Neuronal involvement in cisplatin neuropathy: prospective clinical and neurophysiological studies

ANTI-NOCICEPTIVE EFFECT OF AGRIMONIA EUPATORIA EXTRACT ON A CISPLATIN-INDUCED NEUROPATHIC MODEL

BACKGROUND

Natural products including Agrimonia eupatoria are considered an incomparable source of molecular diversity that has led to the medicines, especially for pain treatment. To investigate the antinociception of Agrimonia eupatoria, we examined its activity in a rat model of cisplatin neuropathy.

MATERIALS AND METHODS

Male Sprague-Dawley rats received intraperitoneal (i.p.) cisplatin twice a week at a dose of 2 mg/kg (cumulative dose, 20 mg/kg) for 4 weeks. Before each injection, 2 ml of sterile saline solution was given subcutaneously to prevent renal damage via hyperhydration. The mice were treated with gabapetin as a positive control drug with a 100mg/kg intraperitoneal injection. A. eupatoria extract of 200mg/kg was solved in saline and then treated by oral administration.

RESULTS

The mice treated with A. eupatoria showed lower withdrawal duration in the pin-prick and plantar tests, and a higher withdrawal threshold in the paw-withdrawal threshold test as compared to control animals in a cisplatin-induced neuropathic model. In the case of cold-allodynia, A. eupatoria treatment increased paw-withdrawal duration in a chemical test. A. eupatoria showed a more outstanding effect than gabapentin in all used tests for preventing cisplatin-induced nerve injury for 4 weeks.

CONCLUSIONS

Our results suggest that A. eupatoria extract showed an antinociceptive effect in the pin-prick test, plantar test, and paw-withdrawal threshold test using a cisplatin-induced neuropathic rat model.

Unemployment risk and income change after testicular cancer diagnosis: A population-based study

BACKGROUND

Among patients with cancer, returning to full working may serve as an indicator for return to normal lifestyle following illness, as opposed to unemployment or shifting to part-time work. The aim of the project was to clarify the association between unemployment risk and decreased income at 4 years after the diagnosis of testicular cancer (TC).

PARTICIPANTS AND METHODS

A case control in a cohort study includes baseline measurement of people participating in the Israeli Central Bureau of Statistics 1995 National Census, and follow-up until 2011. Cancer incidence, employment status, and income level were ascertained through the Israel Cancer Registry and Tax Authority, respectively. A matched group was sampled from the population in the census. Binary logistic regression analyses were used to assess odds ratios (ORs) for study׳s outcomes, while controlling for age, ethnicity, education, and socioeconomic and employment status at 2 years before diagnosis.

RESULTS

A total of 113 cases of TC and 468 persons in the matched group were included in the study after excluding persons who died during the study period. No association was found between TC and subsequent risk after the 4 years of unemployment (OR = 1.12, 95% CI: 0.65-1.95) or decreased income (OR = 1.41, 95% CI: 0.84-2.36). Predictors of subsequent unemployment were unemployment 2 years before diagnosis (OR = 6.91, 95% CI: 4.39-10.86) and increasing age (OR = 1.03 per year, 95% CI: 1.01-1.06).

CONCLUSION

TC survivorship is not associated with subsequent unemployment or decreased income at 4 years after diagnosis.

Curcumin Ameliorates Functional and Structural Abnormalities in Cisplatin-induced Neuropathy

Peripheral neuropathy is one of the major side effects of cisplatin; however, effective treatments are lacking. Curcumin is a polyphenol found in the root of Curcuma longa and has been shown neuroprotective against several neurological diseases. Nevertheless, its effects on cisplatin neuropathy remain unclear. This study aimed to clarify this issue by inducing neuropathy in the rats with intraperitoneal injection of cisplatin 2 mg/kg twice a week for 5 consecutive weeks. Curcumin 200 mg/kg/day was given by gavage to a group of cisplatin-treated rats during these five weeks. The results showed that cisplatin induced thermal hypoalgesia in the 5^th week which could be prevented by curcumin. In the 5^th and 8^th weeks, sciatic motor nerve conduction velocity was reduced in the cisplatin compared with the control groups. Curcumin significantly attenuated this deficit. Morphometric analysis of L4 dorsal root ganglia from the cisplatin group revealed nuclear and nucleolar atrophy including loss of neurons in the 8^th week. These alterations were significantly blocked by curcumin. Moreover, curcumin also ameliorated the reduced myelin thickness in the sciatic nerve of cisplatin-treated rats. Taken together, our findings suggest the favorable effects of curcumin on both functional and structural abnormalities in cisplatin neuropathy. Future studies are needed to clarify the exact underlying mechanisms.

