Allison C. Ross

Relationship between Inflammatory Markers, Endothelial Activation Markers, and Carotid Intima-Media Thickness in HIV-Infected Patients Receiving Antiretroviral Therapy

BACKGROUND Human immunodeficiency virus (HIV)-infected patients are at increased risk of cardiovascular disease, which may be related to chronic inflammation and endothelial dysfunction despite virological control with antiretroviral therapy. The relationship between carotid intima-media thickness (IMT), a surrogate marker for cardiovascular disease, proinflammatory cytokines, and endothelial activation markers has not been fully explored in HIV-infected patients who are receiving antiretroviral therapy. METHODS We conducted a prospective, cross-sectional, observational study of treated HIV-infected patients and healthy control subjects to evaluate the relationship between carotid IMT, proinflammatory cytokines, endothelial activation biomarkers, and metabolic parameters in treated HIV-infected patients, compared with healthy control subjects. RESULTS We enrolled 73 HIV-infected patients and 21 control subjects. Common carotid artery and internal carotid artery IMT measurements, as well as tumor necrosis factor-alpha, high-sensitivity C-reactive protein, interleukin-6, myeloperoxidase, and soluble vascular cell adhesion molecule-1 levels were higher in the HIV-infected group. High-sensitivity C-reactive protein was the only biomarker that was positively correlated with carotid IMT in both groups. In the HIV-infected group, soluble vascular cell adhesion molecule-1 was positively correlated with all inflammatory cytokine levels. In multiple regression analysis, soluble vascular cell adhesion molecule-1, myeloperoxidase, and tumor necrosis factor-alpha levels were all associated with internal carotid artery IMT in the HIV-infected group, whereas age was associated with both common carotid artery and internal carotid artery IMT. CONCLUSIONS Enhanced endothelial activation, inflammation, and increased carotid IMT occur in HIV-infected patients despite antiretroviral therapy. Inflammatory markers are associated with endothelial activation, and both are associated with internal carotid artery IMT, supporting a potential role of inflammation in endothelial activation and cardiovascular disease in HIV infection.

Endothelial Activation Markers Are Linked to HIV Status and Are Independent of Antiretroviral Therapy and Lipoatrophy

Objectives:To assess the association of inflammatory and endothelial activation biomarkers with the presence of lipoatrophy in HIV-infected subjects and to examine the role of HIV, antiretroviral therapy (ART), and metabolic parameters in endothelial activation and inflammation. Design:Prospective, cross-sectional study including 4 groups: HIV+ on ART with HIV-1 RNA <1000 copies/mL with and without clinical lipoatrophy, HIV+ ART naive, and healthy controls. Methods:We measured plasma levels of inflammatory cytokines (tumor necrosis factor-α, soluble tumor necrosis factor receptors I and II, interleukin-6, C-reactive protein, and myeloperoxidase) and endothelial activation markers (soluble intercellular and vascular cell adhesion molecules and von Willebrand factor). Results:We enrolled 182 subjects. Limb fat and lipoatrophy status were not correlated with endothelial markers. Endothelial markers were higher in HIV+ ART naive when compared with healthy controls and with HIV+ on ART but were similar between HIV+ on ART and healthy controls. Neither endothelial nor inflammatory markers were correlated with HIV duration, CD4 count, lipids, glucose, or specific ART. Strong correlations were found between some inflammatory cytokines and endothelial markers. Conclusions:There is enhanced endothelial activation in ART naive, whereas HIV+ on ART has similar values to healthy controls. Lipoatrophy did not seem to affect endothelial activation. Results highlight a potential association between heightened inflammation and endothelial activation.

Vitamin D is linked to carotid intima-media thickness and immune reconstitution in HIV-positive individuals

