Oxaliplatin-induced neurotoxicity: changes in axonal excitability precede development of neuropathy

Small-Fiber Neuropathy: An Etiology-Oriented Review

BACKGROUND

Small-fiber neuropathy (SFN), affecting Aδ or C nerve fibers, is characterized by alterations of pain and temperature sensation, as well as autonomic dysfunction. Its diagnosis may still remain challenging as methods specifically assessing small nerve fibers are not always readily available, and standard techniques for large-fiber neuropathies, such as electroneuromyography, yield negative results. Still, skin biopsy for epidermal innervation and quantitative sensory testing allow for diagnosis in the presence of a congruent clinical picture.

OBJECTIVES

Many different etiologies may underlie small-fiber neuropathy, of which metabolic (diabetes mellitus/impaired glucose tolerance) and idiopathic remain prevalent. The aim of this narrative review is to provide a general picture of SFN while focusing on the different etiologies described in the literature in order to raise awareness of the variegated set of different causes of SFN and promote adequate diagnostic investigation.

METHODS

The term "Small-Fiber Neuropathy" was searched on the PubMed database with its different recognized etiologies: the abstracts of the articles were reviewed and described in the article if relevant for a total of 40 studies.

RESULTS

Many different disorders have been associated with SFN, even though often in the form of case reports or small case series.

CONCLUSIONS

Idiopathic forms of SFN remain the most prevalent in the literature, but association with different disorders (e.g., infectious, autoimmune) should prompt investigation for SFN in the presence of a congruent clinical picture (e.g., pain with neuropathic features).

Peripheral nerve excitability abnormalities in Neuronal Intranuclear Inclusion Disease: Assessment with histopathological analysis

OBJECTIVE

Neuronal Intranuclear Inclusion Disease (NIID) is a neurodegenerative disease affecting the central and peripheral nerves. We aimed to assess the pathophysiological features of peripheral nerve dysfunction in NIID.

METHODS

We observed six unrelated NIID patients through clinical records, nerve conduction studies, and multiple measures of motor nerve excitability. Additionally, we reviewed one NIID patientt who underwent a nerve biopsy. Control measures were obtained from 22 age-matched normal subjects.

RESULTS

The NIID patients exhibited mild conduction slowing and distinct nerve excitability abnormalities, including a significant decrease in excitability through hyperpolarizing threshold electrotonus (TE) and increased overshoots in both depolarizing and hyperpolarizing conditions. Histopathology revealed thinly myelinated fibers and axonal degeneration. Mathematical modeling suggested that reduced leak conductance was the key factor contributing to the observed excitability changes.

CONCLUSIONS

The findings indicate that NIID involves a complex interplay of axonal degeneration and myelin dysfunction, leading to unique peripheral nerve excitability changes. These results provide new insights into the pathophysiology of NIID.

SIGNIFICANCE

Nerve excitability testing offers insight into particular axonal excitability abnormalities especially combined with histopathologic studies.

Dietary quality and chemotherapy-induced peripheral neuropathy in colon cancer

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and dose-limiting chemotoxicity caused by oxaliplatin. This study investigated the relationship between dietary quality and the development of moderate and/or severe CIPN in colon cancer survivors using data from the Focus on Reducing Dose-Limiting Toxicities in Colon Cancer with Resistance Exercise trial (ClinicalTrials.gov identifier NCT03291951).

METHODS

Diet quality was collected using a 127-item food-frequency questionnaire and was scored using the Alternative Healthy Eating Index-2010 (AHEI-2010). CIPN was assessed with the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events at each chemotherapy cycle. The association of dietary quality with time to the first moderate-to-severe (moderate-severe) or severe event of CIPN was estimated using Cox proportional hazards models. Only participants who received oxaliplatin were included in this analysis (n = 132).

RESULTS

Seventy-four participants (56.1%) reported moderate-severe CIPN. Higher dietary quality was associated with a significantly decreased risk of moderate-severe CIPN (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.93-0.99) and severe CIPN (HR, 0.91; 95% CI, 0.85-0.98). Consumption of red and processed meat (HR, 1.78; 95% CI, 1.07-2.83) and sugar-sweetened beverages (HR, 1.33; 95% CI, 1.10-1.59) was associated with an increased risk of moderate-severe CIPN. Consumption of sugar-sweetened beverages also was associated with an increased risk of severe CIPN (HR, 1.57; 95% CI, 1.14-2.18), whereas vegetable consumption was associated with a reduced risk of severe CIPN (HR, 0.29; 95% CI, 0.09-0.73).

CONCLUSIONS

Among patients with colon cancer who received oxaliplatin-based chemotherapy, higher baseline dietary quality was associated with a reduced risk of moderate-severe CIPN.

Gene expression in the dorsal root ganglion and the cerebrospinal fluid metabolome in polyneuropathy and opioid tolerance in rats

First-line pharmacotherapy for peripheral neuropathic pain (NP) of diverse pathophysiology consists of antidepressants and gabapentinoids, but only a minority achieve sufficient analgesia with these drugs. Opioids are considered third-line analgesics in NP due to potential severe and unpredictable adverse effects in long-term use. Also, opioid tolerance and NP may have shared mechanisms, raising further concerns about opioid use in NP. We set out to further elucidate possible shared and separate mechanisms after chronic morphine treatment and oxaliplatin-induced and diabetic polyneuropathies, and to identify potential diagnostic markers and therapeutic targets. We analysed thermal nociceptive behaviour, the transcriptome of dorsal root ganglia (DRG) and the metabolome of cerebrospinal fluid (CSF) in these three conditions, in rats. Several genes were differentially expressed, most following oxaliplatin and least after chronic morphine treatment, compared with saline-treated rats. A few genes were differentially expressed in the DRGs in all three models (e.g. Csf3r and Fkbp5). Some, e.g. Alox15 and Slc12a5, were differentially expressed in both diabetic and oxaliplatin models. Other differentially expressed genes were associated with nociception, inflammation, and glial cells. The CSF metabolome was most significantly affected in the diabetic rats. Interestingly, we saw changes in nicotinamide metabolism, which has been associated with opioid addiction and withdrawal, in the CSF of morphine-tolerant rats. Our results offer new hypotheses for the pathophysiology and treatment of NP and opioid tolerance. In particular, the role of nicotinamide metabolism in opioid addiction deserves further study.

Oxaliplatin-induced transient ischemic attack (TIA): A rare presentation

ABSTRACT

Oxaliplatin is a common drug used in the management of colorectal malignancies. Rare neurological side effects including amaurosis fugax, urinary retention, stroke, cranial nerve palsy, dysarthria, and dysphagia have been reported in the literature. Usually, such incidences are reported immediately after 1st dose of oxaliplatin infusion. We report a rare transient ischemic attack (TIA))-like side effects after 2nd dose of oxaliplatin infusion.

Motor disorders related to oxaliplatin-induced peripheral neuropathy: long-term severity and impact on quality of life

PURPOSE

Sensory chemotherapy-induced peripheral neuropathy (CIPN) is well-recognized, but motor CIPN remains understudied. This secondary analysis focused on the long-term severity and impact of motor disorders, their relation to sensory CIPN, neuropathic pain, psychological distress, and health-related quality of life (HRQoL) after oxaliplatin-based chemotherapy in colorectal cancer (CRC) survivors.

METHODS

Data from a multicenter, cross-sectional study were re-analyzed to explore motor CIPN among CRC survivors up to 5 years post-chemotherapy, with no longitudinal follow-up. Questionnaires assessed sensory and motor CIPN (QLQ-CIPN20), neuropathic pain (DN4), anxiety and depression (HADS), and HRQoL (QLQ-C30).

RESULTS

Among 405 CRC survivors, 31.1% had sensory CIPN as previously described. When categorizing the 405 CRC survivors based on the years since their last oxaliplatin-based chemotherapy, the motor scores derived from the QLQ-CIPN20 showed no significant difference between years (p = 0.08). Motor CIPN scores correlated with female gender, higher oxaliplatin dose intensity, sensory CIPN, and neuropathic pain. Motor CIPN also linked to decreased HRQoL and increased psychological distress.