Gender differences in a mouse model of chemotherapy-induced neuropathic pain

Chemotherapy-induced neuropathic pain is one of the major problems for cancer patients. Although paclitaxel and cisplatin are widely used in women, most laboratory studies of chemotherapy-induced neuropathic pain have been conducted on male animals. The current study examined the gender differences in chemotherapy-induced neuropathic pain in mice. Neuropathic pain was induced by intraperitoneal injection of paclitaxel (2 mg/kg) for five consecutive days and cisplatin (1 mg/kg) for seven consecutive days. Cold allodynia was evaluated by measuring the paw withdrawal frequency and duration of paw licking in mice; however, mechanical allodynia was assessed by von Frey filaments. Neuropathic pain began to manifest after a few days ( P < 0.001). Cold allodynia was more robust in female mice ( P < 0.001) treated with paclitaxel, while no differences were observed between the two genders in the manifestation of paclitaxel-induced mechanical allodynia. Interestingly, no gender differences were observed in cisplatin-induced cold and mechanical allodynia tests. In conclusion, gender differences play a major role in neuropathic pain induced by paclitaxel. The differences between male and female animals should be considered in future studies and the findings should be generalized to humans with caution.

The preventive effect of oxytocin to Cisplatin-induced neurotoxicity: an experimental rat model

Peripheral neurotoxicity is a frequent dose-limiting side effect of the chemotherapeutic agent cisplatin. This study was conducted to investigate the preventive effect of oxytocin (OT) on cisplatin-induced neurotoxicity in rats. Forty-four adult female rats were included in the study. Thirty-six rats were administered intraperitoneally (i.p.) single dose cisplatin 10 mg/kg and divided in to 3 groups. The first group (n = 12) received saline i.p., whereas the second group (n = 12) and the third group (n = 12) were injected with 80 µg/kg and 160 µg/kg OT, respectively, for 10 days. The remaining 8 rats served as the control group. Electromyography (EMG) studies were recorded and blood samples were collected for the measurement of plasma lipid peroxidation (malondialdehyde; MDA), tumor necrosis factor (TNF)-α, and glutathione (GSH) levels. EMG findings revealed that compound muscle action potential amplitude was significantly decreased and distal latency was prolonged in the nontreated cisplatin-injected rats compared with the control group (P < 0.005). Also, nontreated cisplatin-injected rats showed significantly higher TNF-α and MDA levels and lower GSH level than control group. The administration of OT significantly ameliorated the EMG alterations, suppressed oxidative stress and inflammatory parameters, and increased antioxidative capacity. We suggest that oxytocin may have beneficial effects against cisplatin-induced neurotoxicity.

Inhibition of anandamide hydrolysis attenuates nociceptor sensitization in a murine model of chemotherapy-induced peripheral neuropathy

Painful neuropathy frequently develops as a consequence of commonly used chemotherapy agents for cancer treatment and is often a dose-limiting side effect. Currently available analgesic treatments are often ineffective on pain induced by neurotoxicity. Although peripheral administration of cannabinoids, endocannabinoids, and inhibitors of endocannabinoid hydrolysis has been effective in reducing hyperalgesia in models of peripheral neuropathy, including chemotherapy-induced peripheral neuropathy (CIPN), few studies have examined cannabinoid effects on responses of nociceptors in vivo. In this study we determined whether inhibition of fatty acid amide hydrolase (FAAH), which slows the breakdown of the endocannabinoid anandamide (AEA), reduced sensitization of nociceptors produced by chemotherapy. Over the course of a week of daily treatments, mice treated with the platinum-based chemotherapy agent cisplatin developed robust mechanical allodynia that coincided with sensitization of cutaneous C-fiber nociceptors as indicated by the development of spontaneous activity and increased responses to mechanical stimulation. Administration of the FAAH inhibitor URB597 into the receptive field of sensitized C-fiber nociceptors decreased spontaneous activity, increased mechanical response thresholds, and decreased evoked responses to mechanical stimuli. Cotreatment with CB1 (AM281) or CB2 (AM630) receptor antagonists showed that the effect of URB597 was mediated primarily by CB1 receptors. These changes following URB597 were associated with an increase in the endocannabinoid anandamide in the skin. Our results suggest that enhanced signaling in the peripheral endocannabinoid system could be utilized to reduce nociceptor sensitization and pain associated with CIPN.

