Publications

BACKGROUND

Most of our knowledge about how antiretrovirals and host immune responses influence the HIV-1 protease gene is derived from studies of subtype B virus. We investigated the effect of protease resistance-associated mutations (PRAMs) and population-based HLA haplotype frequencies on polymorphisms found in CRF01_AE pro.

METHODS

We used all CRF01_AE protease sequences retrieved from the LANL database and obtained regional HLA frequencies from the dbMHC database. Polymorphisms and major PRAMs in the sequences were identified using the Stanford Resistance Database, and we performed phylogenetic and selection analyses using HyPhy. HLA binding affinities were estimated using the Immune Epitope Database and Analysis.

RESULTS

Overall, 99% of CRF01_AE sequences had at least 1 polymorphism and 10% had at least 1 major PRAM. Three polymorphisms (L10 V, K20RMI and I62 V) were associated with the presence of a major PRAM (P < 0.05). Compared to the subtype B consensus, six additional polymorphisms (I13 V, E35D, M36I, R41K, H69K, L89M) were identified in the CRF01_AE consensus; all but L89M were located within epitopes recognized by HLA class I alleles. Of the predominant HLA haplotypes in the Asian regions of CRF01_AE origin, 80% were positively associated with the observed polymorphisms, and estimated HLA binding affinity was estimated to decrease 19-40 fold with the observed polymorphisms at positions 35, 36 and 41.

CONCLUSION

Polymorphisms in CRF01_AE protease gene were common, and polymorphisms at residues 10, 20 and 62 most likely represent selection by use of protease inhibitors, whereas R41K and H69K were more likely attributable to recognition of epitopes by the HLA haplotypes of the host population.

OBJECTIVES

This study was designed to determine whether erectile dysfunction (ED) predicts cardiovascular disease (CVD) beyond traditional risk factors.

BACKGROUND

Both ED and CVD share pathophysiological mechanisms and often co-occur. It is unknown whether ED improves the prediction of CVD beyond traditional risk factors.

METHODS

This was a prospective, population-based study of 1,709 men (of 3,258 eligible) age 40 to 70 years. The ED data were measured by self-report. Subjects were followed for CVD for an average follow-up of 11.7 years. The association between ED and CVD was examined using the Cox proportional hazards regression model. The discriminatory capability of ED was examined using C statistics. The reclassification of CVD risk associated with ED was assessed using a method that quantifies net reclassification improvement.

RESULTS

Of the prospective population, 1,057 men with complete risk factor data who were free of CVD and diabetes at baseline were included. During follow-up, 261 new cases of CVD occurred. We found ED was associated with CVD incidence controlling for age (hazard ratio [HR]: 1.42, 95% confidence interval [CI]: 1.05 to 1.90), age and traditional CVD risk factors (HR: 1.41, 95% CI: 1.05 to 1.90), as well as age and Framingham risk score (HR: 1.40, 95% CI: 1.04 to 1.88). Despite these significant findings, ED did not significantly improve the prediction of CVD incidence beyond traditional risk factors.

CONCLUSIONS

Independent of established CVD risk factors, ED is significantly associated with increased CVD incidence. Nonetheless, ED does not improve the prediction of who will and will not develop CVD beyond that offered by traditional risk factors.