CONCLUSION

The study underscores the detrimental impact of motor disorders on CRC survivors post-oxaliplatin-based chemotherapy. Oncologists should prioritize assessing and managing motor manifestations alongside sensory symptoms to enhance post-cancer quality of life.

TRIAL REGISTRATION

NCT02970526 (2016-11-22). https://classic.

CLINICALTRIALS

gov/ct2/show/NCT02970526?term=NCT02970526&draw=2&rank=1 .

Change of hand sensation and function in patients with malignant lymphoma during early-stage vincristine chemotherapy: A single-center observational study

This study aimed to investigate changes in hand sensation (finger tactile threshold and two-point discrimination) and function in patients with malignant lymphoma, particularly during the early stages of chemotherapy with vincristine. Eighteen patients with malignant lymphoma were enrolled in this study. Data on the Common Terminology Criteria for Adverse Events Version 4.0, the visual analog scale for hand numbness, the Semmes Weinstein monofilament test, static and moving two-point discrimination (2PD), grip strength, pinch strength, and the Purdue Pegboard test were collected at 3 time points: before the start of chemotherapy (T0), after the first cycle of chemotherapy (T1), and after the second cycle of chemotherapy (T2). No significant changes were observed in Semmes Weinstein monofilament test at T0, T1, or T2 in either hand. However, the static 2PD was significantly worse for the right ring, little, and left middle fingers, whereas the moving 2PD was significantly worse for the right ring, left index, middle, and ring fingers. Furthermore, the visual analog scale scores for hand numbness and left-hand grip strength worsened significantly. Right-hand grip strength, pinch strength of both hands, and Purdue Pegboard test showed no significant deterioration. Chemotherapy with vincristine may affect hand sensation and function in patients with malignant lymphoma by exacerbating finger 2PD and hand numbness. Additionally, during the early stages of vincristine chemotherapy, it is important to monitor for a decrease in grip strength specifically in the left hand.

Morphofunctional characterisation of axonal damage in different rat models of chemotherapy-induced peripheral neurotoxicity: The role of nerve excitability testing

BACKGROUND AND AIMS

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a common and long-lasting adverse event of several anticancer compounds, for which treatment has not yet been developed. To fill this gap, preclinical studies are warranted, exploiting highly translational outcome measure(s) to transfer data from bench to bedside. Nerve excitability testing (NET) enables to test in vivo axonal properties and can be used to monitor early changes leading to axonal damage.

METHODS

We tested NET use in two different CIPN rat models: oxaliplatin (OHP) and paclitaxel (PTX). Animals (female) were chronically treated with either PTX or OHP and compared to respective control animals. NET was performed as soon as the first injection was administered. At the end of the treatment, CIPN onset was verified via a multimodal and robust approach: nerve conduction studies, nerve morphometry, behavioural tests and intraepidermal nerve fibre density.

RESULTS

NET showed the typical pattern of axonal hyperexcitability in the 72 h following the first OHP administration, whereas it showed precocious signs of axonal damage in PTX animals. At the end of the month of treatment, OHP animals showed a pattern compatible with a mild axonal sensory polyneuropathy. Instead, PTX cohort was characterised by a rather severe sensory axonal polyneuropathy with minor signs of motor involvement.

INTERPRETATION

NET after the first administration demonstrated the ongoing OHP-related channelopathy, whereas in PTX cohort it showed precocious signs of axonal damage. Therefore, NET could be suggested as an early surrogate marker in clinical trials, to detect precocious changes leading to axonal damage.

Axonal excitability as an early biomarker of nerve involvement in hereditary transthyretin amyloidosis

OBJECTIVES

The treatment of hereditary transthyretin amyloidosis polyneuropathy (ATTRv-PN) has been revolutionised by genetic therapies, with dramatic improvements in patient outcomes. Whilst the optimal timing of treatment initiation remains unknown, early treatment is desirable. Consequently, the aim of the study was to develop biomarkers of early nerve dysfunction in ATTRv-PN.

METHODS

Ulnar motor and sensory axonal excitability studies were prospectively undertaken on 22 patients with pathogenic hereditary transthyretin amyloid (ATTRv) gene variants, 12 with large fibre neuropathy (LF+) and 10 without (LF-), with results compared to age- and sex-matched healthy controls.

RESULTS

In motor axons we identified a continuum of change from healthy controls, to LF- and LF+ ATTRv with progressive reduction in hyperpolarising threshold electrotonus (TEh40(10-20 ms): p = 0.04, TEh40(20-40 ms): p = 0.01 and TEh40(90-10 ms): p = 0.01), suggestive of membrane depolarisation. In sensory axons lower levels of subexcitability were observed on single (SubEx) and double pulse (SubEx2) recovery cycle testing in LF+ (SubEx: p = 0.015, SubEx2: p = 0.015, RC(2-1): p = 0.04) suggesting reduced nodal slow potassium conductance, which promotes sensory hyperexcitability, paraesthesia and pain. There were no differences in sensory or motor excitability parameters when comparing different ATTRv variants.

CONCLUSIONS

These progressive changes seen across the disease spectrum in ATTRv-PN suggest that axonal excitability has utility to identify early and progressive nerve dysfunction in ATTRv, regardless of genotype.

SIGNIFICANCE

Axonal excitability is a promising early biomarker of nerve dysfunction in ATTRv-PN.

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.

The role of neuromuscular ultrasound in diagnostics of peripheral neuropathies induced by cytostatic agents or immunotherapies

A relevant number of cancer patients who receive potentially neurotoxic cytostatic agents develop a chemotherapy-induced peripheral neuropathy over time. Moreover, the increasing use of immunotherapies and targeted agents leads to a raising awareness of treatment-associated peripheral neurotoxicity, e.g., axonal and demyelinating neuropathies such as Guillain-Barré-like syndromes. To date, the differentiation of these phenomena from concurrent neurological co-morbidities or (para-)neoplastic nerve affection as well as their longitudinal monitoring remain challenging. Neuromuscular ultrasound (NMUS) is an established diagnostic tool for peripheral neuropathies. Performed by specialized neurologists, it completes clinical and neurophysiological diagnostics especially in differentiation of axonal and demyelinating neuropathies. No generally approved biomarkers of treatment-induced peripheral neurotoxicity have been established so far. NMUS might significantly extend the repertoire of diagnostic and neuromonitoring methods in this growing patient group in short term. In this article, we present enlargements of the dorsal roots both in cytostatic and in immunotherapy-induced neurotoxicity for the first time. We discuss related literature regarding new integrative applications of NMUS for cancer patients by reference to two representative case studies. Moreover, we demonstrate the integration of NMUS in a diagnostic algorithm for suspected peripheral neurotoxicity independently of a certain cancer treatment regimen emphasizing the emerging potential of NMUS for clinical routine in this interdisciplinary field and prospective clinical trials.

Axonal degeneration in chemotherapy-induced peripheral neurotoxicity: clinical and experimental evidence

Multiple pathological mechanisms are involved in the development of chemotherapy-induced peripheral neurotoxicity (CIPN). Recent work has provided insights into the molecular mechanisms underlying chemotherapy-induced axonal degeneration. This review integrates evidence from preclinical and clinical work on the onset, progression and outcome of axonal degeneration in CIPN. We review likely triggers of axonal degeneration in CIPN and highlight evidence of molecular pathways involved in axonal degeneration and their relevance to CIPN, including SARM1-mediated axon degeneration pathway. We identify potential clinical markers of axonal dysfunction to provide early identification of toxicity as well as present potential treatment strategies to intervene in axonal degeneration pathways. A greater understanding of axonal degeneration processes in CIPN will provide important information regarding the development and progression of axonal dysfunction more broadly and will hopefully assist in the development of successful interventions for CIPN and other neurodegenerative disorders.

