Managing HIV peripheral neuropathy

Feasibility of therapeutic Chinese massage (tui na) for peripheral neuropathy among people with human immunodeficiency virus: findings of a pilot randomized controlled trial

Background

Peripheral neuropathy (PN) is prevalent in people with human immunodeficiency virus (PHIV) with no Food and Drug Administration-approved treatment. Therapeutic Chinese massage (TCM) is a promising noninvasive and non-harmful intervention for HIV-related PN. However, relevant research is lacking. The purpose of this study is to evaluate the feasibility of TCM for HIV-related PN.

Method

We conducted a pilot, single-centered, two-arm, double-blinded, randomized controlled trial. Twenty eligible PHIV were recruited primarily from the AIDS Foundation Houston, Inc. in Texas and were randomly assigned into two groups. Ten participants in the intervention group received three weekly 25-min TCM sessions by a certified TCM therapist. The remaining ten control group participants received the same therapist's three weekly 25-min placebo massage sessions on their lower extremities. The outcome was the feasibility of this study as measured by recruitment and completion rates, participant safety, and treatment adherence and compliance, as well as the effect size of the intervention.

Results

The study population comprised 20 PHIV (mean age 55.23). This study showed high feasibility as measured by a high rate of recruitment, a 100% rate of completion, and zero serious adverse events. As we inquired 21 respondents for eligibility for the study, all except one had HIV-related PN. All respondents were willing to participate in the study and adhered to the group assignment after they enrolled in the study. The participants' baseline pain was at a medium to a high level (6.30 [2.15] out of 10).

Conclusion

Chinese massage is a feasible intervention in PHIV. Future relevant randomized controlled trials are expected.

Clinical trial registration

https://clinicaltrials.gov/, NCT05379140.

Tui Na for painful peripheral neuropathy in people with human immunodeficiency virus: A randomized, double-blind, placebo-controlled trial protocol

Background

Peripheral neuropathy (PN), including numbness, loss of sensation, paresthesia, a burning sensation, and stabbing pain in extremities, is a common complication in people with human immunodeficiency virus (PHIV). Medications commonly used to treat HIV-related PN are not effective and lead to many side effects. HIV-related PN symptoms may be alleviated or treated with a series of therapeutic Chinese foot massages (TCFM), which are non-invasive and relatively safe. However, relevant studies are lacking.

Study design

This proposed trial is a prospective, two-arm, parallel, double-blinded, randomized controlled trial.

Aim

This proposed trial aims to assess the effectiveness of TCFM on HIV-related PN in people with HIV (PHIV).

Outcomes

The primary outcomes, measured at baseline, end of TCFM/placebo, and twelve weeks after, include (1), lower extremity pain, (2) lower extremity functioning, and (3) health-related quality of life. The secondary outcomes, measured throughout the trial process, include (1) recruitment and completion rate (No. of referred, No. of eligible, No. of enrolled, No. of withdrawals, trial recruitment rate, and trial completion rate), (2) participants' safety (No. and severity of adverse events), (3) treatment adherence (average time of each message session, No. of completed sessions, and No. of missed sessions), and (4) compliance (No. of participants completing the trial following the initial group assignment).

Sample size

An estimated 142 participants in total, or 71 participants in each arm, will be needed for this trial.

Trial status

This trial was registered at ClinicalTrials.gov of the National Institute of Health on Oct 26, 2022 (ClinicalTrials.gov Identifier: NCT05596123). The researchers expect to recruit participants starting in Feb. 2023 and ending in Feb 2025.

Neuropathy in Human Immunodeficiency Virus: A Review of the Underlying Pathogenesis and Treatment

This article explores the various causes of the human immunodeficiency virus (HIV), and its associated neuropathy, including the effects of HIV on the nervous system and the long-standing therapy that is often provided to patients with HIV. Several studies regarding the neurotoxic effects of combined antiretroviral therapy (cART) and HIV were reviewed and various hypotheses were discussed. Furthermore, we present the nature of HIV-sensory neuropathy (HIV-SN) among different demographic populations and their subsequent risk factors predisposing them to this condition. It was observed that the incidence of the disease increases in increased survival of the patients as well as in males. Finally, the current approach to HIV-SN and its overlapping features with other causes of peripheral neuropathy have been discussed which demonstrates that a clinical examination is the most important clue for a healthcare professional to suspect the disease. Our main aim was to study the current perspectives and guidelines for diagnosing and managing a patient with HIV-SN to reduce disease prevalence and bring about a more aware frame of mind when following up with an HIV patient.

