Continued high prevalence and adverse clinical impact of human immunodeficiency virus-associated sensory neuropathy in the era of combination antiretroviral therapy: the CHARTER Study

Elevated Biomarkers of Inflammation and Vascular Dysfunction Are Associated with Distal Sensory Polyneuropathy in People with HIV

Distal sensory polyneuropathy (DSP) is a disabling, chronic condition in people with HIV (PWH), even those with viral suppression of antiretroviral therapy (ART), and with a wide range of complications, such as reduced quality of life. Previous studies demonstrated that DSP is associated with inflammatory cytokines in PWH. Adhesion molecules, essential for normal vascular function, are perturbed in HIV and other conditions linked to DSP, but the link between adhesion molecules and DSP in PWH is unknown. This study aimed to determine whether DSP signs and symptoms were associated with a panel of plasma biomarkers of inflammation (d-dimer, sTNFRII, MCP-1, IL-6, IL-8, IP-10, sCD14) and vascular I integrity (ICAM-1, VCAM-1, uPAR, MMP-2, VEGF, uPAR, TIMP-1, TIMP-2) and differed between PWH and people without HIV (PWoH). A cross-sectional study was conducted among 143 participants (69 PWH and 74 PWoH) assessed by studies at the UC San Diego HIV Neurobehavioral Research Program. DSP signs and symptoms were clinically assessed for all participants. DSP was defined as two or more DSP signs: bilateral symmetrically reduced distal vibration, sharp sensation, and ankle reflexes. Participant-reported symptoms were neuropathic pain, paresthesias, and loss of sensation. Factor analyses reduced the dimensionality of the 15 biomarkers among all participants, yielding six factors. Logistic regression was used to assess the associations between biomarkers and DSP signs and symptoms, controlling for relevant demographic and clinical covariates. The 143 participants were 48.3% PWH, 47 (32.9%) women, and 47 (33.6%) Hispanics, with a mean age of 44.3 ± 12.9 years. Among PWH, the median (IQR) nadir and current CD4+ T-cells were 300 (178-448) and 643 (502-839), respectively. Participants with DSP were older but had similar distributions of gender and ethnicity to those without DSP. Multiple logistic regression showed that Factor 2 (sTNFRII and VCAM-1) and Factor 4 (MMP-2) were independently associated with DSP signs in both PWH and PWoH (OR [95% CI]: 5.45 [1.42-21.00], and 15.16 [1.07-215.22]), respectively. These findings suggest that inflammation and vascular integrity alterations may contribute to DSP pathogenesis in PWH, but not PWoH, possibly through endothelial dysfunction and axonal degeneration.

Recruitment and retention of clinical trial participants: understanding motivations of patients with chronic pain and other populations

This paper aims to present and discuss the issues, challenges, and strategies related to recruitment and retention in clinical trials involving participants with chronic pain. The randomized controlled clinical trial (RCT) is widely regarded as the gold standard for evaluating clinical interventions. However, it is crucial to acknowledge and address the challenges associated with recruiting and retaining participants. To prioritize the experience of the study population, targeted outreach strategies and a patient-centric approach are necessary. Researchers should consider incorporating recruitment and retention strategies during the study design phase. Implementing multi-pronged recruitment methods, leveraging relationships with community providers, and involving representatives of the patient population are helpful approaches. Effective communication and maintaining a professional environment are vital for optimizing engagement and supporting the successful execution of clinical trials involving participants with chronic pain.

Chronic Morphine Treatment and Antiretroviral Therapy Exacerbate HIV-Distal Sensory Peripheral Neuropathy and Induce Distinct Microbial Alterations in the HIV Tg26 Mouse Model

Distal Sensory Peripheral Neuropathy (DSP) is a common complication in HIV-infected individuals, leading to chronic pain and reduced quality of life. Even with antiretroviral therapy (ART), DSP persists, often prompting the use of opioid analgesics, which can paradoxically worsen symptoms through opioid-induced microbial dysbiosis. This study employs the HIV Tg26 mouse model to investigate HIV-DSP development and assess gut microbiome changes in response to chronic morphine treatment and ART using 16S rRNA sequencing. Our results reveal that chronic morphine and ART exacerbate HIV-DSP in Tg26 mice, primarily through mechanical pain pathways. As the gut microbiome may be involved in chronic pain persistence, microbiome analysis indicated distinct bacterial community changes between WT and Tg26 mice as well as morphine- and ART-induced microbial changes in the Tg26 mice. This study reveals the Tg26 mouse model to be a relevant system that can help elucidate the pathogenic mechanisms of the opioid- and ART-induced exacerbation of HIV-associated pain. Our results shed light on the intricate interplay between HIV infection, ART, opioid use, and the gut microbiome in chronic pain development. They hold implications for understanding the mechanisms underlying HIV-associated pain and microbial dysbiosis, with potential for future research focused on prevention and treatment strategies.

Neuroinflammation in the Dorsal Root Ganglia and Dorsal Horn Contributes to Persistence of Nociceptor Sensitization in SIV-Infected Antiretroviral Therapy-Treated Macaques

Despite the development of antiretroviral therapy (ART), HIV-associated distal sensory polyneuropathy remains prevalent. Using SIV-infected rhesus macaques, this study examined molecular mechanisms of peripheral and central sensitization to infer chronic pain from HIV infection. Previous studies identified atrophy in nociceptive neurons during SIV infection, which was associated with monocyte infiltration into the dorsal root ganglia (DRG). However, the sensory signaling mechanism connecting this pathology to symptoms remains unclear, especially because pain persists after resolution of high viremia and inflammation with ART. We hypothesized that residual DRG and dorsal horn neuroinflammation contributes to nociceptive sensitization. Using three cohorts of macaques [uninfected (SIV-), SIV-infected (SIV+), and SIV infected with ART (SIV+/ART)], this study showed an increase in the cellular and cytokine inflammatory profiles in the DRG of SIV+/ART macaques compared with uninfected animals. It found significant increase in the expression of nociceptive ion channels, TRPV1, and TRPA1 among DRG neurons in SIV+/ART compared with uninfected animals. SIV-infected and SIV+/ART animals showed reduced innervation of the nonpeptidergic nociceptors into the dorsal horn compared with uninfected animals. Finally, there were a significantly higher number of CD68+ cells in the dorsal horn of SIV+/ART macaques compared with uninfected animals. In summary, these data demonstrate that neuroinflammation, characteristics of nociceptor sensitization, and central terminal atrophy persists in SIV+/ART animals.

Strategies Used to Manage Chronic Pain in HIV-Disease: Comparing Persons Prescribed Opioids Versus Persons not Receiving Opioids

Chronic pain is common in people living with HIV (PLWH), causes substantial disability and is associated with limitations in daily activities. Opioids are commonly prescribed for pain treatment among PLWH, but evidence of sustained efficacy is mixed. There is little information available on how PLWH who have chronic pain use multimodal strategies in pain management. The current cross-sectional study examined background characteristics, self-reported pain, and the use of other pain treatments among 187 PLWH with chronic pain and depressive symptoms who were and were not prescribed opioids. Approximately 20.9% of participants reported using prescription opioids at the time of the study interview. These individuals were significantly more likely to report having engaged in physical therapy or stretching, strengthening or aerobic exercises in the previous 3 months, recent benzodiazepine use, and receiving disability payments. There were no significant differences in pain characteristics (pain-related interference, average pain severity, and worst pain severity) between the two groups. Those not prescribed opioids were more likely to report better concurrent physical functioning and general health, and fewer physical role limitations, but higher depression symptom severity. Our findings suggest that many PLWH with chronic pain and depressive symptoms express high levels of pain with deficits in physical function or quality of life despite their use of opioids. The high rate of co-use of opioids and benzodiazepines (30.8%) is a concern because it may increase risk of overdose. An integrated care approach that includes a variety of effective non-pharmacologic treatment strategies such as physical therapy may be beneficial in reducing the reliance on opioids for pain management.

Pathogenic mechanisms of human immunodeficiency virus (HIV)-associated pain

Chronic pain is a prevalent neurological complication among individuals living with human immunodeficiency virus (PLHIV) in the post-combination antiretroviral therapy (cART) era. These individuals experience malfunction in various cellular and molecular pathways involved in pain transmission and modulation, including the neuropathology of the peripheral sensory neurons and neurodegeneration and neuroinflammation in the spinal dorsal horn. However, the underlying etiologies and mechanisms leading to pain pathogenesis are complex and not fully understood. In this review, we aim to summarize recent progress in this field. Specifically, we will begin by examining neuropathology in the pain pathways identified in PLHIV and discussing potential causes, including those directly related to HIV-1 infection and comorbidities, such as antiretroviral drug use. We will also explore findings from animal models that may provide insights into the molecular and cellular processes contributing to neuropathology and chronic pain associated with HIV infection. Emerging evidence suggests that viral proteins and/or antiretroviral drugs trigger a complex pathological cascade involving neurons, glia, and potentially non-neural cells, and that interactions between these cells play a critical role in the pathogenesis of HIV-associated pain.

