Quantitative assessment of chemotherapy-induced peripheral neurotoxicity using a point-of-care nerve conduction device

Current understanding of the molecular mechanisms of chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is the most common off-target adverse effects caused by various chemotherapeutic agents, such as cisplatin, oxaliplatin, paclitaxel, vincristine and bortezomib. CIPN is characterized by a substantial loss of primary afferent sensory axonal fibers leading to sensory disturbances in patients. An estimated of 19-85% of patients developed CIPN during the course of chemotherapy. The lack of preventive measures and limited treatment options often require a dose reduction or even early termination of life-saving chemotherapy, impacting treatment efficacy and patient survival. In this Review, we summarized the current understanding on the pathogenesis of CIPN. One prominent change induced by chemotherapeutic agents involves the disruption of neuronal cytoskeletal architecture and axonal transport dynamics largely influenced by the interference of microtubule stability in peripheral neurons. Due to an ineffective blood-nerve barrier in our peripheral nervous system, exposure to some chemotherapeutic agents causes mitochondrial swelling in peripheral nerves, which lead to the opening of mitochondrial permeability transition pore and cytochrome c release resulting in degeneration of primary afferent sensory fibers. The exacerbated nociceptive signaling and pain transmission in CIPN patients is often linked the increased neuronal excitability largely due to the elevated expression of various ion channels in the dorsal root ganglion neurons. Another important contributing factor of CIPN is the neuroinflammation caused by an increased infiltration of immune cells and production of inflammatory cytokines. In the central nervous system, chemotherapeutic agents also induce neuronal hyperexcitability in the spinal dorsal horn and anterior cingulate cortex leading to the development of central sensitization that causes CIPN. Emerging evidence suggests that the change in the composition and diversity of gut microbiota (dysbiosis) could have direct impact on the development and progression of CIPN. Collectively, all these aspects contribute to the pathogenesis of CIPN. Recent advances in RNA-sequencing offer solid platform for in silico drug screening which enable the identification of novel therapeutic agents or repurpose existing drugs to alleviate CIPN, holding immense promises for enhancing the quality of life for cancer patients who undergo chemotherapy and improve their overall treatment outcomes.

Assessment of neuropathic pain following cancer treatment

Neuropathic cancer pain (NCP) is prevalent affecting up to 58% of those with persistent pain following cancer treatment. Neuropathic pain can develop from malignancy, after neural tissue insult during surgery and/or exposure to radiation or neurotoxic agents used as part of cancer treatment regimens. Pain following cancer treatment is commonly under-treated and one barrier identified is poor recognition of pain and inadequate assessment. Recognition of the presence of NCP is important to inform pain management, which is challenging to treat and warrants the use of specific treatments to target neuropathic mechanisms. In this review, approaches for screening and classifying NCP are described. These include screening questionnaires and the application of the updated neuropathic pain grading system in a cancer context. The evidence from neuropathic pain related assessments in cancer populations is provided and highlighted under different neuropathic pain grades. Recommendations for assessment in practice are provided.

Antinociceptive and neuroprotective effect of echinacoside on peripheral neuropathic pain in mice through inhibiting P2X7R/FKN/CX3CR1 pathway

Clinically, neuropathic pain treatment remains a challenging issue because the major therapy, centred around pharmacological intervention, is not satisfactory enough to patient by reason of low effectiveness and more adverse reaction. Therefore, it is still necessary to find more effective and safe therapy to ameliorate neuropathic pain. The purpose of this study was to explore the antinociceptive effect of Echinacoside (ECH), an active compound of Cistanche deserticola Ma, on peripheral neuropathic pain induced by chronic constriction injury (CCI) in mice, and to demonstrate its potential mechanism in vivo and vitro. In the present study, results showed that intraperitoneal administration of ECH (50, 100, and 200 mg/kg) could alleviate mechanical allodynia, cold allodynia and thermal hyperalgesia via behavioural test. Moreover, the structure and function of injured sciatic nerve by CCI were taken a turn for the better to a certain extent after ECH treatment using histopathological and electrophysiological test. Furthermore, ECH repressed the expression of the P2X7R and FKN and reduced the expression and release of the IL-1β, IL-6 and TNF-α. Besides, ECH could decrease Ca2+ influx and Cats efflux and inhibit phosphorylation of p38MAPK. To sum up, the present study illustrated that ECH could alleviate peripheral neuropathic pain by inhibiting microglia overactivation and inflammation through P2X7R/FKN/CX3CR1 signalling pathway in spinal cord. This study would provide a new perspective and strategy for the pharmacological treatment on neuropathic pain.

Repetitive transcranial magnetic stimulation for chemotherapy-induced peripheral neuropathy in multiple myeloma: A pilot study

Objective

Chemotherapy-induced peripheral neuropathy is one of the major toxicities in multiple myeloma patients, often resulting in dose reductions or treatment interruptions. Repetitive transcranial magnetic stimulation is a safe non-invasive neuromodulation therapy with potential benefits for chemotherapy-induced peripheral neuropathy. The objective of this study was to investigate the efficacy of repetitive transcranial magnetic stimulation treatment on chemotherapy-induced peripheral neuropathy in multiple myeloma patients.