Expression of Human Immunodeficiency Virus Transactivator of Transcription (HIV-Tat1-86) Protein Alters Nociceptive Processing that is Sensitive to Anti-Oxidant and Anti-Inflammatory Interventions

Despite the success of combined antiretroviral therapy (cART) in reducing viral load, a substantial portion of Human Immunodeficiency Virus (HIV)+ patients report chronic pain. The exact mechanism underlying this co-morbidity even with undetectable viral load remains unknown, but the transactivator of transcription (HIV-Tat) protein is of particular interest. Functional HIV-Tat protein is observed even in cerebrospinal fluid of patients who have an undetectable viral load. It is hypothesized that Tat protein exposure is sufficient to induce neuropathic pain-like manifestations via both activation of microglia and generation of oxidative stress. iTat mice conditionally expressed Tat_(1-86) protein in the central nervous system upon daily administration of doxycycline (100 mg/kg/d, i.p., up to 14 days). The effect of HIV-Tat protein exposure on the well-being of the animal was assessed using sucrose-evoked grooming and acute nesting behavior for pain-depressed behaviors, and the development of hyperalgesia assessed with warm-water tail-withdrawal and von Frey assays for thermal hyperalgesia and mechanical allodynia, respectively. Tissue harvested at select time points was used to assess ex vivo alterations in oxidative stress, astrocytosis and microgliosis, and blood-brain barrier integrity with assays utilizing fluorescence-based indicators. Tat protein induced mild thermal hyperalgesia but robust mechanical allodynia starting after 4 days of exposure, reaching a nadir after 7 days. Changes in nociceptive processing were associated with reduced sucrose-evoked grooming behavior without altering acute nesting behavior, and in spinal cord dysregulated free radical generation as measured by DCF fluorescence intensity, altered immunohistochemical expression of the gliotic markers, Iba-1 and GFAP, and increased permeability of the blood-brain barrier to the small molecule fluorescent tracer, sodium fluorescein, in a time-dependent manner. Pretreatment with the anti-inflammatory, indomethacin (1 mg/kg/d, i.p.), the antioxidant, methylsulfonylmethane (100 mg/kg/d i.p.), or the immunomodulatory agent, dimethylfumarate (100 mg/kg/d p.o.) thirty minutes prior to daily injections of doxycycline (100 mg/kg/d i.p.) over 7 days significantly attenuated the development of Tat-induced mechanical allodynia. Collectively, the data suggests that even acute exposure to HIV-1 Tat protein at pathologically relevant levels is sufficient to produce select neurophysiological and behavioral manifestations of chronic pain consistent with that reported by HIV-positive patients.

Sympathetic Nerves and Innate Immune System in the Spleen: Implications of Impairment in HIV-1 and Relevant Models

The immune and sympathetic nervous systems are major targets of human, murine and simian immunodeficiency viruses (HIV-1, MAIDS, and SIV, respectively). The spleen is a major reservoir for these retroviruses, providing a sanctuary for persistent infection of myeloid cells in the white and red pulps. This is despite the fact that circulating HIV-1 levels remain undetectable in infected patients receiving combined antiretroviral therapy. These viruses sequester in immune organs, preventing effective cures. The spleen remains understudied in its role in HIV-1 pathogenesis, despite it hosting a quarter of the body’s lymphocytes and diverse macrophage populations targeted by HIV-1. HIV-1 infection reduces the white pulp, and induces perivascular hyalinization, vascular dysfunction, tissue infarction, and chronic inflammation characterized by activated epithelial-like macrophages. LP-BM5, the retrovirus that induces MAIDS, is a well-established model of AIDS. Immune pathology in MAIDs is similar to SIV and HIV-1 infection. As in SIV and HIV, MAIDS markedly changes splenic architecture, and causes sympathetic dysfunction, contributing to inflammation and immune dysfunction. In MAIDs, SIV, and HIV, the viruses commandeer splenic macrophages for their replication, and shift macrophages to an M2 phenotype. Additionally, in plasmacytoid dendritic cells, HIV-1 blocks sympathetic augmentation of interferon-β (IFN-β) transcription, which promotes viral replication. Here, we review viral–sympathetic interactions in innate immunity and pathophysiology in the spleen in HIV-1 and relevant models. The situation remains that research in this area is still sparse and original hypotheses proposed largely remain unanswered.