Chemotherapy-induced peripheral neuropathy: What do we know about mechanisms?

Cisplatin, oxaliplatin, paclitaxel, vincristine and bortezomib are some of the most effective drugs successfully employed (alone or in combinations) as first-line treatment for common cancers. However they often caused severe peripheral neurotoxicity and neuropathic pain. Structural deficits in Dorsal Root Ganglia and sensory nerves caused symptoms as sensory loss, paresthesia, dysaesthesia and numbness that result in patient' suffering and also limit the life-saving therapy. Several scientists have explored the various mechanisms involved in the onset of chemotherapy-related peripheral neurotoxicity identifying molecular targets useful for the development of selected neuroprotective strategies. Dorsal Root Ganglia sensory neurons, satellite cells, Schwann cells, as well as neuronal and glial cells in the spinal cord, are the preferential sites in which chemotherapy neurotoxicity occurs. DNA damage, alterations in cellular system repairs, mitochondria changes, increased intracellular reactive oxygen species, alterations in ion channels, glutamate signalling, MAP-kinases and nociceptors ectopic activation are among the events that trigger the onset of peripheral neurotoxicity and neuropathic pain. In the present work we review the role of the main players in determining the pathogenesis of anticancer drugs-induced peripheral neuropathy.

Sensory neuronopathy complicating systemic lupus erythematosus: a case report

Introduction

Systemic lupus erythematosus is a multi-system connective tissue disorder. Peripheral neuropathy is a known and underestimated complication in systemic lupus erythematosus. Ganglionopathy manifests when neuronal cell bodies in the dorsal root ganglion are involved. Autoimmune disorders are a known etiology, with systemic lupus erythematosus being a rare cause.

Case presentation

A 32-year-old South Asian woman presented with oral ulceration involving her lips following initiation of treatment for a febrile illness associated with dysuria. She had a history of progressively worsening numbness over a period of 4 months involving both the upper and lower limbs symmetrically while sparing the trunk. Her vibration sense was impaired, and her reflexes were diminished. For the past 4 years, she had had a bilateral, symmetrical, non-deforming arthritis involving the upper and lower limbs. Her anti-nuclear antibody and anti-double-stranded deoxyribonucleic acid status were positive. Although her anti-Ro antibodies were positive, she did not have clinical features suggestive of Sjögren syndrome. Nerve conduction studies revealed sensory neuronopathy. A diagnosis of systemic lupus erythematosus complicated by sensory neuronopathy was made. Treatment with intravenous immunoglobulin resulted in clinical and electrophysiological improvement.

Conclusion

Peripheral neuropathy in systemic lupus erythematosus can, by itself, be a disabling feature. Nerve conduction studies should be considered when relevant. Neuropathy in systemic lupus erythematosus should be given greater recognition, and rarer forms of presentation should be entertained in the differential diagnosis when the clinical picture is atypical. Intravenous immunoglobulin may have role in treatment of sensory neuronopathy in systemic lupus erythematosus.