β-Caryophyllene Inhibits Oxaliplatin-Induced Peripheral Neuropathy in Mice: Role of Cannabinoid Type 2 Receptors, Oxidative Stress and Neuroinflammation

Peripheral neuropathy is an important adverse effect caused by some chemotherapeutic agents, including oxaliplatin (OXA). OXA-induced peripheral neuropathy (OIPN) is a challenging condition due to diagnostic complexities and a lack of effective treatment. In this study, we investigated the antiallodynic effect of β-caryophyllene (BCP), a cannabinoid type 2 (CB2) receptor agonist, in a mouse model of OIPN. BCP treatment inhibited OXA-induced mechanical and cold allodynia in both preventive and therapeutic drug treatment regimens. Experiments with the CB2 receptor agonist GW405833 confirmed the role of CB2 receptors in OIPN. The CB2 antagonist SR144528 abrogated the anti-nociceptive effect of BCP on mechanical allodynia, without impacting OXA-induced sensitivity to cold. BCP decreased neuroinflammation, as inferred from TNF, IL-1β, IL-6, and IL-10 profiling, and also reduced ROS production, lipid peroxidation, and 4-hydroxynonenal protein adduct formation in the spinal cords of OXA-treated mice. BCP did not affect the antitumor response to OXA or its impact on blood cell counts, implying that the cytotoxicity of OXA was preserved. These results underscore BCP as a candidate drug for OIPN treatment via CB2 receptor-dependent mechanisms, and anti-inflammatory and antioxidant responses in the spinal cord.

Unusual stroke-like symptoms with oxaliplatin use

INTRODUCTION

Oxaliplatin has become the mainstay of treatment for many cancers, but its use can be accompanied by unusual side effects.

CASE REPORT

We describe herein a 74-year-old patient with pancreatic cancer who developed severe motor weakness affecting lower extremities after starting treatment with oxaliplatin on three separate occasions. Our patient also experienced slurred speech, with decreased ability to phonate and word-finding difficulty. Brain imaging studies did not suggest recent brain ischemia, and the symptoms resolved within 15-20 h.

MANAGEMENT AND OUTCOME

Oxaliplatin had to be discontinued due to suboptimal tolerance and a short-lived clinical response. After discontinuation of oxaliplatin, she did not experience any more similar symptoms. A score of 9 on the Naranjo nomogram supported a definite causality relationship between oxaliplatin and the observed neurologic toxicity.

DISCUSSION

Rare reports of stroke-like events have previously been described with oxaliplatin. While the exact mechanism of these phenomena is not known, alterations in neuronal sodium channels might be involved. Clinicians, pharmacists, and patients need to be aware of these rare but important side effects of oxaliplatin. Nonetheless, work-up for a cerebrovascular accident is still warranted as hypercoagulability related to malignancy can also predispose the patients to strokes.

Prospective assessment of vincristine-induced peripheral neuropathy in paediatric acute lymphoblastic leukemia

OBJECTIVE

Vincristine is a mainstay treatment for paediatric cancers, particularly acute lymphoblastic leukemia (ALL), with common toxicity including vincristine-induced peripheral neuropathy (VIPN). The present study comprehensively assessed VIPN outcomes in patients receiving vincristine treatment for ALL.

METHODS

Children diagnosed with ALL commencing vincristine treatment were prospectively evaluated (baseline, post-induction, pre-reinduction, post-reinduction, follow-up). VIPN was examined clinically using the Balis sensory/motor scale, neurophysiologically using axonal excitability techniques and quality-of-life using Pediatric Quality of Life Inventory.

RESULTS

Thirty-one patients were recruited to this study (age = 6.8 ± 4.4; 61.3% female). Incidence of motor VIPN (motor Balis grade > 0) symptoms were higher than sensory VIPN (sensory Balis grade > 0) at post-induction (92.0% vs 36.0%) and post-reinduction (81.8% vs 22.7%) vincristine treatment. Neurophysiological assessment also demonstrated greater change in motor axonal excitability parameters compared to sensory parameters including changes in depolarising threshold electrotonus (P < 0.0125), superexcitability and subexcitability parameters (all P < 0.0125). Follow-up assessment demonstrated persisting VIPN symptoms with reduced quality-of-life scores compared to baseline.

CONCLUSIONS

Clinical and neurophysiological evaluation of VIPN suggests vincristine produces a motor-prominent sensorimotor neuropathy in children which persisted at follow-up.

SIGNIFICANCE

VIPN signs and symptoms develop early in the treatment course, in line with axonal excitability profiles. Early detection of significant nerve changes may support timely implementation of neuroprotection strategies.

TRPM3 as a novel target to alleviate acute oxaliplatin-induced peripheral neuropathic pain

ABSTRACT

Chemotherapy-induced peripheral neuropathic pain (CIPNP) is an adverse effect observed in up to 80% of patients of cancer on treatment with cytostatic drugs including paclitaxel and oxaliplatin. Chemotherapy-induced peripheral neuropathic pain can be so severe that it limits dose and choice of chemotherapy and has significant negative consequences on the quality of life of survivors. Current treatment options for CIPNP are limited and unsatisfactory. TRPM3 is a calcium-permeable ion channel functionally expressed in peripheral sensory neurons involved in the detection of thermal stimuli. Here, we focus on the possible involvement of TRPM3 in acute oxaliplatin-induced mechanical allodynia and cold hypersensitivity. In vitro calcium microfluorimetry and whole-cell patch-clamp experiments showed that TRPM3 is functionally upregulated in both heterologous and homologous expression systems after acute (24 hours) oxaliplatin treatment, whereas the direct application of oxaliplatin was without effect. In vivo behavioral studies using an acute oxaliplatin model for CIPNP showed the development of cold and mechano hypersensitivity in control mice, which was lacking in TRPM3 deficient mice. In addition, the levels of protein ERK, a marker for neuronal activity, were significantly reduced in dorsal root ganglion neurons derived from TRPM3 deficient mice compared with control after oxaliplatin administration. Moreover, intraperitoneal injection of a TRPM3 antagonist, isosakuranetin, effectively reduced the oxaliplatin-induced pain behavior in response to cold and mechanical stimulation in mice with an acute form of oxaliplatin-induced peripheral neuropathy. In summary, TRPM3 represents a potential new target for the treatment of neuropathic pain in patients undergoing chemotherapy.

Oxaliplatin-induced peripheral neurotoxicity in colorectal cancer patients: mechanisms, pharmacokinetics and strategies

Oxaliplatin-based chemotherapy is a standard treatment approach for colorectal cancer (CRC). However, oxaliplatin-induced peripheral neurotoxicity (OIPN) is a severe dose-limiting clinical problem that might lead to treatment interruption. This neuropathy may be reversible after treatment discontinuation. Its complicated mechanisms are related to DNA damage, dysfunction of voltage-gated ion channels, neuroinflammation, transporters, oxidative stress, and mitochondrial dysfunction, etc. Several strategies have been proposed to diminish OIPN without compromising the efficacy of adjuvant therapy, namely, combination with chemoprotectants (such as glutathione, Ca/Mg, ibudilast, duloxetine, etc.), chronomodulated infusion, dose reduction, reintroduction of oxaliplatin and topical administration [hepatic arterial infusion chemotherapy (HAIC), pressurized intraperitoneal aerosol chemotherapy (PIPAC), and hyperthermic intraperitoneal chemotherapy (HIPEC)]. This article provides recent updates related to the potential mechanisms, therapeutic strategies in treatment of OIPN, and pharmacokinetics of several methods of oxaliplatin administration in clinical trials.