Prevalent neuropathy in a cohort of HIV-infected Kenyan sex workers using antiretroviral drugs

INTRODUCTION

Several risk factors including stavudine and age have been strongly associated with polyneuropathy. However, conflicting data exist on height as an independent risk factor in polyneuropathy. The objective of this study is to exclude height as an independent polyneuropathy risk factor in a cohort of human immunodeficiency virus (HIV)-infected Kenyan sex workers.

METHODS

This was an analysis of prospectively collected data of treatment-naive subjects initiating either stavudine or tenofovir diphosphate fumarate or zidovudine-based antiretroviral therapy (ART) regimens from January 2008 to August 2012. Polyneuropathy was characterised as burning sensation, numbness, or dysesthesia. The study used arithmetic means of weight (kg) and height (cm) measured in duplicates using calibrated scales.

RESULTS

After exclusion of duplicate data sets and un-confirmed cases of polyneuropathy, the study identified 212 patients without polyneuropathy, 14 pre-ART and 94 post-ART related polyneuropathy cases. Polyneuropathy cases were older but did not differ in demographic, clinical and laboratory parameters at baseline. There was a significant difference in first-line ART regimens with more patients on tenofovir disoproxil fumarate in the post-ART group (p=0.017).

CONCLUSION

Polyneuropathy is a common disorder among HIV-infected Kenyan sex workers. These data cannot support the postulated increased risk by height after matching for gender and ART duration. Though stavudine is associated with polyneuropathy, in this study many patients previously not exposed to stavudine developed polyneuropathy. This suggests the involvement of unknown risk factors such as genetic and metabolite differences in the development of polyneuropathy.

Unraveling the pathogenesis of HIV peripheral neuropathy: insights from a simian immunodeficiency virus macaque model

Peripheral neuropathy (PN) is the most frequent neurologic complication in individuals infected with human immunodeficiency virus (HIV). It affects over one third of infected patients, including those receiving effective combination antiretroviral therapy. The pathogenesis of HIV-associated peripheral neuropathy (HIV-PN) remains poorly understood. Clinical studies are complicated because both HIV and antiretroviral treatment cause damage to the peripheral nervous system. To study HIV-induced peripheral nervous system (PNS) damage, a unique simian immunodeficiency virus (SIV)/pigtailed macaque model of HIV-PN that enabled detailed morphologic and functional evaluation of the somatosensory pathway throughout disease progression was developed. Studies in this model have demonstrated that SIV induces key pathologic features that closely resemble HIV-induced alterations, including inflammation and damage to the neuronal cell bodies in somatosensory ganglia and decreased epidermal nerve fiber density. Insights generated in the model include: finding that SIV alters the conduction properties of small, unmyelinated peripheral nerves; and that SIV impairs peripheral nerve regeneration. This review will highlight the major findings in the SIV-infected pigtailed macaque model of HIV-PN, and will illustrate the great value of a reliable large animal model to show the pathogenesis of this complex, HIV-induced disorder of the PNS.

Over-reported peripheral neuropathy symptoms in a cohort of HIV infected and uninfected Rwandan women: the need for validated locally appropriate questionnaires

BACKGROUND

Peripheral neuropathy symptoms (PNS) are commonly manifested in HIV-infected (HIV+) individuals, although data are limited on the prevalence and predictors of PNS in HIV+ patients from sub-Saharan Africa.

OBJECTIVE

To determine the prevalence and predictors of PNS in HIV+ and HIV-uninfected (HIV-) Rwandan women.

METHODS

Data were analysed from 936 (710 HIV+ and 226 HIV-) women from the Rwanda Women Interassociation Study and Assessment (RWISA), an observational prospective cohort study investigating the effectiveness and toxicity of ART in HIV+ women.

RESULTS

Of 936 enrolled, 920 (98.3%) were included in this analysis with 44% of HIV- and 52% of the HIV+ women reporting PNS (p=0.06). CD4+ count was not associated with PNS, although there was a non-significant trend towards higher prevalence in those with lower CD4+ counts. For the HIV- women, only alcohol and co-trimoxazole use were independently associated with PNS. WHO HIV stage IV illness and albumin ≤ 3.5 were associated with PNS in HIV+ women.