BACKGROUND Patients with HIV infection are at increased risk of cardiovascular disease (CVD). Vitamin D insufficiency has been associated with increased CVD risk in non-HIV populations. This study sought to determine the relationship between vitamin D status and markers of CVD and HIV-related factors in HIV-positive patients. METHODS Patients with HIV infection on antiretroviral therapy and healthy controls were prospectively enrolled. Fasting lipids, glucose, insulin, inflammatory markers (soluble tumour necrosis factor-α receptor I, interleukin-6 and high-sensitivity C-reactive protein) and endothelial markers (soluble intercellular adhesion molecule-1 and soluble vascular cell adhesion molecule-1) were measured. Fasting 25-hydroxyvitamin D (25(OH)D) was measured from stored serum samples. The internal carotid artery and common carotid artery (CCA) intima-media thickness (IMT) were measured in a subset of HIV-positive patients. Baseline cross-sectional data were analysed. RESULTS A total of 149 HIV-positive patients (56 with carotid IMT) and 34 controls were included. Controls had higher adjusted mean 25(OH)D levels than HIV-positive patients (P=0.02). In multivariable linear regression among the HIV-positive patients, 25(OH)D was positively associated with CD4(+) T-cell restoration after antiretroviral therapy (ΔCD4 = current - nadir CD4(+) T-cell; P<0.01), but was not associated with inflammatory or endothelial markers. In multivariable logistic regression, odds of having CCA IMT above the median were more than 10× higher in those with lower 25(OH)D levels (OR=10.62, 95% CI 1.37-82.34; P<0.01). CONCLUSIONS Vitamin D status in HIV-positive patients was positively associated with improved immune restoration after antiretroviral therapy and negatively associated with CCA IMT. These findings suggest that vitamin D may play a role in HIV-related CVD and in immune reconstitution after antiretroviral therapy.

Bone turnover, osteoprotegerin/RANKL and inflammation with antiretroviral initiation: Tenofovir versus non-tenofovir regimens

BACKGROUND Bone mineral density decreases with antiretroviral therapy (ART) initiation, although the pathogenesis, including the role of tenofovir (TDF), is unclear. This study assessed changes in bone-turnover markers, osteoprotegerin (OPG), soluble receptor activator for nuclear factor-κβ ligand (sRANKL), and inflammation in subjects initiating TDF- versus non-TDF-containing regimens, and determined the relationship between bone turnover, OPG/sRANKL and inflammation. METHODS This was a longitudinal observational study comparing levels of bone turnover markers (C-terminal telopeptide of type I collagen [CTX] and osteocalcin [OC]), OPG, sRANKL and inflammatory cytokines (soluble tumour necrosis factor [TNF]-α receptor [sTNFR]-I, sTNFR-II and interleukin-6) prior to ART and 6-12 months after ART initiation with a TDF- versus non-TDF-containing regimen in HIV-infected subjects 18-50 years old. RESULTS A total of 87 subjects were enrolled (TDF n=44 and non-TDF n=43). Groups were similar except subjects on TDF had a lower CD4(+) T-cell nadir (P<0.01) and were more likely to receive a protease inhibitor (PI; P=0.03). At pre-ART, 35% and 1% of subjects had CTX and OC above the normal range, respectively. Both increased with ART initiation, whereas OPG, sRANKL and inflammatory markers significantly decreased. In multivariate models, increases in OC were associated with TDF use, PI use and pre-ART levels of sTNFR-I, whereas increases in CTX were associated with CD4(+) T-cell nadir <50 cell/mm³. Increases in bone markers were unrelated to pre-ART levels of OPG/sRANKL and changes in OPG/sRANKL after ART initiation. CONCLUSIONS TDF use, PI use, TNF-α activity and advanced HIV disease are associated with changes in bone turnover markers, underscoring the complicated interaction between ART, bone turnover, inflammation and immune status, which extend beyond the OPG/RANKL system.

Heightened inflammation is linked to carotid intima-media thickness and endothelial activation in HIV-infected children☆☆☆

OBJECTIVES HIV+ patients are at increased risk of cardiovascular disease (CVD). Inflammation plays a role in adults, but has not yet been assessed in HIV+ children. We compared proinflammatory cytokines and adhesion molecules in HIV+ children versus healthy controls, and assessed their relationship to carotid intima-media thickness (IMT). METHODS Evaluations were performed on 27 HIV+ children and 30 HIV-healthy controls (2-21 years) who were prospectively enrolled in our pediatric cohort. Measurements included internal carotid artery (ICA) and common carotid artery (CCA) IMT, fasting lipids, insulin, proinflammatory markers (TNF-alpha, soluble TNF receptors (sTNFR-I, -II), IL-6, high sensitivity C-reactive protein (hsCRP), myeloperoxidase (MPO)), and adhesion molecules (soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1 (sVCAM-1), von Willebrand factor). RESULTS Among HIV+, mean age was 11 years, 33% males, 70% black. 96% acquired HIV vertically; median CD4 count (CD4%) was 1058 (35%) cells/ml; 96% were on antiretroviral therapy (ART); 70% had HIV-1 RNA <50copies/ml. Groups were similar in age, race, sex, BMI, proinflammatory cytokines, adhesion markers, and carotid IMT except for hsCRP which was higher in HIV+ (P<0.001). In multiple regression analyses, hCRP, age, and female sex were positively associated with IMT. ART duration and sTNFR-II were positively associated with sVCAM-1. CONCLUSIONS This study shows increased hsCRP in HIV+ children compared to healthy controls. As seen in adults, hCRP was associated with carotid IMT, which support a role for inflammation in CVD risk of HIV+ children.

