Infection
Correspondence
The Possible Association between Serum
Cholesterol Concentration and Decreased Bone
Mineral Density as well as Intravertebral Marrow
Fat in HIV-1 Infected Patients
Metabolic and morphologic abnormalities as well as disturbances in bone mineral density (BMD) are prevalent
among HIV-infected patients, particularly during highly
active antiretroviral treatment (HAART) [1–3]. Hyperlipidaemia may affect up to 60–80% of HIV-infected patients
treated with protease inhibitors (PI) and is commonly associated with abnormalities in body composition [1]. Osteoporosis and osteopenia affects at least a half of antiretroviral treated HIV-infected population [2]. Even though
the relationship between metabolic and bone alterations
has not been clearly established, it has received increased
attention in the recent years [4].
In the general population BMD is correlated with serum
lipids in one study: negatively for HDL cholesterol and positively for triglycerides and LDL cholesterol [5]. Moreover,
data emerging from other clinical studies demonstrate that
lipid-lowering agents, mainly statins, enhance bone mineralization and may reduce the risk of osteoporotic fractures
in non-HIV infected patients [6]. The mechanism underlying this relationship remains largely unknown. Some authors cite the role of lipid oxidation products in osteoclast
differentiation and osteoblast inhibition, which results in
the induction of bone resorption [7].
The most commonly used technique to assess BMD is
dual-energy X-ray absorptiometry. In the recent years,
vertebral marrow fat content as assessed by proton
magnetic resonance spectroscopy (1H-MRS) has been
recommended as a valuable tool of the evaluation of
bone disorders [8]. Schellinger et al. [9] demonstrated a
relationship between bone marrow fat content and bone
mineral density and suggested that the combination of
DEXA and MR spectroscopy may contribute to higher
accuracy in estimating bone weakeness. The exact mechanism of this relationship is unclear, though the presence of
decreased marrow fat and osteopenia in HIV-infected population has been reported [10]. The aim of our study is to
evaluate the relationship between abnormalities in serum lipids and BMD and intravertebral marrow fat content in HIVinfected individuals.
We performed a cross-sectional analysis of 55 HIVinfected individuals (39 males, 16 females, aged from 20
to 53 years, median 37) treated in the outpatient Clinic of
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Infectious Diseases of the Medical University of Bialystok.
Thirty seven of them received HAART for a minimum duration of 6 months (median: 22 months) including NRTIs
and at least one PI, including lopinavir/r (n = 24; 64.9%),
saquinavir/r (n = 7; 18.9%), and nelfinavir/r (n = 6; 16.2%).
None of the patients had received NNRTIs. NRTI exposure
included AZT/3TC (n = 22; 59.5%) and d4T/3TC (n = 15;
40.5%). Among HAART individuals, ten were in stage B
and twenty seven in stage C. The 18 patients not receiving
HAART at the time of evaluation were treatment naive.
Six subjects without HAART were in A stage according to
CDC [11] and twelve in B stage. All individuals recruited
were Caucasians. None of the participants studied demonstrated signs of acute or chronic exacerbated concomitant
infection. Additional exclusion criteria included steroid or
other hormone agents treatment (i.e., oral steroids, contraceptives, anabolic agents, growth hormone) in the last
12 months, postmenopausal state or long immobility periods ( > 3 months), diabetes mellitus, use of lipid lowering
agents or symptomatic lactic acidosis.