Materials and methods

We screened 30 multiple myeloma patients with chemotherapy-induced peripheral neuropathy who underwent repetitive transcranial magnetic stimulation treatment in this study. Prior to and following repetitive transcranial magnetic stimulation treatment, patients were assessed with nerve conduction velocity, visual analog scale and the European Organization of Research and Treatment of Cancer Quality of Life Questionnaire-CIPN 20-item scale (EORTC QLQ-CIPN20). Categorical and continuous variables were analyzed using Fisher's exact test and Mann-Whitney U test respectively. A p-value < 0.05 (2-tailed) was considered statistically significant.

Results

Following repetitive transcranial magnetic stimulation treatment, 24/30 (80.0%) patients reported a reduction in chemotherapy-induced peripheral neuropathy symptoms. Meanwhile, all 15 patients with grade 2 chemotherapy-induced peripheral neuropathy experienced improvements about themselves, compared to 8/10 patient with grade 3 chemotherapy-induced peripheral neuropathy and 1/5 with grade 4 chemotherapy-induced peripheral neuropathy. Visual analog scale scores decreased after repetitive transcranial magnetic stimulation treatment (5.40 ± 1.94 vs 3.10 ± 1.60, p < 0.001). We also observed enhancements in both motor conduction velocity and sensory conduction velocity of patients in bilateral median nerves, posterior tibial nerves, common ulnar nerves and peroneal nerves following repetitive transcranial magnetic stimulation treatment. Analysis of the European Organization of Research and Treatment of Cancer Quality of Life Questionnaire-CIPN 20-item scale data (17.68 ± 8.14 vs 10.50 ± 9.55, p < 0.001) revealed significant reductions in scores. Patients with grade 2-3 (n = 25) exhibited a mean reduction of 8.89 ± 4.24 points, while those with grade 4 (n = 5) showed a difference value of 3.54 ± 3.45, p < 0.001. No adverse events were observed.

Conclusion

Our findings suggest that repetitive transcranial magnetic stimulation is a safe and effective therapeutic approach for ameliorating peripheral nerve injury and alleviating the chemotherapy-induced peripheral neuropathy symptoms in multiple myeloma patients. Early initiation of repetitive transcranial magnetic stimulation treatment may yield more favorable outcomes for these patients.

A Comparison of Self-reported Pain Measures Between Sensory Phenotypes in HIV-associated Sensory Neuropathy

Painful HIV-associated neuropathy (HIV-SN) is a prevalent co-morbidity of HIV infection. Sensory phenotyping, using quantitative sensory testing (QST) could allow for improved stratification to guide personalized treatment. However, previous methods of QST interpretation have demonstrated limited association with self-reported pain measures. This study sought to identify differences in self-reported pain measures between composite QST-derived sensory phenotypes, and to examine any differences in participants reporting multi-site, multi-etiology chronic pain. In this cross-sectional observational study of participants with HIV (n = 133), individuals were allocated to neuropathy and neuropathic pain groups through clinical assessment and nerve conduction testing. They completed symptom-based questionnaires and underwent standardized QST. Participants were assigned, by pre-determined algorithm, to a QST-derived sensory phenotype. Symptoms were compared between sensory phenotypes. Symptom characteristics and Neuropathic Pain Symptom Inventory scores differed between QST-derived sensory phenotypes: 'sensory loss' was associated with more paroxysmal and paraesthetic symptoms compared to 'thermal hyperalgesia' and 'healthy' phenotypes (P = .023-0.001). Those with painful HIV-SN and additional chronic pain diagnoses were more frequently allocated to the 'mechanical hyperalgesia' phenotype compared to those with painful HIV-SN alone (P = .006). This study describes heterogeneous sensory phenotypes in people living with HIV. Differences in self-reported pain outcomes between sensory phenotypes has the potential to guide future stratified trials and eventually more targeted therapy. PERSPECTIVE: This article presents quantitative sensory testing derived phenotypes, thought to reflect differing pathophysiological pain mechanisms and relates them to self-reported pain measures in people with HIV infection. This could help clinicians stratify patients to individualize analgesic interventions more effectively.

Analgesic effect of nobiletin against neuropathic pain induced by the chronic constriction injury of the sciatic nerve in mice

Neuropathic pain is chronic pain resulting from central or peripheral nerve damage that remains difficult to treat. Current evidence suggests that nobiletin, isolated from Citrus reticulata Blanco, possesses analgesic and neuroprotective effects. However, its effect on neuropathic pain has not been reported. This study evaluated the analgesic effect of nobiletin on neuropathic pain induced by chronic constriction injury (CCI) in mice. In vivo, mice were intragastrically administered with nobiletin (30, 60, 120 mg/kg) for eight consecutive days, respectively. Our study indicated that nobiletin ameliorated mechanical allodynia, cold allodynia and thermal hyperalgesia on CCI mice at doses that do not induce significant sedation. Moreover, nobiletin could ameliorate axonal and myelin injury of the sciatic nerve and further restore abnormal sciatic nerve electrical activity on CCI mice. In vitro studies indicated that nobiletin could suppress the proteins and mRNA expression of the IRF5/P2X4R/BDNF signalling pathway in fibronectin-induced BV2 cells. Overall, our results indicated that nobiletin might exert an analgesic effect on CCI-induced neuropathic pain in mice by inhibiting the IRF5/P2X4R/BDNF signalling pathway in spinal microglia. This study provided a novel potential therapeutic drug for neuropathic pain and new insights into the pharmacological action of nobiletin.

