HIV-related neuropathy: current perspectives

Peripheral neuropathy and associated factors among children living with HIV on antiretroviral therapy in Gamo zone, Southern Ethiopia: an institution-based cross-sectional study

BACKGROUND

Peripheral neuropathy (PN) is a common neurological complication of HIV (Human Immunodeficiency Virus) that can significantly affect patients' quality of life. In Ethiopia, children living with HIV are at an increased risk of developing peripheral neuropathy due to comorbidities such as anemia, tuberculosis, malnutrition, and poor socio-economic status. Our study aims to evaluate the prevalence of peripheral neuropathy among children living with HIV in Ethiopia using a simple clinical screening tool.

METHODS

A health institution-based cross-sectional study was conducted among 148 children aged 5 to 18 years living with HIV who are receiving treatment at the antiretroviral therapy (ART) clinic of the randomly selected public health institutions in the Gamo zone. An interview and neurologic examination were conducted. A binary logistic regression model was used to identify factors associated with the outcome variable. Variables with p-value < 0.25 in the bi-variable logistic regression analysis were entered and checked for association in a multivariable logistic regression model. The level of statistical significance was declared at the p-value < 0.05.

RESULT

In this study, 148 children participated, making a response rate of 97.5%. The mean ± standard deviation (SD) age of the respondents was 15.03 ± 2.99 years, and 81(54.7%) were male. The magnitude of PN was 20.9% (31/148). Children in the age category of 15-18 (adjusted odds ratio (AOR) = 1.88, 95%CI; 1.24-4.60), low BMI for age (AOR = 1.66, 95%CI; 1.12-4.15), last exposure to isoniazid within 1 year (AOR = 2.31, 95%CI; 1.12-8.53). Longer duration of HIV illness (AOR = 2.17, 95%CI; 1.54-4.64), and past tuberculosis (TB) treatment (AOR = 2.11, 95%CI; 1.08-7.48) were significantly associated factors with peripheral neuropathy.

CONCLUSION

Our analysis revealed that being in the age category of 15-18 years, low BMI for age, Isoniazid exposure, longer Duration of HIV illness, and past TB treatment were significantly associated with peripheral neuropathy in children living with HIV. These disease-related factors may contribute to the development and progression of peripheral neuropathy in this population.

CLINICAL TRIAL NUMBER

Not applicable.

Neurological Complications Caused by Human Immunodeficiency Virus (HIV) and Associated Opportunistic Co-infections: A Review on their Diagnosis and Therapeutic Insights

Neurocognitive disorders associated with human immunodeficiency virus (HIV) infected individuals increase the risk of mortality and morbidity that remain a prevalent clinical complication even in the antiretroviral therapy era. It is estimated that a considerable number of people in the HIV community are developing neurological complications at their early stages of infection. The daily lives of people with chronic HIV infections are greatly affected by cognitive declines such as loss of attention, learning, and executive functions, and other adverse conditions like neuronal injury and dementia. It has been found that the entry of HIV into the brain and subsequently crossing the blood-brain barrier (BBB) causes brain cell damage, which is the prerequisite for the development of neurocognitive disorders. Besides the HIV replication in the central nervous system and the adverse effects of antiretroviral therapy on the BBB, a range of opportunistic infections, including viral, bacterial, and parasitic agents, augment the neurological complications in people living with HIV (PLHIV). Given the immuno-compromised state of PLHIV, these co-infections can present a wide range of clinical syndromes with atypical manifestations that pose challenges in diagnosis and clinical management, representing a substantial burden for the public health system. Therefore, the present review narrates the neurological complications triggered by HIV and their diagnosis and treatment options. Moreover, coinfections that are known to cause neurological disorders in HIV infected individuals are highlighted.

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

Background

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

Method

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

Results

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

Conclusion

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

Clinical trial registration

https://clinicaltrials.gov/, NCT05379140.

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

Background

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

Study design

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

Aim

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

Outcomes

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

Sample size

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

Trial status

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

Drosophila as a Model for Human Viral Neuroinfections

The study of human neurological infection faces many technical and ethical challenges. While not as common as mammalian models, the use of Drosophila (fruit fly) in the investigation of virus–host dynamics is a powerful research tool. In this review, we focus on the benefits and caveats of using Drosophila as a model for neurological infections and neuroimmunity. Through the examination of in vitro, in vivo and transgenic systems, we highlight select examples to illustrate the use of flies for the study of exogenous and endogenous viruses associated with neurological disease. In each case, phenotypes in Drosophila are compared to those in human conditions. In addition, we discuss antiviral drug screening in flies and how investigating virus–host interactions may lead to novel antiviral drug targets. Together, we highlight standardized and reproducible readouts of fly behaviour, motor function and neurodegeneration that permit an accurate assessment of neurological outcomes for the study of viral infection in fly models. Adoption of Drosophila as a valuable model system for neurological infections has and will continue to guide the discovery of many novel virus–host interactions.

Chronic comorbidities in persons living with HIV within three years of exposure to antiretroviral therapy at Pantang Antiretroviral Center in Ghana: a retrospective study

INTRODUCTION

uptake of antiretroviral therapy (ART) and retention in care are associated with increased life expectancy but increased the risk of comorbid conditions in persons living with HIV (PLWH) and taking antiretroviral drugs. This study describes comorbid conditions among PLWH in Ghana.

METHODS

PLWH (n=222) out of a sample population of 900, randomly selected at Pantang ART Center participated in the study from June to July of 2020. Socio-demographic characteristics, HIV biomarkers, medication type and adherence, and diagnostic confirmed chronic conditions were extracted from medical records of PLWH. Cox proportional-hazard models and Kaplan-Meier curves graphing risk of experiencing comorbid conditions were performed. Log-rank test was performed at p<0.05.

RESULTS

fifty three point two percent of PLWH (222) experienced a comorbid condition including, respiratory conditions (17.6%), anaemia (12.2%), hypertension (12.2%), cardiovascular diseases (10.8%),and neurological conditions (10.8%).Factors associated with some of these conditions were medication adherence (aHR=0.43, 95% CI: 0.21-0.90) and visual changes (aHR=2.64, 95% CI: 1.08-6.45) for respiratory conditions, age (aHR=10.03, 95% CI; 1.22-82.37) for hypertension, and World Health Organization (WHO) clinical stages (stage II (aHR=13.36, 95% CI=1.54-115.63) and III (aHR=11.71, 95% CI=1.41-97.26))for peripheral neuropathy. Kaplan-Meier curves show significant risk of comorbid conditions for age, CD4 count ≤350 cells/mm2, WHO clinical stages III and IV, and ART non-adherence.

CONCLUSION

understanding the types of comorbidities in PLWH is integral to providing feedback to primary care providers to monitor.

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.

Aberrant Synaptic Pruning in CNS Diseases: A Critical Player in HIV-Associated Neurological Dysfunction?

Even in the era of effective antiretroviral therapies, people living with Human Immunodeficiency Virus (HIV) are burdened with debilitating neurological dysfunction, such as HIV-associated neurocognitive disorders (HAND) and HIV-associated pain, for which there are no FDA approved treatments. Disruption to the neural circuits of cognition and pain in the form of synaptic degeneration is implicated in developing these dysfunctions. Glia-mediated synaptic pruning is a mechanism of structural plasticity in the healthy central nervous system (CNS), but recently, it has been discovered that dysregulated glia-mediated synaptic pruning is the cause of synaptic degeneration, leading to maladaptive plasticity and cognitive deficits in multiple diseases of the CNS. Considering the essential contribution of activated glial cells during the development of HAND and HIV-associated pain, it is possible that glia-mediated synaptic pruning is the causative mechanism of synaptic degeneration induced by HIV. This review will analyze the known examples of synaptic pruning during disease in order to better understand how this mechanism could contribute to the progression of HAND and HIV-associated pain.

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.