The control group consisted of 15 healthy, HIV-negative volunteers, aged from 28 to 43 years. Approval for the
study was obtained from the Bioethical Committee of the
Medical University of Bialystok. Written informed consent
Infection 2007; 35: 46–48
DOI 10.1007/s15010-007-5033-3
A. Wiercinska-Drapalo (corresponding author), J. Jaroszewicz
Dept. of Infectious Diseases, Medical University of Bialystok, Zurawia 14,
15-540 Bialystok, Poland; Phone: (+48-85-7416)-921 Fax: -921
e-mail: [email protected]
E. Tarasow
Dept.of Radiology, Medical University of Bialystok, Bialystok, Poland
L. Siergiejczyk
Institute of Chemistry, University of Bialystok, Bialystok, Poland
D. Prokopowicz
Dept. of Infectious Diseases, Medical University of Bialystok, Bialystok,
Poland
Received: October 16, 2005 • Revision accepted: November 13, 2006
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A. Wiercinska-Drapalo et al. Cholesterol and Bone in HIV Infection
was obtained from every patient involved in our study. All
procedures were conducted in accordance with the Helsinki Declaration of 1975 as revised in 2004.
The percentage and absolute counts of peripheral
CD4(+) and CD8(+) T cells were determined by means of
three-color flow cytometric analysis (Beckton-Dickinson,
Franklin Lakes, NJ, USA ). Plasma HIV-1 RNA was evaluated using the Amplicor system (Roche Diagnostics, Basel, Switzerland), with sensitivity ranging from 50 to 75,000
RNA copies per ml.
Bone mineral density (BMD) of lumbar spine (L2–L4)
was assessed by dual-energy X-ray absorptiometry (Lunar
DPX, Lunar Radiation Corporation, Madison WI, USA).
Osteopenia and osteoporosis were classified according to
WHO criteria [12]. 1H MR spectra of the lumbar vertebral bodies were recorded at 1.5 T system (Picker Eclipse,
Picker International Inc., Highland Heights, OH, USA) using the PRESS pulse sequence (point-resolved single voxel
localized spectroscopy) in all HAART patients (n = 37).
Intravertebral marrow fat content was presented in relative
units (RU) in reference to the signal of non-suppressed water [13], according to the formula: Metabolite/H2O = area
of the metabolite ´ 1000/ area of non-suppressed water.
Serum osteocalcin concentrations were measured by a
solid phase Enzyme Amplified Sensitivity Immunoassay
(Biosource, Nivelles, Belgium), according to the manufacturer’s instructions. Minimal detectable concentration of
osteoclacin by this assay is 0.4 ng/ml. According to manufacturer information, the intra-assay CV is 2.5% (n = 20)
and the inter-assay CV is 9.2% (n = 10).
Statistical analyses. Values were expressed as the mean
and standard error of the mean (±SE). The bivariate analyses were performed by use of a non-parametric U MannWhitney test and Spearman correlation test. Multivariate
analyses were carried out by a step-wise logistic regression
model. Values of P < 0.05 were considered to be significant.
The statistical models were created by use of Statistica 5.1
for Windows (Statsof, Inc., Tulsa, USA).
Osteopenia was observed in 18 (35%) of subjects, osteoporosis in 10 (19%). No bone density alterations were
detected in 23 (46%) of HIV(+) individuals. The mean
L2–L4 BMD was lower in HAART+ group than in HIVinfected participants without antiretroviral treatment.
However, this difference was not significant (1,008 v.
1,163 g/cm2, p = 0.06). There was a negative correlation
between serum total cholesterol and L2–L4 lumbar spine
BMD (r = –0.66, P < 0.001) in HAART patients, but not
untreated patients. The comparison between different
HAART regimens was not performed because of limited
number of subjects in subgroups. Age, sex, body mass index, HIV-1 viral load and lactate concentration did not influence BMD, serum osteocalcin, and intravertebral marrow fat content in a multivariate regression analysis (data
not shown).
H1 magnetic resonance spectroscopy of lumbar vertebral body showed significantly less intravertebral marrow
Infection 35 · 2007 · No. 1 © URBAN & VOGEL
5033.indd 47
fat in HIV (+) patients undergoing HAART compared
to HIV (–) (197.9 ± 19.5 vs. 265.7 ± 27.4 relative units,
P = 0.042). There was no significant relationship between
intravertebral marrow fat and BMD in studied HIV-infected individuals (r = 0.27, P = 0.1). Marrow fat content
was negatively correlated with total cholesterol concentrations (r = 0.70, P < 0.001) in HIV(+), while its relationship
with triglycerides was not significant.