Assessment of chemotherapy-induced neurotoxicity using a point-of-care nerve conduction study device

BACKGROUND

Management for chemotherapy-induced peripheral neuropathy (CIPN) includes prompt recognition and dose reduction or discontinuation of the neurotoxic agents. CIPN remains under-detected in routine clinical practice and better methods for its early detection are warranted.

AIMS

To evaluate the feasibility of a point-of-care device in the early detection of CIPN.

METHODS AND RESULTS

Cancer patients (n = 12) scheduled to receive neurotoxic chemotherapy docetaxel, oxaliplatin (OX), or vincristine were recruited for the pilot study (NCT04778878). The patients were assessed with a point-of-care nerve conduction study device (Mediracer® NCS), EORTC QLQ-CIPN20 and NPSI questionnaires, and healthcare professional-assessed CTCAE-based grading at baseline and thereafter every 6-weeks up to 18 weeks or until chemotherapy discontinuation. The set-up of point-of-care device was easy but it only provide successful NCS measurement results in 55% of the patients. The factors related to failed measurement were older age, more frequent comorbidities, and a history of smoking. With the follow-up measurements, decreasing median nerve mean conduction velocity and amplitude, and increasing median nerve mean distal latency were detected on OX-patients. Of the used questionnaires, NPSI was found to be non-feasible with majority of the patients failing to complete the questionnaire while CIPN20 was feasible on all the subjects. CIPN20 score did not show any changes in the follow-up.

CONCLUSIONS

Point-of-care assessment for NCS was feasible but measurements frequently failed especially on patients with pre-existing high-risk for neuropathy. OX-treated showed decreasing NCS results while other measures were unable to access the change. The system should be further validated with a larger patient cohort preferably treated with OX and low-risk for pre-existing neuropathy.

Comparison of Clinical Symptoms and Neurophysiological Findings in Patients With Chemotherapy Induced Peripheral Neuropathy

Introduction

Taxanes are associated with a distal sensory neuropathy, significantly affecting cancer survivor quality of life. However, chemotherapy-induced peripheral neuropathy (CIPN) assessments are primarily based on clinical symptoms rather than objective neurophysiologic findings. Therefore, we investigated neurophysiologic changes in symptomatic subjects, comparing them with symptom severity.

Materials and Methods

Medical charts of 111 subjects who were referred for CIPN diagnosis after chemotherapy for breast or ovarian cancer between May 1, 2016, and December 31, 2019, were retrospectively reviewed. Demographics, anthropometric parameters, and Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) pain scale data were collected. The nerve conduction study (NCS) results, including sensory nerve action potentials recorded from sural nerves, were analyzed relative to clinical symptoms. To optimize follow-up (FU) NCS diagnostic sensitivity, relative references of FU sural amplitude reductions to >30% and an absolute reference <10 μV were used.

Results

Eighty-eight female patients met the criteria, and 20 underwent FU NCS. Baseline and FU sural amplitudes showed significant positive correlation with respective LANSS scores (p < 0.01). FU sural amplitude was significantly lower than the initial result (p < 0.05). The FU LANSS score was not different from the initial score. Initial NCS sensitivity and specificity for clinically suspected CIPN diagnoses with LANSS were 69.7 and 47.3%, respectively. All 20 subjects with FU evaluation were clinically compatible with CIPN (LANSS >12) at initial and FU assessments. Among them, only six (30.0%) had abnormal sural amplitudes (<10μV for ≤50 s, <3 μV for 60 s, <1 μV for 70 s) in the initial NCS. In the FU NCS, sural amplitude became abnormal in five additional subjects. Between the initial and FU NCS, sural amplitude was reduced by > 30% in eight subjects (40.0%). NCS sensitivity increased to 65.0% when including either abnormal sural amplitudes or a > 30% reduction in sural amplitude in FU studies.

Conclusions

Although clinical symptoms and NCS results were positively correlated, a single NCS point had limited value for suspected CIPN electrophysiological diagnoses. Serial NCS during chemotherapy might help assess the degree of chemotherapy-induced nerve damage, attain evidence of CIPN prior to symptom aggravation, and monitor the progression of CIPN. Further study is needed to find specific relative references for variable patient factors to increase the sensitivity of electrophysiological studies of clinically suspected CIPN.

Chemotherapy-Induced Peripheral Neuropathy: Epidemiology, Pathomechanisms and Treatment

PURPOSE

This review provides an update on the current clinical, epidemiological and pathophysiological evidence alongside the diagnostic, prevention and treatment approach to chemotherapy-induced peripheral neuropathy (CIPN).