Global Prevalence of Chronic Pain in Women with HIV: A Systematic Review and Meta-analysis

Chronic pain is common among people with human immunodeficiency virus (HIV) and detrimental to quality of life and overall health. It is often underdiagnosed, undertreated, and frankly dismissed in women with HIV, despite growing evidence that it is highly prevalent in this population. Thus, we conducted a systematic review and meta-analysis to estimate the global prevalence of chronic pain in women with HIV. The full protocol can be found on PROSPERO (identifier CRD42022301145). Of the 2984 references identified in our search, 36 were included in the systematic review and 35 in the meta-analysis. The prevalence of chronic pain was 31.2% (95% confidence interval [CI], 24.6%-38.7%; I2 = 98% [95% CI, 97%-99%]; P < .0001). In this global assessment, we found a high prevalence of chronic pain among women with HIV, underscoring the importance of understanding the etiology of chronic pain, identifying effective treatments, and conducting regular assessments in clinical practice.

Article Topic: Neuropathies Due to Infections and Antimicrobial Treatments

Purpose of eview

The aim of this review is to discuss the presentation, diagnosis, and management of polyneuropathy (PN) in selected infections. Overall, most infection related PNs are an indirect consequence of immune activation rather than a direct result of peripheral nerve infection,  Schwann cell infection, or toxin production, though note this review will describe infections that cause PN through all these mechanisms. Rather than dividing them by each infectious agent separately, we have grouped the infectious neuropathies according to their presenting phenotype, to serve as a guide to clinicians. Finally, toxic neuropathies related to antimicrobials are briefly summarized.

Recent findings

While PN from many infections is decreasing, increasing evidence links infections to variants of GBS. Incidence of neuropathies secondary to use of HIV therapy has decreased over the last few years.

Summary

In this manuscript, a general overview of the more common infectious causes of PN will be discussed, dividing them across clinical phenotypes: large- and small-fiber polyneuropathy, Guillain-Barré syndrome (GBS), mononeuritis multiplex, and autonomic neuropathy. Rare but important infectious causes are also discussed.

Syndemic conditions and quality of life in the PISCIS Cohort of people living with HIV in Catalonia and the Balearic Islands: a cross sectional study

BACKGROUND

People living with HIV (PLWH) face structural and psychosocial factors that affect health-related quality of life (HRQoL). We aimed to evaluate how syndemic conditions affected HRQoL in PLWH.

METHODS

A cross-sectional survey was conducted among 861 PLWH, to determine whether syndemic conditions (monthly income; sexual satisfaction; depressive symptoms; social role satisfaction; social isolation; cognitive function; nicotine dependence; perception of stigma) have an effect on HRQoL. A linear regression model and measures of Additive Interaction (AI) were used to determine the effects of syndemic conditions on HRQoL, controlling for other risk factors.

RESULTS

Overall, the most frequently observed were stigma perception (56.9%), poor cognitive function (50.6%) and the perception of social isolation (51.6%). The presence of depressive symptoms was the risk factor most associated with worse Physical Health (PH) (B 3.93, 2.71-5.15) and Mental Health (MH) (B 5.08, 3.81-6.34) in linear regression model. Specifically, an interaction was observed between poor cognitive function and poor satisfaction with social role on worse PH and MH (AI 2.08, 0.14-4.02; AI 2.69, 0.15-5.22, respectively); and low income and perception of stigma (AI 2.98, 0.26-5.71), low income and perception of social isolation (AI 2.79, 0.27-5.32), and low income and poor satisfaction with social role (AI 3.45, 0.99-5.91) on MH.

CONCLUSION

These findings provide evidence that syndemic factors impact HRQoL. HIV prevention programs should screen and address co-occurring health problems to improve patient-centered health care and outcomes.

Functional Impairment and Cognitive Symptoms Among People with HIV Infection on Chronic Opioid Therapy for Pain: The Impact of Gabapentin and Other Sedating Medications

Gabapentin is associated with dizziness, falls, and somnolence yet commonly prescribed to people with HIV (PWH) treated with chronic opioid therapy (COT). Physical function and cognition are understudied when prescribed together. Among PWH on COT, we evaluated whether co-prescribed gabapentin is associated with (a) functional impairment; (b) trouble thinking clearly; and (c) difficulty controlling drowsiness using logistic regression models adjusted for prescribed opioid dose, other (non-gabapentin) sedating medication, substance use disorder, and mental/physical health indicators in a cross-sectional study. Among 166 participants, 40% were prescribed gabapentin, 41% reported functional impairment, 41% trouble thinking clearly, and 38% difficulty controlling drowsiness. Gabapentin co-prescribed with COT was significantly associated with trouble thinking clearly but not with functional impairment or difficulty controlling drowsiness. Clinicians should be cognizant of potential problems with thinking clearly when co-prescribing gabapentin and opioid medication.

HIV peripheral neuropathy-related degeneration of white matter tracts to sensorimotor cortex

Human immunodeficiency virus-associated distal sensory polyneuropathy (HIV-DSP) affects up to 50% of people with HIV and is associated with depression, unemployment, and generally worsened quality of life. Previous work on the cortical mechanism of HIV neuropathy found decreased gray matter volume in the bilateral midbrain, thalamus, and posterior cingulate cortex, but structural connectivity in this context remains under-studied. Here we examine alterations in white matter microstructure using diffusion imaging, hypothesizing that cortical white matter degeneration would be observed in continuation of the peripheral white matter atrophy previously observed in HIV-DSP. Male HIV seropositive patients (n = 57) experiencing varying degrees of HIV neuropathy underwent single-shell diffusion tensor imaging with 51 sampling directions. The scans were pooled using tractography and connectometry to create a quantitative map of white matter tract integrity, measured in generalized fractional anisotropy (GFA). The relationship between GFA and neuropathy severity was evaluated with linear regression. Correction for multiple comparisons was done using false discovery rate (FDR), a statistical method commonly used in genomics and imaging to minimize false positives when thousands of individual comparisons are made. Neuropathy severity was associated with decreased GFA along thalamocortical radiations leading along the lateral thalamus to sensorimotor cortex, with r = -0.405 (p < 0.001; FDR), as well as with the superior bilateral cingulum (r = -0.346 (p < 0.05; FDR)). Among a population of HIV neuropathy patients, greater neuropathy severity was correlated with lower white matter integrity running from midbrain to somatosensory cortex. This suggests ascending deafferentation extending from damaged peripheral nerves further downstream than seen previously, into the axons of third-order neurons. There is also evidence of cingulum degeneration, implying some more complex mechanism beyond the ascending atrophy observed here.

Distal neuropathic pain in HIV is associated with functional connectivity patterns in default mode and salience networks

HIV-associated distal neuropathic pain (DNP) is one of the most prevalent, disabling, and treatment-resistant complications of HIV, but its biological underpinnings are incompletely understood. While data specific to mechanisms underlying HIV DNP are scarce, functional neuroimaging of chronic pain more broadly implicates the role of altered resting-state functional connectivity within and between salience network (SN) and default mode network (DMN) regions. However, it remains unclear the extent to which HIV DNP is associated with similar alterations in connectivity. The current study aimed to bridge this gap in the literature through examination of resting-state functional connectivity patterns within SN and DMN regions among people with HIV (PWH) with and without DNP. Resting state functional magnetic resonance imaging (rs-fMRI) scans were completed among 62 PWH with HIV-associated peripheral neuropathy, of whom 27 reported current DNP and 35 did not. Using subgrouping group iterative multiple estimation, we compared connectivity patterns in those with current DNP to those without. We observed weaker connectivity between the medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC) and stronger connectivity between the anterior cingulate cortex (ACC) and thalamus among those reporting DNP. Overall, these findings implicate altered within DMN (i.e., MPFC-PCC) and within SN (i.e., ACC-thalamus) connectivity as potential manifestations of adaptation to pain from neuropathy and/or mechanisms underlying the development/maintenance of DNP. Findings are discussed in the context of differential brain response to pain (i.e., mind wandering, pain aversion, pain facilitation/inhibition) and therapeutic implications.

Surgeon Variation in Perioperative Opioid Prescribing and Medium- or Long-term Opioid Utilization after Total Knee Arthroplasty: A Cross-sectional Analysis

BACKGROUND

Whether a particular surgeon's opioid prescribing behavior is associated with prolonged postoperative opioid use is unknown. This study tested the hypothesis that the patients of surgeons with a higher propensity to prescribe opioids are more likely to utilize opioids long-term postoperatively.