Goshajinkigan, a traditional Japanese medicine, prevents oxaliplatin-induced acute peripheral neuropathy by suppressing functional alteration of TRP channels in rat

The acute peripheral neuropathy induced by oxaliplatin treatment occurs very frequently and is aggravated by exposure to cold. Goshajinkigan (GJG), a traditional Japanese (kampo) medicine, was recently shown to be effective against oxaliplatin-induced acute neuropathy. However, because the effects of GJG and its mechanism in relation to those of its ingredients and its mechanism are not well understood, we examined the effects of GJG on acute neuropathy. Further, we investigated whether GJG affects the functions and gene expressions of transient receptor potential (TRP) channels using a rat model of oxaliplatin-induced neuropathy. Administration of oxaliplatin increased withdrawal responses from cold stimulation, and GJG or calcium gluconate/magnesium sulfate significantly inhibited the oxaliplatin-induced cold hypersensitivity. Application of menthol, a TRPA1/TRPM8 agonist, or allyl isothiocyanate (AITC), a selective TRPA1 agonist, to the hind paw of oxaliplatin-treated rats enhanced the nocifensive behaviors evoked by each agonist, whereas oxaliplatin had no significant effect on nocifensive behaviors evoked by capsaicin, a TRPV1 agonist. GJG treatment reduced menthol- or AITC-evoked withdrawal responses potentiated by oxaliplatin. Furthermore, GJG suppressed the increase of TRPA1 and TRPM8 mRNA expression induced by oxaliplatin in dorsal root ganglia. These findings suggest that GJG prevented oxaliplatin-induced acute peripheral neuropathy by suppressing functional alteration of TRP channels, especially TRPA1 and TRPM8.

Selenium partially prevents cisplatin-induced neurotoxicity: a preliminary study

Cisplatin is an anticancer drug and it has neurotoxic effects. On the other hand, the neuroprotective effect of selenium was observed in previous studies. However, the effect of selenium on cisplatin-induced neurotoxicity has not been studied yet. Therefore, we aimed to investigate whether selenium prevent cisplatin-induced neurotoxicity. Twenty-one male Wistar albino rats were divided into three groups: control (C), cisplatin (CS), cisplatin and selenium (CSE, n=7 in each group). Cisplatin (12 mg/kg/day, i.p.) was administered for 3 days to CS and CSE groups. Also, CSE group received via oral gavage 3 mg/kg/day (twice-a-day as 1.5 mg/kg) selenium 5 days before of cisplatin injection and continued for 11 consecutive days. The same volumes of saline were intraperitoneally and orally administered to C group at same time. At the end of experimental protocol, electrophysiological and histopathological examinations were performed. The nerve conduction velocity, amplitude of compound action potential and number of axon of CS group were significantly lower than the C group. However, the same parameters of CSE group were significantly higher than the CS group. Although, cisplatin has a peripheral neurotoxic effect in rats, this effect was partially prevented by selenium treatment. Thus, it appears that co-administration of selenium and cisplatin may be a useful approach to decrease severity of peripheral neurotoxicity.

Analgesic effects of clinically used compounds in novel mouse models of polyneuropathy induced by oxaliplatin and cisplatin

BACKGROUND

Peripheral neuropathy is the major dose-limiting side effect of cisplatin and oxaliplatin, and there are currently no effective treatments available. The aim of this study was to assess the pharmacological mechanisms underlying chemotherapy-induced neuropathy in novel animal models based on intraplantar administration of cisplatin and oxaliplatin and to systematically evaluate the analgesic efficacy of a range of therapeutics.

METHODS

Neuropathy was induced by a single intraplantar injection of cisplatin or oxaliplatin in C57BL/6J mice and assessed by quantification of mechanical and thermal allodynia. The pharmacological basis of cisplatin-induced neuropathy was characterized using a range of selective pharmacological inhibitors. The analgesic effects of phenytoin, amitriptyline, oxcarbazepine, mexiletine, topiramate, retigabine, gabapentin, fentanyl, and Ca(2+/)Mg(2+) were assessed 24 hours after induction of neuropathy.

RESULTS

Intraplantar administration of cisplatin led to the development of mechanical allodynia, mediated through Nav1.6-expressing sensory neurons. Unlike intraplantar injection of oxaliplatin, cold allodynia was not observed with cisplatin, consistent with clinical observations. Surprisingly, only fentanyl was effective at alleviating cisplatin-induced mechanical allodynia despite a lack of efficacy in oxaliplatin-induced cold allodynia. Conversely, lamotrigine, phenytoin, retigabine, and gabapentin were effective at reversing oxaliplatin-induced cold allodynia but had no effect on cisplatin-induced mechanical allodynia. Oxcarbazepine, amitriptyline, mexiletine, and topiramate lacked efficacy in both models of acute chemotherapy-induced neuropathy.