CONCLUSIONS

The rate of peripheral neuropathy symptoms reported in this cohort of HIV-infected African women seems implausible, and rather suggests that the screening tool for peripheral neuropathy in culturally diverse African settings be locally validated.

Loss of corneal sensory nerve fibers in SIV-infected macaques: an alternate approach to investigate HIV-induced PNS damage

Peripheral neuropathy is the most frequent neurological complication of HIV infection, affecting more than one-third of infected patients, including patients treated with antiretroviral therapy. Although emerging noninvasive techniques for corneal nerve assessments are increasingly being used to diagnose and monitor peripheral neuropathies, corneal nerve alterations have not been characterized in HIV. Here, to determine whether SIV infection leads to corneal nerve fiber loss, we immunostained corneas for the nerve fiber marker βIII tubulin. We developed and applied both manual and automated methods to measure nerves in the corneal subbasal plexus. These counting methods independently indicated significantly lower subbasal corneal nerve fiber density among SIV-infected animals that rapidly progressed to AIDS compared with slow progressors. Concomitant with decreased corneal nerve fiber density, rapid progressors had increased levels of SIV RNA and CD68-positive macrophages and expression of glial fibrillary acidic protein by glial satellite cells in the trigeminal ganglia, the location of the neuronal cell bodies of corneal sensory nerve fibers. In addition, corneal nerve fiber density was directly correlated with epidermal nerve fiber length. These findings indicate that corneal nerve assessment has great potential to diagnose and monitor HIV-induced peripheral neuropathy and to set the stage for introducing noninvasive techniques to measure corneal nerve fiber density in HIV clinical settings.

Insulin-like growth factor-1 prevents dorsal root ganglion neuronal tyrosine kinase receptor expression alterations induced by dideoxycytidine in vitro

Dideoxycytidine (zalcitabine, ddC) produces neurotoxic effects. It is particularly important to understand the toxic effects of ddC on different subpopulations of dorsal root ganglion (DRG) neurons which express distinct tyrosine kinase receptor (Trk) and to find therapeutic factors for prevention and therapy for ddC-induced peripheral sensory neuropathy. Insulin-like growth factor-1 (IGF-1) has been shown to have neurotrophic effects on DRG sensory neurons. However, little is known about the effects of ddC on distinct Trk (TrkA, TrkB, and TrkC) expression in DRG neurons and the neuroprotective effects of IGF-1 on ddC-induced neurotoxicity. Here, we have tested the extent to which the expression of TrkA, TrkB, and TrkC receptors in primary cultured DRG neurons is affected by ddC in the presence or absence of IGF-1. In this experiment, we found that exposure of 5, 25, and 50 μmol/L ddC caused a dose-dependent decrease of the mRNA, protein, and the proportion of TrkA-, TrkB-, and TrkC-expressing neurons. IGF-1 (20 nmol/L) could partially reverse the decrease of TrkA and TrkB, but not TrkC, expression with ddC exposure. The phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 (10 μmol/L) blocked the effects of IGF-1. These results suggested that the subpopulations of DRG neurons which express distinct TrkA, TrkB, and TrkC receptors were affected by ddC exposure. IGF-1 might relieve the ddC-induced toxicity of TrkA- and TrkB-, but not TrkC-expressing DRG neurons. These data offer new clues for a better understanding of the association of ddC with distinct Trk receptor expression and provide new evidence of the potential therapeutic role of IGF-1 on ddC-induced neurotoxicity.

HIV neuropathy induced Charcot neuroarthropathy: a case discussion

Charcot neuroarthropathy is a devastating joint condition that affects persons with neuropathy. With HIV/AIDS treatments prolonging the lives of these persons, it is likely that long-term sequelae of the disease will become more evident in the near future. Patients with this disease frequently develop peripheral neuropathy. A high index of suspicion must be raised in any patient with peripheral neuropathy of any cause and a red, hot, swollen, painful foot for Charcot neuroarthropathy to give these patients proper treatment to help prevent the devastating effects of Charcot neuropathy with its potential consequences including foot ulceration and amputation. We present a case of an individual with HIV peripheral neuropathy and Charcot neuroarthropathy.

Lipodystrophy and adrenal insufficiency: potential mediators of peripheral neuropathy in HIV infection?

