used to examine the relationship between viral subtype, CD4+ T cell count and viral load levels before antiretroviral therapy. Hazard ratio (Cox regression) was used to evaluate factors associated with viral suppression (viral load < 50 copies/mL at six months).

RESULTS

Main HIV-1 subtypes included B (29.4%), C (28.2%), and CRF31_BC (23.5%). Subtypes B and C showed a similar trend in CD4+ T cell decline. Comparison of non-B (C and CRF31_BC) and B subtypes revealed no significant difference in the proportion of patients with viral suppression at six months (week 24). Higher CD4+ T cell count and lower viral load were independently associated with viral suppression.

CONCLUSION

No significant differences were found between subtypes; however, lower viral load and higher CD4+ T cell count before therapy were associated with better response.

High prevalence and association of HIV-1 non-B subtype with specific sexual transmission risk among antiretroviral naïve patients in Porto Alegre, RS, Brazil

In South Brazil the circulation of two HIV-1 subtypes with different characteristics represents an important scenario for the study of the impact of HIV-1 diversity on the evolution of the HIV-1 epidemic and AIDS disease. HIV-1 B, the predominant variant in industrialized countries and HIV-1 C, the most prevalent subtype in areas with rapid epidemic growth, are implicated in most infections. We evaluated blood samples from 128 antiretroviral (ARV) naïve patients recruited at entry to the largest HIV outpatient service in Porto Alegre. Based on partial pol region sequencing, HIV-1 C was observed in 29%, HIV-1 B in 22.6% and, the recently identified CRF31_BC, in 23.4% of 128 volunteers. Other variants were HIV-1 F in 10% and other mosaics in 5.5%. In order to evaluate the association of socio-behavioral characteristics and HIV-1 subtypes, interviews and laboratory evaluation were performed at entry. Our data suggest an established epidemic of the three major variants, without any evidence of partitioning in either of the subgroups analyzed. However, anal sex practices were associated with subtype B, which could indicate a greater transmissibility of non-B variants by vaginal intercourse. This study provides baseline information for epidemiologic surveillance of the changes of the molecular characteristics of HIV-1 epidemics in this region.

Metabolic changes associated with antiretroviral therapy in HIV-positive patients

OBJECTIVE: To evaluate metabolic changes associated with highly active antiretroviral therapy (HAART) in HIV-positive patients, and to identify risk factors associated. METHODS: Retrospective study that included 110 HIV-positive patients who where on HAART in the city of Porto Alegre (Southern Brazil) between January 2003 and March 2004. Data on demographic variables, cigarette smoking, diabetes mellitus, cholesterol and triglyceride levels, stage of HIV infection, antiretroviral therapy and HCV coinfection were collected. General linear models procedure for repeated measures was used to test the interaction between HAART and HCV coinfection or protease inhibitor treatment. RESULTS: Total cholesterol, triglycerides, and glucose levels significantly increased after receiving HAART (p<0.001 for all variables), but no interaction with protease inhibitors was seen for total cholesterol, glucose and triglyceride levels (interaction treatment*protease inhibitors p=0.741, p=0.784, and p=0.081, respectively). An association between total cholesterol levels and HCV coinfection was found both at baseline and follow-up (effect of HCV coinfection, p=0.011). Glucose levels were increased by HAART (treatment effect, p=0.036), but the effect was associated to HCV coinfection (treatment*HCV effect, p=0.018). Gender, smoking habit, intravenous drug use and age were not significantly associated with cholesterol, triglyceride and glucose changes. CONCLUSIONS: HCV-infected patients at baseline were significantly less likely to develop hypercholesterolemia. The results provide further evidence of the role of HAART for the development of metabolic disturbances.