CONCLUSION

This study established a novel animal model of cisplatin-induced mechanical allodynia consistent with the A-fiber neuropathy seen clinically. Systematic assessment of a range of therapeutics identified several candidates that warrant further clinical investigation.

Incidence, predictive factors, and prognosis for winged scapula in breast cancer patients after axillary dissection

PURPOSE

Axillary lymph node dissection is part of breast cancer surgery, and winged scapula is a possible sequela. Data regarding its incidence, predictive factors, and patient prognosis remains inconsistent. Ignorance of its diagnosis may lead to undertreatment with physical morbidity.

METHODS

Breast cancer patients with axillary lymph node dissection were prospectively recruited. Postoperative examinations by the physiotherapy staff were performed.

RESULTS

One hundred eighty-seven patients were recruited during July-October 2012; 51 patients had a positive diagnosis (27.2 %), with 38 patients (86 %) who recovered completely from the winged scapula, while 6 patients (13 %) still had winged scapula at 6 months after surgery. One hundred thirty patients underwent mastectomy and 100 cases had immediate reconstruction. Age, BMI, previous shoulder joint morbidity, and breast surgery were not associated with winged scapula. Neoadjuvant treatment, mastectomy or conservative surgery, immediate reconstruction, tumor size, and nodal involvement also did not show any correlation. Breast reconstruction with prosthesis, even with serratus muscle dissection, does not increase the incidence of winged scapula.

CONCLUSION

Winged scapula is not an uncommon incidence after breast cancer surgery. Physiotherapy is related to the complete recovery. The severity or grading of the winged scapula and the recovery time after physiotherapy should be investigated in the future studies.

Chemotherapy-induced peripheral neurotoxicity: a critical analysis

With a 3-fold increase in the number of cancer survivors noted since the 1970s, there are now over 28 million cancer survivors worldwide. Accordingly, there is a heightened awareness of long-term toxicities and the impact on quality of life following treatment in cancer survivors. This review will address the increasing importance and challenge of chemotherapy-induced neurotoxicity, with a focus on neuropathy associated with the treatment of breast cancer, colorectal cancer, testicular cancer, and hematological cancers. An overview of the diagnosis, symptomatology, and pathophysiology of chemotherapy-induced peripheral neuropathy will be provided, with a critical analysis of assessment strategies, neuroprotective approaches, and potential treatments. The review will concentrate on neuropathy associated with taxanes, platinum compounds, vinca alkaloids, thalidomide, and bortezomib, providing clinical information specific to these chemotherapies.

Cisplatin : an old drug with a newfound efficacy -- from mechanisms of action to cytotoxicity

INTRODUCTION

Cisplatin is a highly effective antineoplastic drug with an extremely current mechanism of action. Cisplatin-induced side effects are dose-dependent and limit the administration of increased dosages, thus compromising its therapeutic efficacy.

AREAS COVERED

This review aims to describe the emerging knowledge about the biochemical mechanisms that mediate cisplatin cytotoxicity and side effects. A specific section is devoted to discuss the pathogenesis of cisplatin-related toxicities and the potential measures to counteract them.

EXPERT OPINION

Although cisplatin has been used for a long time, only recently its exact mechanism of action has been better defined. The cytotoxic activity of cisplatin is largely dependent on the glycolytic metabolism of tumor cells: cisplatin redirects cancer cells to oxidative phosphorylation from the 'Warburg effect', which is considered one of the most important mechanisms of tumor cell survival. The interference of cisplatin with glucose metabolism is also a cause of its relevant toxicities. The emerging knowledge on the complex mechanisms, which mediate cisplatin cytotoxicity and side effect, may lead to a more appropriate and safe use of this drug. Further studies are warranted to define and implement its effectiveness in combination with targeted drugs able to interfere with cellular energy metabolism, such as mTOR inhibitors.