The mechanisms behind certain co-morbid conditions associated with chronic HIV disease still remain elusive. HIV-associated peripheral neuropathy is one among those rarely studied manifestations in HIV-1 infection. Numerous underlying factors associated with peripheral neuropathy have been described in HIV disease. Herein, we hypothesized certain heretofore undescribed potential mechanisms that lead to HIV associated neuropathy. Being a multifactoral manifestation, HIV-associated neuropathy is presumed to have an association with physiological factors namely, adrenal inadequacy/steroid resistance and lipodystrophy-induced cushion-effect loss in peripheral nerves. Therefore, management of the adrenals with steroids at the time-point of high inflammatory burden thereby preventing lipodystrophy by selecting the optimum treatment regimen could markedly alleviate the severity of HIV-associated neuropathic manifestations.

Epidemiology of HIV-related neuropathy: a systematic literature review

We sought to identify and summarize the incidence and prevalence of neuropathy among HIV patients and subgroups. A systematic search of the literature was performed using MEDLINE and EMBASE. The relevant literature was identified based on predefined criteria. Prevalence data were collected from cross-sectional and cohort studies. Incidence data were collected from cohort and case-control studies. Thirty-seven studies were included of which there were 23 cohort studies, 13 cross-sectional studies, and one case-control study. The prevalence of neuropathy among HIV patients derived from 25 studies varied from 1.2% to 69.4%. Regarding the development of neuropathy among HIV-positive patients, standardized by study duration, the rates per 100 person-years ranged from 0.7 to 39.7. Among older patients there is a greater risk of neuropathy. The same seems to be the case for patients with more severe disease. Currently available studies providing information on the incidence and prevalence of neuropathy among HIV patients suggest a significant burden, but there is a great variation in results across studies. There is no definitive explanation for the variation. However, it underscores the fact that complexity of the disease, along with absence of standardized diagnostic criteria, has considerably influenced the methodologies and outcomes of the studies.

Delineating HIV-associated neurocognitive disorders using transgenic models: the neuropathogenic actions of Vpr

HIV-associated neurocognitive disorders (HAND) represent a constellation of neurological disabilities defined by neuropsychological impairments, neurobehavioral abnormalities and motor deficits. To gain insights into the mechanisms underlying the development of these disabilities, several transgenic models have been developed over the past two decades, which have provided important information regarding the cellular and molecular factors contributing to the neuropathogenesis of HAND. Herein, we concentrate on the neuropathogenic effects of HIV-1 Vpr expressed under the control of c-fms, resulting transgene expression in myeloid cells in both the central and peripheral nervous systems. Vpr's actions, possibly through its impact on cell cycle machinery, in brain culminate in neuronal and astrocyte injury and death through apoptosis involving activation of caspases-3, -6 and -9 depending on the individual target cell type. Indeed, these outcomes are also induced by soluble Vpr implying Vpr's effects stem from direct interaction with target cells. Remarkably, in vivo transgenic Vpr expression induces a neurodegenerative phenotype defined by neurobehavioral deficits and neuronal loss in the absence of frank inflammation. Implantation of another viral protein, hepatitis C virus (HCV) core, into Vpr transgenic animals' brains stimulated neuroinflammation and amplified the neurodegenerative disease phenotype, thereby recapitulating HCV's putative neuropathogenic actions. The availability of different transgenic models to study HIV neuropathogenesis represents exciting and innovative approaches to understanding disease mechanisms and perhaps developing new therapeutic strategies in the future.

Macrophage-mediated dorsal root ganglion damage precedes altered nerve conduction in SIV-infected macaques

Peripheral neuropathy is the most common neurological complication of HIV-1 infection, affecting over one-third of infected individuals, including those treated with antiretroviral therapy. To study the pathogenesis of HIV-induced peripheral nervous system disease, we established a model in which SIV-infected macaques developed changes closely resembling alterations reported in components of the sensory pathway in HIV-infected individuals. Significant declines in epidermal nerve fiber density developed in SIV-infected macaques, similar to that of HIV-infected individuals with neuropathy. Changes in dorsal root ganglia (DRG) included macrophage infiltration, SIV replication in macrophages, immune activation of satellite cells, and neuronal loss. To determine whether dorsal root ganglion damage was associated with altered nerve function, we measured unmyelinated C-fiber conduction velocities (CV) in nerves of SIV-infected macaques and compared CV changes with DRG alterations. Twelve weeks postinoculation, SIV-infected macaques had significantly lower C-fiber conduction velocity in sural nerves than uninfected animals and the magnitude of conduction velocity decline correlated strongly with extent of DRG macrophage infiltration. Thus, injury to neurons in the DRG-mediated by activated macrophages-preceded altered conduction of unmyelinated nerve fibers in SIV-infected macaques, suggesting that macrophage-mediated DRG damage may be the initiating event in HIV-induced sensory neuropathy.