METHODS

The study identified 612,378 Medicare fee-for-service patients undergoing total knee arthroplasty between January 1, 2011, and December 31, 2016. "High-intensity" surgeons were defined as those whose patients were, on average, in the upper quartile of opioid utilization in the immediate perioperative period (preoperative day 7 to postoperative day 7). The study then estimated whether patients of high-intensity surgeons had higher opioid utilization in the midterm (postoperative days 8 to 90) and long-term (postoperative days 91 to 365), utilizing an instrumental variable approach to minimize confounding from unobservable factors.

RESULTS

In the final sample of 604,093 patients, the average age was 74 yr (SD 5), and there were 413,121 (68.4%) females. A total of 180,926 patients (30%) were treated by high-intensity surgeons. On average, patients receiving treatment from a high-intensity surgeon received 36.1 (SD 35.0) oral morphine equivalent (morphine milligram equivalents) per day during the immediate perioperative period compared to 17.3 morphine milligram equivalents (SD 23.1) per day for all other patients (+18.9 morphine milligram equivalents per day difference; 95% CI, 18.7 to 19.0; P < 0.001). After adjusting for confounders, receiving treatment from a high-intensity surgeon was associated with higher opioid utilization in the midterm opioid postoperative period (+2.4 morphine milligram equivalents per day difference; 95% CI, 1.7 to 3.2; P < 0.001 [11.4 morphine milligram equivalents per day vs. 9.0]) and lower opioid utilization in the long-term postoperative period (-1.0 morphine milligram equivalents per day difference; 95% CI, -1.4 to -0.6; P < 0.001 [2.8 morphine milligram equivalents per day vs. 3.8]). While statistically significant, these differences are clinically small.

CONCLUSIONS

Among Medicare fee-for-service patients undergoing total knee arthroplasty, surgeon-level variation in opioid utilization in the immediate perioperative period was associated with statistically significant but clinically insignificant differences in opioid utilization in the medium- and long-term postoperative periods.

EDITOR’S PERSPECTIVE

Age-related neuroendocrine, cognitive, and behavioral co-morbidities are promoted by HIV-1 Tat expression in male mice

In the U.S. about half of the HIV-infected individuals are aged 50 and older. In men living with HIV, secondary hypogonadism is common and occurs earlier than in seronegative men, and its prevalence increases with age. While the mechanisms(s) are unknown, the HIV-1 trans-activator of transcription (Tat) protein disrupts neuroendocrine function in mice partly by dysregulating mitochondria and neurosteroidogenesis. We hypothesized that conditional Tat expression in middle-aged male transgenic mice [Tat(+)] would promote age-related comorbidities compared to age-matched controls [Tat(−)]. We expected Tat to alter steroid hormone milieu consistent with behavioral deficits. Middle-aged Tat(+) mice had lower circulating testosterone and progesterone than age-matched controls and greater circulating corticosterone and central allopregnanolone than other groups. Young Tat(+) mice had greater circulating progesterone and estradiol-to-testosterone ratios. Older age or Tat exposure increased anxiety-like behavior (open field; elevated plus-maze), increased cognitive errors (radial arm water maze), and reduced grip strength. Young Tat(+), or middle-aged Tat(−), males had higher mechanical nociceptive thresholds than age-matched counterparts. Steroid levels correlated with behaviors. Thus, Tat may contribute to HIV-accelerated aging.

Neuropathic pain correlates with worsening cognition in people with human immunodeficiency virus

Neuropathic pain and cognitive impairment are among the HIV-related conditions that have most stubbornly resisted amelioration by virally suppressive antiretroviral therapy. Overlaps between the regional brain substrates and mechanisms of neuropathic pain and cognitive disorders are increasingly recognized, yet no studies have examined the longitudinal relationship between these two disorders. Participants in the prospective, observational CNS HIV AntiRetroviral Therapy Effects Research (CHARTER) cohort underwent standardized clinical evaluations for clinical examination findings of distal sensory polyneuropathy, reporting distal neuropathic pain and neurocognitive performance at study entry (baseline) and an average of 12 years later. Change in neuropathic pain and neuropathy status from baseline to follow-up was by self-report and repeat examination, and change in neurocognitive performance was assessed using a previously published summary regression-based change score. Relationships between incident or worsened neuropathic pain and neurocognitive change were evaluated using uni- and multivariable regressions, including age at baseline and other relevant covariates. Participants were 385 people with HIV, 91 (23.6%) females, mean ± standard deviation (SD) age at baseline 43.5 (7.81) years, ethnicity 44.9% African American, 10.6% Hispanic, 42.6% non-Hispanic white and 1.82% other. Baseline median (interquartile range) nadir CD4 was 175 (34 309) cells/µl and current CD4 was 454 (279 639). Incident or worsened distal neuropathic pain occurred in 98 (25.5%) over the follow-up period. People with HIV with incident or worsened distal neuropathic pain had significantly worsened neurocognitive performance at follow-up compared to those without incident or worsened distal neuropathic pain (summary regression-based change score mean ± SD -0.408 ± 0.700 versus -0.228 ± 0.613; P = 0.0158). This effect remained significant when considering viral suppression on antiretroviral therapy, incident diabetes and other covariates as predictors. Overall neurocognitive change related to neuropathic pain was driven primarily by changes in the domains of executive function and speed of information processing. Those with incident distal neuropathy signs did not have neurocognitive worsening, nor did individuals who used opioid analgesics or other pain-modulating drugs such as amitriptyline. Worsened neurocognitive performance in people with HIV was associated with worsened neuropathic pain but not with changes in physical signs of neuropathy, and this was not attributable to therapies for pain or depression or to differences in viral suppression. This finding implies that incident or worsened pain may signal increased risk for neurocognitive impairment, and deserves more investigation, particularly if better pain management might stabilize or improve neurocognitive performance.

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.

Update on Toxic Neuropathies

Purpose of Review

Toxic neuropathies are an important preventable and treatable form of peripheral neuropathy. While many forms of toxic neuropathies have been recognized for decades, an updated review is provided to increase vigilant in this area of neurology. A literature review was conducted to gather recent information about toxic neuropathies, which included the causes, clinical findings, and treatment options in these conditions.

Recent Findings

Toxic neuropathies continue to cause significant morbidity throughout the world and the causative agents, particularly with regards to medications, do not appear to be diminishing. A wide variety of causes of toxic neuropathies exist, which include alcohol, industrial chemicals, biotoxins, and medications. Unfortunately, no breakthrough treatments have been developed and prevention and symptom management remain the standard of care.

Summary

A detailed medication, occupational and hobby exposure history is critical to identifying toxic neuropathies. Increased research is warranted to identify mechanisms of neurotoxic susceptibility and potential common pathomechanistic pathways for treatment across diverse toxic neuropathies.

HIV-1 Tat endocytosis and retention in endolysosomes affects HIV-1 Tat-induced LTR transactivation in astrocytes

The presence of latent HIV-1 reservoirs in the periphery and brain represents a major obstacle to curing HIV-1 infection. As an essential protein for HIV-1 viral replication, HIV-1 Tat, mostly intracellular, has been implicated in latent HIV-1 infection. From HIV-1 infected cells, HIV-1 Tat is actively secreted and bystander cells uptake the released Tat whereupon it is endocytosed and internalized into endolysosomes. However, to activate the HIV-1 LTR promoter and increase HIV-1 replication, HIV-1 Tat must first escape from the endolysosomes and then enter the nucleus. Here, we tested the hypothesis that HIV-1 Tat can accumulate in endolysosomes and contribute to the activation of latent HIV-1 in astrocytes. Using U87MG astrocytoma cells expressing HIV-1 LTR-driven luciferase and primary human astrocytes we found that exogenous HIV-1 Tat enters endolysosomes, resides in endolysosomes for extended periods of time, and induces endolysosome de-acidification as well as enlargement. The weak base chloroquine promoted the release of HIV-1 Tat from endolysosomes and induced HIV-1 LTR transactivation. Similar results were observed by activating endolysosome Toll-like receptor 3 (TLR3) and TLR7/8. Conversely, pharmacological block of TLRs and knocking down expression levels of TLR3 and TLR7, but not TLR8, prevented endolysosome leakage and attenuated HIV-1 Tat-mediated HIV-1 LTR transactivation. Our findings suggest that HIV-1 Tat accumulation in endolysosomes may play an important role in controlling HIV-1 transactivation.

Peripheral artery disease and physical function in women with and without HIV

OBJECTIVES

Peripheral artery disease (PAD) is associated with decreased physical function and increased mortality in the general population. We previously found that PAD is common in middle-aged women with and without HIV infection, but its association with functional decline is unclear. We examine the contribution of PAD to functional decline in the Women's Interagency HIV Study, controlling for traditional cardiovascular risk factors and HIV-related factors.