CCAAT enhancer binding protein gamma (C/EBP-γ): An understudied transcription factor

The CCAAT enhancer binding protein (C/EBP) family of transcription factors are important transcriptional mediators of a wide range of physiologic processes. C/EBP-γ is the shortest C/EBP protein and lacks a canonical activation domain for the recruitment of transcriptional machinery. Despite its ubiquitous expression and ability to dimerize with other C/EBP proteins, C/EBP-γ has been studied far less than other C/EBP proteins, and, to our knowledge, no review of its functions has been written. This review seeks to integrate the current knowledge about C/EBP-γ and its physiologic roles, especially in cell proliferation, the integrated stress response, oncogenesis, hematopoietic and nervous system development, and metabolism, as well as to identify areas for future research.

Magnitude of Peripheral Sensory Neuropathy and Associated Factors Among HIV/AIDS Clients Receiving Care at Public Health Institutions, Northwest Ethiopia

Background: In the mid-1990s, the development of combination antiretroviral therapy converted HIV infection into a chronic condition, with newly diagnosed patients now living longer than the general population. HIV affects both the central and peripheral nerve systems, resulting in a variety of clinical problems, including peripheral neuropathy, which is a common neurological consequence. Despite this, there is a scarcity of data on the extent of peripheral sensory neuropathy and its underlying factors in Ethiopia, necessitating this study. Objective: The primary goal of this study is to assess the degree of peripheral sensory neuropathy and its related factors among HIV/AIDS clients on follow up at public health institutions in Northwest Ethiopia. Methodology: Institution based cross-sectional study was conducted from November 1 to 30 December 2020 at selected south Gondar zone public health institutions ART clinic. Multistage sampling technique was used to select the study participants. Standardized Questioner adapted from other study was used to collect the data. Moreover, Brief Peripheral Neuropathy Screening tool (BPNS) was used to assess peripheral sensory neuropathy. The data were entered with epi-data manager version 4.4 and analyzed using STATA version 16. Result: A total of 555 adult PLWHIV agreed to participate in the study, resulting in a response rate of 96.8%. The prevalence of Peripheral sensory neuropathy was 32.25, 95% CI (28.28, 36.26). The participant’s age, DM comorbidity, viral load level, and disease clinical stage were all found to have a statistically significant association with peripheral sensory neuropathy. Conclusion: Peripheral sensory neuropathy was incredibly common. Accordingly, peripheral sensory neuropathy was found considerably associated with age, viral load level, stage of the disease, and DM comorbidity. It is vital to integrate routine peripheral sensory neuropathy screening strategies for clients who are on ART follow up for prevention and early identification of the problem.

The Interplay Between Neuroinfections, the Immune System and Neurological Disorders: A Focus on Africa

Neurological disorders related to neuroinfections are highly prevalent in Sub-Saharan Africa (SSA), constituting a major cause of disability and economic burden for patients and society. These include epilepsy, dementia, motor neuron diseases, headache disorders, sleep disorders, and peripheral neuropathy. The highest prevalence of human immunodeficiency virus (HIV) is in SSA. Consequently, there is a high prevalence of neurological disorders associated with HIV infection such as HIV-associated neurocognitive disorders, motor disorders, chronic headaches, and peripheral neuropathy in the region. The pathogenesis of these neurological disorders involves the direct role of the virus, some antiretroviral treatments, and the dysregulated immune system. Furthermore, the high prevalence of epilepsy in SSA (mainly due to perinatal causes) is exacerbated by infections such as toxoplasmosis, neurocysticercosis, onchocerciasis, malaria, bacterial meningitis, tuberculosis, and the immune reactions they elicit. Sleep disorders are another common problem in the region and have been associated with infectious diseases such as human African trypanosomiasis and HIV and involve the activation of the immune system. While most headache disorders are due to benign primary headaches, some secondary headaches are caused by infections (meningitis, encephalitis, brain abscess). HIV and neurosyphilis, both common in SSA, can trigger long-standing immune activation in the central nervous system (CNS) potentially resulting in dementia. Despite the progress achieved in preventing diseases from the poliovirus and retroviruses, these microbes may cause motor neuron diseases in SSA. The immune mechanisms involved in these neurological disorders include increased cytokine levels, immune cells infiltration into the CNS, and autoantibodies. This review focuses on the major neurological disorders relevant to Africa and neuroinfections highly prevalent in SSA, describes the interplay between neuroinfections, immune system, neuroinflammation, and neurological disorders, and how understanding this can be exploited for the development of novel diagnostics and therapeutics for improved patient care.

The role of Pannexin-1 channels and extracellular ATP in the pathogenesis of the human immunodeficiency virus

Only recently, the role of large ionic channels such as Pannexin-1 channels and Connexin hemichannels has been implicated in several physiological and pathological conditions, including HIV infection and associated comorbidities. These channels are in a closed stage in healthy conditions, but in pathological conditions including HIV, Pannexin-1 channels and Connexin hemichannels become open. Our data demonstrate that acute and chronic HIV infection induces channel opening (Pannexin and Connexin channels), ATP release into the extracellular space, and subsequent activation of purinergic receptors in immune and non-immune cells. We demonstrated that Pannexin and Connexin channels contribute to HIV infection and replication, the long-term survival of viral reservoirs, and comorbidities such as NeuroHIV. Here, we discuss the available data to support the participation of these channels in the HIV life cycle and the potential therapeutic approach to prevent HIV-associated comorbidities.

Peripheral neuropathy in HIV-infected children attending care and treatment clinic, at Muhimbili National Hospital, Dar es Salaam: a cross sectional study

BACKGROUND

Peripheral neuropathy (PN) is a neurological complication of untreated Human Immunodeficiency Virus (HIV) infection or exposure to certain antiretroviral drugs. In Tanzania where HIV is a major public health problem, the burden of HIV associated peripheral neuropathy has not yet been well defined in children.Thisstudy investigated the prevalence and associated factors for peripheral neuropathy among children living with HIV, attending Care and Treatment Clinic (CTC) at Muhimbili National Hospital (MNH).

MATERIALS AND METHODS

A cross-sectional study was conducted among 383 HIV positive children aged 5 to 18 years at MNH, CTC in Dar es Salaam between October to December 2019. All participants provided written assent/consent. Structured questionnaires designed for this study was used to collect data and screening for peripheral neuropathy was done on each participant using the Pediatric modified Total Neuropathy Score (Ped m TNS) that includes subjective and objective assessment. A score of 5 or greater on the Ped m TNS was used to define peripheral neuropathy. Data analysis was done using SPSS Version 23.

RESULTS

The prevalence of peripheral neuropathy among HIV infected children was 14.1 % (95 % CI (10.8 - 18 %). Common neuropathic symptoms were numbness, tingling sensation, reduced ankle reflexes and reduced sensation to light touch and pain that was limited to the toes. Low CD4 cell count (OR = 12.21; 95 % CI3.75-39.66; p = 0.0001), high viral load (OR = 10.54; 95 % CI 3.19-34.77; p = 0.0001), ART regime containing NRTI plus PI (OR = 3.93; 95 % CI 1.43- 10.74; p = 0.01) and the last exposure to isoniazid more than 6 months ago (OR = 3.71; 95 % CI 1.57-8.77; p = 0.003) were independent predictors for peripheral neuropathy.

CONCLUSION

Peripheral neuropathy is common among HIV infected children attending CTC at MNH and its frequency increases with advanced disease. The choice of ART regimen and other drugs for treating comorbid conditions should carefully be evaluated.

Biochemical profiling of anti-HIV prodrug Elsulfavirine (Elpida®) and its active form VM1500A against a panel of twelve human carbonic anhydrase isoforms

The non-nucleoside reverse transcriptase inhibitor VM1500A is approved for the treatment of HIV/AIDS in its N-acyl sulphonamide prodrug form elsulfavirine (Elpida^®). Biochemical profiling against twelve human carbonic anhydrase (CA, EC 4.2.1.1) isoforms showed that while elsulfavirine was a weak inhibitor of all isoforms, VM1500A potently and selectively inhibited human (h) hCA VII isoform, a proven target for the therapy of neuropathic pain. The latter is a common neurologic complication of HIV infection and we hypothesise that by using Elpida^® in patients may help alleviate this debilitating symptom.