Longitudinal changes in carotid intima-media thickness and cardiovascular risk factors in human immunodeficiency virus-infected children and young adults compared with healthy controls.

Objectives: HIV-infected patients are at increased risk of cardiovascular disease (CVD). This study assessed longitudinal changes in carotid intima-media thickness (cIMT) as a surrogate marker for CVD, and determined the relationship between cIMT and cardiovascular risk factors in HIV-infected children/young adults. Methods: This was a longitudinal, observational study comparing cIMT, fasting metabolic profile, and C-reactive protein in HIV-infected subjects 2 to 21 years old to matched controls at baseline and 48 weeks. Results: Thirty-five HIV+ subjects and 37 controls were included in the analysis. Among HIV+ subjects, the median age was 10 years, body mass index was 18.7 kg/m2, 37% were male, CD4 count was 32%, 77% had HIV-RNA <400 copies/mL, and 86% were on antiretrovirals. At baseline, HIV+ had higher lipids and C-reactive protein. HIV-infected had higher internal carotid artery (ICA) and common carotid artery (CCA) IMT (mm) (ICA: HIV+, 0.90; controls, 0.78 [P = 0.01]; CCA: HIV+, 1.00; controls, 0.95 [P = 0.05]). At 48 weeks, CD4% increased and low-density lipoprotein decreased in HIV-infected subjects. ICA and CCA median changes for HIV-infected subjects were −0.23 and −0.15 mm, respectively (both P < 0.01). In controls, only CCA changed (P = 0.04). Between-group changes were not significant, except when only 31 perinatally infected HIV+ subjects and the controls were compared (CCA P = 0.04). In multiple regression analyses of HIV+ subjects, antiretroviral therapy duration and CD4% were associated with cIMT changes. Conclusions: Higher cIMT was found in HIV-infected subjects than in healthy controls, but at 48 weeks, cIMT was similar between groups. These data suggest that HIV-infected children/young adults are at high risk of CVD, but lipid control, immune restoration, and viral suppression with continuous antiretroviral therapy may prevent its worsening.

Rosiglitazone improves lipoatrophy in patients receiving thymidine-sparing regimens

Objective:Thymidine reverse transcriptase inhibitors (tNRTI) are strong inhibitors of PPAR-γ and clearly implicated as a cause of lipoatrophy. Thiazolidenediaones (TZD), potent PPAR-γ agonists, would be expected to be beneficial in HIV lipoatrophy, but prior studies have been conflicting. None specifically excluded the use of tNRTIs. We report the first study in individuals treated with tNRTI-sparing regimens using a TZD for treatment of HIV lipoatrophy. Design:This double-blind, placebo-controlled study evaluated limb fat in HIV-infected individuals with lipoatrophy who discontinued tNRTI at least 24 weeks prior to enrollment. Methods:Individuals were randomized to rosiglitazone vs. placebo for 48 weeks. Dual energy X-ray absorptiometry (DEXA)-scans and fasting metabolic assessments were serially performed. Results:We enrolled 71 individuals, 17% were female and 51% white. Baseline characteristics were similar between groups except for higher total cholesterol in the placebo group (P = 0.04). At 48 weeks, limb fat (grams) increased significantly (P = 0.02) more in the rosiglitazone than in the placebo group: median (IQR) 448 (138, 1670) vs. 153 (−100, 682), respectively. Of lipids parameters, only total cholesterol increased significantly more in the rosiglitazone group (P = 0.008). Prevalence of metabolic syndrome and total bone mineral density did not change between or within groups. Conclusion:In the absence of tNRTI, rosiglitazone significantly improves lipoatrophy without deleterious effect on bone mineral density. Total cholesterol, but not triglycerides, significantly increased in the rosiglitazone arm. The glitazones may be a promising addition for accelerating fat recovery in individuals who had switched off tNRTI and remain with significant lipoatrophy.

Increased mtDNA levels without change in mitochondrial enzymes in peripheral blood mononuclear cells of infants born to HIV-infected mothers on antiretroviral therapy.

