Predictors of worsening neuropathy and neuropathic pain after 12 years in people with HIV

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.

Peripheral Neuropathy in Virologically Suppressed People Living with HIV: Evidence from the PIVOT Trial

The aim of this study is to identify the factors associated with peripheral neuropathy and to explore neurofilament light chain (NfL) as a biomarker for peripheral neuropathy (PN) in effectively virologically suppressed adults living with HIV. All protease inhibitor monotherapy versus ongoing triple therapy in the long-term management of HIV infection (PIVOT) trial participants with data on PN at baseline were included in the study. NfL plasma levels (pNfL) were measured in a sub-set of participants. Multivariable logistic regression was used to examine the associations of PN with potential risk factors (including age, sex, nadir CD4 cell count, history of dideoxynucleoside (d-drugs) exposure, and blood glucose levels) and NfL levels. Of the 585 participants included, 131 (22.4%) reported PN during the study period (median of 44 months). The participants were predominantly male (76.6%), White (68.2%), and virologically suppressed for a median period of 37 months (range of 20-63) before recruitment. The age at baseline was 44.3 years (standard deviation (SD) of 9.2). PN was independently associated with age (adjusted odds ratio (aOR) = 1.35, 95% CI of 1.20-1.52; additional 5 years), history of d-drugs (aOR 1.88, 95% CI of 1.12-3.16), height (aOR 1.19, 95% CI of 1.05-1.35; additional 5 cm), nadir CD4 cell count (aOR 1.10 CI of 1.00-1.20; 50 cells fewer), and metabolic syndrome (aOR 2.31, 95% CI of 1.27 4.20), but not pNfL. The excess risk for PN associated with d-drug use remains after the exposure has stopped for years, suggesting non-reversible toxicity. In people with HIV, metabolic syndrome is independently associated with PN. There was no additional value for pNfL as a screening test for peripheral neuropathy in effectively virologically suppressed adults living with HIV.

Increasing Neuroinflammation Relates to Increasing Neurodegeneration in People with HIV

BACKGROUND

HIV infection causes neuroinflammation and immune activation (NIIA) and systemic inflammation and immune activation (SIIA), which in turn drive neurodegeneration (ND). Cross-sectionally, higher levels of NIIA biomarkers correlate with increased biomarkers of ND. A more convincing confirmation would be a longitudinal demonstration.

METHODS

PWH in the US multisite CHARTER Aging project were assessed at a baseline visit and after 12 years using standardized evaluations. We measured a panel of 14 biomarkers of NIIA, SIIA, and ND in plasma and CSF at two time points and calculated changes from baseline to the 12-year visit. Factor analysis yielded simplified indices of NIIA, SIIA, and ND.

RESULTS

The CSF NIIA factor analysis yielded Factor1 loading on soluble tumor necrosis factor type-2 (sTNFR-II) and neopterin, and Factor2, loading on MCP1, soluble CD14, and IL-6. The SIIA factor analysis yielded Factor1 loading on CRP, D-dimer, and Neopterin; Factor2 loading on sTNFR-II. The ND analysis yielded Factor1 loading on Phosphorylated tau (p-tau) and Aβ42; Factor2 loading on NFL. NIIA Factor1, but not Factor2, correlated with increases in CSF NFL (r = 0.370, p = 0.0002).

CONCLUSIONS

Increases in NIIA and SIIA in PWH were associated with corresponding increases in ND, suggesting that reducing neuro/systemic inflammation might slow or reverse neurodegeneration.

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.

Higher Levels of Cerebrospinal Fluid and Plasma Neurofilament Light in Human Immunodeficiency Virus-Associated Distal Sensory Polyneuropathy

BACKGROUND

Neurofilament light (NFL) chain concentrations, reflecting axonal damage, are seen in several polyneuropathies but have not been studied in human immunodeficiency virus (HIV) distal sensory polyneuropathy (DSP). We evaluated NFL in cerebrospinal fluid (CSF) and plasma in relation to DSP in people with HIV (PWH) from 2 independent cohorts and in people without HIV (PWoH).

METHODS

Cohort 1 consisted of PWH from the CHARTER Study. Cohort 2 consisted of PWH and PWoH from the HIV Neurobehavioral Research Center (HNRC). We evaluated DSP signs and symptoms in both cohorts. Immunoassays measured NFL in CSF for all and for plasma as well in Cohort 2.

RESULTS

Cohort 1 consisted of 111 PWH, mean ± SD age 56.8 ± 8.32 years, 15.3% female, 38.7% Black, 49.6% White, current CD4+ T-cells (median, interquartile range [IQR]) 532/µL (295, 785), 83.5% with plasma HIV RNA ≤50 copies/mL. Cohort 2 consisted of 233 PWH of similar demographics to PWH in Cohort 1 but also 51 PWoH, together age 58.4 ± 6.68 years, 41.2% female, 18.0% Black, Hispanic, non-Hispanic White 52.0%, 6.00% White. In both cohorts of PWH, CSF and plasma NFL were significantly higher in both PWH with DSP signs. Findings were similar, albeit not significant, for PWoH. The observed relationships were not explained by confounds.

CONCLUSIONS

Both plasma and CSF NFL were elevated in PWH and PWoH with DSP. The convergence of our findings with others demonstrates that NFL is a reliable biomarker reflecting peripheral nerve injury. Biomarkers such as NFL might provide, validate, and optimize clinical trials of neuroregenerative strategies in HIV DSP.

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.

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.