METHODS

Analysis included 1839 participants (72% with HIV) with measured ankle-brachial index (ABI) and 4 m gait speed. ABI values categorized PAD severity. Linear models with repeated measures estimated the association of PAD severity with log-transformed gait speed after controlling for demographic, behavioral, and metabolic risk factors, and HIV/hepatitis C virus status.

RESULTS

Median age was 50 years and more than 70% were Black. Compared with normal ABI, there was a dose-response relationship between increasing PAD severity and slower gait speed in univariable analyses: 6% slower gait speed for low-normal ABI [95% confidence interval (CI): 4-9%], 10% for borderline PAD (95% CI: 6-13%), 14% for mild PAD (95% CI: 9-18%), and 16% for moderate-severe PAD (95% CI: 5-25%). PAD severity remained associated with slower gait speed in multivariable analyses. HIV/hepatitis C virus co-infection was independently associated with 9% (95% CI: 4-14%) slower gait speed compared with those with neither infection. Among women with HIV, neither CD4+ cell count nor HIV-RNA level was associated with gait speed.

CONCLUSION

In middle-aged women with and without HIV infection, greater PAD severity is associated with progressively slower gait speed. Early detection of subclinical PAD may decrease the risk of lower extremity functional impairment and its long-term health consequences.

Reduced Gut Microbiome Diversity in People With HIV Who Have Distal Neuropathic Pain

Gut dysbiosis, defined as pathogenic alterations in the distribution and abundance of different microbial species, is associated with neuropathic pain in a variety of clinical conditions, but this has not been explored in the context of neuropathy in people with HIV (PWH). We assessed gut microbial diversity and dysbiosis in PWH and people without HIV (PWoH), some of whom reported distal neuropathic pain (DNP). DNP was graded on a standardized, validated severity scale. The gut microbiome was characterized using 16S rRNA sequencing and diversity was assessed using phylogenetic tree construction. Songbird analysis (https://github.com/mortonjt/songbird) was used to produce a multinomial regression model predicting counts of specific microbial taxa through metadata covariate columns. Participants were 226 PWH and 101 PWoH, mean (SD) age 52.0 (13.5), 21.1% female, 54.7% men who have sex with men, 44.7% non-white. Among PWH, median (interquartile range, IQR) nadir and current CD4 were 174 (21, 302) and 618 (448, 822), respectively; 90% were virally suppressed on antiretroviral therapy. PWH and PWoH did not differ with respect to microbiome diversity as indexed by Faith's phylogenetic diversity (PD). More severe DNP was associated with lower alpha diversity as indexed by Faith's phylogenetic diversity in PWH (Spearman's ρ = .224, P = 0.0007), but not in PWoH (Spearman's ρ = .032, P = .748). These relationships were not confounded by demographics or disease factors. In addition, the log-ratio of features identified at the genus level as Blautia to Lachnospira was statistically significantly higher in PWH with DNP than in PWH without DNP (t-test, P = 1.01e-3). Furthermore, the log-ratio of Clostridium features to Lachnospira features also was higher in PWH with DNP than in those without (t-test, P = 6.24e-5). Our results, in combination with previous findings in other neuropathic pain conditions, suggest that gut dysbiosis, particularly reductions in diversity and relative increases in the ratios of Blautia and Clostridium to Lachnospira, may contribute to prevalent DNP in PWH. Two candidate pathways for these associations, involving microbial pro-inflammatory components and microbially-produced anti-inflammatory short chain fatty acids, are discussed. Future studies might test interventions to re-establish a healthy gut microbiota and determine if this prevents or improves DNP. PERSPECTIVE: The association of neuropathic pain in people with HIV with reduced gut microbial diversity and dysbiosis raises the possibility that re-establishing a healthy gut microbiota might ameliorate neuropathic pain in HIV by reducing proinflammatory and increasing anti-inflammatory microbial products.

Pathophysiological Consequences of At-Risk Alcohol Use; Implications for Comorbidity Risk in Persons Living With Human Immunodeficiency Virus

At-risk alcohol use is a significant risk factor associated with multisystemic pathophysiological effects leading to multiorgan injury and contributing to 5.3% of all deaths worldwide. The alcohol-mediated cellular and molecular alterations are particularly salient in vulnerable populations, such as people living with HIV (PLWH), diminishing their physiological reserve, and accelerating the aging process. This review presents salient alcohol-associated mechanisms involved in exacerbation of cardiometabolic and neuropathological comorbidities and their implications in the context of HIV disease. The review integrates consideration of environmental factors, such as consumption of a Western diet and its interactions with alcohol-induced metabolic and neurocognitive dyshomeostasis. Major alcohol-mediated mechanisms that contribute to cardiometabolic comorbidity include impaired substrate utilization and storage, endothelial dysfunction, dysregulation of the renin-angiotensin-aldosterone system, and hypertension. Neuroinflammation and loss of neurotrophic support in vulnerable brain regions significantly contribute to alcohol-associated development of neurological deficits and alcohol use disorder risk. Collectively, evidence suggests that at-risk alcohol use exacerbates cardiometabolic and neurocognitive pathologies and accelerates biological aging leading to the development of geriatric comorbidities manifested as frailty in PLWH.

South African men and women living with HIV have similar distributions of pain sites

Background

No studies have investigated sex differences in the location and number of pain sites in people living with human immunodeficiency virus (HIV) (PLWH), despite evidence that women, in general, bear a greater burden of pain than men.

Aim

To determine sex differences in the location and number of pain sites, and whether there were demographic or disease-related differences in the number of pain sites.

Setting

South African tertiary hospital HIV clinics and a community healthcare centre

Methods

We conducted a retrospective analysis of records from South African PLWH who had pain.

Results

Of the 596 participant records, 19% were male (115/596) and the median number of pain sites for both sexes was 2 (interquartile range [IQR]: 1 to 3). Pain was most frequently experienced in the head (men: 12%, women: 38%), feet and ankles (men: 42%, women: 28%), abdomen (men = 19%, women = 28%) and chest (men = 20%, women = 20%). After correcting for multiple comparisons, males were less likely to experience headache than females (Fisher’s exact text, odds ratio [OR] = 0.23, 95% confidence interval [CI]: 0.12 – 0.42, p = 0.000). Pain at other body sites was experienced similarly between the sexes. There was no meaningful variation in the number of pain sites between the sexes (logistic regression, p = 0.157).

Conclusion

A similar location and number of pain sites were experienced by male and female South African PLWH. The locations of pain sites were different from previous reports, however, suggesting that research into pain in PLWH cannot necessarily be generalised across cultures.

Chronic pain and infection: mechanisms, causes, conditions, treatments, and controversies

Throughout human history, infection has been the leading cause of morbidity and mortality, with pain being one of the cardinal warning signs. However, in a substantial percentage of cases, pain can persist after resolution of acute illness, manifesting as neuropathic, nociplastic (eg, fibromyalgia, irritable bowel syndrome), or nociceptive pain. Mechanisms by which acute infectious pain becomes chronic are variable and can include immunological phenomena (eg, bystander activation, molecular mimicry), direct microbe invasion, central sensitization from physical or psychological triggers, and complications from treatment. Microbes resulting in a high incidence of chronic pain include bacteria such as the Borrelia species and Mycobacterium leprae, as well as viruses such as HIV, SARS-CoV-2 and herpeses. Emerging evidence also supports an infectious cause in a subset of patients with discogenic low back pain and inflammatory bowel disease. Although antimicrobial treatment might have a role in treating chronic pain states that involve active infectious inflammatory processes, their use in chronic pain conditions resulting from autoimmune mechanisms, central sensitization and irrevocable tissue (eg, arthropathy, vasculitis) or nerve injury, are likely to cause more harm than benefit. This review focuses on the relation between infection and chronic pain, with an emphasis on common viral and bacterial causes.

Association of painful human immunodeficiency virus distal sensory polyneuropathy with aberrant expectation of pain relief: functional magnetic resonance imaging evidence

Mechanisms underlying chronic neuropathic pain associated with HIV-associated distal sensory polyneuropathy are poorly understood, yet 40% of those with distal neuropathy (or 20% of all people with HIV) suffer from this debilitating condition. Central pain processing mechanisms are thought to contribute to the development of HIV neuropathic pain, yet studies investigating central mechanisms for HIV neuropathic pain are few. Considering the motivational nature of pain, we aimed to examine the degree to which expectation of pain onset and expectation of pain offset are altered in sixty-one male patients with HIV-related distal sensory polyneuropathy with (N = 30) and without (N = 31) chronic neuropathic pain. By contrasting painful (foot) and non-painful (hand) sites between those with and without neuropathic pain, we could identify unique neural structures that showed altered activation during expectation of pain offset or relief. Our results showed no evidence for peripheral mechanisms evidenced by lack of significant between group differences in thermo-sensation, subjective pain response or epidermal nerve fibre density. Likewise, we found no significant differences between groups in subjective or brain mechanisms underlying the expectation of pain onset. Conversely, we found significant interaction within right anterior insula during expectation of pain offset in our study in that individuals in the pain group compared to the no-pain group exhibited increased anterior insula activation on the painful compared to the non-painful site. Our findings are consistent with abnormal processing of expectation of pain offset or abnormal pain relief-related mechanisms potentially due to increased emotional distress regarding the experience of chronic endogenous pain.