Long Non-coding RNA Uc.48+ Small Interfering RNA Alleviates Neuroinflammatory Hyperalgesia in Gp120-Treated Rats via the P2Y12 Receptor

Human immunodeficiency virus envelope glycoprotein 120 (gp120) leads to hyperalgesia. Long non-coding RNAs are characterized by the lack of a protein-coding sequence and may contribute to the development and maintenance of inflammatory and neuroinflammatory pain. Rats with neuroinflammatory pain were established by gp120 treatment, which is featured by intensified pain behaviors. Long non-coding RNA uc.48+ was increased in the dorsal root ganglia of gp120-treated rats, and small interfering RNA that targets uc.48+ markedly alleviated hyperalgesia in gp120-treated rats. Notably, uc.48+ overexpression increased P2Y12 expression in control rats dorsal root ganglia and induced hyperalgesia. Uc.48+ small interfering RNA inhibited P2Y12 expression in gp120-treated rats. Uc.48+ potentiated P2Y12 receptor functions in the neurons and heterologous cells. Therefore, uc.48+ siRNA treatment reduced the upregulation of P2Y12 expression and function in DRG neurons, and, hence, alleviated hyperalgesia in gp120-treated rats.

Lepromatous leprosy as a presenting feature of HIV

Various bacterial, mycobacterial and fungal opportunistic infections occur frequently in immunocompromised individuals, however, leprosy in retroviral disease is a relatively rare association. Hereby, we report a case of lepromatous leprosy that presented with clinical features mimicking other opportunistic infections and subsequently led to the diagnosis of HIV. The myriad challenges associated with the diagnosis and management of HIV-leprosy coinfection are also discussed. Thus, although uncommon, atypical cutaneous lesions in HIV-seropositive patients warrant investigation for leprosy.

Prevention of HIV-1 TAT Protein-Induced Peripheral Neuropathy and Mitochondrial Disruption by the Antimuscarinic Pirenzepine

HIV-associated distal sensory polyneuropathy (HIV-DSP) affects about one third of people with HIV and is characterized by distal degeneration of axons. The pathogenesis of HIV-DSP is not known and there is currently no FDA-approved treatment. HIV trans-activator of transcription (TAT) is associated with mitochondrial dysfunction and neurotoxicity in the brain and may play a role in the pathogenesis of HIV-DSP. In the present study, we measured indices of peripheral neuropathy in the doxycycline (DOX)-inducible HIV-TAT (iTAT) transgenic mouse and investigated the therapeutic efficacy of a selective muscarinic subtype-1 receptor (M₁R) antagonist, pirenzepine (PZ). PZ was selected as we have previously shown that it prevents and/or reverses indices of peripheral neuropathy in multiple disease models. DOX alone induced weight loss, tactile allodynia and paw thermal hypoalgesia in normal C57Bl/6J mice. Conduction velocity of large motor fibers, density of small sensory nerve fibers in the cornea and expression of mitochondria-associated proteins in sciatic nerve were unaffected by DOX in normal mice, whereas these parameters were disrupted when DOX was given to iTAT mice to induce TAT expression. Daily injection of PZ (10 mg/kg s.c.) prevented all of the disorders associated with TAT expression. These studies demonstrate that TAT expression disrupts mitochondria and induces indices of sensory and motor peripheral neuropathy and that M₁R antagonism may be a viable treatment for HIV-DSP. However, some indices of neuropathy in the DOX-inducible TAT transgenic mouse model can be ascribed to DOX treatment rather than TAT expression and data obtained from animal models in which gene expression is modified by DOX should be accompanied by appropriate controls and treated with due caution.

Targeting the endocannabinoid system for management of HIV-associated neuropathic pain: A systematic review

Human immunodeficiency virus (HIV) infection and antiretroviral therapy can independently induce HIV-associated neuropathic pain (HIV-NP). There is a dearth of drugs or therapeutic modalities that can alleviate HIV-NP. Smoked cannabis has been reported to improve pain measures in patients with neuropathic pain. Cannabis, phytocannabinoids, and the endocannabinoids such N-arachidonoylethanolamine (anandamide; AEA) and 2-arachidonoylglycerol (2-AG), produce some of their effects via cannabinoid receptors (CBRs). Endocannabinoids are degraded by various enzymes such as fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase. We searched PubMed, Google Scholar, clinicaltrials.gov and clinicaltrialsregister.eu using various key words and their combinations for published papers that studied HIV-NP and cannabis, cannabinoids, or endocannabinoids up to 27th December 2020. All original research articles that evaluated the efficacy of molecules that modulate the endocannabinoid system (ECS) for the prevention and/or treatment of pain in HIV-NP animal models and patients with HIV-NP were included. The PubMed search produced a total of 117 articles, whereas the Google Scholar search produced a total of 9467 articles. Amongst the 13 articles that fulfilled the inclusion criteria 11 articles were found in both searches whereas 2 articles were found in Google Scholar only. The clinicaltrials.gov and clinicaltrialsregister.eu searches produced five registered trials of which three were completed and with results. Ten preclinical studies found that the endocannabinoids (2-AG and AEA), synthetic mixed CB1R/CB2R agonist WIN 55,212-2, a CB2R-selective phytocannabinoid β-caryophyllene, synthetic CB2R-selective agonists (AM1710, JWH015, JWH133 and Gp1a, but not HU308); FAAH inhibitors (palmitoylallylamide, URB597 and PF-3845) and a drug combination of indomethacin plus minocycline, which produces its effects in a CBR-dependent manner, either prevented the development of and/or attenuated established HIV-NP. Two clinical trials demonstrated greater efficacy of smoked cannabis over placebo in alleviating HIV-NP, whereas another clinical trial demonstrated that cannabidivarin, a cannabinoid that does not activate CBRs, did not reduce HIV-NP. The available preclinical results suggest that targeting the ECS for prevention and treatment of HIV-NP is a plausible therapeutic option. Clinical evidence shows that smoked cannabis alleviates HIV-NP. Further research is needed to find out if non-psychoactive drugs that target the ECS and are delivered by other routes than smoking could be useful as treatment options for HIV-NP.

Cutaneous Neuroimmune Interactions in Peripheral Neuropathic Pain States

Bidirectional interplay between the peripheral immune and nervous systems plays a crucial role in maintaining homeostasis and responding to noxious stimuli. This crosstalk is facilitated by a variety of cytokines, inflammatory mediators and neuropeptides. Dysregulation of this delicate physiological balance is implicated in the pathological mechanisms of various skin disorders and peripheral neuropathies. The skin is a highly complex biological structure within which peripheral sensory nerve terminals and immune cells colocalise. Herein, we provide an overview of the sensory innervation of the skin and immune cells resident to the skin. We discuss modulation of cutaneous immune response by sensory neurons and their mediators (e.g., nociceptor-derived neuropeptides), and sensory neuron regulation by cutaneous immune cells (e.g., nociceptor sensitization by immune-derived mediators). In particular, we discuss recent findings concerning neuroimmune communication in skin infections, psoriasis, allergic contact dermatitis and atopic dermatitis. We then summarize evidence of neuroimmune mechanisms in the skin in the context of peripheral neuropathic pain states, including chemotherapy-induced peripheral neuropathy, diabetic polyneuropathy, post-herpetic neuralgia, HIV-induced neuropathy, as well as entrapment and traumatic neuropathies. Finally, we highlight the future promise of emerging therapies associated with skin neuroimmune crosstalk in neuropathic pain.

HIV-related Neuropathy: Pathophysiology, Treatment and Challenges

HIV-sensory neuropathy (HIV-SN) is a debilitating complication in HIV patients with or without anti-retroviral treatment (ART). Common symptoms of HIV-SN include pain, decreased sensation, paresthesias, and dysesthesias in a symmetric stocking-glove distribution. While HIV-1 protein such as gp120 is implicated in HIV-SN (e.g. impaired large-diameter fiber), ART itself was recently shown to contribute to HIV-SN in HIV patients and impair thin fiber. Multiple host mechanisms may play roles during the pathogenesis of HIV-SN, including neuron-glia interactions in the spinal dorsal horn (SDH), inflammation, mitochondrial dysfunction and endoplasmic reticulum stress. Concurrent infections, such as tuberculosis, also carry a higher likelihood of HIV-SN as well as environmental or genetic predisposition. Pro-inflammatory cytokines such as IL-1, IL2 receptor-alpha, and tumor necrosis factor (TNF) along with abnormal lactate levels have been identified as potential players within the complex pathophysiology of this condition. In this paper, we review the pathophysiology of HIV neuropathy, focusing on the various treatment options available or under investigation. Although several treatment options are available e.g., the capsaicin patch and spinal cord stimulation, symptomatic control of HIV-SN are often challenging. Alternative approaches such as self-hypnosis, resistance exercise, cannabinoids, and acupuncture have all shown promising results, but need further investigation.