FINDINGS

The incidence of cancer and long-term survival after treatment is increasing. CIPN affects sensory, motor and autonomic nerves and is one of the most common adverse events caused by chemotherapeutic agents, which in severe cases leads to dose reduction or treatment cessation, with increased mortality. The primary classes of chemotherapeutic agents associated with CIPN are platinum-based drugs, taxanes, vinca alkaloids, bortezomib and thalidomide. Platinum agents are the most neurotoxic, with oxaliplatin causing the highest prevalence of CIPN. CIPN can progress from acute to chronic, may deteriorate even after treatment cessation (a phenomenon known as coasting) or only partially attenuate. Different chemotherapeutic agents share both similarities and key differences in pathophysiology and clinical presentation. The diagnosis of CIPN relies heavily on identifying symptoms, with limited objective diagnostic approaches targeting the class of affected nerve fibres. Studies have consistently failed to identify at-risk cohorts, and there are no proven strategies or interventions to prevent or limit the development of CIPN. Furthermore, multiple treatments developed to relieve symptoms and to modify the underlying disease in CIPN have failed.

IMPLICATIONS

The increasing prevalence of CIPN demands an objective approach to identify at-risk patients in order to prevent or limit progression and effectively alleviate the symptoms associated with CIPN. An evidence base for novel targets and both pharmacological and non-pharmacological treatments is beginning to emerge and has been recognised recently in publications by the American Society of Clinical Oncology and analgesic trial design expert groups such as ACTTION.

Relative Risk of Peripheral Neuropathy With Ado-Trastuzumab Emtansine (T-DM1) Compared to Taxane-Based Regimens in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Cancers: A Systematic Review and Meta-Analysis

Background

Peripheral neuropathy (PN), especially peripheral sensory neuropathy (PSN), is significant toxicity of taxanes, the most used class of microtubule inhibitors for human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients. Ado-trastuzumab emtansine (T-DM1) is a HER2-targeted antibody-drug conjugate, consisting of trastuzumab and a microtubule inhibitor DM1, which has been approved for HER2-positive breast cancer. T-DM1 has also been found to cause significant PN, including PSN.

Methods

We conducted a systematic review and meta-analysis of phase 3 randomized controlled trials using T-DM1 in the experimental arm and a taxane-based regimen in the control arm to determine the relative risk of PN and PSN associated with T-DM1 as compared to taxanes. A total of 1,857 patients were included in the analysis. The Cochran-Mantel-Haenszel method and the random-effects model were used to calculate the pooled risk ratio (RR) with a 95% confidence interval (CI) for all-grade and grade ≥3 PN and PSN. 

Results

The relative risks of all-grade PN and all-grade PSN were lower with T-DM1 compared to taxanes. The pooled RR of all-grade PN was 0.59, 95% CI: 0.39-0.89, P = 0.01, and the pooled RR of all-grade PSN was 0.58, 95% CI: 0.46-0.74, P < 0.0001.

Conclusions

Our meta-analysis demonstrated that T-DM1 is associated with a relatively lower risk of all-grade PN and PSN than the taxane-based regimens for HER2-positive cancers. It could be an area of consideration in selecting therapy for HER2-positive breast cancer patients at high risk of developing or having pre-existing PN and PSN.

Effects of Curcumin and Its Different Formulations in Preclinical and Clinical Studies of Peripheral Neuropathic and Postoperative Pain: A Comprehensive Review

Lesion or disease of the somatosensory system leads to the development of neuropathic pain. Peripheral neuropathic pain encompasses damage or injury of the peripheral nervous system. On the other hand, 10–15% of individuals suffer from acute postoperative pain followed by persistent pain after undergoing surgeries. Antidepressants, anticonvulsants, baclofen, and clonidine are used to treat peripheral neuropathy, whereas opioids are used to treat postoperative pain. The negative effects associated with these drugs emphasize the search for alternative therapeutics with better efficacy and fewer side effects. Curcumin, a polyphenol isolated from the roots of Curcuma longa, possesses antibacterial, antioxidant, and anti-inflammatory properties. Furthermore, the low bioavailability and fast metabolism of curcumin have led to the advent of various curcumin formulations. The present review provides a comprehensive analysis on the effects of curcumin and its formulations in preclinical and clinical studies of neuropathic and postoperative pain. Based on the positive outcomes from both preclinical and clinical studies, curcumin holds the promise of mitigating or preventing neuropathic and postoperative pain conditions. However, more clinical studies with improved curcumin formulations are required to involve its use as adjuvant to neuropathic and postoperative drugs.

Psychometric testing of the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) subscale in a longitudinal study of cancer patients treated with chemotherapy

Background

The aim of this study was to evaluate the psychometric properties of the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group—Neurotoxicity (FACT/GOG-Ntx) subscale in a longitudinal study of cancer patients treated with chemotherapy.

Methods

Patients were assessed with the FACT/GOG-Ntx subscale, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Chemotherapy-Induced Peripheral Neuropathy Scale 20 (EORTC QLQ-CIPN20), National Cancer Institute -Common Terminology Criteria for Adverse Events (NCI-CTCAE), and light touch test using 10 g monofilament for up to ten assessment points from baseline (prior to initiation of first chemotherapy), after the end of each cycle (up to 6 cycles, 3 weeks per cycle), and at 6, 9, and 12 months after starting chemotherapy. Psychometric analyses included internal consistency reliability, convergent validity, factorial validity, sensitivity to change and responsiveness (minimal clinically important difference, MCID).