Prior Methamphetamine Use Disorder History Does Not Impair Interoceptive Processing of Soft Touch in HIV Infection

Introduction: Interoception, defined as the sense of the internal state of one’s body, helps motivate goal-directed behavior. Prior work has shown that methamphetamine (METH) use disorder is associated with altered interoception, and that this may contribute to risky behavior. As people with HIV (PWH) may also experience disrupted bodily sensations (e.g., neuropathy), an important question is whether PWH with a history of METH use disorder might exhibit greater impairment of interoceptive processing. Methods: Eighty-three participants stratified by HIV infection and a past history of methamphetamine use disorder experienced a soft touch paradigm that included slow brush strokes on the left forearm and palm during blood-oxygen level-dependent functional MRI acquisition. To assess differences in interoception and reward, voxelwise analyses were constrained to the insula, a hub for the evaluation of interoceptive cues, and the striatum, which is engaged in reward processing. Results: Overall, individuals with a history of METH use disorder had an attenuated neural response to pleasant touch in both the insula and striatum. Longer abstinence was associated with greater neural response to touch in the insula, suggesting some improvement in responsivity. However, only PWH with no METH use disorder history had lower brain activation in the insula relative to non-using seronegative controls. Conclusions: Our findings suggest that while METH use disorder history and HIV infection independently disrupt the neural processes associated with interoception, PWH with METH use disorder histories do not show significant differences relative to non-using seronegative controls. These findings suggest that the effects of HIV infection and past methamphetamine use might not be additive with respect to interoceptive processing impairment.

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.

Current Considerations for Clinical Management and Care of People with HIV: Findings from the 11th Annual International HIV and Aging Workshop

The number of people with HIV (PWH) aged 50 years or older continues to steadily increase. The convergence of age- and HIV-related complications in these individuals presents a challenge for both patients and clinicians alike. New findings continue to emerge, as numerous researchers evaluate the combined impact of these two factors on quality of life, physiological systems, and mental health in PWH. Since its first occurrence in 2009, the International Workshop on HIV and Aging has served as a multidisciplinary meeting to share basic biomedical data, clinical trial results, treatment strategies, and epidemiological recommendations, toward better understanding and outcomes among like-minded scientific professionals. In this article, we share a selection of key findings presented in plenary talks at the 11th Annual International Workshop on HIV and Aging, held virtually from September 30, 2020 to October 2, 2020. We will also address the future directions of HIV and aging research, to further assess how the aging process intersects with chronic HIV.

Predictive variables for peripheral neuropathy in treated HIV type 1 infection revealed by machine learning

OBJECTIVE

Peripheral neuropathies (PNPs) in HIV-infected patients are highly debilitating because of neuropathic pain and physical disabilities. We defined prevalence and associated predictive variables for PNP subtypes in a cohort of persons living with HIV.

DESIGN

Adult persons living with HIV in clinical care were recruited to a longitudinal study examining neurological complications.

METHODS

Each patient was assessed for symptoms and signs of PNP with demographic, laboratory, and clinical variables. Univariate, multiple logistic regression and machine learning analyses were performed by comparing patients with and without PNP.

RESULTS

Three patient groups were identified: PNP (n = 111) that included HIV-associated distal sensory polyneuropathy (n = 90) or mononeuropathy (n = 21), and non-neuropathy (n = 408). Univariate analyses showed multiple variables differed significantly between the non-neuropathy and PNP groups including age, estimated HIV type 1 (HIV-1) duration, education, employment, neuropathic pain, peak viral load, polypharmacy, diabetes, cardiovascular disorders, AIDS, and prior neurotoxic nucleoside antiretroviral drug exposure. Classification algorithms distinguished those with PNP, all with area under the receiver operating characteristic curve values of more than 0.80. Random forest models showed greater accuracy and area under the receiver operating characteristic curve values compared with the multiple logistic regression analysis. Relative importance plots showed that the foremost predictive variables of PNP were HIV-1 duration, peak plasma viral load, age, and low CD4+ T-cell levels.

CONCLUSION

PNP in HIV-1 infection remains common affecting 21.4% of patients in care. Machine-learning models uncovered variables related to PNP that were undetected by conventional analyses, emphasizing the importance of statistical algorithmic approaches to understanding complex neurological syndromes.

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.

Prevalence of pain in women living with HIV aged 45-60: associated factors and impact on patient-reported outcomes

As the population of women with HIV ages, an increasing proportion are experiencing the menopause, with potential associated pain. Among 844 participants in the Positive Transitions Through the Menopause (PRIME) study (72.3% black African; median age 49 (interquartile-range 47-53) years; 20.9%, 44.0% and 35.1% pre-, peri- and post-menopausal), 376 (44.6%) and 73 (8.7%) reported moderate or extreme pain. Women had been diagnosed with HIV for 14 (9-18) years, 97.7% were receiving antiretroviral therapy and 88.4% had a suppressed viral load. In adjusted ordinal logistic regression, peri-menopausal status (adjusted odds ratio (1.80) [95% confidence interval 1.22-2.67]), current smoking (1.85 [1.11-3.09]), number of comorbid conditions (1.95 [1.64-2.33] /condition) and longer duration of HIV (1.12 [1.00-1.24]/5 years) were independently associated with increased reported pain, whereas being in full-time work (0.61 [0.45-0.83]) and having enough money for basic needs (0.47 [0.34-0.64]) were associated with decreased pain reporting. Increasing pain was independently related to insomnia symptoms (moderate: 2.76 [1.96-3.90]; extreme: 8.09 [4.03-16.24]) and severe depressive symptoms (PHQ4 ≥ 6; moderate: 3.96 [2.50-6.28]; extreme: 9.13 [4.45-18.72]). Whilst our analyses cannot determine the direction of any associations, our findings point to the importance of eliciting a history of pain and addressing symptoms in order to improve wellbeing.