Treatment of Human Immunodeficiency Virus Infection With Tenofovir Disoproxil Fumarate-Containing Antiretrovirals Maintains Low Bone Formation Rate, But Increases Osteoid Volume on Bone Histomorphometry

The anti-HIV drug abacavir stimulates β-catenin activity in osteoblast lineage cells

Bone mineral density (BMD) loss in people living with HIV occurs with the initiation of combined antiretroviral therapy (cART), particularly with tenofovir disoproxil fumarate (TDF) containing cART. Switching from TDF to abacavir (ABC) or dolutegravir (DTG) leads to increased BMD. Whether BMD gains are due to cessation of TDF or anabolic effects of ABC or DTG is unclear. We investigated the effects of ABC and DTG on osteoblast lineage cells in vitro and in vivo. Primary human osteoblasts and male C57BL/6 mice were treated with individual antiretrovirals (ARVs) or a combination of ABC/DTG/lamivudine (3TC). Nearly all ARVs and cART inhibited osteogenic activity in vitro. Due to the importance of Wnt/β-catenin in bone formation, we further investigated ARV effects on the Wnt/β-catenin pathway. ABC, alone and as part of ABC/DTG/3TC, increased osteoblastic β-catenin activity as indicated by increased TOPFlash activity, hypo-phosphorylated (active) β-catenin staining, and β-catenin targeted gene expression. Mice treated with TDF had decreased lumbar spine BMD and trabecular connectivity density in the vertebrae, while those treated with ABC/DTG/3TC reduced cortical area and thickness in the femur. Mice treated with ABC alone had no bone structural changes, increased circulating levels of the bone formation marker, P1NP, and elevated expression of the Wnt/β-catenin target gene, Lef1, in osteocyte enriched samples. Further, bones from ARV-treated mice were isolated to evaluate ARV distribution. All ARVs were detected in the bone tissue, which was inclusive of bone marrow, but when bone marrow was removed, only TDF, ABC, and DTG were detected at ~0.1% of the circulating levels. Overall, our findings demonstrate that ABC activates Wnt/β-catenin signaling, but whether this leads to increased bone formation requires further study. Assessing the impact of ARVs on bone is critical to informing ARV selection and/or discovery of regimens that do not negatively impact the skeleton.

Effects of Tenofovir Disoproxil Fumarate on Bone Quality beyond Bone Density-A Scoping Review of the Literature

Tenofovir disoproxil fumarate (TDF) is a widely used pharmacological agent for the treatment of human immunodeficiency virus infection. While prolonged exposure to TDF has been associated with a decrease in bone mineral density (BMD) and increased fracture risk, limited discussion exists on its effects on various aspects of bone quality. This scoping review aims to provide a comprehensive overview of the impact of TDF on bone quality beyond BMD. A literature search was conducted using the PubMed and Scopus databases to identify studies investigating the effects of TDF on bone quality. Original research articles written in English, irrespective of study type or publication year, were included in the review. Seven articles met the inclusion criteria. Findings indicate that prolonged exposure to TDF adversely affects bone microarchitecture and strength, impeding fracture healing and skeletal microdamage repair. The observed effects suggest a complex interplay involving bone cell signalling, cytokines and bone remodelling processes as potential mechanisms underlying TDF's impact on bone quality. As a conclusion, TDF impairs bone remodelling and microarchitecture by influencing dynamic bone cell behaviour and signalling pathways. Future studies should delve deeper into understanding the intricate negative effects of TDF on bone and explore strategies for reversing these effects.

Bone Health in People Living with HIV/AIDS: An Update of Where We Are and Potential Future Strategies

The developments in Human Immunodeficiency Virus (HIV) treatment and in the care of people living with HIV (PLWHIV) and Acquired Immunodeficiency Syndrome (AIDS) over the last three decades has led to a significant increase in life expectancy, on par with HIV-negative individuals. Aside from the fact that bone fractures tend to occur 10 years earlier than in HIV-negative individuals, HIV is, per se, an independent risk factor for bone fractures. A few available antiretroviral therapies (ARVs) are also linked with osteoporosis, particularly those involving tenofovir disoproxil fumarate (TDF). HIV and hepatitis C (HCV) coinfection is associated with a greater risk of osteoporosis and fracture than HIV monoinfection. Both the Fracture Risk Assessment Tool (FRAX) and measurement of bone mineral density (BMD) via a DEXA scan are routinely used in the assessment of fracture risk in individuals living with HIV, as bone loss is thought to start between the ages of 40 and 50 years old. The main treatment for established osteoporosis involves bisphosphonates. Supplementation with calcium and vitamin D is part of clinical practice of most HIV centers globally. Further research is needed to assess (i) the cut-off age for assessment of osteoporosis, (ii) the utility of anti-osteoporotic agents in PLWHIV and (iii) how concomitant viral infections and COVID-19 in PLWHIV can increase risk of osteoporosis.