Initiating antiretrovirals during tuberculosis treatment: a drug safety review

INTRODUCTION

Integrating HIV and tuberculosis (TB) treatment can reduce mortality substantially. Practical barriers to treatment integration still exist and include safety concerns related to concomitant drug use because of drug interactions and additive toxicities. Altered therapeutic concentrations may influence the chances of treatment success or toxicity.

AREAS COVERED

The available data on drug-drug interactions between the rifamycin class of anti-mycobacterials and the non-nucleoside reverse transcriptase inhibitor and the protease inhibitor classes of antiretrovirals are discussed with recommendations for integrated use. Additive drug toxicities, the impact of immune reconstitution inflammatory syndrome (IRIS) and the latest data on survival benefits of integrating treatment are elucidated.

EXPERT OPINION

Deferring treatment of HIV to avoid drug interactions with TB treatment or the occurrence of IRIS is not necessary. In the integrated management of TB-HIV co-infection, rational drug combinations aimed at reducing toxicities while effecting TB cure and suppressing HIV viral load are possible.

Prevalence, self-care behaviors, and self-care activities for peripheral neuropathy symptoms of HIV/AIDS

As part of a larger randomized controlled trial examining the efficacy of an HIV/AIDS symptom management manual (n = 775), this study examined the prevalence of peripheral neuropathy in HIV-infected individuals at 12 sites in the USA, Puerto Rico, and Africa. Neuropathy was reported by 44% of the sample; however, only 29.4% reported initiating self-care behaviors to address the neuropathy symptoms. Antiretroviral therapy was found to increase the frequency of neuropathy symptoms, with an increased mean intensity of 28%. A principal axis factor analysis with Promax rotation was used to assess the relationships in the frequency of use of the 18 self-care activities for neuropathy, revealing three distinct factors: (i) an interactive self-care factor; (ii) a complementary medicine factor; and (iii) a third factor consisting of the negative health items of smoking, alcohol, and street drugs. The study's results suggest that peripheral neuropathy is a common symptom and the presence of neuropathy is associated with self-care behaviors to ameliorate HIV symptoms. The implications for nursing practice include the assessment and evaluation of nursing interventions related to management strategies for neuropathy.

HIV-1 viral protein R causes peripheral nervous system injury associated with in vivo neuropathic pain

Painful peripheral neuropathy has become the principal neurological disorder in HIV/AIDS patients. Herein, we investigated the effects of a cytotoxic HIV-1 accessory protein, viral protein R (Vpr), on the peripheral nervous system (PNS). Host and viral gene expression was investigated in peripheral nerves from HIV-infected individuals and in HIV-infected human dorsal root ganglion (DRG) cultures by RT-PCR and immunocytochemistry. Cytosolic calcium ([Ca(2+)]) fluxes and neuronal membrane responses were analyzed in cultured DRGs. Neurobehavioral responses and cytokine levels were assessed in a transgenic mouse model in which the vpr transgene was expressed in an immunodeficient background (vpr/RAG1(-/-)). Vpr transcripts and proteins were detected in peripheral nerves and DRGs from HIV-infected patients. Exposure of rat or human cultured DRG neurons to Vpr rapidly increased [Ca(2+)] and action potential frequency while increasing input resistance. HIV infection of human DRG cultures caused neurite retraction (P<0.05), accompanied by induction of interferon-α (IFN-α) transcripts (P<0.05). vpr/RAG1(-/-) mice expressed Vpr together with increased IFN-α (P<0.05) in the PNS and also exhibited mechanical allodynia, unlike their vpr/RAG1(-/-) littermates (P<0.05). Herein, Vpr caused DRG neuronal damage, likely through cytosolic calcium activation and cytokine perturbation, highlighting Vpr's contribution to HIV-associated peripheral neuropathy and ensuing neuropathic pain.