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.

Sleep Deprivation and Neurological Disorders

Sleep plays an important role in maintaining neuronal circuitry, signalling and helps maintain overall health and wellbeing. Sleep deprivation (SD) disturbs the circadian physiology and exerts a negative impact on brain and behavioural functions. SD impairs the cellular clearance of misfolded neurotoxin proteins like α-synuclein, amyloid-β, and tau which are involved in major neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. In addition, SD is also shown to affect the glymphatic system, a glial-dependent metabolic waste clearance pathway, causing accumulation of misfolded faulty proteins in synaptic compartments resulting in cognitive decline. Also, SD affects the immunological and redox system resulting in neuroinflammation and oxidative stress. Hence, it is important to understand the molecular and biochemical alterations that are the causative factors leading to these pathophysiological effects on the neuronal system. This review is an attempt in this direction. It provides up-to-date information on the alterations in the key processes, pathways, and proteins that are negatively affected by SD and become reasons for neurological disorders over a prolonged period of time, if left unattended.

Lateral amyotrophic sclerosis-like onset after combined antiretroviral treatment initiation

Motor neuron disease (MND) have an incidence of 2 in 100 000 persons, resulting in the death of 1 in every 500 people affected. The most common disease in MND spectrum is amyotrophic lateral sclerosis (ALS). We describe the case of an ALS-like syndrome in a HIV patient.

This case report presents a 38 years old male from Peru with HIV who after 2 months of combined antiretroviral treatment (cART) initiation was admitted to the hospital for spastic paraplegia. On his first admission, rapid plasma reagent (RPR) was positive and he was treated for neurosyphilis and discharged. Nevertheless, one month after, he was admitted for the second time because paraplegia persisted. Laboratory tests, electromyography and imaging were performed, and ALS was diagnosed. Normally, HIV treated patient with ALS tend to have a better prognosis, however this was not the case.

In this case report, we discuss possible association between ALS and immune reconstitution inflammatory syndrome in HIV patients.

Assessment and Management of HIV Distal Sensory Peripheral Neuropathy: Understanding the Symptoms

Distal sensory peripheral neuropathy (HIV-DSP) affects upwards of 50% of people living with HIV. Causing often debilitating symptoms of tingling, numbness and burning, HIV-DSP can result in disability, unemployment and low quality of life. Comorbidities further complicate nursing care, heightening risk of polypharmacy and symptom exacerbation. Therefore, a neurological sensory assessment, combined with the patient's self-report of symptoms, can help nurse practitioners visualize, quantify and understand symptoms. Common pharmacological interventions include antiepileptics, antidepressants, analgesics and medical marijuana. The complexity of care for individuals with HIV-DSP merits a comprehensive approach. Implications for practice include interdisciplinary management with neurologists, podiatrists, mental health providers, and nurse-led counseling inclusive of patient safety teaching.

Biology of the human blood-nerve barrier in health and disease

A highly regulated endoneurial microenvironment is required for normal axonal function in peripheral nerves and nerve roots, which structurally consist of an outer collagenous epineurium, inner perineurium consisting of multiple concentric layers of specialized epithelioid myofibroblasts that surround the innermost endoneurium, which consists of myelinated and unmyelinated axons embedded in a looser mesh of collagen fibers. Endoneurial homeostasis is achieved by tight junction-forming endoneurial microvessels that control ion, solute, water, nutrient, macromolecule and leukocyte influx and efflux between the bloodstream and endoneurium, and the innermost layers of the perineurium that control interstitial fluid component flux between the freely permeable epineurium and endoneurium. Strictly speaking, endoneurial microvascular endothelium should be considered the blood-nerve barrier (BNB) due to direct communication with circulating blood. The mammalian BNB is considered the second most restrictive vascular system after the blood-brain barrier (BBB) based on classic in situ permeability studies. Structural alterations in endoneurial microvessels or interactions with hematogenous leukocytes have been described in several human peripheral neuropathies; however major advances in BNB biology in health and disease have been limited over the past 50 years. Guided by transcriptome and proteome studies of normal and pathologic human peripheral nerves, purified primary and immortalized human endoneurial endothelial cells that form the BNB and leukocytes from patients with well-characterized peripheral neuropathies, validated by in situ or ex vivo protein expression studies, data are emerging on the molecular and functional characteristics of the human BNB in health and in specific peripheral neuropathies, as well as chronic neuropathic pain. These early advancements have the potential to not only increase our understanding of how the BNB works and adapts or fails to adapt to varying insult, but provide insights relevant to pathogenic leukocyte trafficking, with translational potential and specific therapeutic application for chronic peripheral neuropathies and neuropathic pain.

Therapeutic Potential of Flavonoids in Pain and Inflammation: Mechanisms of Action, Pre-Clinical and Clinical Data, and Pharmaceutical Development

Pathological pain can be initiated after inflammation and/or peripheral nerve injury. It is a consequence of the pathological functioning of the nervous system rather than only a symptom. In fact, pain is a significant social, health, and economic burden worldwide. Flavonoids are plant derivative compounds easily found in several fruits and vegetables and consumed in the daily food intake. Flavonoids vary in terms of classes, and while structurally unique, they share a basic structure formed by three rings, known as the flavan nucleus. Structural differences can be found in the pattern of substitution in one of these rings. The hydroxyl group (-OH) position in one of the rings determines the mechanisms of action of the flavonoids and reveals a complex multifunctional activity. Flavonoids have been widely used for their antioxidant, analgesic, and anti-inflammatory effects along with safe preclinical and clinical profiles. In this review, we discuss the preclinical and clinical evidence on the analgesic and anti-inflammatory proprieties of flavonoids. We also focus on how the development of formulations containing flavonoids, along with the understanding of their structure-activity relationship, can be harnessed to identify novel flavonoid-based therapies to treat pathological pain and inflammation.

β-Caryophyllene, a CB2-Receptor-Selective Phytocannabinoid, Suppresses Mechanical Allodynia in a Mouse Model of Antiretroviral-Induced Neuropathic Pain

Neuropathic pain associated with nucleoside reverse transcriptase inhibitors (NRTIs), therapeutic agents for human immunodeficiency virus (HIV), responds poorly to available drugs. Smoked cannabis was reported to relieve HIV-associated neuropathic pain in clinical trials. Some constituents of cannabis (Cannabis sativa) activate cannabinoid type 1 (CB1) and cannabinoid type 2 (CB2) receptors. However, activation of the CB1 receptor is associated with side effects such as psychosis and physical dependence. Therefore, we investigated the effect of β-caryophyllene (BCP), a CB2-selective phytocannabinoid, in a model of NRTI-induced neuropathic pain. Female BALB/c mice treated with 2′-3′-dideoxycytidine (ddC, zalcitabine), a NRTI, for 5 days developed mechanical allodynia, which was prevented by cotreatment with BCP, minocycline or pentoxifylline. A CB2 receptor antagonist (AM 630), but not a CB1 receptor antagonist (AM 251), antagonized BCP attenuation of established ddC-induced mechanical allodynia. β-Caryophyllene prevented the ddC-induced increase in cytokine (interleukin 1 beta, tumor necrosis factor alpha and interferon gamma) transcripts in the paw skin and brain, as well as the phosphorylation level of Erk1/2 in the brain. In conclusion, BCP prevents NRTI-induced mechanical allodynia, possibly via reducing the inflammatory response, and attenuates mechanical allodynia through CB2 receptor activation. Therefore, BCP could be useful for prevention and treatment of antiretroviral-induced neuropathic pain.