Bone Quality in Relation to HIV and Antiretroviral Drugs

PURPOSE OF REVIEW

People living with HIV (PLWH) are at an increased risk for osteoporosis, a disease defined by the loss of bone mineral density (BMD) and deterioration of bone quality, both of which independently contribute to an increased risk of skeletal fractures. While there is an emerging body of literature focusing on the factors that contribute to BMD loss in PLWH, the contribution of these factors to bone quality changes are less understood. The current review summarizes and critically reviews the data describing the effects of HIV, HIV disease-related factors, and antiretroviral drugs (ARVs) on bone quality.

RECENT FINDINGS

The increased availability of high-resolution peripheral quantitative computed tomography has confirmed that both HIV infection and ARVs negatively affect bone architecture. There is considerably less data on their effects on bone remodeling or the composition of bone matrix. Whether changes in bone quality independently predict fracture risk, as seen in HIV-uninfected populations, is largely unknown. The available data suggests that bone quality deterioration occurs in PLWH. Future studies are needed to define which factors, viral or ARVs, contribute to loss of bone quality and which bone quality factors are most associated with increased fracture risk.

Osteoporosis and HIV Infection

Life expectancy of people living with HIV (PLWH) is now close to that of the HIV-uninfected population. As a result, age-related comorbidities, including osteoporosis, are increasing in PLWH. This narrative review describes the epidemiology of bone fragility in PLWH, changes of bone features over the course of HIV infection and their determinants, as well as the available evidence regarding the management of osteoporosis in PLWH. The risk of fracture is higher and increases about 10 years earlier compared to the general population. The classical risk factors of bone fragility are very widespread and are major determinants of bone health in this population. The majority of bone loss occurs during virus replication and during immune reconstitution at antiretroviral therapies (ART) initiation, which both increase osteoclast activity. Abnormalities in bone formation and mineralization have also been shown in histomorphometric studies in untreated PLWH. Measurement of bone mineral density (BMD) is the first line tool for assessing fracture risk in postmenopausal women, men above 50 years, and other HIV-infected patients with clinical risk factors for osteoporosis. FRAX underestimates fracture probability in PLWH. In case of indication for anti-osteoporotic drug, bisphosphonates remain the reference option. Calcium and vitamin D supplementation should be considered as ART initiation, since it may attenuate bone loss at this stage. Bone-protective ART regimens improve BMD compared to other regimens, but to a lesser extent than bisphosphonate, and without available data on their influence on the incidence of fracture.

Bone deleterious effects of different nrtis in treatment-naïve HIV patients after 12 and 48 weeks of treatment

Background

Bone alterations have been observed in the course of HIV infection, characterized by a marked decrease in bone mineral density (BMD) and an increase in the frequency of fractures as a result of fragility. We aim to evaluate early changes in bone metabolic profile and the possible association with tenofovir and other nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs) in treatment-naïve HIV patients.

Methods

We conducted a prospective study in naïve HIV-infected adults (under 50 years), separated into three groups according to NRTI therapy: tenofovir disoproxil fumarate (TDF); tenofovir alafenamide (TAF) and abacavir (ABC). BMD and epidemiological, immunological and metabolic bone parameters were evaluated. Bone markers were analyzed in plasma at baseline, 12 and 48 weeks after initiating treatment.

Results

Average age of patients was 34.8 years (± 9.6). 92.4% of them with CD4 count > 200 cel/μL. At week 12 after starting treatment, both TDF [increase in PN1P (31.7%, p = 0.004), TRAP (11.1%, p = 0.003), OPN (19.3%, p = 0.045) and OC (38.6%, p = 0.001); decrease in OPG (-23.4%, p = 0.003)] and TAF [increase in 42.6% for CTX (p = 0.011), 27.3% for OC (p = 0.001) and 21% for TRAP (p = 0.008); decrease in OPG (-28.8%, p = 0.049)] presented a deep resorption profile compared to ABC, these differences in bone molecular markers, a tendency to equalize at week 48, where no significant differences were observed. Patients treated with TDF showed the greatest decrease in Z-score in both lumbar spine (LS) and femoral neck (FN) at week 48 without statistically significant differences.

Conclusion

Treatment-naïve HIV patients have a high prevalence of low bone density. Treatment with TDF is associated with greater bone deterioration at 12 and 48 weeks. TAF seems to present similar early bone deterioration at 12 weeks which disappears at 48 weeks.

Epigenetic Age in Young African American Adults With Perinatally Acquired HIV

BACKGROUND

Prior studies have measured accelerated aging in people with HIV using a DNA methylation (DNAm)-based biomarker of aging, "epigenetic age," but data are limited in African American (AA) young adults with perinatally acquired HIV infection (PHIV).

METHODS

We performed a cross-sectional study of AA young adults aged 20-35 years with PHIV (N = 31) and seronegative controls (N = 30) using DNAm measured in whole blood and cognitive function measured by the NIH Toolbox. Illumina EPIC array was used to measure DNAm age and accelerated aging markers including epigenetic age acceleration (EAA), as well as extrinsic (EEAA) and intrinsic (IEAA) EAA.