HIV-Proteins-Associated CNS Neurotoxicity, Their Mediators, and Alternative Treatments

Human immunodeficiency virus (HIV)-infected people's livelihoods are gradually being prolonged with the use of combined antiretroviral therapy (ART). Conversely, despite viral suppression by ART, the symptoms of HIV-associated neurocognitive disorder (HAND) endure. HAND persists because ART cannot really permanently confiscate the virus from the body. HAND encompasses a variety of conditions based on clinical presentation and severity level, comprising asymptomatic neurocognitive impairment, moderate neurocognitive disorder, and HIV-associated dementia. During the early stages of HIV infection, inflammation compromises the blood-brain barrier, allowing toxic virus, infected monocytes, macrophages, T-lymphocytes, and cellular products from the bloodstream to enter the brain and eventually the entire central nervous system. Since there are no resident T-lymphocytes in the brain, the virus will live for decades in macrophages and astrocytes, establishing a reservoir of infection. The HIV proteins then inflame neurons both directly and indirectly. The purpose of this review is to provide a synopsis of the effects of these proteins on the central nervous system and conceptualize avenues to be considered in mitigating HAND. We used bioinformatics repositories extensively to simulate the transcription factors that bind to the promoter of the HIV-1 protein and possibly could be used as a target to circumvent HIV-associated neurocognitive disorders. In the same vein, a protein-protein interaction complex was also deduced from a Search Tool for the Retrieval of Interacting Genes. In conclusion, this provides an alternative strategy that could be used to avert HAND.

Monoacylglycerol Lipase Inhibitor MJN110 Reduces Neuronal Hyperexcitability, Restores Dendritic Arborization Complexity, and Regulates Reward-Related Behavior in Presence of HIV-1 Tat

While current therapeutic strategies for people living with human immunodeficiency virus type 1 (HIV-1) suppress virus replication peripherally, viral proteins such as transactivator of transcription (Tat) enter the central nervous system early upon infection and contribute to chronic inflammatory conditions even alongside antiretroviral treatment. As demand grows for supplemental strategies to combat virus-associated pathology presenting frequently as HIV-associated neurocognitive disorders (HAND), the present study aimed to characterize the potential utility of inhibiting monoacylglycerol lipase (MAGL) activity to increase inhibitory activity at cannabinoid receptor-type 1 receptors through upregulation of 2-arachidonoylglycerol (2-AG) and downregulation of its degradation into proinflammatory metabolite arachidonic acid (AA). The MAGL inhibitor MJN110 significantly reduced intracellular calcium and increased dendritic branching complexity in Tat-treated primary frontal cortex neuron cultures. Chronic MJN110 administration in vivo increased 2-AG levels in the prefrontal cortex (PFC) and striatum across Tat(+) and Tat(–) groups and restored PFC N-arachidonoylethanolamine (AEA) levels in Tat(+) subjects. While Tat expression significantly increased rate of reward-related behavioral task acquisition in a novel discriminative stimulus learning and cognitive flexibility assay, MJN110 altered reversal acquisition specifically in Tat(+) mice to rates indistinguishable from Tat(–) controls. Collectively, our results suggest a neuroprotective role of MAGL inhibition in reducing neuronal hyperexcitability, restoring dendritic arborization complexity, and mitigating neurocognitive alterations driven by viral proteins associated with latent HIV-1 infection.

Review Article "Spotlight on Ultrasonography in the Diagnosis of Peripheral Nerve Disease: The Evidence to Date"

Neuromuscular ultrasound is rapidly becoming incorporated into clinical practice as a standard tool in the assessment of peripheral nerve diseases. Ultrasound complements clinical phenotyping and electrodiagnostic evaluation, providing critical structural anatomical information to enhance diagnosis and identify structural pathology. This review article examines the evidence supporting neuromuscular ultrasound in the diagnosis of compressive mononeuropathies, traumatic nerve injury, generalised peripheral neuropathy and motor neuron disease. Extending the sonographic evaluation of nerves beyond simple morphological measurements has the potential to improve diagnostics in peripheral neuropathy, as well as advancing the understanding of pathological mechanisms, which in turn will promote precise therapies and improve therapeutic outcomes.

Brief Report: Association Between Pain, Pulmonary Function, and Respiratory Symptoms in People With HIV

BACKGROUND

People with HIV (PWH) experience chronic pain and respiratory symptoms, which are closely related in the general population. Pain may affect the impaired pulmonary function seen in PWH beyond its association with HIV alone. Our objective was to investigate the relationship of pain severity to pulmonary function, respiratory symptoms, and sleep disturbance in PWH.

SETTING

Study sites included the University of Pittsburgh, University of California San Francisco, and University of Washington.

METHODS

Pain, dyspnea, and sleep were assessed using the Brief Chronic Pain Questionnaire, St. George's Respiratory Questionnaire, and Pittsburgh Sleep Quality Index. Participants performed prebronchodilator and postbronchodilator spirometry and 6-minute walk test. Associations between pain severity, lung function, dyspnea, and sleep were assessed with bivariate and multiple quantile regression analysis adjusted for age, sex, race, body mass index, and smoking status.

RESULTS

Of 159 PWH, the median age was 56 years with 30.8% women. Two-thirds experienced pain in the past week, with 40.3% reporting chronic pain. Pain severity was higher with female sex (P = 0.038), non-White race (P = 0.005), current smoking (P = 0.003), and lower CD4+ count (P = 0.035). In adjusted analysis, higher pain severity was correlated with reduced postbronchodilator forced expiratory volume in 1 second %predicted (P = 0.008), reduced postbronchodilator forced vital capacity %predicted (P = 0.019), and chronic obstructive pulmonary disease (P = 0.032). Greater pain severity was strongly associated with a higher St. George's Respiratory Questionnaire score (P < 0.001) and sleep disturbance (P < 0.001).

CONCLUSIONS

In PWH, pain is common and associated with airflow obstruction, dyspnea, and sleep disturbance. Future studies assessing pain severity and pulmonary function over time could clarify the direction of this association and the impact on quality of life.

Paresthesia Predicts Increased Risk of Distal Neuropathic Pain in Older People with HIV-Associated Sensory Polyneuropathy

OBJECTIVE

Distal sensory polyneuropathy (DSP) is a disabling consequence of human immunodeficiency virus (HIV), leading to poor quality of life and more frequent falls in older age. Neuropathic pain and paresthesia are prevalent symptoms; however, there are currently no known curative treatments and the longitudinal course of pain in HIV-associated DSP is poorly characterized.

METHODS

This was a prospective longitudinal study of 265 people with HIV (PWH) enrolled in the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) study with baseline and 12-year follow-up evaluations. Since pain and paresthesia are highly correlated, statistical decomposition was used to separate the two symptoms at baseline. Multivariable logistic regression analyses of decomposed variables were used to determine the effects of neuropathy symptoms at baseline on presence and worsening of distal neuropathic pain at 12-year follow-up, adjusted for covariates.

RESULTS

Mean age was 56 ± 8 years, and 21% were female at follow-up. Nearly the entire cohort (96%) was on antiretroviral therapy (ART), and 82% had suppressed (≤50 copies/mL) plasma viral loads at follow-up. Of those with pain at follow-up (n = 100), 23% had paresthesia at the initial visit. Decomposed paresthesia at baseline increased the risk of pain at follow-up (odds ratio [OR] 1.56; 95% confidence interval [CI] 1.18, 2.07), and decomposed pain at baseline predicted a higher frequency of pain at follow-up (OR 1.96 [95% CI 1.51, 2.58]).

CONCLUSIONS

Paresthesias are a clinically significant predictor of incident pain at follow-up among aging PWH with DSP. Development of new therapies to encourage neuroregeneration might take advantage of this finding to choose individuals likely to benefit from treatment preventing incident pain.