Red Ginger Extract Prevents the Development of Oxaliplatin-Induced Neuropathic Pain by Inhibiting the Spinal Noradrenergic System in Mice

Oxaliplatin is a well-known chemotherapeutic drug that is widely used to treat colorectal cancer. However, it can induce acute side effects in up to 90% of patients. Serotonin and norepinephrine reuptake inhibitors (SNRIs) are used as first-choice drugs; however, even SNRIs are known to be effective only in treatment and not for prevention. Therefore, finding a drug that can prevent the development of cold and mechanical forms of allodynia induced by oxaliplatin is needed. This study demonstrated that multiple oral administrations of 100 mg/kg and 300 mg/kg of red ginger extract could significantly prevent pain development in mice. The role of the noradrenergic system was investigated as an underlying mechanism of action. Both the spinal α1- and α2-adrenergic receptors were significantly downregulated after treatment. Furthermore, the noradrenaline levels in the serum and spinal cord were upregulated and downregulated after treatment with paclitaxel and red ginger, respectively. As the active sub-component of red ginger, ginsenoside Rg3 (Rg3) was identified and quantified using HPLC. Moreover, multiple intraperitoneal injections of Rg3 prevented the development of pain in paclitaxel-treated mice, suggesting that RG3 may induce the effect of red ginger extract.

[Mechanisms of platinum-induced peripheral neuropathy in cancer patients]

Chemoinduced polyneuropathy (CIPNP) is a common side-effect of chemotherapy, significantly impairing quality of life in patients treated for cancer. Platinum preparations are the most commonly used chemotherapeutic agents used in the treatment of ovarian, testicular, breast, lung and colon cancers. Clinical examination reveals restrictions on the motor, sensory and autonomic functions of the upper and lower extremities, which occur at different stages of antitumor treatment, seriously complicating the treatment of the underlying disease. Pain and sensory disturbances may persist for months or even years after chemotherapy is completed. Thus, CIPNP is a major problem because it is impossible to predict which patients will develop neurological symptoms, to estimate their timing of manifestation, which can occur at any time during the course of chemotherapy, there is no early indication to reduce the dose of the cytotoxic drug, and there are no drugs that effectively prevent or alleviate the course of neuropathy. This review focuses on neurotoxicity with the use of platinum drugs, including the frequency of occurrence, risk factors, cumulative doses, various pathogenetic mechanisms for the development of CIPNP, clinical features and variants of the neurophysiological picture.

[Neuropathic pain caused by the toxic effect of chemotherapy in patients with malignant neoplasms]

This article discusses chemotherapy-induced peripheral neuropathic pain (CIPNP) and its associated neuropathic pain syndrome that occurs in patients with malignant neoplasms (MN) during cytostatic therapy. The overall prevalence of CIPNP in patients with malignant neoplasms associated with chemotherapy with neurotoxic drugs is estimated, according to various sources, to be about 70%. The pathophysiological mechanisms of CIPNP have not been fully studied, but it is known that they are based on: impaired axonal transport, oxidative stress, induction of apoptosis, DNA damage, dysfunction of voltage-gated ion channels, and central mechanisms. It is important to recognize CIPNP in the clinical symptoms of patients with cancer treated with cytostatics, since these disorders can lead to serious restrictions in the motor, sensory and autonomic functions of the upper and lower extremities, as well as reduce the quality of life and daily functioning of such patients, forcing them to adjust the dose of chemotherapy drugs, transfer the next cycles and even interrupt the treatment of cancer carried out according to vital needs. In addition to the clinical examination, scales and questionnaires have been developed to identify symptoms of CIPNP, but it is most important for neurological and oncological specialists to know and be able to recognize such symptoms in patients. The mandatory research methods for identifying the symptoms of polyneuropathy include electroneuromyography (ENMG), which allows you to assess muscle activity, functional characteristics and the state of the function of peripheral nerves. The methods used to reduce symptoms are screening patients for the development of CIPNP and identifying patients at high risk of CIPNP and, if necessary, reducing the dose or changing cytostatics. Methods for correcting this disorder using different classes of drugs require more detailed study and further research.

Neurological Complications of Conventional and Novel Anticancer Treatments

Various neurological complications, affecting both the central and peripheral nervous system, can frequently be experienced by cancer survivors after exposure to conventional chemotherapy, but also to modern immunotherapy. In this review, we provide an overview of the most well-known adverse events related to chemotherapy, with a focus on chemotherapy induced peripheral neurotoxicity, but we also address some emerging novel clinical entities related to cancer treatment, including chemotherapy-related cognitive impairment and immune-mediated adverse events. Unfortunately, efficacious curative or preventive treatment for all these neurological complications is still lacking. We provide a description of the possible mechanisms involved to drive future drug discovery in this field, both for symptomatic treatment and neuroprotection.

Emerging platinum(0) nanotherapeutics for efficient cancer therapy

Platinum (Pt)-based chemotherapy has been necessary for clinical cancer treatment. However, traditional bivalent drugs are hindered by poor physicochemical properties, severe toxic side effects, and drug resistance. Currently, elemental Pt(0) nanotherapeutics (NTs) have emerged to tackle the dilemma. The inherent acid-responsiveness of Pt(0) NTs could help to improve tumor selectivity and alleviate toxic effects. Moreover, the metal nature of Pt facilitates the great combination of Pt(0) NTs with photothermal and photodynamic therapy and imaging-guided diagnosis. Based on recent important researches, this review provides an updated introduction to Pt(0) NTs. First, the challenges of traditional Pt-based chemotherapy have been outlined. Then, Pt(0) NTs with multiple applications of tumor theranostics have been overviewed. Furthermore, the combinations of Pt(0) NTs with other therapeutical modalities are introduced. Last but not least, we envision the possible challenges and prospects associated with Pt(0) NTs.

Recent Advances in Light-Controlled Activation of Pt(IV) Prodrugs

Pt(IV) prodrugs remain one of the most promising alternatives to conventional Pt(II) therapy due to their versatility in axial ligand choice and delayed mode of action. Selective activation from an external source is especially attractive due to the opportunity to control the activity of an antitumor drug in space and time and avoid damage to normal tissues. In this review, we discuss recent advances in photoabsorber-mediated photocontrollable activation of Pt(IV) prodrugs. Two main approaches developed are the focus of the review. The first one is the photocatalytic strategy based on the flavin derivatives that are not covalently bound to the Pt(IV) substrate. The second one is the conjugation of photoactive molecules with the Pt(II) drug via axial position, yielding dual-action Pt(IV) molecules capable of the controllable release of Pt(II) cytotoxic agents. Thus, Pt(IV) prodrugs with a light-controlled mode of activation are non-toxic in the absence of light, but show high antiproliferative activity when irradiated. The susceptibility of Pt(IV) prodrugs to photoreduction, photoactivation mechanisms, and biological activity is considered in this review.

RgIA4 Prevention of Acute Oxaliplatin-Induced Cold Allodynia Requires α9-Containing Nicotinic Acetylcholine Receptors and CD3+ T-Cells

Chemotherapy-induced neuropathic pain is a debilitating and dose-limiting side effect. Oxaliplatin is a third-generation platinum and antineoplastic compound that is commonly used to treat colorectal cancer and commonly yields neuropathic side effects. Available drugs such as duloxetine provide only modest benefits against oxaliplatin-induced neuropathy. A particularly disruptive symptom of oxaliplatin is painful cold sensitivity, known as cold allodynia. Previous studies of the Conus regius peptide, RgIA, and its analogs have demonstrated relief from oxaliplatin-induced cold allodynia, yielding improvement that persists even after treatment cessation. Moreover, underlying inflammatory and neuronal protection were shown at the cellular level in chronic constriction nerve injury models, consistent with disease-modifying effects. Despite these promising preclinical outcomes, the underlying molecular mechanism of action of RgIA4 remains an area of active investigation. This study aimed to determine the necessity of the α9 nAChR subunit and potential T-cell mechanisms in RgIA4 efficacy against acute oxaliplatin-induced cold allodynia. A single dose of oxaliplatin (10 mg/kg) was utilized followed by four daily doses of RgIA4. Subcutaneous administration of RgIA4 (40 µg/kg) prevented cold allodynia in wildtype mice but not in mice lacking the α9 nAChR-encoding gene, chrna9. RgIA4 also failed to reverse allodynia in mice depleted of CD3⁺ T-cells. In wildtype mice treated with oxaliplatin, quantitated circulating T-cells remained unaffected by RgIA4. Together, these results show that RgIA4 requires both chrna9 and CD3⁺ T-cells to exert its protective effects against acute cold-allodynia produced by oxaliplatin.