Drug-induced neuropathies

Although drug-induced neuropathies account for only 2-4% of referrals, their identification is important. Numerically, chemotherapy and antiretroviral drugs are the most important worldwide. Research is currently focused on elucidating pathogenic mechanisms and the earliest presymptomatic changes using neurophysiological and pharmacogenetic techniques in order to avoid the drug or make dosage changes before irreversible damage occurs. Chemoprotectants against chemotherapy-induced neuropathy are also an active area of research. This chapter focuses on the pathophysiology of drug-induced neuropathies in general, followed by detailed reviews of neuropathy due to; newer compounds such as TNF (tumor necrosis factor) α antagonists and antibiotics such as linezolid; chemotherapeutic agents, old and new, where significant progress has been made; antiretroviral drugs; and amiodarone, which is unusual in that it causes a demyelinating neuropathy. The controversial issue of statin-induced neuropathy is also reviewed.

Neurophysiological approach to disorders of peripheral nerve

Disorders of the peripheral nerve system (PNS) are heterogeneous and may involve motor fibers, sensory fibers, small myelinated and unmyelinated fibers and autonomic nerve fibers, with variable anatomical distribution (single nerves, several different nerves, symmetrical affection of all nerves, plexus, or root lesions). Furthermore pathological processes may result in either demyelination, axonal degeneration or both. In order to reach an exact diagnosis of any neuropathy electrophysiological studies are crucial to obtain information about these variables. Conventional electrophysiological methods including nerve conduction studies and electromyography used in the study of patients suspected of having a neuropathy and the significance of the findings are discussed in detail and more novel and experimental methods are mentioned. Diagnostic considerations are based on a flow chart classifying neuropathies into eight categories based on mode of onset, distribution, and electrophysiological findings, and the electrophysiological characteristics in each type of neuropathy are discussed.

Persistent hyperalgesia in the cisplatin-treated mouse as defined by threshold measures, the conditioned place preference paradigm, and changes in dorsal root ganglia activated transcription factor 3: the effects of gabapentin, ketorolac, and etanercept

BACKGROUND

Painful neuropathy is a dose-limiting side effect in cancer chemotherapy. To characterize this phenomenon, we examined pain behavior and analgesic actions in a mouse model of cisplatin polyneuropathy.

METHODS

Male C57BL/6 mice received intraperitoneal cisplatin or saline (2.3 mg/kg/d) every other day 6 times over 2 weeks for a total dose of 13.8 mg/kg. Thermal escape latencies, mechanical allodynia using von Frey hairs, and observation of behavior/morbidity and body weights were assessed. After onset of allodynia, we examined the actions of intraperitoneal gabapentin (100 mg/kg), etanercept (20 and 40 mg/kg), ketorolac (15 mg/kg), and morphine (1, 3, and 10 mg/kg). Additionally, using the conditioned place preference (CPP) paradigm, we examined the effects of gabapentin and ketorolac on the presumed pain state initiated by cisplatin. Additionally, we examined the spinal cord and dorsal root ganglia (DRG) of cisplatin-treated mice.

RESULTS

Cisplatin, but not saline treatment, produced persistent hindpaw tactile allodynia, which persisted 46 days with no effect on thermal escape. Gabapentin and morphine, but neither etanercept nor ketorolac, produced a complete but transient (2-hour) reversal of the allodynia. Etanercept (40 mg/kg) pretreatment resulted in a delay in onset of mechanical allodynia. Using CPP, gabapentin, but not ketorolac, in cisplatin animals resulted in a significant preference for the drug-associated treatment compartment. There was no place preference in non-cisplatin-treated (nonallodynic) mice after gabapentin injection. Immunohistochemistry in cisplatin-treated mice showed no change in glial fibrillary acidic protein (astrocyte) or Iba1 (ionized calcium binding adaptor molecule 1) (microglia) activation states, but a significant increase in activated transcription factor 3 was observed in the DRG.

CONCLUSIONS

Cisplatintreated mice display allodynia and an activation of DRG activated transcription factor 3, which is paralleled by its effects on behavior in the CPP system, wherein gabapentin, but not ketorolac, in the presence of the cisplatin polyneuropathy, is positively rewarding, confirming that this neuropathy is an aversive (painful) state that is ameliorated by gabapentin.