Serum osteocalcin concentration was significantly
higher in the HIV-infected group in comparison with the
control group (6.7 ± 0.8 v. 3.3 ± 0.54 ng/ml, P < 0.001). The
highest levels of osteocalcin were observed in HAART
subjects (7.5 ± 1.1 ng/ml, difference not significant versus
group without HAART). A positive correlation between
serum osteocalcin and total cholesterol (r = 0.59, P = 0.01),
HDL cholesterol (r = 0.54, P = 0.03), triglycerides (r = 0.68,
P = 0.01) was ascertained in the multiple regression
analysis in HAART subjects.
In our study we found high prevalence of reduced
BMD in HIV-infected individuals. Osteopenia affected
over 30%. Osteoporosis was detected in almost one fifth
of the studied population. This finding is consistent with
other previously published reports [2, 14]. In multivariate
analysis (data not presented), mean BMD was not affected
by CD4(+) lymphocyte count, HIV viral load, and antiretroviral treatment. Nevertheless, the lack of relationship
between those variables should be interpreted with caution
because of the cross-sectional nature of our study.
Our results show a significant negative association between BMD and serum total cholesterol concentrations.
Similar relationship, however not explained pathogenetically, was observed in clinical studies, including the associations in the opposite direction as well as HIV-infected
patients [4, 5]. This association may be further indirectly
supported by a beneficial influence of lipid-lowering agents
on bone density in general population [6]. However, a recently published large prospective study covering non-HIV
infected individuals showed no significant association between total cholesterol and BMD [15]. It is important that
any comparison of results between HIV-infected and uninfected patients should be done cautiously.
The relationship between lipids and bone metabolism
requires exploration. It was shown that lipids accumulate around bone vessels [16]. Parhami et al. found that
oxidized lipids and hyperlipidemia may inhibit osteoblastic
differentiation [17]. Since immature osteoblasts are located
in immediate adjacent to subendothelial matrix of bone
vessels, these cells may be susceptible to damage caused by
lipids oxidation products. Additionally, oxidized lipids may
induce endothelial expression of M-CSF, which is a potent
stimulator of osteclastic differentiation [18]. In a recent
work, Kha et al. [7] showed that specific oxysterols – products of cholesterol oxidation – act synergistically with bone
morphogenic protein 2 in inducing osteogenic differentiation. The increased osteoclastic bone resorption was also
found in animal models of hyperlipidemic mice [19].
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A. Wiercinska-Drapalo et al. Cholesterol and Bone in HIV Infection
Another finding in our study is the lower intravertebral marrow fat content in 1H MRS in HIV-infected
patients in comparison to the control group. Recently,
Schellinger et al. [9] found that bone marrow fat content
and BMD are of significant help in detecting bone weakness, more valuable than any of these parameters alone.
Marrow fat reduction in HIV infection has been previously
reported and linked to low BMD and body fat redistribution [20]. The exact mechanism of a possible relationship
in unknown. Adipocytes and osteoblasts share the common progenitor cells (mesynchyal cells) in bone marrow. In
addition there is evidence suggesting the influence of adipogenesis on osteoblastogenesis. Mature adipocytes may
impair osteoblastogenesis through release of unsaturated
fatty acids [21]. However, the possible relationship between adipogenesis and osteoblastogenesis in HIV infected
population may be due to mechanisms, such as direct HIV
influence, chronic inflammation as well as antiretroviral associated toxicities should be considered [10].
In brief, the results of our cross-sectional study indicate
that serum cholesterol concentration may be associated with
decreased bone density and marrow fat in HIV patients.
However, this relationship needs to be further explored.
A. Wiercinska-Drapalo, J. Jaroszewicz, E. Tarasow,
L. Siergiejczyk, D. Prokopowicz
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