Peripheral neuropathy in patients with human immunodeficiency viral infection at a tertiary hospital in Ghana

Peripheral neuropathy (PN) is the most frequent neurological complication in people living with HIV/AIDS. Neurological damage was identified to not only be caused by the viral infection itself but also through neurotoxic antiretroviral therapy (ART). PN is associated with a variety of risk factors; however, detailed knowledge is scarce for sub-Saharan African populations, bearing among the highest HIV/AIDS infection burden.In a cross-sectional study, we assessed the prevalence of PN in 525 adult outpatients suffering from HIV/AIDS and admitted to the largest tertiary hospital in Ghana. Through a detailed questionnaire and clinical examination including neurologic assessment and laboratory blood sample testing, this study investigated associations of PN with demographic and health determinants and identified risk factors associated with sensory neuropathy.The prevalence of PN in the Ghanaian cohort was 17.7% and increased odd ratios (OR) when patients were taller (> 1.57 m; OR = 3.84; 95% CI 1.38-10.66) or reached the age > 34 years (p = 0.124). Respondents with longer education duration had significantly less PN (≥ 9 years of education; OR = 0.49; 95% CI 0.26-0.92). The study also identified significant association of PN to both waist and hip girth and neutrophil counts. Curiously, higher adjusted odd ratios (aOR) of PN of patients under ART treatment were observed when CD4 lymphocytes were elevated (aOR = 0.81; 95% CI 0.36-1.83 and aOR = 2.17; 95% CI 0.93-5.05, for 300 and 600 counts, respectively). For patients on ART, an increase of 10 CD4 cell count units increased their chance of developing PN by 1% (aOR = 1.01; 95% CI 1.00 to 1.03).Despite current drug application regulations, prevalence of PN is still unacceptably high in sub-Saharan African populations. Reduction in chronic morbidity through a health system with routine monitoring, early diagnosis and prompt intervention, and effective case management can improve people living with HIV/AIDS' quality of life.

HIV-1 gp120 Promotes Lysosomal Exocytosis in Human Schwann Cells

Human immunodeficiency virus type 1 (HIV-1) associated neuropathy is the most common neurological complication of HIV-1, with debilitating pain affecting the quality of life. HIV-1 gp120 plays an important role in the pathogenesis of HIV neuropathy via direct neurotoxic effects or indirect pro-inflammatory responses. Studies have shown that gp120-induced release of mediators from Schwann cells induce CCR5-dependent DRG neurotoxicity, however, CCR5 antagonists failed to improve pain in HIV- infected individuals. Thus, there is an urgent need for a better understanding of neuropathic pain pathogenesis and developing effective therapeutic strategies. Because lysosomal exocytosis in Schwann cells is an indispensable process for regulating myelination and demyelination, we determined the extent to which gp120 affected lysosomal exocytosis in human Schwann cells. We demonstrated that gp120 promoted the movement of lysosomes toward plasma membranes, induced lysosomal exocytosis, and increased the release of ATP into the extracellular media. Mechanistically, we demonstrated lysosome de-acidification, and activation of P2X4 and VNUT to underlie gp120-induced lysosome exocytosis. Functionally, we demonstrated that gp120-induced lysosome exocytosis and release of ATP from Schwann cells leads to increases in intracellular calcium and generation of cytosolic reactive oxygen species in DRG neurons. Our results suggest that gp120-induced lysosome exocytosis and release of ATP from Schwann cells and DRG neurons contribute to the pathogenesis of HIV-1 associated neuropathy.

Variations in plantar pressure and balance in HIV-infected children in antiretroviral therapy

Balance disorders have been poorly investigated and somewhat neglected in people infected with the human immunodeficiency virus, especially in children, whose have intrinsic and extrinsic risk factors that may compromise the balance. To evaluate the foot plantar pressures and the balance in children with acquired immunodeficiency. We recruited 53 children aged between 6 and 15 years: 33 healthy children, and 20 children with positive serology for the human immunodeficiency virus. A physical examination included anthropometric, reflexes, tactile sensitivity of the foot and orthopedic evaluation. We also collected data of them using Pediatric Equilibrium Scale, baropodometry, and stabilometry. We considered significance level of 0.05 for statistics. Both groups were aged-, sex-matched and similar body mass index and scores of the Pediatric Equilibrium Scale. Three infected children had altered tactile sensitivity, and none had orthopedic or reflex alteration. Infected children had higher mean plantar pressure in the hindfoot than of the control group (p = 0.02). There was higher maximum plantar pressure in the hindfoot of the infected children than of the controls (p = 0.04). Controls had lower maximum plantar pressure in the forefoot than the infected children (p = 0.04). Infected children had larger displacement of the center of pressure (p = 0.006), larger mean velocity of displacement (p = 0.006), and longer duration between successive peaks of displacement than the controls (p = 0.02). Children living with the human immunodeficiency virus discharges great plantar pressures in the hindfoot and to present balance disturbances in the absence of neurological symptomatology.

Altered Immunity and Microbial Dysbiosis in Aged Individuals With Long-Term Controlled HIV Infection

The introduction of highly active antiretroviral therapy (HAART) resulted in a significant increase in life expectancy for HIV patients. Indeed, in 2015, 45% of the HIV+ individuals in the United States were ≥55 years of age. Despite improvements in diagnosis and treatment of HIV infection, geriatric HIV+ patients suffer from higher incidence of comorbidities compared to age-matched HIV- individuals. Both chronic inflammation and dysbiosis of the gut microbiome are believed to be major contributors to this phenomenon, however carefully controlled studies investigating the impact of long-term (>10 years) controlled HIV (LTC-HIV) infection are lacking. To address this question, we profiled circulating immune cells, immune mediators, and the gut microbiome from elderly (≥55 years old) LTC-HIV+ and HIV- gay men living in the Palm Springs area. LTC-HIV+ individuals had lower frequency of circulating monocytes and CD4+ T-cells, and increased frequency CD8+ T-cells. Moreover, levels of systemic INFγ and several growth factors were increased while levels of IL-2 and several chemokines were reduced. Upon stimulation, immune cells from LTC-HIV+ individuals produced higher levels of pro-inflammatory cytokines. Last but not least, the gut microbiome of LTC-HIV+ individuals was enriched in bacterial taxa typically found in the oral cavity suggestive of loss of compartmentalization, while levels of beneficial butyrate producing taxa were reduced. Additionally, prevalence of Prevotella negatively correlated with CD4+ T-cells numbers in LTC-HIV+ individuals. These results indicate that despite long-term adherence and undetectable viral loads, LTC-HIV infection results in significant shifts in immune cell frequencies and gut microbial communities.

Plant-derived medicines for neuropathies: a comprehensive review of clinical evidence

Neuropathy is defined as the damage to the peripheral or central nervous system accompanied by pain, numbness, or muscle weakness, which can be due to congenital diseases or environmental factors such as diabetes, trauma, or viral infections. As current treatments are not sufficiently able to control the disease, studies focusing on the identification and discovery of new therapeutic agents are necessary. Natural products have been used for a long time for the management of different neurological problems including neuropathies. The aim of the present study is to review the current clinical data on the beneficial effects of medicinal plants in neuropathy. Electronic databases including PubMed, Scopus, and Cochrane Library were searched with the keywords ‘neuropathy’ in the title/abstract and ‘plant’ or ‘extract’ or ‘herb’ in the whole text from inception until August 2017. From a total of 3679 papers, 22 studies were finally included. Medicinal plants were evaluated clinically in several types of neuropathy, including diabetic neuropathy, chemotherapy-induced peripheral neuropathy, carpal tunnel syndrome, and HIV-associated neuropathy. Some studies reported the improvement in pain, nerve function, nerve conduction velocity, and quality of life. Cannabis sativa (hemp), Linum usitatissimum (linseed oil), capsaicin, and a polyherbal Japanese formulation called Goshajinkigan had the most evidence regarding their clinical efficacy. Other investigated herbal medicines in neuropathy, such as Matricaria chamomilla (chamomile), Curcuma longa (turmeric), and Citrullus colocynthis (colocynth), had only one clinical trial. Thus, future studies are necessary to confirm the safety and efficacy of such natural medicines as a complementary or alternative treatment for neuropathy.