A transient inflammatory response contributes to oxaliplatin neurotoxicity in mice

OBJECTIVES

Peripheral neuropathy is a relevant dose-limiting adverse event that can affect up to 90% of oncologic patients with colorectal cancer receiving oxaliplatin treatment. The severity of neurotoxicity often leads to dose reduction or even premature cessation of chemotherapy. Unfortunately, the limited knowledge about the molecular mechanisms related to oxaliplatin neurotoxicity leads to a lack of effective treatments to prevent the development of this clinical condition. In this context, the present work aimed to determine the exact molecular mechanisms involved in the development of oxaliplatin neurotoxicity in a murine model to try to find new therapeutical targets.

METHODS

By single-cell RNA sequencing (scRNA-seq), we studied the transcriptomic profile of sensory neurons and satellite glial cells (SGC) of the Dorsal Root Ganglia (DRG) from a well-characterized mouse model of oxaliplatin neurotoxicity.

RESULTS

Analysis of scRNA-seq data pointed to modulation of inflammatory processes in response to oxaliplatin treatment. In this line, we observed increased levels of NF-kB p65 protein, pro-inflammatory cytokines, and immune cell infiltration in DRGs and peripheral nerves of oxaliplatin-treated mice, which was accompanied by mechanical allodynia and decrease in sensory nerve amplitudes.

INTERPRETATION

Our data show that, in addition to the well-described DNA damage, oxaliplatin neurotoxicity is related to an exacerbated pro-inflammatory response in DRG and peripheral nerves, and open new insights in the development of anti-inflammatory strategies as a treatment for preventing peripheral neuropathy induced by oxaliplatin.

Recent updates in the treatment of diabetic polyneuropathy

Distal symmetric diabetic peripheral polyneuropathy (DPN) is the most common form of neuropathy in the world, affecting 30 to 50% of diabetic individuals and resulting in significant morbidity and socioeconomic costs. This review summarizes updates in the diagnosis and management of DPN. Recently updated clinical criteria facilitate bedside diagnosis, and a number of new technologies are being explored for diagnostic confirmation in specific settings and for use as surrogate measures in clinical trials. Evolving literature indicates that distinct but overlapping mechanisms underlie neuropathy in type 1 versus type 2 diabetes, and there is a growing focus on the role of metabolic factors in the development and progression of DPN. Exercise-based lifestyle interventions have shown therapeutic promise. A variety of potential disease-modifying and symptomatic therapies are in development. Innovations in clinical trial design include the incorporation of detailed pain phenotyping and biomarkers for central sensitization.

Repurposing FDA-approved drugs against the toxicity of platinum-based anticancer drugs

Platinum-based anticancer drugs (PADs), mainly cisplatin, carboplatin, and oxaliplatin, are widely used efficacious long-standing anticancer agents for treating several cancer types. However, clinicians worry about PAD chemotherapy and its induction of severe non-targeted organ toxicity. Compelling evidence has shown that toxicity of PAD on delicate body organs is associated with free radical generation, DNA impairment, endocrine and mitochondrial dysfunctions, oxidative inflammation, apoptosis, endoplasmic reticulum stress, and activation of regulator signaling proteins, cell cycle arrest, apoptosis, and pathways. The emerging trend is the repurposing of FDA-approved non-anticancer drugs (FNDs) for combating the side effects toxicity of PADs. Thus, this review chronicled the mechanistic preventive and therapeutic effects of FNDs against PAD organ toxicity in preclinical studies. FNDs are potential clinical drugs for the modulation of toxicity complications associated with PAD chemotherapy. Therefore, FNDs may be suggested as non-natural agent inhibitors of unpalatable side effects of PADs.

Sodium-Calcium Exchanger 2: A Pivotal Role in Oxaliplatin Induced Peripheral Neurotoxicity and Axonal Damage?

Oxaliplatin (OHP)-induced peripheral neurotoxicity (OIPN) is a frequent adverse event of colorectal cancer treatment. OIPN encompasses a chronic and an acute syndrome. The latter consists of transient axonal hyperexcitability, due to unbalance in Na+ voltage-operated channels (Na+VOC). This leads to sustained depolarisation which can activate the reverse mode of the Na+/Ca2+ exchanger 2 (NCX2), resulting in toxic Ca2+ accumulation and axonal damage (ADa). We explored the role of NCX2 in in vitro and in vivo settings. Embryonic rat Dorsal Root Ganglia (DRG) organotypic cultures treated with SEA0400 (SEA), a NCX inhibitor, were used to assess neuroprotection in a proof-of-concept and pilot study to exploit NCX modulation to prevent ADa. In vivo, OHP treated mice (7 mg/Kg, i.v., once a week for 8 weeks) were compared with a vehicle-treated group (n = 12 each). Neurophysiological and behavioural testing were performed to characterise acute and chronic OIPN, and morphological analyses were performed to detect ADa. Immunohistochemistry, immunofluorescence, and western blotting (WB) analyses were also performed to demonstrate changes in NCX2 immunoreactivity and protein expression. In vitro, NCX inhibition was matched by ADa mitigation. In the in vivo part, after verifyingboth acute and chronic OIPN had ensued, we confirmed via immunohistochemistry, immunofluorescence, and WB that a significant NCX2 alteration had ensued in the OHP group. Our data suggest NCX2 involvement in ADa development, paving the way to a new line of research to prevent OIPN.

Potential Drug Interactions Between Psychotropics and Intravenous Chemotherapeutics Used by Patients With Cancer

Introduction: Patients undergoing cancer treatment usually have comorbidities, and psychiatric disorders are commonly seen in these patients. For the treatment of these psychiatric disorders, the use of psychotropic drugs is common, turning these patients susceptible to untoward drug interactions. Therefore, the aim of this study was to estimate the prevalence of clinically relevant drug-drug interactions (DDI) between chemotherapeutic and psychotropic agents in patients with cancer treated at an oncology service in southern Brazil. Methods: An observational epidemiological study with a cross-sectional census-type design was carried out between October and December 2020. The drug-drug interactions were identified through consultation and analysis of the Medscape Drug Interaction Check and Micromedex databases. The interactions were classified as major, when the interaction can be fatal and/or require medical intervention to avoid or minimize serious adverse effects and moderate, when the interaction can exacerbate the patient's condition and/or requires changes in therapy. Results: A total of 74 patients was included in the study among the 194 patients seen in the oncology service during the period studied. A total of 24 (32.4%) DDIs were found, 21 (87.5%) of which were classified as being of major risk and 3 (12.5%) as moderate risk. According to the mechanism of action, 19 (79.1%) were classified as pharmacodynamic interactions and 5 (20.9%) as pharmacokinetic interactions. Conclusion: It was shown that a considerable percentage of patients undergoing intravenous chemotherapy are at risk of pharmacological interaction with psychotropic drugs. Thus, it is essential that the oncologist considers all psychotropic drugs and other drugs used by patients in order to avoid drug-drug interactions.