Chronic Pain in HIV

The evolution of therapeutics for and management of human immunodeficiency virus-1 (HIV-1) infection has shifted it from predominately manifesting as a severe, acute disease with high mortality to a chronic, controlled infection with a near typical life expectancy. However, despite extensive use of highly active antiretroviral therapy, the prevalence of chronic widespread pain in people with HIV remains high even in those with a low viral load and high CD4 count. Chronic widespread pain is a common comorbidity of HIV infection and is associated with decreased quality of life and a high rate of disability. Chronic pain in people with HIV is multifactorial and influenced by HIV-induced peripheral neuropathy, drug-induced peripheral neuropathy, and chronic inflammation. The specific mechanisms underlying these three broad categories that contribute to chronic widespread pain are not well understood, hindering the development and application of pharmacological and nonpharmacological approaches to mitigate chronic widespread pain. The consequent insufficiencies in clinical approaches to alleviation of chronic pain in people with HIV contribute to an overreliance on opioids and alarming rise in active addiction and overdose. This article reviews the current understanding of the pathogenesis of chronic widespread pain in people with HIV and identifies potential biomarkers and therapeutic targets to mitigate it.

Combining In Vivo Corneal Confocal Microscopy With Deep Learning-Based Analysis Reveals Sensory Nerve Fiber Loss in Acute Simian Immunodeficiency Virus Infection

PURPOSE

To characterize corneal subbasal nerve plexus features of normal and simian immunodeficiency virus (SIV)-infected macaques by combining in vivo corneal confocal microscopy (IVCM) with automated assessments using deep learning-based methods customized for macaques.

METHODS

IVCM images were collected from both male and female age-matched rhesus and pigtailed macaques housed at the Johns Hopkins University breeding colony using the Heidelberg HRTIII with Rostock Corneal Module. We also obtained repeat IVCM images of 12 SIV-infected animals including preinfection and 10-day post-SIV infection time points. All IVCM images were analyzed using a deep convolutional neural network architecture developed specifically for macaque studies.

RESULTS

Deep learning-based segmentation of subbasal nerves in IVCM images from macaques demonstrated that corneal nerve fiber length and fractal dimension measurements did not differ between species, but pigtailed macaques had significantly higher baseline corneal nerve fiber tortuosity than rhesus macaques (P = 0.005). Neither sex nor age of macaques was associated with differences in any of the assessed corneal subbasal nerve parameters. In the SIV/macaque model of human immunodeficiency virus, acute SIV infection induced significant decreases in both corneal nerve fiber length and fractal dimension (P = 0.01 and P = 0.008, respectively).

CONCLUSIONS

The combination of IVCM and robust objective deep learning analysis is a powerful tool to track sensory nerve damage, enabling early detection of neuropathy. Adapting deep learning analyses to clinical corneal nerve assessments will improve monitoring of small sensory nerve fiber damage in numerous clinical settings including human immunodeficiency virus.

A qualitative study of the experience and impact of neuropathic pain in people living with HIV

Painful distal symmetrical polyneuropathy is common in HIV and is associated with reduced quality of life. Research has not explored the experience of neuropathic pain in people with HIV from a person-centred perspective. Therefore, a qualitative interview study was conducted to more deeply understand the experience and impact of neuropathic pain in this population. Semistructured interviews were conducted with 26 people with HIV and peripheral neuropathic pain symptoms. Interviews explored the impact of pain and participants' pain management strategies. Interviews were transcribed verbatim and analysed using thematic analysis. Four themes and 11 subthemes were identified. Theme 1 reflects the complex characterisation of neuropathic pain, including the perceived unusual nature of this pain and diagnostic uncertainty. Theme 2 centred on the interconnected impacts of pain on mood and functioning and includes how pain disrupts relationships and threatens social inclusion. Theme 3 reflects the struggle for pain relief, including participants' attempts to "exhaust all options" and limited success in finding lasting relief. The final theme describes how pain management is complicated by living with HIV; this theme includes the influence of HIV stigma on pain communication and pain as an unwanted reminder of HIV. These data support the relevance of investigating and targeting psychosocial factors to manage neuropathic pain in HIV.

Neuroinflammation in HIV-Related Neuropathic Pain

In the management of human immunodeficiency virus (HIV) infection around the world, chronic complications are becoming a new problem along with the prolonged life expectancy. Chronic pain is widespread in HIV infected patients and even affects those with a low viral load undergoing long-term treatment with antiviral drugs, negatively influencing the adherence to disease management and quality of life. A large proportion of chronic pain is neuropathic pain, which defined as chronic pain caused by nervous system lesions or diseases, presenting a series of nervous system symptoms including both positive and negative signs. Injury caused by HIV protein, central and peripheral sensitization, and side effects of antiretroviral therapy lead to neuroinflammation, which is regarded as a maladaptive mechanism originally serving to promote regeneration and healing, constituting the main mechanism of HIV-related neuropathic pain. Gp120, as HIV envelope protein, has been found to be the major toxin that induces neuropathic pain. Particularly, the microglia, releasing numerous pro-inflammatory substances (such as TNFα, IL-1β, and IL-6), not only sensitize the neurons but also are the center part of the crosstalk bridging the astrocytes and oligodendrocytes together forming the central sensitization during HIV infection, which is not discussed detailly in recent reviews. In the meantime, some NRTIs and PIs exacerbate the neuroinflammation response. In this review, we highlight the importance of clarifying the mechanism of HIV-related neuropathic pain, and discuss about the limitation of the related studies as future research directions.

Feasibility randomized-controlled trial of online acceptance and commitment therapy for painful peripheral neuropathy in people living with HIV: The OPEN study

BACKGROUND

Neuropathic pain negatively affects quality of life among people living with HIV (PLWH). This study examined the feasibility of conducting a full-scale randomized-controlled trial of online acceptance and commitment therapy ("ACT OPEN") for neuropathic pain in PLWH.

METHODS

Using a parallel-groups design, thirty-eight participants were randomized to ACT OPEN or a waitlist control (2:1). Participants completed standard self-report outcome measures at baseline, and two- and five-months post-randomization. Participants were aware of their allocation, but assessment was blinded.

RESULTS

Twenty-five participants were randomized to ACT OPEN and 13 to the control (of 133 referrals). ACT OPEN completion was 69% and two-month trial retention was 82%. Treatment credibility and satisfaction scores for ACT OPEN were comparable to scores reported in previous trials of cognitive-behavioural treatments for pain. Four adverse events were reported during the study, including one serious adverse event; all of these were unrelated to the research procedures. Small to moderate effects and 95% confidence intervals suggest that the true effect may favour ACT OPEN for improvements in pain intensity/interference and depression.

CONCLUSIONS

A full-scale RCT of online ACT for pain management in PLWH may be feasible with refinements to trial design to facilitate recruitment.

SIGNIFICANCE

Research on pain management in people living with HIV has primarily focused on pharmacological treatments with limited success. This is the first study to show the potential feasibility of a psychological treatment based on acceptance and commitment therapy delivered online and tailored for pain management in people with HIV ("ACT OPEN"). ACT OPEN may be a promising treatment in this population and further evaluation in a full-scale randomized-controlled trial appears warranted.

TRIAL REGISTRATION

The trial was registered (clinicaltrials.gov; NCT03584412).

Acupuncture for HIV-associated distal symmetric peripheral neuropathy: A protocol for systematic review and meta-analysis

BACKGROUND

Human immunodeficiency virus (HIV)-associated distal symmetric peripheral neuropathy (DSPN) is one of the most frequent neurological complications of HIV infection, and causes pain and dysaesthesias in millions globally. Many individuals with this infection report using acupuncture to manage their symptoms, but evidence supporting the use of acupuncture is limited. This systematic review will assess the effectiveness and safety of acupuncture for patients with HIV-associated DSPN.

METHODS

Databases including MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Scopus, Web of science, AMED (Allied and Complementary Medicine), the Chinese Biomedical Literature Database, the China National Knowledge Infrastructure, Wanfang Database, VIP Database and clinical trials registers (the WHO International Clinical Trials Registry Platform portal and www.ClinicalTrials.gov) will be electronically searched from inception to December 1, 2020. All randomized controlled trials in English or Chinese without restriction on publication status will be included. Selection of studies, extraction of data, and assessment of studies quality will be independently performed by 2 reviewers. The primary outcome measure will be the change in pain intensity assessed by validated scales. Secondary outcomes include change in neurologic summary scores, quality of life, physical function evaluated by admitted tools, and adverse events related to acupuncture reported in the included trials. If possible, a meta-analysis will be conducted to provide an estimate of the pooled treatment effect using Review Manager 5.3 statistical software. Otherwise, qualitative descriptive analysis will be given. The results will be presented as the risk ratio for binary data and the mean difference (MD) or standardized MD for continuous data.

RESULTS

The results of the systematic review will be disseminated via publication in a peer-reviewed journal and presented at a relevant conference.

CONCLUSION

This review will be the first review entirely focused on assessing the effectiveness and safety of acupuncture for HIV-associated DSPN.

PROSPERO REGISTRATION NUMBER

CRD42020210994.