Results

Cronbach’s alpha coefficients of the FACT/GOG-Ntx subscale were 0.82–0.89 across assessment points. The subscale strongly correlated with the EORTC QLQ-CIPN20 (r = 0.79–0.93) but low-to-moderately correlated with the NCI-CTCAE sensory (r_s = 0.23–0.45) and motor items (r_s = 0.15–0.50) as well as the monofilament test (r_s = 0.23–0.47). The hypothesized 4-factor structure of the FACT/GOG-Ntx subscale was not confirmed at assessment points (χ2/df = 2.26–8.50; all P < 0.001). The subscale exhibited small-to-moderate sensitivity to change (r = 0.17–0.37). The MCIDs were between 1.38 and 3.68.

Conclusion

The FACT/GOG-Ntx subscale has satisfactory reliability, validity, sensitivity to change and responsiveness to evaluate CIPN in cancer patients. Future research is needed to explore the factorial structure of the FACT/GOG-Ntx subscale as the published four-factor structure was not supported in this study.

Serum neurofilament light chain levels as a biomarker of neuroaxonal injury and severity of oxaliplatin-induced peripheral neuropathy

We set out to determine the usability of serum neurofilament light chain (sNfL), serum glial fibrillary acidic protein (sGFAP), and retinal parameters by using optical coherence tomography (OCT) as reliable biomarkers of the progression of oxaliplatin-induced peripheral neuropathy (OIPN). Forty-three patients scheduled to undergo oxaliplatin-based chemotherapy at the National Cancer Center of Korea between June 2018 and October 2019 were prospectively assessed at baseline, 3 months, and 6 months of chemotherapy. Patients were assessed on clinical scales and underwent OCT, sNfL, and sGFAP level measurement at each follow-up visit. By applying the National Cancer Institute-Common Toxicity Criteria (NCI-CTC), OIPN was classified as grade 1 in 12 (28%) patients, grade 2 in 25 (58%), and grade 3 in 5 (12%) at 6 months of chemotherapy. sNfL levels increased during oxaliplatin administration, while serial sGFAP levels or retinal parameters did not change. Patients with grade-3 OIPN showed significantly higher mean sNfL levels than patients with grade 0-2 OIPN at 6 months of treatment. At 4-6 months after completion of chemotherapy, sNfL levels were significantly reduced compared to the levels at 6 months of chemotherapy. Monitoring of sNfL during chemotherapy can indicate ongoing neuroaxonal injury and the severity of OIPN.

Effectiveness and Tolerability of Nab-paclitaxel in Younger versus Elderly Patients With Metastatic HR-positive/HER2-negative Breast Cancer: Results From the Noninterventional, Prospective Study NABUCCO

BACKGROUND

There are only scarce data on treatment of elderly patients with nab-paclitaxel for metastatic breast cancer, especially from the real-world setting. Here we present data from the noninterventional study NABUCCO with special focus on taxane-induced peripheral neuropathy (TIPN) in younger and elderly patients.

PATIENTS AND METHODS

A total of 407 patients with HR-positive/HER2-negative metastatic breast cancer were enrolled between April 2012 and April 2015 into the prospective, multicenter, noninterventional study NABUCCO. Details on effectiveness, tolerability, and safety of nab-paclitaxel were evaluated for younger (<70 years) and elderly (≥70 years) patients.

RESULTS

Neither median time to progression (TTP, younger 6.0 months, 95% confidence interval [CI], 5.5-7.1; elderly 6.9 months, 95% CI, 5.5-8.6) nor median overall survival (younger 16.4 months, 95% CI, 14.2-18.1; elderly 14.5 months, 95% CI, 11.9-17.4) differed by age group, also not in view of prior treatments. A multivariate regression model revealed that age did not significantly influence the TTP. TIPN was reported by 49.0% younger (44.3% common terminology criteria for adverse events [CTCAE] grade 1/2, 4.7% grade 3/4) and 45.8% elderly patients (41.1% CTCAE grade 1/2, 4.7% grade 3/4). The cumulative nab-paclitaxel dose did not correlate with the severity/grading of TIPN.

CONCLUSION

Treatment with nab-paclitaxel in first- or further-line of metastatic HR-positive/HER2-negative breast cancer resulted in similar effectiveness and safety, irrespective of age. Therefore, nab-paclitaxel is a valid treatment option for elderly and partially heavily pretreated patients. However, incidence of TIPN is high, influencing the patients' quality of life. A close monitoring and awareness for early TIPN symptoms is warranted.

In Vitro and In Vivo Effects of Flavonoids on Peripheral Neuropathic Pain

Neuropathic pain is a common symptom and is associated with an impaired quality of life. It is caused by the lesion or disease of the somatosensory system. Neuropathic pain syndromes can be subdivided into two categories: central and peripheral neuropathic pain. The present review highlights the peripheral neuropathic models, including spared nerve injury, spinal nerve ligation, partial sciatic nerve injury, diabetes-induced neuropathy, chemotherapy-induced neuropathy, chronic constriction injury, and related conditions. The drugs which are currently used to attenuate peripheral neuropathy, such as antidepressants, anticonvulsants, baclofen, and clonidine, are associated with adverse side effects. These negative side effects necessitate the investigation of alternative therapeutics for treating neuropathic pain conditions. Flavonoids have been reported to alleviate neuropathic pain in murine models. The present review elucidates that several flavonoids attenuate different peripheral neuropathic pain conditions at behavioral, electrophysiological, biochemical and molecular biological levels in different murine models. Therefore, the flavonoids hold future promise and can be effectively used in treating or mitigating peripheral neuropathic conditions. Thus, future studies should focus on the structure-activity relationships among different categories of flavonoids and develop therapeutic products that enhance their antineuropathic effects.