Membrane transporters as mediators of Cisplatin effects and side effects

Transporters are important mediators of specific cellular uptake and thus, not only for effects, but also for side effects, metabolism, and excretion of many drugs such as cisplatin. Cisplatin is a potent cytostatic drug, whose use is limited by its severe acute and chronic nephro-, oto-, and peripheral neurotoxicity. For this reason, other platinum derivatives, such as carboplatin and oxaliplatin, with less toxicity but still with antitumoral action have been developed. Several transporters, which are expressed on the cell membranes, have been associated with cisplatin transport across the plasma membrane and across the cell: the copper transporter 1 (Ctr1), the copper transporter 2 (Ctr2), the P-type copper-transporting ATPases ATP7A and ATP7B, the organic cation transporter 2 (OCT2), and the multidrug extrusion transporter 1 (MATE1). Some of these transporters are also able to accept other platinum derivatives as substrate. Since membrane transporters display a specific tissue distribution, they can be important molecules that mediate the entry of platinum derivatives in target and also nontarget cells possibly mediating specific effects and side effects of the chemotherapeutic drug. This paper summarizes the literature on toxicities of cisplatin compared to that of carboplatin and oxaliplatin and the interaction of these platinum derivatives with membrane transporters.

Acute inflammatory demyelinating polyradiculoneuropathy in a patient receiving oxaliplatin-based chemotherapy

We report a case of acute inflammatory demyelinating polyradiculoneuropathy (AIDP) that developed in a patient with cholangiocarcinoma after receiving oxaliplatin-based chemotherapy. A 62-year-old man had multiple hypodense lesions with delayed enhancement in the both lobes of the liver on abdominal computed tomography. He was treated with 5-fluorouracil, leucovorin and oxaliplatin (100 mg/m(2)). After eight cycles of treatment and a cumulative oxaliplatin dose of 780 mg/m(2), he developed an unsteady gait, dysphagia, weakness of both the upper and lower limbs and impairment of all sensory modalities. Nerve conduction studies confirmed the diagnosis of AIDP. Immunoglobulin G i.v. was administered for 5 days but the neurological deficits of both his upper and lower limbs did not improve. This case highlights unusual peripheral nervous system manifestations in a patient who received chemotherapy with oxaliplatin.

The neurologic side effects of chemotherapeutic agents

Neurologic dysfunction is a common side effect of many chemotherapy drugs. For several agents neurotoxicity is common, severe, and can be dose limiting. As the list of newer chemotherapy agents and systemic targeted therapies grows, so does the number and variety of potential neurotoxicities. This article reviews the clinical features of chemotherapy-induced syndromes involving the central and peripheral nervous systems.

Long-term and late effects of germ cell testicular cancer treatment and implications for follow-up

Germ cell testicular cancer (TC) represents a malignancy with high cure rates. Since the introduction of cisplatin-based chemotherapy in the late 1970s, the 5-year survival rate has increased considerably, and it is currently above 95%. Because TC is usually diagnosed before the age of 40 years, these men can expect to live for another 40 to 50 years after being successfully treated. This success, however, is hampered by an increased risk of long-term and late effects of treatment. Secondary malignant neoplasms and cardiovascular disease represent the most common potentially life-threatening late effects, typically occurring more than 10 years after treatment. Other long-term effects include pulmonary toxicity, nephrotoxicity, neurotoxicity, decreased fertility, hypogonadism, and psychosocial problems. The incidence and time to onset of these various adverse effects vary according to treatment type and intensity. There is still little knowledge about underlying mechanisms and genetic susceptibility of the various adverse effects. Apart from treatment burden, it is not yet possible to identify patients who are at high risk for certain late effects after TC treatment. In this clinical review, we present the current status regarding different somatic and psychosocial long-term late effects after treatment for TC, based on Medline searches and our own research. Moreover, we postulate recommendations for general medical evaluations that should begin after treatment is completed and continue during follow-up.

