Prevalence of and risk factors for low bone mineral density in untreated HIV infection: a substudy of the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial

OBJECTIVES

HIV infection is associated with a higher prevalence of low bone mineral density (BMD) and fractures than that found in the general population. There are limited data in HIV-positive adults, naïve to antiretroviral therapy (ART), with which to estimate the relative contribution of untreated HIV infection to bone loss.

METHODS

The primary objective of the Strategic Timing of AntiRetroviral Treatment (START) Bone Mineral Density Substudy is to compare the effect of immediate versus deferred initial ART on bone. We evaluated traditional, demographic, HIV-related and immunological factors for their associations with baseline hip and lumbar spine BMD, measured by dual-energy X-ray absorptiometry, using multiple regression.

RESULTS

A total of 424 ART-naïve participants were enrolled at 33 sites on six continents; the mean age was 34 years [standard deviation (SD) 10.1 years], 79.0% were nonwhite, 26.0% were women, and 12.5% had a body mass index (BMI) < 20 kg/m(2) . Mean (SD) Z-scores were -0.41 (0.94) at the spine and -0.36 (0.88) for total hip; 1.9% had osteoporosis and 35.1% had low BMD (hip or spine T-score < -1.0). Factors independently associated with lower BMD at the hip and spine were female sex, Latino/Hispanic ethnicity, lower BMI and higher estimated glomerular filtration rate. Longer time since HIV diagnosis was associated with lower hip BMD. Current or nadir CD4 cell count and HIV viral load were not associated with BMD.

CONCLUSIONS

In this geographically and racially diverse population of ART-naïve adults with normal CD4 cell counts, low BMD was common, but osteoporosis was rare. Lower BMD was significantly associated with traditional risk factors but not with CD4 cell count or viral load.

Abstract P5-09-11: BP1, a homeoprotein, regulates estrogen receptor alpha and induces estrogen independence

Introduction: BP1 is a member of the homeobox gene family of transcription factors. Our recent studies have shown that BP1 may play a role in breast cancer cell survival, aggressiveness and metastasis. BP1 protein (pBP1) is expressed in 80% of invasive ductal breast tumors. Moreover, 100% of inflammatory breast tumors are BP1 positive. These data led us to define the mechanism of BP1-related tumorigenesis and aggressiveness in breast cancer.

Materials and Methods: MCF-7/O1, O2 and O4 cells overexpressing BP1 and control V1 and V2 cells were tested for growth in estrogen free media, malignant potential and invasiveness using cell viability assays, soft agar assays and matrigel assays, respectively. To determine the influence of BP1 overexpression on tumor characteristics, empty vector cells (V1) and overexpressor cells (O2 and O4) were injected into the fat pads of athymic nude mice. Mice were supplemented with estrogen pellets or were unsupplemented. Chromatin immunoprecipitation assays (ChIP) were used to validate the binding of pBP1 to ERa and EP300. The effects of BP1 expression on ERα and EP300 were investigated using immunoblotting and qRT-PCR. Effects of BP1 overexpression on tamoxifen sensitivity were measured using the MTT assay.

Results: Cells overexpressing BP1 showed higher viability (p&lt;0.05) when grown in the absence of serum, greater invasive potential (p&lt;0.05) and formed larger and more rapidly growing colonies (p&lt;0.0001) compared with cells containing the empty vector. Tumors were larger in mice receiving O1, O2 or O4 cells than in mice receiving V1 or V2 cells (p&lt;0.0001). There was also a positive correlation between BP1 mRNA levels and tumor size in patients (p = 0.01). 20% of mice injected with O2 or O4 developed tumors in the absence of estrogen, in contrast to control mice which did not develop tumors. Several mechanisms of estrogen independence related to BP1 were established: (1) an indirect mechanism, in which BP1 stabilizes ERα protein by transcriptional activation of p300, and (2) a direct mechanism, in which BP1 binds to the first intron of ERα and upregulates ERα RNA and protein expression. In addition, breast cancer anti-estrogen resistance 1 (BCAR1) RNA expression was higher in O2 as compared to V1 cells. Consistent with these findings, O2 cells exhibited increased proliferation when treated with tamoxifen, while V1 cells showed growth inhibition.