Effects of Oxaliplatin on Facial Sensitivity to Cool Temperatures and TRPM8 Expressing Trigeminal Ganglion Neurons in Mice

The chemotherapeutic agent oxaliplatin is commonly used to treat colorectal cancer. Although effective as a chemotherapeutic, it frequently produces painful peripheral neuropathies. These neuropathies can be divided into an acute sensitivity to cool temperatures in the mouth and face, and chronic neuropathic pain in the limbs and possible numbness. The chronic neuropathy also includes sensitivity to cool temperatures. Neurons that detect cool temperatures are reported to utilize Transient Receptor Potential Cation Channel, Subfamily M, Member 8 (TRPM8). Therefore, we investigated the effects of oxaliplatin on facial nociception to cool temperatures (18°C) in mice and on TRPM8 expressing trigeminal ganglion (TRG) neurons. Paclitaxel, a chemotherapeutic that is used to treat breast cancer, was included for comparison because it produces neuropathies, but acute cool temperature sensitivity in the oral cavity or face is not typically reported. Behavioral testing of facial sensitivity to 18°C indicated no hypersensitivity either acutely or chronically following either chemotherapeutic agent. However, whole cell voltage clamp experiments in TRPM8 expressing TRG neurons indicated that both oxaliplatin and paclitaxel increased Hyperpolarization-Activated Cyclic Nucleotide-Gated channel (HCN), voltage gated sodium channel (Nav), and menthol evoked TRPM8 currents. Voltage gated potassium channel (Kv) currents were not altered. Histological examination of TRPM8 fibers in the skin of the whisker pads demonstrated that the TRPM8 expressing axons and possible Merkel cell-neurite complexes were damaged by oxaliplatin. These findings indicate that oxaliplatin induces a rapid degeneration of TRG neuron axons that express TRPM8, which prevents evoked activation of the sensitized neurons and likely leads to reduced sensitivity to touch and cool temperatures. The changes in HCN, Nav, and TRPM8 currents suggest that spontaneous firing of action potentials may be increased in the deafferented neurons within the ganglion, possibly producing spontaneously induced cooling or nociceptive sensations.

Imbalanced Subthreshold Currents Following Sepsis and Chemotherapy: A Shared Mechanism Offering a New Therapeutic Target?

Both sepsis and treatment of cancer with chemotherapy are known to cause neurologic dysfunction. The primary defects seen in both groups of patients are neuropathy and encephalopathy; the underlying mechanisms are poorly understood. Analysis of preclinical models of these disparate conditions reveal similar defects in ion channel function contributing to peripheral neuropathy. The defects in ion channel function extend to the central nervous system where lower motoneurons are affected. In motoneurons the defect involves ion channels responsible for subthreshold currents that convert steady depolarization into repetitive firing. The inability to correctly translate depolarization into steady, repetitive firing has profound effects on motor function, and could be an important contributor to weakness and fatigue experienced by both groups of patients. The possibility that disruption of function, either instead of, or in addition to neurodegeneration, may underlie weakness and fatigue leads to a novel approach to therapy. Activation of serotonin (5HT) receptors in a rat model of sepsis restores the normal balance of subthreshold currents and normal motoneuron firing. If an imbalance of subthreshold currents also occurs in other central nervous system neurons, it could contribute to encephalopathy. We hypothesize that pharmacologically restoring the proper balance of subthreshold currents might provide effective therapy for both neuropathy and encephalopathy in patients recovering from sepsis or treatment with chemotherapy.

Metallodrugs in cancer nanomedicine

Metal complexes are extensively used for cancer therapy. The multiple variables available for tuning (metal, ligand, and metal-ligand interaction) offer unique opportunities for drug design, and have led to a vast portfolio of metallodrugs that can display a higher diversity of functions and mechanisms of action with respect to pure organic structures. Clinically approved metallodrugs, such as cisplatin, carboplatin and oxaliplatin, are used to treat many types of cancer and play prominent roles in combination regimens, including with immunotherapy. However, metallodrugs generally suffer from poor pharmacokinetics, low levels of target site accumulation, metal-mediated off-target reactivity and development of drug resistance, which can all limit their efficacy and clinical translation. Nanomedicine has arisen as a powerful tool to help overcome these shortcomings. Several nanoformulations have already significantly improved the efficacy and reduced the toxicity of (chemo-)therapeutic drugs, including some promising metallodrug-containing nanomedicines currently in clinical trials. In this critical review, we analyse the opportunities and clinical challenges of metallodrugs, and we assess the advantages and limitations of metallodrug delivery, both from a nanocarrier and from a metal-nano interaction perspective. We describe the latest and most relevant nanomedicine formulations developed for metal complexes, and we discuss how the rational combination of coordination chemistry with nanomedicine technology can assist in promoting the clinical translation of metallodrugs.

Axonal excitability does not differ between painful and painless diabetic or chemotherapy-induced distal symmetrical polyneuropathy in a multi-centre observational study

Objective

Axonal excitability reflects ion channel function, and it is proposed that this may be a biomarker in painful (vs painless) polyneuropathy. Our objective was to investigate the relationship between axonal excitability parameters and chronic neuropathic pain in deeply phenotyped cohorts with diabetic or chemotherapy‐induced distal symmetrical polyneuropathy.

Methods

Two hundred thirty‐nine participants with diabetic polyneuropathy were recruited from sites in the UK and Denmark, and 39 participants who developed chemotherapy‐induced polyneuropathy were recruited from Denmark. Participants were separated into those with probable or definite neuropathic pain and those without neuropathic pain. Axonal excitability of large myelinated fibers was measured with the threshold tracking technique. The stimulus site was the median nerve, and the recording sites were the index finger (sensory studies) and abductor pollicis brevis muscle (motor studies).

Results

Participants with painless and painful polyneuropathy were well matched across clinical variables. Sensory and motor axonal excitability measures, including recovery cycle, threshold electrotonus, strength–duration time constant, and current–threshold relationship, did not show differences between participants with painful and painless diabetic polyneuropathy, and there were only minor changes for chemotherapy‐induced polyneuropathy.

Interpretation

Axonal excitability did not significantly differ between painful and painless diabetic or chemotherapy‐induced polyneuropathy in a multicenter observational study. Threshold tracking assesses the excitability of myelinated axons; the majority of nociceptors are unmyelinated, and although there is some overlap of the "channelome" between these axonal populations, our results suggest that alternative measures such as microneurography are required to understand the relationship between sensory neuron excitability and neuropathic pain. ANN NEUROL 2022;91:506–520

Recent updates in the treatment of diabetic polyneuropathy

Distal symmetric diabetic peripheral polyneuropathy (DPN) is the most common form of neuropathy in the world, affecting 30 to 50% of diabetic individuals and resulting in significant morbidity and socioeconomic costs. This review summarizes updates in the diagnosis and management of DPN. Recently updated clinical criteria facilitate bedside diagnosis, and a number of new technologies are being explored for diagnostic confirmation in specific settings and for use as surrogate measures in clinical trials. Evolving literature indicates that distinct but overlapping mechanisms underlie neuropathy in type 1 versus type 2 diabetes, and there is a growing focus on the role of metabolic factors in the development and progression of DPN. Exercise-based lifestyle interventions have shown therapeutic promise. A variety of potential disease-modifying and symptomatic therapies are in development. Innovations in clinical trial design include the incorporation of detailed pain phenotyping and biomarkers for central sensitization.

The additional diagnostic value of motor nerve excitability testing in chronic axonal neuropathy

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Nerve excitability testing was correlated with conventional nerve conduction studies.

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Nerve excitability testing was similar in patients with and without neuropathy and normal nerve conduction.

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There is no support for the potential additional diagnostic value of nerve excitability testing in mixed etiology neuropathy.

Objective

To explore potential differences in motor nerve excitability testing (NET) variables at group levels between patients with a clinical diagnosis of polyneuropathy (PNP), which did not fulfil diagnostic criteria of conventional nerve conduction studies (NCS) and patients without polyneuropathy. Such differences could support a role for NET in increasing the diagnostic sensitivity of NCS in chronic axonal PNP.

Methods

Motor NET was performed using the median nerve in patients with a clinical suspicion of PNP in addition to conventional NCS, skin biopsies, corneal confocal microscopy and structured clinical evaluation including scoring of neuropathy symptoms and signs.