Improvement of peripheral vascular impairment by a phosphodiesterase type 5 inhibitor tadalafil prevents oxaliplatin-induced peripheral neuropathy in mice

Oxaliplatin, a platinum-based chemotherapeutic drug, frequently induces peripheral neuropathy. Accumulating evidences suggest a possible relationship between peripheral vascular impairment and peripheral neuropathy. In this study, we investigated the effects of vasodilators on cumulative peripheral neuropathy induced by repeated injections of oxaliplatin (10 mg/kg) once a week for 8 weeks in mice. Single injections of vasodilators, including a phosphodiesterase type 5 inhibitor tadalafil acutely alleviated oxaliplatin-induced cold hypersensitivity, while tadalafil had no effect on the mechanical hypersensitivity. By contrast, long-term administration of tadalafil (0.1% in chow diets) during the oxaliplatin injection period reduced the oxaliplatin-induced decreases in skin temperature and blood flow without affecting platinum concentrations in blood, sciatic nerves, and dorsal root ganglion. The long-term administration significantly suppressed cold, mechanical, and electrical current hypersensitivities as well as thermal hypoesthesia. Furthermore, it prevented the decreases in sensory nerve conductance velocity and the number of endoneurial microvessels, and axon degeneration in the sciatic nerves. In vitro studies confirmed that tadalafil does not interfere with the cytotoxicity of oxaliplatin against human cancer cell lines. Altogether, these results suggest that improvement of peripheral vascular impairment by tadalafil could alleviate and prevent oxaliplatin-induced peripheral neuropathy.

Peripheral neuropathy following bortezomib therapy in multiple myeloma patients: association with cumulative dose, heparanase, and TNF-α

Multiple myeloma (MM) is a plasma cell neoplasm which constitutes about 10% of all hematologic malignancies. Despite bortezomib is a promising new generation of drugs for MM, its clinical use is limited by peripheral neurotoxicity in the vast majority of patients, which can be severe and require a reduction of dose or even treatment withdrawal. Tumor necrosis factor-α (TNF-α), as the most important inflammatory factor, could induce the inflammatory response and expression of heparanase (HPSE), which may play a crucial role in peripheral neuropathy after chemotherapy. However, the role of TNF-α in bortezomib-induced peripheral neuropathy (BIPN) has not been reported. In this study, treatment-emergent neuropathy was assessed by total neuropathy score and electrophysiological examination. The expression level of TNF-α and HPSE were evaluated by enzyme-linked immunosorbent assay. The effects of anti-TNF-α on the evolution of neuropathy were tested in rat models of neurotoxicity. The results indicated that with the augment of cumulative dose of bortezomib, the incidence of neuropathy was increased. Moreover, bortezomib administration induced the expression of TNF-α. With the increased expression of TNF-α, neuropathy was exacerbated. TNF-α-induced expression of HSPE was secondary to the development of neuropathy. Co-administration of anti-TNF-α in bortezomib therapy has a potential neuroprotective effect on BIPN in rats. TNF-α participates in the pathogenesis of BIPN, which represents an attractive target for future therapeutic intervention.

Validity and reliability of a point-of-care nerve conduction device in diabetes patients

AIMS/INTRODUCTION

Although nerve conduction study (NCS) using a standard electromyography system (EMGS) is considered to be the gold standard in evaluating diabetic polyneuropathy, this examination requires expensive equipment and well-trained technicians. We aimed to validate a point-of-care device, NC-stat/DPNCheck™, that has been developed for widespread use of NCS in diabetic polyneuropathy.

MATERIALS AND METHODS

Diabetes patients underwent two kinds of NCS: DPNCheck™ and electromyography system. Inter-/intrarater reliability of DPNCheck™ were also determined by the intraclass correlation coefficient.

RESULTS

A total of 57 patients were evaluated. The parameters of NCS between the two methods correlated well (r = 0.7734 for the sural nerve conduction velocity, r = 0.6155 for the amplitude of sural nerve action potential). The intraclass correlation coefficients were excellent (intrarater: the velocity 0.767, the amplitude 0.811; interrater: the velocity 0.974, the amplitude 0.834).

CONCLUSIONS

The point-of-care device has excellent reproducibility and good agreement with standard electromyography system. The device might be useful to evaluate diabetic polyneuropathy.