Establishment and characterisation of a stavudine (d4T)-induced rat model of antiretroviral toxic neuropathy (ATN) using behavioural and pharmacological methods

Human immuno-deficiency virus (HIV) associated sensory neuropathy (SN) is a frequent complication of HIV infection. It is extremely difficult to alleviate and hence the quality of life of affected individuals is severely and adversely impacted. Stavudine (d4T) is an antiretroviral drug that was widely used globally prior to 2010 and that is still used today in resource-limited settings. Its low cost and relatively good efficacy when included in antiretroviral dosing regimens means that there is a large population of patients with d4T-induced antiretroviral toxic neuropathy (ATN). As there are no FDA approved drugs for alleviating ATN, it is important to establish rodent models to probe the pathobiology and to identify potentially efficacious new drug treatments. In the model establishment phase, d4T administered intravenously at a cumulative dose of 375 mg/kg in male Wistar Han rats evoked temporal development of sustained mechanical allodynia in the hindpaws from day 10 to day 30 after initiation of d4T treatment. As this d4T dosing regimen was also well tolerated, it was used for ATN model induction for subsequent pharmacological profiling. Both gabapentin at 30-100 mg/kg and morphine at 0.3-2 mg/kg given subcutaneously produced dose-dependent relief of mechanical allodynia with estimated ED₅₀'s of 19 mg/kg and 0.4 mg/kg, respectively. In contrast, intraperitoneal administration of meloxicam or amitriptyline up to 30 mg/kg and 7 mg/kg, respectively, lacked efficacy. Our rat model of ATN is suitable for investigation of the pathophysiology of d4T-induced SN as well as for profiling novel molecules from analgesic drug discovery programs.

Human immunodeficiency virus neuropathy: A new mimicker of leprous neuropathy

Peripheral neuropathy is usually the domain of the physician or neurologist. Still, many times patients land up in dermatology department with complaints such as sensory loss, paresthesia, and trophic ulcers. Usually, these patients are evaluated for leprosy and then referred to departments of internal medicine or neurology. We report one such patient who was initially seen by a dermatologist but was ultimately found to be suffering from human immunodeficiency virus neuropathy.

Early detection of peripheral neuropathy using stimulated skin wrinkling test in human immunodeficiency virus infected patients: A cross-sectional study

Peripheral neuropathy is a common condition of human immunodeficiency virus (HIV)-infected patients, which often remains undetected. We assessed the performance of stimulated skin wrinkling-eutectic mixture of local anesthetic (SSW-EMLA) test compared with brief peripheral neuropathy screening (BPNS) to detect HIV neuropathy.This is a cross-sectional study conducted in HIV-positive patients. A modified skin wrinkling grading was used to assess SSW-EMLA effect. BPNS-detectable neuropathy was assessed by a combination of neuropathy severity scoring scale (subjective) and objective method of sensory and tendon reflex examination. The SSW-EMLA test accuracy with reference to BPNS was assessed using sensitivity and specificity and predictive values.In a total of 99 HIV patients, 61.6% were males and the majority age group were between 30 and 40 years (52%). The neuropathy detection was SSW-EMLA test 36.4% versus BPNS 15.2% (P = .04). The sensitivity of SSW-EMLA test was 60.0% [95% confidence interval (95% CI) 34.5-81.7], specificity 67% (95% CI 63.3-3-71.7), and overall accuracy of 66.7% (95% CI 58.9-73.2).The SSW-EMLA test detected many more peripheral neuropathy cases than BPNS in HIV patients and has potential as an alternative test for screening for HIV neuropathy in resource-constraint hospitals in Indonesia.

Racial and socioeconomic disparities in the symptom reporting of persons living with HIV

Persons living with HIV (PLWH) today can survive decades with the disease, making the symptom experience much more relevant to their lifestyle and health outcomes. The goal of the research reported here was to assess the symptom reporting of PLWH in the Unites States (US) in the combined antiretroviral therapy (cART) age of the epidemic. We conducted an anonymous online survey of symptomatic PLWH in the US and asked participants to report the frequency and intensity of 28 frequently occurring symptoms in the past 30 days. The relationship between symptom reporting and demographic factors was investigated using the adaptive least absolute shrinkage and selection operator (LASSO) method. Fatigue was the most frequently reported symptom in our study population. Those with the lowest income were more likely to report more burdensome symptoms. In comparison to other racial and ethnic groups, Black non-Hispanic participants were significantly more likely to report a lower symptom burden score for fatigue, depression, muscle aches, anxiety, difficulties with memory and concentration. There were no racial/ ethnic differences in the burden of the symptoms related to sleep or neuropathy. Findings from this study present new evidence on the symptom reporting of PLWH in the US. Neuropathy continues to be a pervasive neurological symptom with no difference noted between racial/ ethnic groups.

A qualitative exploration of chronic pain and opioid treatment among HIV patients with drug use disorders

OBJECTIVE

The study explored high-risk participants' experiences with pain management regarding clinical access to and use of prescription opioids.

DESIGN

Qualitative semistructured interviews and focus groups.

SETTING

Data were collected August 2014 to May 2015 at an urban community-based research facility in Baltimore City, MD.

PARTICIPANTS

HIV participants with chronic pain and a history of illicit drug use.

METHODS

Qualitative coding and analysis used an iterative, inductive, and thematic approach and coders achieved inter-coder consistency.

RESULTS

The authors identified two major themes. First, participants had positive and negative interactions with healthcare providers regarding chronic pain treatment. Participants perceived that providers lacked empathy for their pain and/or were not adequately managing their pain. These interactions resulted in participants seeking new providers or mistrusting the medical system. Further, providers' surveillance of participants' pain treatment regimen contributed to distress surrounding pain management. The second theme centered on participants' pain management experiences with prescribed opioid analgesics. Participants felt they were receiving dosages and classes of analgesics that did not sufficiently address their pain, and consequently modified their dosages or rationed prescription opioids. Other participants were reluctant to take analgesics due to their history of illicit drug use. Some participants relapsed to illicit drug use when they felt their prescription opioids did not adequately address their pain needs.

CONCLUSIONS

Participant struggles with receiving and managing prescribed opioid analgesics suggest a need for: therapies beyond these medications; guidelines for providers specific to this population; and harm reduction trainings for providers.

Resveratrol-decreased hyperalgesia mediated by the P2X7 receptor in gp120-treated rats

Background

Chronic pain is a common symptom in human immunodeficiency virus (HIV)-1 infection/acquired immunodeficiency syndrome patients. The literature shows that the HIV envelope glycoprotein 120 (gp120) can directly cause hyperalgesia by stimulating primary sensory afferent nerves. The P2X₇ receptor in the dorsal root ganglia (DRG) is closely related to neuropathic and inflammatory pain. In this study, we aimed to explore the effect of resveratrol (RES) on gp120-induced neuropathic pain that is mediated by the P2X₇ receptor in the rat DRG.

Results

Mechanical hyperalgesia in rats treated with gp120 was increased compared with that in the sham group. The P2X₇ expression levels in rats treated with gp120 were higher than those in the sham group. Co-localization of the P2X₇ receptor and glial fibrillary acidic protein (GFAP, a marker of satellite glial cells [SGCs]) in the DRG SGCs of the gp120 group exhibited more intense staining than that of the sham group. RES decreased the mechanical hyperalgesia and P2X₇ expression levels in gp120 treatment rats. Co-localization of the P2X₇ receptor and GFAP in the gp120+ RES group was significantly decreased compared to the gp120 group. RES decreased the IL-1β and TNF-α receptor (R) expression levels and ERK1/2 phosphorylation levels as well as increased IL-10 expression in the DRG of gp120-treated rats. Whole cell clamping demonstrated that RES significantly inhibited adenosine triphosphate-activated currents in HEK293 cells that were transfected with the P2X₇ plasmid.

Conclusions

RES relieved mechanical hyperalgesia in gp120-treated rats by inhibiting the P2X₇ receptor.

