[show abstract][hide abstract] ABSTRACT: Those receiving tenofovir/emtricitabine (TDF-FTC) had greater bone loss compared with abacavir/lamivudine (ABC-3TC) in a randomized simplification trial (STEAL study). Previous studies associated increased bone turnover and bone loss with initiation of antiretroviral treatment, however it is unclear whether change in bone mineral density (BMD) was a result of specific drugs, from immune reconstitution or from suppression of HIV replication. This analysis determined predictors of BMD change in the hip and spine by dual-energy x-ray absorptiometry in virologically suppressed participants through week 96.
Bone turnover markers (BTMS) tested were: formation [bone alkaline phosphatase, procollagen type 1 N-terminal propeptide (P1NP)]; resorption (C-terminal cross-linking telopeptide of type 1 collagen [CTx]); and bone cytokine-signalling (osteoprotegerin, RANK ligand). Independent predictors of BMD change were determined using forward, stepwise, linear regression. BTM changes and fracture risk (FRAX®) at week 96 were compared by t-test. Baseline characteristics (n = 301) were: 98% male, mean age 45 years, current protease-inhibitor (PI) 23%, tenofovir/abacavir-naïve 52%. Independent baseline predictors of greater hip and spine bone loss were TDF-FTC randomisation (p ≤ 0.013), lower fat mass (p-trend ≤ 0.009), lower P1NP (p = 0.015), and higher hip T score/spine BMD (p-trend ≤ 0.006). Baseline PI use was associated with greater spine bone loss (p = 0.004). TDF-FTC increased P1NP and CTx through Wk96 (p<0.01). Early changes in BTM did not predict bone loss at week 96. No significant between-group difference was found in fracture risk.
Tenofovir/emtricitabine treatment, lower bone formation and lower fat mass predicted subsequent bone loss. There was no association between TDF-FTC and fracture risk.
PLoS ONE 01/2012; 7(6):e38377. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Biomarkers are being increasingly used in basic and clinical research of HIV disease as well as clinical management of infected individuals. Bone metabolism can be assessed by measurement of bone turnover markers, molecules released during bone formation and removal of old bone (resorption). In HIV-infected adults, there is a higher prevalence of low bone mineral density and fractures compared to the general population. This review discusses the findings regarding bone turnover markers in HIV-uninfected and -infected populations and their potential role in assessing fracture risk and predicting bone loss. Studies in postmenopausal women and elderly men show that increased bone turnover markers levels are associated with bone loss, and high levels of resorption markers may predict fractures independently of bone mineral density. Several HIV-related factors, including HIV infection and inflammation, have been found to affect the balance between bone formation and resorption. Some clinical studies found increased levels of bone turnover markers in HIV-infected adults compared to uninfected controls. Furthermore, bone turnover marker levels increased following initiation or switch to different antiretroviral agents in recent randomized trials. The clinical value of bone turnover markers is currently limited due to different sources of variability and limited data from studies in HIV-infected populations. Further research is needed to explore the potential value of bone turnover markers as additional measurements to bone mineral density in fracture risk assessment and monitoring treatment-induced bone effects in HIV-infected patients.
AIDS reviews 10/2011; 13(4):240-50. · 4.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: Despite virally suppressive combination antiretroviral therapy (cART), some HIV-infected patients exhibit suboptimal CD4(+) T-cell recovery. This study aimed to determine the effect of intensification of cART with raltegravir or addition of hyperimmune bovine colostrum (HIBC) on CD4(+) T-cell count in such patients.
We randomized 75 patients to 4 treatment groups to receive raltegravir, HIBC, placebo, or both raltegravir and HIBC in a factorial, double-blind study. The primary endpoint was time-weighted mean change in CD4(+) T-cell count from baseline to week 24. T-cell activation (CD38(+) and HLA-DR(+)), plasma markers of microbial translocation (lipopolysaccharide, 16S rDNA), monocyte activation (soluble (s) CD14), and HIV-RNA (lowest level of detection 4 copies/mL) were monitored. Analysis was performed using linear regression methods.
Compared with placebo, the addition of neither raltegravir nor HIBC to cART for 24 weeks resulted in a significant change in CD4(+) T-cell count (mean difference, 95% confidence interval [CI]: 3.09 cells/μL, -14.27; 20.45, P = .724 and 9.43 cells/μL, -7.81; 26.68, P = .279, respectively, intention to treat). There was no significant interaction between HIBC and raltegravir (P = .275). No correlation was found between CD4(+) T-cell count and plasma lipopolysaccharide, 16S rDNA, sCD14, or HIV-RNA.
The determinants of poor CD4(+) T-cell recovery following cART require further investigation.
ClinicalTrials.gov identifier: NCT00772590, Australia New Zealand Clinical Trials Registry: ACTRN12609000575235.
The Journal of Infectious Diseases 09/2011; 204(10):1532-40. · 5.85 Impact Factor
[show abstract][hide abstract] ABSTRACT: Histamine is a chemical mediator that acts at four known types of histamine receptors and has been widely implicated in the development of nociception and neuropathic pain. Blocking histamine H(1) and H(2) receptors has been shown to reduce hyperalgesia following nerve injury, but the role of histamine H(3) and H(4) receptors in neuropathic pain has not been studied. Here, we used blockers of histamine H(3) and H(4) receptors to assess their effects on neuropathic pain behavior and mast cell numbers following peripheral nerve injury. In addition, we assessed the effect of activating H(4) receptors on neuropathic pain behavior.
Rats were subjected to a partial ligation of the sciatic nerve, a model of neuropathic pain, and were treated either systemically or locally (hindpaw) with the H(3)/H(4) receptor inverse agonist thioperamide, the specific H(4) receptor antagonist JNJ 7777120, or the H(4) receptor agonist VUF 8430. Measurements of mechanical hyperalgesia were carried out by Randall-Selitto test for 1-3 weeks, and sciatic nerve tissues were analyzed for numbers of intact mast cells by histology at 9 h after surgery.
Rats treated with thioperamide or JNJ 7777120 showed significantly enhanced mechanical hyperalgesia after partial ligation of the sciatic nerve. The number of intact mast cells in the injured nerve of these rats was higher than in control rats suggesting reduced mast cell degranulation, but was still significantly lower than in intact nerves. Rats treated with VUF 8430 showed significantly reduced mechanical hyperalgesia.
We propose that the increase in mechanical hyperalgesia produced by thioperamide and JNJ 7777120 and the decrease in mechanical hyperalgesia produced by VUF 8430 may represent a direct effect of these agents on mechanospecific primary afferents, or an indirect effect of these agents via injury-induced inflammation.