The Evaluation of the Effects of N-Acetylcysteine on Cisplatin-Induced Alterations in Exploratory Activity in Elevated Plus Maze Test in Rats

The aim of this study was to evaluate the potential beneficial effect of N-acetylcysteine (NAC) on cisplatin-induced alterations in anxiety levels in rats, by means of parameters of the exploratory activity obtained in the elevated plus maze (EPM) test. Animals were divided into four groups: control group, cisplatin group (7.5 mg/kg/weekly of cisplatin), N-acetylcysteine group (500 mg/kg/weekly of NAC), and cisplatin plus N-acetylcysteine group (7.5 mg/kg/weekly of cisplatin, and 500 mg/kg/weekly of NAC). After two weeks of treatment, exploratory activity (estimated by means of the number of rearings, head-dippings and the number of total exploratory activity episodes) was significantly reduced in cisplatin group comparing to control values. Although NAC induced no alterations in exploratory activity when applied alone, simultaneous administration with cisplatin resulted in significant attenuation of cisplatin-induced decline in exploratory activity. The exploratory activity gradually decreased in time-dependent manner during five minutes of EPM test in all groups. The results of this study confirmed clear beneficial effect of NAC supplementation against cisplatin- induced neurotoxicity in rats. Antioxidative properties of NAC were manifested through restoration of exploratory activity, confirming that NAC administration can attenuate anxiogenic effect of cisplatin therapy. Those results could recommend NAC supplementation as a potential protection against cisplatin-induced neurotoxicity.

Acupuncture in adults with Chemotherapy-Induced Peripheral Neuropathy: a systematic review

Objective:

to analyze and synthesize knowledge about the effect of acupuncture on chemotherapy-induced peripheral neuropathy symptoms in adults with cancer.

Method:

the method used was a Systematic Review. Potential articles were identified by searching in the PubMed of National Library of Medicine, Cumulative Index to Nursing and Allied Health Literature, Embase, Cochrane Central and Scopus. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses strategy, 607 articles were identified. After removing the duplicates, all titles and abstracts were reviewed, and seven articles were selected for full review. After the full review, five studies were selected for inclusion.

Results:

of the five articles included, four were cohort studies and one was a quasi-experimental study. All articles showed that acupuncture was associated with an improvement in the peripheral neuropathy, but the type of protocol, use of medications, time of treatment, and different outcome measures made it difficult to compare the studies.

Conclusion:

the use of acupuncture appears to be associated with an improvement in the symptoms of chemotherapy-induced peripheral neuropathy and has no side effects. In order to improve the evidence about benefits associated with acupuncture, more experimental studies using both subjective and objective measures are needed.

The utility of a point-of-care sural nerve conduction device for detection of diabetic polyneuropathy: A cross-sectional study

INTRODUCTION

Rapid and accessible methods for diagnosing diabetic polyneuropathy (DPN) have been developed, but not validated, in large cohorts of people with diabetes.

METHODS

The performance of a point-of-care device (POCD) was studied in 168 patients with type 2 diabetes, estimating the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) compared with conventional sural nerve conduction studies (NCS).

RESULTS

A POCD amplitude limit of 6 µV increased the sensitivity (96%) and NPV (98%), but decreased the specificity (71%) and PPV (54%) compared with the 4-µV limit, which had values of 78%, 92%, 89%, and 71%, respectively. POCD on both legs showed better performance than on 1 leg. POCD amplitudes and conduction velocities correlated significantly with conventional sural NCS, but POCD values were underestimated compared with NCS.

DISCUSSION

The POCD may be used as a suitable screening tool for detection of DPN. Patients with abnormal and borderline results should undergo conventional NCS. Muscle Nerve 59:187-193, 2019.

Difference in normal limit values of nerve conduction parameters between Westerners and Japanese people might need to be considered when diagnosing diabetic polyneuropathy using a Point-of-Care Sural Nerve Conduction Device (NC-stat®/DPNCheck™)

AIM/INTRODUCTION

Studies on a novel point-of-care device for nerve conduction study called DPNCheck have been limited to Westerners. We aimed to clarify Japanese normal limits of nerve action potential amplitude (Amp) and conduction velocity by DPNCheck (investigation I), and the validity of DPNCheck to identify diabetic symmetric sensorimotor polyneuropathy (DSPN; investigation II).

MATERIALS AND METHODS

For investigation I, 463 non-neuropathic Japanese participants underwent DPNCheck examinations. Regression formulas calculating the normal limits of Amp and conduction velocity (Japanese regression formulas [JRF]) were determined by quantile regression and then compared with regression formulas of individuals from the USA (USRF). For investigation II, in 92 Japanese diabetes patients, 'probable DSPN' was diagnosed and nerve conduction abnormalities (NCA1: one or more abnormalities, and NCA2: two abnormalities in Amp and conduction velocity) were determined. Validity of NCAs to identify 'probable DSPN' was evaluated by determining sensitivity, specificity, reproducibility (kappa-coefficient) and the area under the curve of receiver operating characteristic curves.

RESULTS

For investigation I, JRF was different from USRF, and normal limits by JRF were higher than that of USRF. The prevalence of Amp abnormality calculated by JRF was significantly higher than that of USRF. For investigation II, the sensitivity, specificity and reproducibility of NCA1 and NCA2 judged from JRF were 85%, 86% and 0.57, and 43%, 100% and 0.56, respectively. These values of JRF were higher than those of USRF. The area under the curve of JRF (0.89) was larger than USRF (0.82).

CONCLUSIONS

A significant difference in the normal limits of nerve conduction parameters by DPNCheck between Japanese and USA individuals was suggested. Validity to identify DSPN of NCAs might improve by changing the judgment criteria from USRF to JRF.