Enhanced accumulation of BiP in transgenic plants confers tolerance to water stress

The binding protein (BiP) is an important component of endoplasmic reticulum stress response of cells. Despite extensive studies in cultured cells, a protective function of BiP against stress has not yet been demonstrated in whole multicellular organisms. Here, we have obtained transgenic tobacco (Nicotiana tabacum L. cv Havana) plants constitutively expressing elevated levels of BiP or its antisense cDNA to analyze the protective role of this endoplasmic reticulum lumenal stress protein at the whole plant level. Elevated levels of BiP in transgenic sense lines conferred tolerance to the glycosylation inhibitor tunicamycin during germination and tolerance to water deficit during plant growth. Under progressive drought, the leaf BiP levels correlated with the maintenance of the shoot turgidity and water content. The protective effect of BiP overexpression against water stress was disrupted by expression of an antisense BiP cDNA construct. Although overexpression of BiP prevented cellular dehydration, the stomatal conductance and transpiration rate in droughted sense leaves were higher than in control and antisense leaves. The rate of photosynthesis under water deficit might have caused a degree of greater osmotic adjustment in sense leaves because it remained unaffected during water deprivation, which was in marked contrast with the severe drought-induced decrease in the CO(2) assimilation in control and antisense leaves. In antisense plants, the water stress stimulation of the antioxidative defenses was higher than in control plants, whereas in droughted sense leaves an induction of superoxide dismutase activity was not observed. These results suggest that overexpression of BiP in plants may prevent endogenous oxidative stress.

Comparative post-operative study of prostheses, with and without an anti-reflux valve system, in the palliative treatment of esophageal carcinoma

BACKGROUND/AIMS

Palliative treatment of advanced esophageal carcinoma by esophageal tunnelization with a prosthesis allows immediate relief of dysphagia. However, the procedure is subject to a high rate of morbidity, including gastroesophageal reflux (GER) present in all patients with a prosthesis positioned through the gastroesophageal junction, resulting in complications (pyrosis, aspiration pneumonias, sleep disorders) and reduced quality of life in these patients who already have a lower rate of survival. In an attempt to reduce GER and its complications, the authors created a surgical prosthesis coupled to an anti-reflux valve system, comparing it to the use of an esophageal prosthesis without an anti-reflux valve mechanism.

METHODOLOGY

Twenty-two patients were allocated to 2 tunnelization groups: esophageal prosthesis without an anti-reflux valve mechanism (group 1) and surgical prosthesis coupled to an anti-reflux valve system (group 2). The GER was quantified measuring esophageal-gastric pH, and using fluoroscopy, contrast radiographs and esophageal emptying scintigraphy. Initially, the pH of secretions in S1 (esophagus) and S2 (stomach) was determined using reagent strips after aspirating their contents with different syringes. First with the patient seated at rest in bed, later performing a Valsalva maneuver, deep breathing and forced coughing. The same procedure was performed with the patient in left lateral decubitus, right lateral decubitus, and dorsal decubitus with the head of the bed lowered to 20 degrees. After finishing these maneuvers, 15 ml of 1 molar acetic acid were infused through the catheter positioned in the antrum, and, after 5 min, S1 and S2 material sampling was repeated in the same positions as mentioned above.

RESULTS

The pH values between the various positions and maneuvers performed in each group separately were not significantly different, but, if we compare the 2 groups, and the secretions obtained in S1 and S2, there was a significant difference in pH measures in all positions. In the patients in group 1, S1 presented a mean pH ranging from 2.87-3.62 in the initial measures, and between 2.17 and 3.5 after the infusion of 15 ml of 1 molar acetic acid. On the other hand, in group 2, the mean pH of S1 remained between 6.34 and 8.32 in the initial measures and between 4.99 and 7.33 in the presence of acid infusion. At the level of S2, the pH remained unchanged between 2 and 2.7, in both groups.

CONCLUSIONS

The authors conclude that the association of an esophageal prosthesis with a valve system significantly reduces GER, as compared with its use alone. Furthermore, it allows marked reduction of the symptoms and resulting complications, and does not interfere clinically with esophageal emptying. It thus significantly improves the quality of life of these patients.