Results

Of the 57 patients included, 32 had PNP, half of which had NCS, which fulfilled criteria for PNP (NCS+ PNP). There were no significant differences for any of the NET variables between PNP patients with non-diagnostic conventional NCS (NCS− PNP) and patients without PNP. Rheobase was increased, and Ted (undershoot) and subexcitability were decreased in NCS+ PNP. Sural amplitude, peroneal nerve F-wave latency and tibial nerve F-wave-latency were correlated with subexcitability, and tibial nerve motor amplitude was correlated with rheobase.

Conclusions

NET was correlated with conventional NCS and no differences were found between NCS− PNP patients and patients without PNP.

Significance

NET does not seem to offer any additional diagnostic value in chronic mixed etiology neuropathy.

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.

Mechanisms, Characteristics, and Treatment of Neuropathic Pain and Peripheral Neuropathy Associated with Dinutuximab in Neuroblastoma Patients

Prognosis of metastatic neuroblastoma is very poor. Its treatment includes induction chemotherapy, surgery, high-dose chemotherapy, radiotherapy, and maintenance with retinoic acid, associated with the anti-GD2 monoclonal antibody (ch14.18) dinutuximab. Immunotherapy determined a significant improvement in survival rate and is also utilized in relapsed and resistant neuroblastoma patients. Five courses of dinutuximab 100 mg/m2 are usually administered as a 10-day continuous infusion or over 5 consecutive days every 5 weeks. Dinutuximab targets the disialoganglioside GD2, which is highly expressed on neuroblastoma cells and minimally present on the surface of normal human neurons, peripheral pain fibers, and skin melanocytes. Anti GD2 antibodies bind to surface GD2 and determine the lysis of neuroblastoma cells induced by immune response via the antibody-dependent cellular cytotoxicity and the complement-dependent cytotoxicity. Dinutuximab has significant side effects, including neuropathic pain, peripheral neuropathy, hypersensitivity reactions, capillary leak syndrome, photophobia, and hypotension. The most important side effect is neuropathic pain, which is triggered by the same antibody-antigen immune response, but generates ectopic activity in axons, which results in hyperalgesia and spontaneous pain. Pain can be severe especially in the first courses of dinutuximab infusion, and requires the administration of gabapentin and continuous morphine infusion. This paper will focus on the incidence, mechanisms, characteristics, and treatment of neuropathic pain and peripheral neuropathy due to dinutuximab administration in neuroblastoma patients.

Chemotherapy-Induced Neuropathy and Diabetes: A Scoping Review

Although cancer and diabetes are common diseases, the relationship between diabetes, neuropathy and the risk of developing peripheral sensory neuropathy while or after receiving chemotherapy is uncertain. In this review, we highlight the effects of chemotherapy on the onset or progression of neuropathy in diabetic patients. We searched the literature in Medline and Scopus, covering all entries until 31 January 2021. The inclusion and exclusion criteria were: (1) original article (2) full text published in English or Spanish; (3) neuropathy was specifically assessed (4) the authors separately analyzed the outcomes in diabetic patients. A total of 259 papers were retrieved. Finally, eight articles fulfilled the criteria, and four more articles were retrieved from the references of the selected articles. The analysis of the studies covered the information about neuropathy recorded in 768 cancer patients with diabetes and 5247 control cases (non-diabetic patients). The drugs investigated are chemotherapy drugs with high potential to induce neuropathy, such as platinum derivatives and taxanes, which are currently the mainstay of treatment of various cancers. The predisposing effect of co-morbid diabetes on chemotherapy-induced peripheral neuropathy depends on the type of symptoms and drug used, but manifest at any drug regimen dosage, although greater neuropathic signs are also observed at higher dosages in diabetic patients. The deleterious effects of chemotherapy on diabetic patients seem to last longer, since peripheral neuropathy persisted in a higher proportion of diabetic patients than non-diabetic patients for up to two years after treatment. Future studies investigating the risk of developing peripheral neuropathy in cancer patients with comorbid diabetes need to consider the duration of diabetes, cancer-induced neuropathic effects per se (prior chemotherapy administration), and the effects of previous cancer management strategies such as radiotherapy and surgery.

Oxaliplatin Neuropathy: Predictive Values of Skin Biopsy, QST and Berve Conduction

BACKGROUND

Oxaliplatin-induced peripheral neuropathy negatively affects the quality of life for patients with gastrointestinal cancers and may cause neuropathic pain. Measures of peripheral nerve structure or function, such as intraepidermal nerve fiber density (IENFD) during treatment could reduce neuropathy severity through individualized dose reduction.

OBJECTIVE

The aim was to evaluate the predictive values of IENFD, quantitative sensory testing (QST), and nerve conduction studies (NCS) for significant neuropathy and neuropathic pain.

METHODS

Fifty-five patients were examined prospectively before, during, and six months following treatment using skin biopsies, QST and NCS. Clinically significant neuropathy six months after treatment was defined as reduced Total Neuropathy Score of more than five and neuropathic pain was assessed according to International Association for the Study of Pain criteria.

RESULTS

Thirty patients had a clinically significant neuropathy, and 14 had neuropathic pain. Vibration detection threshold (VDT) before treatment was correlated with clinically significant neuropathy six months after treatment (OR 0.54, p = 0.01) and reductions in cold detection threshold (CDT) after 25% of treatment (OR 1.38, p = 0.04) and heat pain threshold (HPT) after 50% of treatment (OR 1.91, p = 0.03) with neuropathic pain. Cut off values of 5 for baseline VDT and changes of more than -0.05 °C and -0.85 °C in CDT and HPT were estimated. Sensitivity and specificity was low to moderate. There was no correlation between changes in IENFD or NCS and significant neuropathy or neuropathic pain.

CONCLUSIONS

Vibration detection thresholds and thermal detection thresholds may be useful for prediction of clinically significant and painful neuropathy, respectively. However, low to moderate sensitivity and specificity may limit the predictive value in clinical practice.

Drug-Induced Peripheral Neuropathy: Diagnosis and Management

Peripheral neuropathy comes in all shapes and forms and is a disorder which is found in the peripheral nervous system. It can have an acute or chronic onset depending on the multitude of pathophysiologic mechanisms involving different parts of nerve fibers. A systematic approach is highly beneficial when it comes to cost-effective diagnosis. More than 30 causes of peripheral neuropathy exist ranging from systemic and auto-immune diseases, vitamin deficiencies, viral infections, diabetes, etc. One of the major causes of peripheral neuropathy is drug induced disease, which can be split into peripheral neuropathy caused by chemotherapy or by other medications. This review deals with the latest causes of drug induced peripheral neuropathy, the population involved, the findings on physical examination and various workups needed and how to manage each case.

Predictive Biomarkers of Oxaliplatin-Induced Peripheral Neurotoxicity

Oxaliplatin (OXA) is a platinum compound primarily used in the treatment of gastrointestinal cancer. OXA-induced peripheral neurotoxicity (OXAIPN) is the major non-hematological dose-limiting toxicity of OXA-based chemotherapy and includes acute transient neurotoxic effects that appear soon after OXA infusion, and chronic non-length dependent sensory neuronopathy symmetrically affecting both upper and lower limbs in a stocking-and-glove distribution. No effective strategy has been established to reverse or treat OXAIPN. Thus, it is necessary to early predict the occurrence of OXAIPN during treatment and possibly modify the OXA-based regimen in patients at high risk as an early diagnosis and intervention may slow down neuropathy progression. However, identifying which patients are more likely to develop OXAIPN is clinically challenging. Several objective and measurable early biomarkers for OXAIPN prediction have been described in recent years, becoming useful for informing clinical decisions about treatment. The purpose of this review is to critically review data on currently available or promising predictors of OXAIPN. Neurological monitoring, according to predictive factors for increased risk of OXAIPN, would allow clinicians to personalize treatment, by monitoring at-risk patients more closely and guide clinicians towards better counseling of patients about neurotoxicity effects of OXA.