Chemotherapy-induced peripheral neuropathy: a review of recent findings

PURPOSE OF REVIEW

Chemotherapy-induced peripheral neuropathy (CIPN) is a common, frequently chronic condition characterized by pain and decreased function. Given the growing number of cancer survivors and an increasing recognition of opioid therapy limitations, there is a need for critical analysis of the literature in directing an informed and thoughtful approach for the management of painful CIPN.

RECENT FINDINGS

A PubMed search for 'chemotherapy-induced peripheral neuropathy AND pain' identifies 259 publications between 1 January 2016 and 31 March 2017. Based on review of this literature, we aim to present a clinically relevant update of painful CIPN. Notably, the use of duloxetine as a first-line agent in treatment of CIPN is confirmed. Moreover, clinical trials focus on nonpharmacologic strategies for managing painful CIPN.

SUMMARY

Despite the volume of recent publications, there are limited preventive or therapeutic strategies for CIPN supported by high-level evidence. Duloxetine remains the only pharmacologic agent with demonstrated benefit; its clinical use should be routinely considered. Moving forward, nonopioid analgesic therapies will likely play an increasing role in CIPN treatment, but further research is necessary to confirm their utility. Promising therapies include vitamin B12 supplementation, physical therapy, and various forms of neuromodulation.

Validity of a point-of-care nerve conduction device for polyneuropathy identification in older adults with diabetes: Results from the Canadian Study of Longevity in Type 1 Diabetes

Objective

Point-of-care nerve conduction devices (POCD) have been studied in younger patients and may facilitate screening for polyneuropathy in non-specialized clinical settings. However, performance may be impaired with advanced age owing to age-related changes in nerve conduction. We aimed to evaluate the validity of a POCD as a proxy for standard nerve conduction studies (NCS) in older adults with type 1 diabetes (T1D).

Methods

Sural nerve amplitude potential (AMP) and sural nerve conduction velocity (CV) was measured in 68 participants with ≥ 50 years T1D duration and 71 controls (from age/sex-matched subgroups) using POCD and NCS protocols. Agreement was determined by the Bland-Altman method, and validity was determined by receiver operating characteristic curves.

Results

T1D were 53% female, aged 66±8yr and had diabetes duration 54yr[52,58]. Controls were 56%(p = 0.69) female and aged 65±8yr(p = 0.36). Mean AMP_POCD and CV_POCD for the 139 participants was 7.4±5.8μV and 45.7±11.2m/s and mean AMP_NCS and CV_NCS was 7.2±6.1μV and 43.3±8.3m/s. Mean difference of AMP_POCD−AMP_NCS was 0.3±3.8μV and was 2.3±8.5m/s for CV_POCD−CV_NCS. A AMP_POCD of ≤6μV had 80% sensitivity and 80% specificity for identifying abnormal AMP_NCS, while a CV_POCD of ≤44m/s had 81% sensitivity and 82% specificity to identify abnormal CV_NCS. Abnormality in AMP_POCD or CV_POCD was associated with 87% sensitivity, while abnormality in both measures was associated with 97% specificity for polyneuropathy identification.

Conclusions

The POCD has strong agreement and diagnostic accuracy for identification of polyneuropathy in a high-risk subgroup and thus may represent a sufficiently accurate and rapid test for routinely detecting those with electrophysiological dysfunction.

Quantitative assessment of chemotherapy-induced peripheral neurotoxicity using a point-of-care nerve conduction device

Chemotherapy-induced peripheral neurotoxicity (CIPN) seriously impairs patients' quality of life cumulatively and dose-dependently. Because assessment of CIPN usually depends on patients' subjective evaluation of symptoms, objective and quantitative measures are needed. We evaluated a point-of-care nerve conduction device (POCD), previously validated for the assessment of diabetic peripheral neuropathy. Sensory nerve action potential (SNAP) amplitude and sensory nerve conduction velocity (SNCV) of the sural nerve were measured using a portable, automated POCD (DPNCheck; NeuroMetrix Inc., Waltham, MA, USA) in patients with a clinical diagnosis of CIPN of grade 1 or higher. We compared SNAP and SNCV among patients with different grades of CIPN according to the Common Terminology Criteria for Adverse Events. A total of 50 patients (22 men, 28 women; median age, 64 years; grade 1/2/3, 21/18/11) were evaluated. Anticancer drugs responsible for CIPN were cisplatin in five patients, oxaliplatin in 15, carboplatin in 5, paclitaxel in 16, docetaxel in 14, nab-paclitaxel in 7, vincristine in 6, and bortezomib in 3. Unadjusted SNAP was 8.45 ± 3.67 μV (mean ± SD) in patients with grade 1 CIPN, 5.42 ± 2.68 μV with grade 2, and 2.45 ± 1.52 μV with grade 3. Unadjusted SNCV was 49.71 ± 4.77 m/s in patients with grade 1 CIPN, 48.78 ± 6.33 m/s with grade 2, and 44.14 ± 7.31 m/s with grade 3. The adjusted SNAP after controlling for age significantly differed between each CTCAE grade (P < 0.001, ancova). The adjusted SNCV after controlling for age and height also differed significantly (P = 0.027). Differences in the severity of CIPN could be detected objectively and quantitatively using this POCD.