P2Y12 receptor upregulation in satellite glial cells is involved in neuropathic pain induced by HIV glycoprotein 120 and 2',3'-dideoxycytidine

The direct neurotoxicity of HIV and neurotoxicity of combination antiretroviral therapy medications both contribute to the development of neuropathic pain. Activation of satellite glial cells (SGCs) in the dorsal root ganglia (DRG) plays a crucial role in mechanical and thermal hyperalgesia. The P2Y₁₂ receptor expressed in SGCs of the DRG is involved in pain transmission. In this study, we explored the role of the P2Y₁₂ receptor in neuropathic pain induced by HIV envelope glycoprotein 120 (gp120) combined with ddC (2',3'-dideoxycytidine). A rat model of gp120+ddC-induced neuropathic pain was used. Peripheral nerve exposure to HIV-gp120+ddC increased mechanical and thermal hyperalgesia in gp120+ddC-treated model rats. The gp120+ddC treatment increased expression of P2Y₁₂ receptor mRNA and protein in DRG SGCs. In primary cultured DRG SGCs treated with gp120+ddC, the levels of [Ca²⁺]_i activated by the P2Y₁₂ receptor agonist 2-(Methylthio) adenosine 5'-diphosphate trisodium salt (2-MeSADP) were significantly increased. P2Y₁₂ receptor shRNA treatment inhibited 2-MeSADP-induced [Ca²⁺]_i in primary cultured DRG SGCs treated with gp120+ddC. Intrathecal treatment with a shRNA against P2Y₁₂ receptor in DRG SGCs reduced the release of pro-inflammatory cytokines, decreased phosphorylation of p38 MAPK in the DRG of gp120+ddC-treated rats. Thus, downregulating the P2Y₁₂ receptor relieved mechanical and thermal hyperalgesia in gp120+ddC-treated rats.

Altered Associations between Pain Symptoms and Brain Morphometry in the Pain Matrix of HIV-Seropositive Individuals

Pain remains highly prevalent in HIV-seropositive (HIV+) patients despite their well-suppressed viremia with combined antiretroviral therapy. Investigating brain abnormalities within the pain matrix, and in relation to pain symptoms, in HIV+ participants may provide objective biomarkers and insights regarding their pain symptoms. We used Patient-Reported Outcome Measurement Information System (PROMIS®) pain questionnaire to evaluate pain symptoms (pain intensity, pain interference and pain behavior), and structural MRI to assess brain morphometry using FreeSurfer (cortical area, cortical thickness and subcortical volumes were evaluated in 12 regions within the pain matrix). Compared to seronegative (SN) controls, HIV+ participants had smaller surface areas in prefrontal pars triangularis (right: p = 0.04, left: p = 0.007) and right anterior cingulate cortex (p = 0.03) and smaller subcortical regions (thalamus: p ≤ 0.003 bilaterally; right putamen: p = 0.01), as well as higher pain scores (pain intensity-p = 0.005; pain interference-p = 0.008; pain-behavior-p = 0.04). Furthermore, higher pain scores were associated with larger cortical areas, thinner cortices and larger subcortical volumes in HIV+ participants; but smaller cortical areas, thicker cortices and smaller subcortical volumes in SN controls (interaction-p = 0.009 to p = 0.04). These group differences in the pain-associated brain abnormalities suggest that HIV+ individuals have abnormal pain responses. Since these abnormal pain-associated brain regions belong to the affective component of the pain matrix, affective symptoms may influence pain perception in HIV+ patients and should be treated along with their physical pain symptoms. Lastly, associations of lower pain scores with better physical or mental health scores, regardless of HIV-serostatus (p < 0.001), suggest adequate pain treatment would lead to better quality of life in all participants.

HIV positive patient with GBS-like syndrome

Introduction. Guillain-Barré Syndrome (GBS) is an acute demyelinating polyneuropathy which can occur post-infection. Criteria of diagnosis of GBS include areflexia with progressive bilateral weakness in arms and legs. GBS can lead to severe respiratory and cardiac complications. The fatality rate can be up to 5 % in patients, depending on the severity of the symptoms. HIV can cause a range of neurological disorders including, on rare occasions, GBS. GBS can occur at any stage of HIV infection, highlighting the complexity of diagnosis of GBS within HIV patients. Case presentation. A 57 year old female with lumbar back pain radiating to the legs, poor mobility and tiredness, with reports of a viral-like illness four days previously, was initially diagnosed with a lower respiratory tract infection and discharged. Seventeen days later the patient was readmitted to hospital with progressive lower and upper limb weakness, areflexia and sensory loss. She was diagnosed with GBS and was unexpectedly discovered to be HIV-positive. HIV avidity was low indicating a recently acquired HIV infection. The patient was treated with intravenous immunoglobulin for five days for the GBS and commenced antriretrovirals for HIV. The patient was discharge from hospital 53 days after admission with walking aids and regular physiotherapy follow-up.

CONCLUSION

. This case highlighted the need for all clinicians to be aware that patients with symptoms of GBS, regardless of clinical history should be offered an HIV test. GBS can be the first sign a patient is HIV-positive.

The impact of antiretroviral therapy on symptom burden among HIV outpatients with low CD4 count in rural Uganda: nested longitudinal cohort study

BACKGROUND

Individuals with HIV have a high prevalence of physical and psychological symptoms throughout their disease course. Despite the clinical and public health implications of unresolved pain and symptoms, little is known about the effect of anti-retroviral therapy (ART) on these outcomes. This study aimed to assess the impact on symptom burden for the year after ART initiation in individuals with a CD4 count <200 cells/uL in Uganda.

METHODS

HIV-infected, ART-naıve adults referred from voluntary testing and counseling services in rural Uganda for enrollment into a randomized controlled trial to test fluconazole as primary prophylaxis against cryptococcal disease were invited to complete the Memorial Symptom Assessment Scale-Short Form (MSAS-SF) prior to commencing ART and at two subsequent follow up visits. This tool measures self-reported 7-day period prevalence and associated burden of physical and psychological symptoms. Changes in the total number of symptoms and distress indices with time on ART and trial arm were investigated through fitting Linear Mixed Models for repeated measures.

RESULTS

During the first year of ART initiation the prevalence of most individual symptoms remained constant. The notable exceptions which improved after commencing ART are as follow; prevalence of pain (prevalence changed from 79% to 60%), weight loss (67% to 31%), lack of appetite (46% to 28%), feeling sad (52% to 25%) and difficulty sleeping (35% to 23%). The total number of symptoms and distress indices reduced after treatment commenced. Of concern was that half or more study participants remained with symptoms of pain (60%), itching (57%), skin changes (53%) and numbness in hands and feet (52%) after starting ART. Sixteen symptoms remained with a burden of 25% or more.

CONCLUSION

Despite the beneficial effect of ART on reducing symptoms, some patients continue to experience a high symptom burden. It is essential that HIV services in sub-Saharan Africa integrate management of symptoms into their programmes.

TRIAL REGISTRATION

CRYPTOPRO [ISRCTN 76481529 ], November 2004.

A comparative study of CIDP in a cohort of HIV-infected and HIV-uninfected patients

OBJECTIVE

To investigate differences in clinical presentation, electrodiagnostic measures, CSF changes, and treatment outcome measures in HIV-infected and HIV-uninfected patients with chronic inflammatory demyelinating polyneuropathy (CIDP).

METHODS

A retrospective analysis of medical records of all patients meeting the European Federation of Neurology diagnostic criteria for idiopathic CIDP was performed in 2 neuromuscular units in Kwa-Zulu Natal between 2003 and 2015.

RESULTS

Eighty-four patients were included in the study; 39 were HIV-infected and 45 were HIV-uninfected. Among the HIV-infected patients, the majority were younger, were female, and had a monophasic progressive illness. Eighty-six percent (86%) were corticosteroid-responsive and 76% were in remission within 6-12 months requiring no further treatment. Among the HIV- uninfected patients, the majority were older, were male, and had a relapsing-remitting course. Twenty-seven percent (27%) were corticosteroid-responsive, 95% required combination therapy, and 33% were not in remission by 18 months on therapy.

CONCLUSION

This study shows that HIV-infected patients with CIDP were younger, were more often female, displayed a monophasic progressive course, were highly steroid-responsive, and went into remission within 12 months of corticosteroid initiation.

