Human Immunodeficiency Virus Envelope Protein Gp120 Induces Proliferation but Not Apoptosis in Osteoblasts at Physiologic Concentrations

Patients with HIV infection have decreased numbers of osteoblasts, decreased bone mineral density and increased risk of fracture compared to uninfected patients; however, the molecular mechanisms behind these associations remain unclear. We questioned whether Gp120, a component of the envelope protein of HIV capable of inducing apoptosis in many cell types, is able to induce cell death in bone-forming osteoblasts. We show that treatment of immortalized osteoblast-like cells and primary human osteoblasts with exogenous Gp120 in vitro at physiologic concentrations does not result in apoptosis. Instead, in the osteoblast-like U2OS cell line, cells expressing CXCR4, a receptor for Gp120, had increased proliferation when treated with Gp120 compared to control (P<0.05), which was inhibited by pretreatment with a CXCR4 inhibitor and a G-protein inhibitor. This suggests that Gp120 is not an inducer of apoptosis in human osteoblasts and likely does not directly contribute to osteoporosis in infected patients by this mechanism

Impact of a genetic counseling requirement prior to genetic testing

Abstract Background Genetic counseling by a Genetic Counselor (GC) is a requirement prior to genetic testing for cancer susceptibility genes (GC-mandate policy) for some insurers. This study evaluated the impact of this policy from the patient perspective. Methods Surveys were sent to individuals for whom their insurer ordered genetic testing for the cancer susceptibility genes BCRA1 and BRCA2 over a 1 year time period that spanned the introduction of a GC-mandate policy. Responses were assessed by time period (before/after policy introduction) and genetic test completion. Results The surveys were completed by 1247/4950 (25.7%) eligible individuals. After policy introduction, there was no change in the proportion of respondents who completed genetic testing (p = 0.13) or had a mutation (p = 0.55). Overall decisional conflict (uncertainty or feeling uninformed) around genetic testing did not change after policy introduction (p = 0.16), but was significantly higher among respondents who did not complete genetic testing (p < 0.01). Although a larger proportion of respondents saw a GC after policy introduction (p < 0.01), fewer did so to better understand their test results (p < 0.01). The proportion of respondents who did not see a GC due to insurance issues/requirements and time restraints was higher among those tested after policy introduction or who did not complete genetic testing (p < 0.01). In multivariate analysis, respondents with a household income of $25,000 or greater were 3-times more likely to complete testing. Conclusions A GC-mandate policy did not improve decisional conflict or increase the number of deleterious mutations identified and low-income respondents were less likely to complete testing. On the contrary, insurance requirements and time constraints may be preventing individuals at risk from receiving appropriate testing

Short Communication: CD4 T Cell Declines Occurring During Suppressive Antiretroviral Therapy Reflect Continued Production of Casp8p41

Most patients on suppressive antiretroviral therapy (ART) experience improvements in CD4 T cell count. However, some patients with undetectable viral load continue to lose CD4 T cells for unknown reasons. Casp8p41 is a host-derived protein fragment that is present only in productively infected cells and that causes the death of HIV-infected cells. We questioned whether ongoing CD4(+) T cell losses while on suppressive ART were associated with subclinical HIV replication causing production of Casp8p41. We analyzed the association of Casp8p41 content with subsequent CD4 losses in patients on continuous suppressive ART and in patients who discontinued ART after Casp8p41 content was determined, adjusting for age, baseline CD4(+) T cell count, and baseline HIV RNA level. Casp8p41 expression in memory CD4(+) T cells was measured by intracellular flow cytometry and was correlated with viral load and CD4(+) T cell change over time. In patients who stopped therapy after Casp8p41 content was determined, baseline Casp8p41 content did not predict CD4(+) T cell change. However, in patients on continuous ART, higher baseline Casp8p41 content was associated with a greater odds of a CD4(+) T cell decline at 6 months (p=0.01). Therefore, patients on suppressive ART, who have ongoing production of Casp8p41, have an increased risk of CD4 T cell losses, suggesting that subclinical HIV replication is driving both Casp8p41, which in turn causes a CD4(+) T cell decline

Short communication: CD4 T cell declines occurring during suppressive antiretroviral therapy reflect continued production of Casp8p41

Most patients on suppressive antiretroviral therapy (ART) experience improvements in CD4 T cell count. However, some patients with undetectable viral load continue to lose CD4 T cells for unknown reasons. Casp8p41 is a host-derived protein fragment that is present only in productively infected cells and that causes the death of HIV-infected cells. We questioned whether ongoing CD4 T cell losses while on suppressive ART were associated with subclinical HIV replication causing production of Casp8p41. We analyzed the association of Casp8p41 content with subsequent CD4 losses in patients on continuous suppressive ART and in patients who discontinued ART after Casp8p41 content was determined, adjusting for age, baseline CD4 T cell count, and baseline HIV RNA level. Casp8p41 expression in memory CD4 T cells was measured by intracellular flow cytometry and was correlated with viral load and CD4 T cell change over time. In patients who stopped therapy after Casp8p41 content was determined, baseline Casp8p41 content did not predict CD4 T cell change. However, in patients on continuous ART, higher baseline Casp8p41 content was associated with a greater odds of a CD4 T cell decline at 6 months (p=0.01). Therefore, patients on suppressive ART, who have ongoing production of Casp8p41, have an increased risk of CD4 T cell losses, suggesting that subclinical HIV replication is driving both Casp8p41, which in turn causes a CD4 T cell decline