HIV-1 Tat promotes age-related cognitive, anxiety-like, and antinociceptive impairments in female mice that are moderated by aging and endocrine status

Hypogonadism is a common comorbidity associated with HIV-1 that is more prevalent among infected individuals over the age of 45. The underlying mechanisms are unknown, but both combined antiretroviral therapeutics and HIV-1 proteins, such as trans-activator of transcription protein (Tat), dysregulate steroid-synthetic mechanisms including lipid storage/synthesis and mitochondrial function. Thus, Tat expression may accelerate age-related comorbidities partly by impairing endocrine function. Few studies exist of Tat-mediated behavioral deficits in aged animals and effects of endocrine status have not been investigated. Accordingly, we tested whether conditional Tat expression in aged (~ 1.5 years old), female, Tat-transgenic [Tat(+)] mice increases anxiety-like behavior, impairs cognition, and augments mechanical allodynia, when compared to age-matched controls that do not express Tat protein [Tat(-)]. We further tested whether aged mice that maintained their endocrine status (pre-estropausal) were more resilient to Tat/age-related comorbidities than peri- or post-estropausal mice. Tat and endocrine aging status exerted separate and interacting effects that influenced anxiety-like and cognitive behaviors. Peri- and post-estropausal mice exhibited greater anxiety-like behavior in the elevated plus-maze and impaired learning in the radial arm water maze compared to pre-estropausal mice. Irrespective of estropause status, Tat(+) mice demonstrated impaired learning, reduced grip strength, and mechanical allodynia compared to Tat(-) mice. Tat exposure reduced circulating estradiol in post-estropausal mice and increased the estradiol-to-testosterone ratio in pre-estropausal mice. Changes in circulating estradiol, testosterone, and progesterone correlated with grip strength. Thus, endocrine status is an important factor in age-related anxiety, cognition, neuromuscular function, and allodynia that can be accelerated by HIV-1 Tat protein.

Acceptability of psychologically-based pain management and online delivery for people living with HIV and chronic neuropathic pain: a qualitative study

OBJECTIVES

Chronic neuropathic pain is common in people living with HIV. Psychological treatments can improve quality of life for people with chronic pain in general, and online delivery can increase access to these treatments. However, the acceptability of psychological treatment and online delivery have not been investigated in-depth in people living with HIV and chronic neuropathic pain. Therefore, a qualitative study was undertaken to explore views about a psychological treatment for pain management in this population and to investigate the acceptability of online treatment delivery.

METHODS

Qualitative interviews were conducted and analysed using inductive thematic analysis, adopting a critical realist perspective. Twenty-six people living with HIV and chronic neuropathic pain completed semi-structured interviews. Their views about a psychological treatment for pain management and online delivery were explored in-depth.

RESULTS

Three themes and 12 subthemes were identified. Theme one represents a desire for a broader approach to pain management, including not wanting to take more pills and having multidimensional goals that were not just focussed on pain relief. Theme two includes barriers to online psychologically-based pain management, including concerns about using the Internet and confidentiality. Theme three describes treatment facilitators, including accessibility, therapist support, social connection, and experiencing success.

CONCLUSIONS

A psychological treatment for chronic neuropathic pain management appears acceptable for people living with HIV. Therapist-supported online delivery of cognitive-behavioural pain management may be acceptable for people living with HIV given appropriate development of the treatment to address identified barriers to engagement. These data can inform developments to enhance engagement in online psychologically-informed pain management in people living with HIV and more broadly in remote delivery of psychological treatments.

Drosophila model of anti-retroviral therapy induced peripheral neuropathy and nociceptive hypersensitivity

The success of antiretroviral therapy (ART) has improved the survival of HIV-infected patients significantly. However, significant numbers of patients on ART whose HIV disease is well controlled show peripheral sensory neuropathy (PSN), suggesting that ART may cause PSN. Although the nucleoside reverse transcriptase inhibitors (NRTIs), one of the vital components of ART, are thought to contribute to PSN, the mechanisms underlying the PSN induced by NRTIs are unclear. In this study, we developed a Drosophila model of NRTI-induced PSN that recapitulates the salient features observed in patients undergoing ART: PSN and nociceptive hypersensitivity. Furthermore, our data demonstrate that pathways known to suppress PSN induced by chemotherapeutic drugs are ineffective in suppressing the PSN or nociception induced by NRTIs. Instead, we found that increased dynamics of a peripheral sensory neuron may possibly underlie NRTI-induced PSN and nociception. Our model provides a solid platform in which to investigate further mechanisms of ART-induced PSN and nociceptive hypersensitivity.

This article has an associated First Person interview with the first author of the paper.

Summary: Nucleoside reverse transcriptase inhibitors (NRTIs) that are important components of anti-retroviral therapies also cause peripheral sensory neuropathies (PSN). This article investigates ways in which NRTIs may cause PSN and outlines ways to better understand the mechanisms underlying it.

Self-Reported Disability in Persons With HIV-Related Neuropathy Is Mediated by Pain Interference and Depression

OBJECTIVE

The purpose of this study was to compare disability in people with HIV and peripheral neuropathy with those without neuropathy and explore how neuropathy and other relevant factors are associated with disability.

METHODS

In this cross-sectional study, participants completed the Brief pain inventory, Beck Depression Inventory II, World Health Organization Disability Assessment Schedule (WHODAS 2.0), and a health and demographic questionnaire. Additional data were extracted from the medical record. A raw score of ≥1 on the Subjective Peripheral Neuropathy Screen questions about lower extremity numbness or paresthesia was used to identify peripheral neuropathy. Predictors of disability (as determined by association with World Health Organization Disability Assessment Schedule 2.0 scores) were evaluated bivariately and in a multivariable model. Path modeling was used to identify a parsimonious model to elucidate the mediated effects of peripheral neuropathy on disability.

RESULTS

Participants with peripheral neuropathy had more depression symptoms, more pain (severity and interference), and higher disability scores compared with participants without neuropathy. The relationship between neuropathy and disability was mediated by pain interference and depression (standardized root mean residual = .056).

CONCLUSION

In this sample of people with HIV, those with lower extremity peripheral neuropathy reported more severe disability, worse pain, and more depression symptoms than those without neuropathy. The relationship between peripheral neuropathy and disability may be mediated though pain interference and depression.

IMPACT

Distal sensory polyneuropathy is a common comorbidity experienced by people living with HIV and frequently causes pain. This study can help providers direct care toward lessening disability experienced among people with HIV and peripheral neuropathy by targeting interventions for treatment of pain and depression.

LAY SUMMARY

People living with HIV may experience disabling painful neuropathy. Treatment for pain and depression may help reduce the disability associated with painful neuropathy.

What Every Neuropathologist Needs to Know: Peripheral Nerve Biopsy

Peripheral neuropathy is a common disorder with many possible etiologies including metabolic diseases, inflammatory conditions, infections, malignancy, inherited diseases, drugs, and toxins. In most instances, diagnosis and treatment plan can be established based on clinical presentation, family history, laboratory results, genetic testing, and electrophysiological studies. But in some situations, a peripheral nerve biopsy remains a valuable tool. This is especially true in patients with rapidly progressive disease, with atypical presentation or for whom other approaches fail to yield a definitive diagnosis. The pathologic examination starts with basic decisions about specimen triage. A few basic questions help to provide an initial framework for the assessment of a nerve biopsy-is the specimen adequate; are there inflammatory changes; are there vascular changes; is there amyloid; are there changes to axonal density and the Schwann cell-myelin-axon unit. In the appropriate context and with such an approach peripheral nerve biopsies can still represent a clinically helpful test.

Higher iron stores and the HFE 187C>G variant delay onset of peripheral neuropathy during combination antiretroviral therapy

OBJECTIVE

People with HIV (PWH) continue to experience sensory neuropathy and neuropathic pain in the combination antiretroviral therapy (cART) era for unclear reasons. This study evaluated the role of iron in a previously reported association of iron-loading hemochromatosis (HFE) gene variants with reduced risk of neuropathy in PWH who received more neurotoxic cART, since an iron-related mechanism also might be relevant to neuropathic symptoms in PWH living in low-resource settings today.

DESIGN

This time-to-event analysis addressed the impact of systemic iron levels on the rapidity of neuropathy onset in PWH who initiated cART.

METHODS

Soluble transferrin receptor (sTFR), the sTFR-ferritin index of iron stores, and high-sensitivity C-reactive protein (hsCRP) levels were determined in stored baseline sera from participants of known HFE genotype from AIDS Clinical Trials Group (ACTG) Study 384, a multicenter randomized clinical trial that evaluated cART strategies. Associations with incident neuropathy were evaluated in proportional-hazards, time-to-event regression models, adjusting for potential confounders.