Voltage-gated calcium channels and their auxiliary subunits: physiology and pathophysiology and pharmacology

Voltage‐gated calcium channels are essential players in many physiological processes in excitable cells. There are three main subdivisions of calcium channel, defined by the pore‐forming α₁ subunit, the Ca_V1, Ca_V2 and Ca_V3 channels. For all the subtypes of voltage‐gated calcium channel, their gating properties are key for the precise control of neurotransmitter release, muscle contraction and cell excitability, among many other processes. For the Ca_V1 and Ca_V2 channels, their ability to reach their required destinations in the cell membrane, their activation and the fine tuning of their biophysical properties are all dramatically influenced by the auxiliary subunits that associate with them. Furthermore, there are many diseases, both genetic and acquired, involving voltage‐gated calcium channels. This review will provide a general introduction and then concentrate particularly on the role of auxiliary α₂δ subunits in both physiological and pathological processes involving calcium channels, and as a therapeutic target.

Antinociceptive effects of topical mepivacaine in a rat model of HIV-associated peripheral neuropathic pain

Background

A consequence of HIV infection is sensory neuropathy, a debilitating condition that degrades the quality of life of HIV patients. Furthermore, life-extending antiretroviral treatment may exacerbate HIV sensory neuropathy. Analgesics that relieve other neuropathic pains show little or no efficacy in ameliorating HIV sensory neuropathy. Thus, there is a need for analgesics for people with this particular pain. While lidocaine is used in the management of painful peripheral neuropathies, another local anesthetic mepivacaine, with a potentially improved bioavailability, could be utilized for the management of HIV neuropathic pain.

Methods

The efficacy of topical anesthetics was evaluated in a preclinical rodent model of painful peripheral neuropathy induced by epineural administration of the HIV envelope protein gp120 delivered using saturated oxidized cellulose implanted around the sciatic nerve. Beginning at 2 weeks following gp120 administration, the effects of local anesthetics topically applied via gauze pads were tested on heat and mechanical hyperalgesia in the hind paw. Rats were tested using several concentrations of mepivacaine or lidocaine during the following 2 weeks.

Results

By 2 weeks following epineural gp120 implantation, the ipsilateral hind paw developed significant hypersensitivity to noxious pressure and heat hyperalgesia. A short-lasting, concentration-dependent amelioration of pressure and heat hyperalgesia was observed following topical application of mepivacaine to the ipsilateral plantar hind paw. By contrast, topical lidocaine ameliorated heat hyperalgesia in a concentration-dependent manner but not pressure hyperalgesia. Equipotent concentrations of mepivacaine and lidocaine applied topically to the tail of mice significantly increased tail withdrawal latencies in the tail flick test, demonstrating that both local anesthetics attenuate responding to a brief noxious stimulus.

Conclusion

These findings showed that mepivacaine, rather than lidocaine, consistently attenuated two distinct symptoms of neuropathic pain and suggest that topical formulations of this local anesthetic could have utility in the alleviation of clinical HIV neuropathic pain.

Self-Injurious Behavior Secondary to Cytomegalovirus-Induced Neuropathy in an SIV-Infected Rhesus Macaque (Macaca mulatta)

A 3.5-y-old, female rhesus macaque (Macaca mulatta) inoculated with SIVmac239 presented 8 mo later for inappetence and facial bruising. Physical examination revealed a superficial skin abrasion below the left eye, bruising below the left brow, and epistaxis of the left nostril. There were no significant findings on CBC, serum chemistry, urinalysis, or radiographs. Differential diagnoses included infectious etiologies, self-injurious behavior, immune-mediated dermatitis, and neoplasia. Lack of response to antibiotic and analgesic therapy and observations of the macaque made it apparent that the skin lesions were self-inflicted. The excoriations rapidly progressed to extend over the nose, and the left palpebrae became edematous. Euthanasia was elected because the macaque appeared to be experiencing continued discomfort despite analgesic therapy. Histopathologic examination revealed systemic cytomegalovirus (CMV) infection involving the facial nerves, periocular nerves, meninges, and perimesenteric lymph nodes. CMV is a common infection in macaques, with adult seroprevalence close to 100% in most colonies. Infection in immunocompetent animals is usually asymptomatic but can cause significant clinical disease in immunodeficient hosts. CMV is associated with a painful peripheral neuropathy in human AIDS patients, and analgesic treatment is often unsatisfactory. Peripheral neuropathy secondary to CMV should be considered as an underlying cause of self-injurious behavior in SIV-infected macaques. Macaques affected by other diseases and disorders may also be at risk for development of painful peripheral neuropathies.

Neuromuscular issues in systemic disease

The neuromuscular system can be involved in several systemic conditions. Clinical manifestations can appear at onset or throughout the course of the disease process. New investigational methods, including imaging of peripheral nerves, new laboratory tests, and antibodies, are available. In addition to symptomatic therapies, specific treatment options, such as for familial amyloid neuropathy and Fabry's disease, are becoming increasingly available. Pathomechanisms vary depending on the underlying disease process. In addition to metabolic, hormonal, immune, and antibody-mediated mechanisms, in some generalized diseases, genetic causes need to be considered. This review focuses on different aspects of the peripheral nervous system including the nerve roots, plexuses, mononeuropathies and generalized neuropathies, neuromuscular junction disorders, muscle, and autonomic nervous system.

Distal leg epidermal nerve fiber density as a surrogate marker of HIV-associated sensory neuropathy risk: risk factors and change following initial antiretroviral therapy

Distal leg epidermal nerve fiber density (ENFD) is a validated predictor of HIV sensory neuropathy (SN) risk. We assessed how ENFD is impacted by initiation of first-time antiretroviral therapy (ART) in subjects free of neuropathy and how it is altered when mitochondrial toxic nucleoside medications are used as part of ART. Serial changes in proximal thigh and distal leg ENFD were examined over 72 weeks in 150 Thai subjects randomized to a regimen of stavudine (d4T) switching to zidovudine (ZDV) at 24 weeks vs ZDV vs tenofovir (TDF) for the entire duration of study, all given in combination with nevirapine. We found individual variations in ENFD change, with almost equal number of subjects who decreased or increased their distal leg ENFD over 72 weeks and no relationship to nucleoside backbone or to development of neuropathic signs or symptoms. Lower baseline distal leg ENFD and greater increases in mitochondrial oxidative phosphorylation complex I (CI) activity were associated with larger increases in distal leg ENFD over 72 weeks. Distal leg ENFD correlated with body composition parameters (body surface area, body mass index, height) as well as with blood pressure measurements. Assessed together with a companion cross-sectional study, we found that mean distal leg ENFD in all HIV+ subjects was lower than in HIV- subjects but similar among HIV+ groups whether ART-naïve or on d4T with/without neuropathy/neuropathic symptoms. The utility of ENFD as a useful predictor of small unmyelinated nerve fiber damage and neuropathy risk in HIV may be limited in certain populations.

Altered expression of the voltage-gated calcium channel subunit α₂δ-1: a comparison between two experimental models of epilepsy and a sensory nerve ligation model of neuropathic pain

The auxiliary α2δ-1 subunit of voltage-gated calcium channels is up-regulated in dorsal root ganglion neurons following peripheral somatosensory nerve damage, in several animal models of neuropathic pain. The α2δ-1 protein has a mainly presynaptic localization, where it is associated with the calcium channels involved in neurotransmitter release. Relevant to the present study, α2δ-1 has been shown to be the therapeutic target of the gabapentinoid drugs in their alleviation of neuropathic pain. These drugs are also used in the treatment of certain epilepsies. In this study we therefore examined whether the level or distribution of α2δ-1 was altered in the hippocampus following experimental induction of epileptic seizures in rats, using both the kainic acid model of human temporal lobe epilepsy, in which status epilepticus is induced, and the tetanus toxin model in which status epilepticus is not involved. The main finding of this study is that we did not identify somatic overexpression of α2δ-1 in hippocampal neurons in either of the epilepsy models, unlike the upregulation of α2δ-1 that occurs following peripheral nerve damage to both somatosensory and motor neurons. However, we did observe local reorganization of α2δ-1 immunostaining in the hippocampus only in the kainic acid model, where it was associated with areas of neuronal cell loss, as indicated by absence of NeuN immunostaining, dendritic loss, as identified by areas where microtubule-associated protein-2 immunostaining was missing, and reactive gliosis, determined by regions of strong OX42 staining.