Lipid, polymeric, inorganic-based drug delivery applications for platinum-based anticancer drugs

The three main FDA-approved platinum drugs in chemotherapy such as carboplatin, cisplatin, and oxaliplatin are extensively applied in cancer treatments. Although the clinical applications of platinum-based drugs are extremely effective, their toxicity profile restricts their extensive application. Therefore, recent studies focus on developing new platinum drug formulations, expanding the therapeutic aspect. In this sense, recent advances in the development of novel drug delivery carriers will help with the increase of drug stability and biodisponibility, concomitantly with the reduction of drug efflux and undesirable secondary toxic effects of platinum compounds. The present review describes the state of the art of platinum drugs with their biological effects, pre- and clinical studies, and novel drug delivery nanodevices based on lipids, polymers, and inorganic.

Oxaliplatin-Induced Neuropathy: Genetic and Epigenetic Profile to Better Understand How to Ameliorate This Side Effect

In the most recent decades, oxaliplatin has been used as a chemotherapeutic agent for colorectal cancer and other malignancies as well. Oxaliplatin interferes with tumor growth predominantly exerting its action in DNA synthesis inhibition by the formation of DNA-platinum adducts that, in turn, leads to cancer cell death. On the other hand, unfortunately, this interaction leads to a plethora of systemic side effects, including those affecting the peripheral and central nervous system. Oxaliplatin therapy has been associated with acute and chronic neuropathic pain that induces physicians to reduce the dose of medication or discontinue treatment. Recently, the capability of oxaliplatin to alter the genetic and epigenetic profiles of the nervous cells has been documented, and the understanding of gene expression and transcriptional changes may help to find new putative treatments for neuropathy. The present article is aimed to review the effects of oxaliplatin on genetic and epigenetic mechanisms to better understand how to ameliorate neuropathic pain in order to enhance the anti-cancer potential and improve patients’ quality of life.

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.

Capsaicin 8% patch Qutenza and other current treatments for neuropathic pain in chemotherapy-induced peripheral neuropathy (CIPN)

PURPOSE OF REVIEW

Current oral treatments for neuropathic pain associated with chemotherapy-induced peripheral neuropathy (CIPN) have limited clinical efficacy, and undesirable side-effects. Topically delivered treatments have the advantage of avoiding CNS side-effects, while relieving pain. We have reviewed treatments of neuropathic pain associated with CIPN, focusing on the Capsaicin 8% patch, which can provide pain relief for up to 3 months or longer after a single 30-60-min application.

RECENT FINDINGS

Capsaicin 8% patch is a licensed treatment in the EU/UK for neuropathic pain and shown to be safe and effective in providing pain relief for patients with CIPN. Repeated daily oral or topical administrations are not required, as with other current treatments. The side-effects are transient and restricted to the time around patch application. New evidence suggests the Capsaicin 8% patch can promote the regeneration and restoration of skin nerve fibres in CIPN, in addition to the pain relief.

SUMMARY

The Capsaicin 8% patch is now often a preferred a treatment option for localised neuropathic pain conditions, including the feet and hands in patients with CIPN. Capsaicin 8% patch can be repeated three-monthly, if needed, for a year. In addition to pain relief, it may have a disease-modifying effect.

Transient Vision Loss - A Rare Oxaliplatin-Induced Ophthalmologic Side Effect: A Report of Two Cases

Oxaliplatin, a platinum-based chemotherapeutic agent, is responsible for induced peripheral sensory neuropathy. Only a few cases of ophthalmologic toxicity have been reported. We report here two cases of sudden transient vision loss after oxaliplatin administration, in one case intraperitoneally. These symptoms likely reflect optic neuritis that could be included in the spectrum of oxaliplatin-induced neuropathy.

Clinical and biochemical markers in CIPN: A reappraisal

The increased survival of cancer patients has raised growing public health concern on associated long-term consequences of antineoplastic treatment. Chemotherapy-induced peripheral neuropathy (CIPN) is a primarily sensory polyneuropathy, which may be accompanied by pain, autonomic disturbances, and motor deficit. About 70% of treated cancer patients might develop CIPN during or after the completion of chemotherapy, and in most of them such complication persists after six months from the treatment. The definition of the potential risk of development and resolution of CIPN according to a clinical and biochemical profile would be certainly fundamental to tailor chemotherapy regimen and dosage on individual susceptibility. In recent years, patient-reported and clinician-related tools along with quality of life instruments have been featured as primary outcomes in clinical setting and randomized trials. New studies on metabolomics markers are further pursuing accurate and easily accessible indicators of peripheral nerve damage. The aim of this review is to outline the strengths and pitfalls of current knowledge on CIPN, and to provide a framework for future potential developments of standardized protocols involving clinical and biochemical markers for CIPN assessment and monitoring.

Hemoglobin, Body Mass Index, and Age as Risk Factors for Paclitaxel- and Oxaliplatin-Induced Peripheral Neuropathy

IMPORTANCE

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating adverse effect of neurotoxic cancer treatments including taxanes and platinum agents. Limited knowledge exists of potential prechemotherapy factors associated with CIPN development.

OBJECTIVE

To identify the association of pretreatment blood-based and clinical factors with CIPN persistence in patients who received paclitaxel or oxaliplatin.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study assessed pretreatment blood-based clinical factors and demographic characteristics of 333 patients treated with paclitaxel and oxaliplatin chemotherapy at urban multicenter cancer clinics and academic institutions in Australia between September 2015 and February 2020. Comprehensive neuropathy assessments were undertaken 3 to 12 months posttreatment. Posttreatment CIPN severity was compared with blood-based factors within 30 days prior to commencing chemotherapy. Data were analyzed between March and December 2020.

EXPOSURES

Paclitaxel or oxaliplatin chemotherapy.

MAIN OUTCOMES AND MEASURES

CIPN was measured using composite neurological grading scales, nerve conduction studies, and assessments of fine motor skills (grooved pegboard test), sensory function (grating orientation test and 2-point discrimination), and patient-reported outcomes. Independent samples t tests and Mann-Whitney U tests with post hoc Bonferroni correction were used to compare CIPN between patients according to blood-based factor normative ranges. Linear regression was used to identify blood-based and clinical associations with CIPN development.

RESULTS

The study included 333 participants (266 [79.9%] women; median [interquartile range] age, 58 [18] years) who were consecutively recruited and referred (228 treated with paclitaxel, 105 treated with oxaliplatin; 138 [41.4%] with breast cancer, 83 [24.9%] with colorectal cancer). Most participants had grade 1 CIPN or higher (238 [71.5%] participants). Participants with low hemoglobin pretreatment had worse CIPN posttreatment (median [IQR] composite neurological grading scale score, 5 [2-8] vs 4 [1-6]; P = .002; grooved pegboard mean [SD] time, 84.2 [28.7] vs 72.9 [21.1] seconds; P = .002; grating orientation task, 4.8 [2.8] vs 3.9 [1.8] mm; P = .03; 2-point discrimination, 45% vs 28%; P = .01), with no other impairments outside normative ranges associated with CIPN. In the multivariable model, several factors were associated with worse CIPN (F4,315 = 18.6; P < .001; r2 = .19) including for lower hemoglobin (β = -0.47; 95% CI, -0.73 to -0.21; P < .001), higher body mass index (β = 0.08; 95% CI, 0.02 to 0.12; P = .007), older age (β = 0.08; 95% CI, 0.06 to 0.11; P < .001), and female sex (β = -1.08; 95% CI, -1.76 to -0.16; P = .01).

CONCLUSIONS AND RELEVANCE

The results of this cohort study suggest that participants with low pretreatment hemoglobin, higher body mass index, older age, and female sex were more likely to develop paclitaxel- or oxaliplatin-induced CIPN posttreatment. Future research should investigate prospectively whether these risk factors are associated with a higher incidence of CIPN development.