RESULTS

PHIV and controls did not differ by sex (45 vs. 43% male), chronological age (26.2 vs. 28.0 years), or ethnicity. Chronological age and DNAm age were correlated (r = 0.56, P < 0.01). PHIV had a higher mean EAA (2.86 ± 6.5 vs. -2.96 ± 3.9, P < 0.01) and EEAA (4.57 ± 13.0 vs. -4.72 ± 6.0, P < 0.01) than controls; however, IEAA was not different between groups. Among PHIV, EAA and EEAA were higher in those with HIV viral load ≥50 copies/mL than <50 copies/mL (EEA: 8.1 ± 5.2 vs. 0.11 ± 5.5, P = 0 < 0.01 and EEAA: 16.1 ± 10.6 vs. -1.83 ± 9.7, P < 0.01). We observed negative correlations (r = -0.36 to -0.31) between EEAA and executive function, attention, and language scores.

CONCLUSIONS

In conclusion, EAA in blood was observed in AA young adults with PHIV on ART using 2 measures, including EEAA which upweights the contribution of immunosenescent cell types. However, there was no evidence of age acceleration with a measure independent of cell type composition.

People living with HIV and fracture risk

PLHIV have an increased risk of osteoporosis and fractures when compared with people of the same age and sex. In this review, we address the epidemiology and the pathophysiology of bone disease and fractures in PLHIV. The assessment of fracture risk and fracture prevention in these subjects is also discussed. The spectrum of HIV-associated disease has changed dramatically since the introduction of potent antiretroviral drugs. Today, the survival of people living with HIV (PLHIV) is close to that of the general population. However, the longer life-span in PLHIV is accompanied by an increased prevalence of chronic diseases. Detrimental effects on bone health are well recognised, with an increased risk of osteoporosis and fractures, including vertebral fractures, compared to the general population. The causes of bone disease in PLHIV are not fully understood, but include HIV-specific risk factors such as use of antiretrovirals and the presence of chronic inflammation, as well as traditional risk factors for fracture. Current guidelines recommend the use of FRAX to assess fracture probability in PLHIV age ≥ 40 years and measurement of bone mineral density in those at increased fracture risk. Vitamin D deficiency, if present, should be treated. Bisphosphonates have been shown to increase bone density in PLHIV although fracture outcomes are not available.

A novel two-step, direct-to-PCR method for virus detection off swabs using human coronavirus 229E

Background

Currently, one of the most reliable methods for viral infection detection are polymerase chain reaction (PCR) based assays. This process is time and resource heavy, requiring multiple steps of lysis, extraction, purification, and amplification procedures. Herein, we have developed a method to detect virus off swabs using solely shaker-mill based mechanical lysis and the transfer of the viral lysate directly to a PCR assay for virus detection, bypassing the substantial reagent and time investments required for extraction and purification steps.

Methods

Using Human Coronavirus 229E (HCoV-229E) as a model system, we spiked swabs in vitro for proof-of-concept testing. Swabs were spiked in serial dilutions from 1.2 × 10⁶ to 1.2 × 10¹ copies/mL and then placed in 2 mL tubes with viral transport media (VTM) to mimic the specimen collection procedures in the clinic prior to processing via shaker-mill homogenization. After homogenization, 1 μL of lysate was processed using RT-qPCR for amplification of the nucleocapsid (N) gene, qualifying viral detection.

Results

HCoV-229E in vitro spiked swabs were processed in a novel two-step, direct-to-PCR methodology for viral detection. After running 54 swabs, we confidently determined our limit of detection to be 1.2 × 10³ viral copies/mL with 96.30% sensitivity.

Conclusion

We have proven that the shaker-mill homogenization-based two-step, direct-to-PCR procedures provides sufficient viral lysis off swabs, where the resulting lysate can be used directly in PCR for the detection of HCoV-229E. This finding allows for reductions in the time and resources required for PCR based virus detection in comparison to the traditional extraction-to-PCR methodology.

Bone Update: Is It Still an Issue Without Tenofovir Disoproxil Fumarate?

PURPOSE OF REVIEW

In the era of modern bone-friendly antiretroviral therapy (ART) regimens for people living with HIV (PLWH), this review discusses the research gaps and management concerns that remain for individuals who have already been exposed to ART with negative effects on bone metabolism, especially children and adolescents who have not acquired peak bone mass, and older adults who have additional risk factors for fracture.

RECENT FINDINGS

Data now support the use of avoidance of TDF and use of bone-friendly regimens that include integrase strand transfer inhibitors in PLWH with increased risk of fracture for either ART initiation or switch. Despite significant advances in our understanding of ART choice for PLWH with regard to bone health, additional diagnostic tests to determine fracture risk and management strategies beyond ART choice are necessary, especially in vulnerable PLWH populations, such as children and adolescents and older adults.