Abstract Background: The effects of gestational nucleoside reverse transcriptase inhibitors (NRTIs) on mitochondrial DNA (mtDNA) are controversial. The effects of mtDNA depletion on mitochondrial function have not been assessed. Method: In peripheral blood mononuclear cells (PBMCs) from infants born to HIV-infected women and infants born to HIV-1-uninfected women, mtDNA copy numbers were determined by quantitative PCR; nuclear (COXIV)- and mitochondrial (COXII)-encoded polypeptides of the oxidative phosphorylation enzyme cytochrome c-oxidase (COX or complex IV) were quantified by Western blot. Results: Overall, 86 infants born to HIV-infected women and 50 controls were studied. HIV-infected mothers had a median CD4 count of 506 cells/μL; 59% had HIV RNA ≤ 50 copies/mL. No infant had clinical evidence of mitochondrial disease. The birth weight was lower (p = .016) and the body length higher (p = .002) in the HIV-exposed newborns. Eighty-one HIV-infected women had received gestational NRTIs (median duration 162 days). Median mtDNA copies/PBMC in the HIV-exposed infants were 505 (range, 120-1365) vs. 213 (27-426) in controls (p < .001). COX II/IV ratios were similar in both groups. Although mtDNA levels correlated inversely with maternal lactate, mitochondrial indices did not correlate with maternal CD4+ count, HIV RNA, smoking, or alcohol consumption. Conclusion: We found elevated mtDNA copy numbers in PBMC of infants born to HIV-infected women, the majority of whom received NRTI-based therapy, when compared to those born to healthy HIV-negative controls, but there was no difference in mtDNA-encoded respiratory chain protein. The clinical consequence of these findings is unknown and requires further investigations.

Frequency and risk factors for deep focus of infection in children with Staphylococcus aureus bacteremia.

Background: Staphylococcus aureus bacteremia (SAB) in children may be associated with development of deep-seated foci of infection, often prompting extensive diagnostic testing. The objective of this study was to establish the frequency and risk factors for deep foci of infection from SAB in pediatric patients. Methods: Medical charts of all children admitted with SAB to a tertiary-care center from January 1992 to June 2006 were reviewed. Study outcome was the presence of a deep focus of infection as documented by positive echocardiogram, bone imaging or abdominal imaging. Results: We studied 298 children, of whom 190 (64%) had echocardiograms, 116 (39%) had abdominal imaging, and 103 (35%) had bone imaging. Forty-seven subjects (16%) had symptoms of a deep focus of infection on discovery of SAB, which then was confirmed by 1 of the 3 tests. Eleven (3.7%) additional subjects had a clinically unsuspected deep focus identified before discharge. All children with an unsuspected deep focus of infection had either an underlying medical condition that potentially obscured the diagnosis or a central venous catheter. More than 1 day of positive blood cultures was associated with an unsuspected deep-seated infection (P < 0.01). Endocarditis was uncommon (2.7%), and occurred only in children with known congenital heart disease or with a central catheter. Conclusions: Deep-seated infections from SAB in children are most often clinically apparent at discovery of bacteremia. Unsuspected deep-seated infection is uncommon and confined to specific hosts. Routine diagnostic imaging is not indicated in all children with SAB.

Carotid Intima Media Thickness, Inflammatory Markers, and Endothelial Activation Markers in HIV Patients with Lipoatrophy Increased at 48 Weeks Regardless of Use of Rosiglitazone or Placebo

Rosiglitazone may be useful for the treatment of antiretroviral therapy-associated lipoatrophy, but an association with cardiovascular disease (CVD) has been questioned in diabetics. We evaluated rosiglitazones effect on surrogate markers of CVD in HIV-infected individuals with lipoatrophy. HIV(+) patients with lipoatrophy on thymidine-sparing regimens were randomized to rosiglitazone vs. placebo for 48 weeks. We serially assessed carotid IMT, fasting metabolic profiles, tumor necrosis factor (TNF)-α, soluble receptors (sTNFRI and II), interleukin (IL)-6, high-sensitivity C-reactive protein (hsCRP), myeloperoxidase (MPO), and endothelial activation markers [von Willebrand factor (vWF), soluble intercellular cell adhesion molecules-1 (sICAM-1), and vascular cell adhesion molecules-1 (sVCAM-1)]. Seventy-one subjects enrolled: 17% were female and 51%were white. Baseline characteristics were similar between groups except for higher total cholesterol in the placebo group (p = 0.04). At 48 weeks, common carotid artery (CCA) IMT changed significantly (p ≤ 0.05) within but not between the groups (p = 0.36): the median (IQR) increase was 0.10 (0.05, 0.25) mm and 0.15 (0, 0.25) mm in the rosiglitazone and placebo groups, respectively. hsCRP, sTNFRI and II, sVCAM-1, and vWF changed significantly (p ≤ 0.02) within but not between groups. Total cholesterol increased significantly in the rosiglitazone group (p = 0.008). In our study of virologically controlled subjects with lipoatrophy, rosiglitazone did not independently increase carotid IMT, endothelial activation, and inflammatory cytokines.