RESULTS

Of 151 eligible participants with stored serum who were included in the original genetic study, 43 had cART-associated neuropathy; 108 had sufficient serum for analysis, including 30 neuropathy cases. Carriers of HFE variants had higher systemic iron (lower sTFR and sTFR-ferritin index) and lower hsCRP levels than non-carriers (all p<0.05). Higher sTFR or iron stores, the HFE 187C>G variant, and lower baseline hsCRP were associated with significantly delayed neuropathy in self-reported whites (n = 28; all p-values<0.05), independent of age, CD4+ T-cell count, plasma HIV RNA, and cART regimen.

CONCLUSIONS

Higher iron stores, the HFE 187C>G variant, and lower hsCRP predicted delayed onset of neuropathy among self-reported white individuals initating cART. These findings require confirmation but may have implications for cART in HIV+ populations in areas with high endemic iron deficiency, especially those PWH in whom older, more neurotoxic antiretroviral drugs are occasionally still used.

Prevalence and clinical characteristics associated with peripheral neuropathy amongst persons on HAART in Busia County, Kenya

Background

Despite improved immunological and viral load control, the prevalence of HIV/AIDS-related peripheral neuropathy among survivors on highly active antiretroviral therapy (HAART) is rising globally raising public health concerns.

Objectives

To determine the prevalence and clinical characteristics of peripheral neuropathy amongst persons on HAART attending Comprehensive Care Clinics in Busia County, Kenya.

Method

This cross-sectional descriptive quantitative study utilised purposive sampling and included 289 adults living with HIV/AIDS. Data collection was undertaken using the Clinical HIV Associated Neuropathy Tool (CHANT) and analysed using the Statistical Package for the Social Sciences version 25.0.

Results

Of people on HAART, 68.17% (197 amongst 289) had peripheral neuropathy. The majority were female 76.8% (n = 222), 38.1% (n = 110) were between 41 and 50, and 35% (n = 101) were widowed. The most common primary symptom was reduced right foot big toe vibration (76.8%, n = 222). There was a strong positive relationship (r = 0.621, P = 0.000) between foot vibration and illness. There was a statistically significant influence of demographic characteristics of persons on HAART on PN as they accounted for 98.5% of the variance (R² = 0.985).

Conclusion

Peripheral neuropathy is prevalent and is significantly influenced by socio-demographic characteristics of persons on HAART-PN. Early diagnosis and exercise guidance by physiotherapists is key in forestalling severe symptoms, disability and poor quality of life.

Clinical implications

There is need to screen persons living with HIV on HAART for PN to establish their medical, physiotherapy and rehabilitation needs. Early diagnosis will encourage healthcare workers to start interventions to prevent progression of impairment, onset of disability and decrease in quality of life. Therefore, adaptation of PN screening tools and physiotherapeutic interventions should be considered.

The Utility of Corneal Nerve Fractal Dimension Analysis in Peripheral Neuropathies of Different Etiology

Purpose

Quantification of corneal confocal microscopy (CCM) images has shown a significant reduction in corneal nerve fiber length (CNFL) in a range of peripheral neuropathies. We assessed whether corneal nerve fractal dimension (CNFrD) analysis, a novel metric to quantify the topological complexity of corneal subbasal nerves, can differentiate peripheral neuropathies of different etiology.

Methods

Ninety patients with peripheral neuropathy, including 29 with diabetic peripheral neuropathy (DPN), 34 with chronic inflammatory demyelinating polyneuropathy (CIDP), 13 with chemotherapy-induced peripheral neuropathy (CIPN), 14 with human immunodeficiency virus-associated sensory neuropathy (HIV-SN), and 20 healthy controls (HCs), underwent CCM for estimation of corneal nerve fiber density (CNFD), CNFL, corneal nerve branch density (CNBD), CNFrD, and CNFrD adjusted for CNFL (ACNFrD).

Results

In patients with DPN, CIDP, CIPN, or HIV-SN compared to HCs, CNFD (P = 0.004-0.0001) and CNFL (P = 0.05-0.0001) were significantly lower, with a further significant reduction among subgroups. CNFrD was significantly lower in patients with CIDP compared to HCs and patients with HIV-SN (P = 0.02-0.0009) and in patients with DPN compared to HCs and patients with HIV-SN, CIPN, or CIDP (P = 0.001-0.0001). ACNFrD was lower in patients with CIPN, CIDP, or DPN compared to HCs (P = 0.03-0.0001) and in patients with DPN compared to those with HIV-SN, CIPN, or CIDP (P = 0.01-0.005).

Conclusions

CNFrD can detect a distinct pattern of corneal nerve loss in patients with DPN or CIDP compared to those with CIPN or HIV-SN and controls.

Translational Relevance

Various peripheral neuropathies are characterized by a comparable degree of corneal nerve loss. Assessment of corneal nerve topology by CNFrD could be useful in differentiating neuropathies based on the pattern of loss.

Heme attenuates beta-endorphin levels in leukocytes of HIV positive individuals with chronic widespread pain

The prevalence of chronic widespread pain (CWP) in people with HIV is high, yet the underlying mechanisms are elusive. Leukocytes synthesize the endogenous opioid, β-endorphin, within their endoplasmic reticulum (ER). When released into plasma, β-endorphin dampens nociception by binding to opioid receptors on sensory neurons. We hypothesized that the heme-dependent redox signaling induces ER stress, which attenuates leukocyte β-endorphins levels/release, thereby increasing pain sensitivity in people with HIV. Results demonstrated that HIV positive individuals with CWP had increased plasma methemoglobin, erythrocytes membrane oxidation, hemolysis, and low plasma heme scavenging enzyme, hemopexin, compared to people with HIV without CWP and HIV-negative individuals with or without pain. In addition, the leukocytes from people with HIV with CWP had attenuated levels of the heme metabolizing enzyme, heme oxygenase-1, which metabolizes free heme to carbon-monoxide and biliverdin. These individuals also had elevated ER stress, and low β-endorphin in leukocytes. In vitro, heme exposure or heme oxygenase-1 deletion, decreased β-endorphins in murine monocytes/macrophages. Treating cells with a carbon-monoxide donor or an ER stress inhibitor, increased β-endorphins. To mimic hemolytic effects in a preclinical model, C57BL/6 mice were injected with phenylhydrazine hydrochloride (PHZ). PHZ increased cell-free heme and ER stress, decreased leukocyte β-endorphin levels and hindpaw mechanical sensitivity thresholds. Treatment of PHZ-injected mice with hemopexin blocked these effects, suggesting that heme-induced ER stress and a subsequent decrease in leukocyte β-endorphin is responsible for hypersensitivity in people with HIV.

Kinematics and temporospatial parameters during gait from inertial motion capture in adults with and without HIV: a validity and reliability study

BACKGROUND

Inertial measurement unit (IMU)-based motion capture systems are gaining popularity for gait analysis outside laboratories. It is important to determine the performance of such systems in specific patient populations. We aimed to validate and determine within-day reliability of an IMU system for measuring lower limb gait kinematics and temporal-spatial parameters (TSP) in people with and without HIV.

METHODS

Gait was recorded in eight adults with HIV (PLHIV) and eight HIV-seronegative participants (SNP), using IMUs and optical motion capture (OMC) simultaneously. Participants performed six gait trials. Fifteen TSP and 28 kinematic angles were extracted. Intraclass correlations (ICC), root-mean-square error (RMSE), mean absolute percentage error and Bland-Altman analyses were used to assess concurrent validity of the IMU system (relative to OMC) separately in PLHIV and SNP. IMU reliability was assessed during within-session retest of trials. ICCs were used to assess relative reliability. Standard error of measurement (SEM) and percentage SEM were used to assess absolute reliability.

RESULTS

Between-system TSP differences demonstrated acceptable-to-excellent ICCs (0.71-0.99), except for double support time and temporophasic parameters (< 0.60). All TSP demonstrated good mean absolute percentage errors (≤7.40%). For kinematics, ICCs were acceptable to excellent (0.75-1.00) for all but three range of motion (ROM) and four discrete angles. RMSE and bias were 0.0°-4.7° for all but two ROM and 10 discrete angles. In both groups, TSP reliability was acceptable to excellent for relative (ICC 0.75-0.99) (except for one temporal and two temporophasic parameters) and absolute (%SEM 1.58-15.23) values. Reliability trends of IMU-measured kinematics were similar between groups and demonstrated acceptable-to-excellent relative reliability (ICC 0.76-0.99) and clinically acceptable absolute reliability (SEM 0.7°-4.4°) for all but two and three discrete angles, respectively. Both systems demonstrated similar magnitude and directional trends for differences when comparing the gait of PLHIV with that of SNP.

CONCLUSIONS

IMU-based gait analysis is valid and reliable when applied in PLHIV; demonstrating a sufficiently low precision error to be used for clinical interpretation (< 5° for most kinematics; < 20% for TSP). IMU-based gait analysis is sensitive to subtle gait deviations that may occur in PLHIV.