Conclusion: High BP1 levels can lead to estrogen independence in ER positive breast cancer cells and tumors in mice by at least two mechanisms, indirect and direct, and are associated with resistance to tamoxifen. These results suggest that BP1 may be an important therapeutic target in ER positive breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-11.

Impact + resistance training improves bone health and body composition in prematurely menopausal breast cancer survivors: a randomized controlled trial

Our randomized controlled trial in prematurely menopausal breast cancer survivors showed that impact + resistance training prevented increases in percentage of body fat compared with controls and also improved BMD at the hip and prevented BMD loss at the spine among exercise-trained women who were menopausal for >1 year.

INTRODUCTION

Cancer treatment-related menopause worsens bone health and body composition in breast cancer survivors (BCS). We investigated whether impact + resistance training could improve bone mineral density (BMD), reduce bone turnover, build muscle, and decrease fat mass in BCS with premature menopause.

METHODS

We conducted a randomized controlled trial in 71 BCS (mean age, 46.5 years) within 5 years of treatment-related menopause. Women were randomly assigned to one of two groups: (1) impact + resistance training (prevent osteoporosis with impact + resistance (POWIR)) or (2) exercise placebo (FLEX) 3×/week for 1 year. Outcomes were hip and spine BMD (in grams per square centimeter) and body composition (percent body fat (%BF) and lean and fat mass (in kilograms)) by DXA and bone turnover markers (serum osteocalcin (in nanograms per milliliter) and urinary deoxypryrodinoline (in nanomoles per milliliter).

RESULTS

There were no significant group × time interactions for bone outcomes when using an intent-to-treat approach on the full sample. In analyses restricted to BCS who were menopausal for ≥1 year, POWIR increased BMD at the hip and slowed BMD loss at the spine compared with FLEX (femoral neck-POWIR, 0.004 ± 0.093 g/cm(2) vs. FLEX, -0.010 ± 0.089 g/cm(2); p < 0.01; spine-POWIR, -0.003 ± 0.114 g/cm(2) vs. FLEX, -0.020 ± 0.110 g/cm(2); p = 0.03). POWIR prevented increases in %BF (POWIR, 0.01 % vs. FLEX, 1.3 %; p < 0.04). Women with attendance to POWIR at ≥64 % had better improvements in %BF than women attending less often (p < 0.03).

CONCLUSION

Impact + resistance training may effectively combat bone loss and worsening body composition from premature menopause in BCS.

Outcome after laparoscopic gastric bypass for super-super obese patients

GOAL

The surgical treatment of the super-super obese (SSO), defined by a body mass index (BMI) superior or equal to 60 kg/m2, is difficult. The goal of this study was to evaluate the results of laparoscopic gastric bypass (LGBP) in this setting.

PATIENTS AND METHODS

Between June 2005 and December 2011, 20 SSO patients underwent LGBP by one surgeon. Postoperative complications, weight loss, evolution of co-morbidities and quality of life were analyzed. The Bariatric Analysis and Reporting Outcome System (BAROS) was used to classify outcomes.

RESULTS

There were 15 women and five men (median age: 37.5 years). Median BMI was 63 kg/m2. Median duration of operation was 180 minutes. One patient was converted to laparotomy. Three complications occurred: one grade I, one grade II and one grade V. The median excess weight loss was 47.1% at 12 months, 55.3% at 24 months, 53.3% at 36 months and 55.3% at 48 months. Among the patients with a follow-up of at least 12 months (n=17), the median quality of life score was 1.75 and the median BAROS score was 5.75. Arterial hypertension and type II diabetes resolved or improved in all patients and sleep apnea resolved in almost half of patients (43%).

CONCLUSIONS

LGBP appears feasible and effective for SSO, both in terms of weight loss and improvement of co-morbidities and quality of life as well, with a low rate of postoperative complications.