Management of treatment-emergent peripheral neuropathy in multiple myeloma

Peripheral neuropathy (PN) is one of the most important complications of multiple myeloma (MM) treatment. PN can be caused by MM itself, either by the effects of the monoclonal protein or in the form of radiculopathy from direct compression, and particularly by certain therapies, including bortezomib, thalidomide, vinca alkaloids and cisplatin. Clinical evaluation has shown that up to 20% of MM patients have PN at diagnosis and as many as 75% may experience treatment-emergent PN during therapy. The incidence, symptoms, reversibility, predisposing factors and etiology of treatment-emergent PN vary among MM therapies, with PN incidence also affected by the dose, schedule and combinations of potentially neurotoxic agents. Effective management of treatment-emergent PN is critical to minimize the incidence and severity of this complication, while maintaining therapeutic efficacy. Herein, the state of knowledge regarding treatment-emergent PN in MM patients and current management practices are outlined, and recommendations regarding optimal strategies for PN management during MM treatment are provided. These strategies include early and regular monitoring with neurological evaluation, with dose modification and treatment discontinuation as indicated. Areas requiring further research include the development of MM-specific, patient-focused assessment tools, pharmacogenomic analysis of patient DNA, and trials to assess the efficacy of pharmacological interventions.

[Sensory neuronopathy of Sjögren's syndrome. A diagnostic challenge]

Sjögren's syndrome is an important differential diagnosis in patients with sensory neuronopathy because immunosuppressive therapy may prevent progressive degeneration of sensory fibres, ganglions and axons. Due to the challenges in the diagnostic process the diagnostic criteria have repeatedly changed over the past few years. In patients with negative antibodies (SSA, SSB antibodies) biopsy of the salivary glands of the lip and the parotid gland can be useful to diagnose Sjögren's syndrome. We report on four patients in whom biopsy of the salivary gland was helpful in establishing the diagnosis of Sjögren's syndrome and consequently immunosuppressive therapy was initiated. One of these patients suffered from hypersalivation. This was probably due to denervation hypersensitivity. To our knowledge this has not been reported yet.

Pronociceptive pain modulation in patients with painful chemotherapy-induced polyneuropathy

CONTEXT

Several chemotherapy agents induce polyneuropathy that is painful for some patients, but not for others. We assumed that these differences might be attributable to varying patterns of pain modulation.

OBJECTIVES

The aim of the present study was to evaluate pain modulation in such patients.

METHODS

Twenty-seven patients with chemotherapy-induced polyneuropathy were tested for detection thresholds (cold, warm, and mechanical) in both the forearm and foot, as well as for heat pain threshold, mechanical temporal summation (TS), and conditioned pain modulation (CPM; also known as the diffuse noxious inhibitory control-like effect), which were tested in the upper limbs.

RESULTS

Positive correlations were found between clinical pain levels and both TS (r=0.52, P=0.005) and CPM (r=0.40, P=0.050) for all patients. In addition, higher TS was associated with less efficient CPM (r=0.56, P=0.004). The group of patients with painful polyneuropathy (n=12) showed a significantly higher warm detection threshold in the foot (P=0.03), higher TS (P<0.01), and less efficient CPM (P=0.03) in comparison to the group with nonpainful polyneuropathy.

CONCLUSION

The painfulness of polyneuropathy is associated with a "pronociceptive" modulation pattern, which may be primary to the development of pain. The higher warm sensory thresholds in the painful polyneuropathy group suggest that the severity of polyneuropathy may be another factor in determining its painfulness.

Differential expression of ATP7A, ATP7B and CTR1 in adult rat dorsal root ganglion tissue

BACKGROUND

ATP7A, ATP7B and CTR1 are metal transporting proteins that control the cellular disposition of copper and platinum drugs, but their expression in dorsal root ganglion (DRG) tissue and their role in platinum-induced neurotoxicity are unknown. To investigate the DRG expression of ATP7A, ATP7B and CTR1, lumbar DRG and reference tissues were collected for real time quantitative PCR, RT-PCR, immunohistochemistry and Western blot analysis from healthy control adult rats or from animals treated with intraperitoneal oxaliplatin (1.85 mg/kg) or drug vehicle twice weekly for 8 weeks.

RESULTS

In DRG tissue from healthy control animals, ATP7A mRNA was clearly detectable at levels similar to those found in the brain and spinal cord, and intense ATP7A immunoreactivity was localised to the cytoplasm of cell bodies of smaller DRG neurons without staining of satellite cells, nerve fibres or co-localisation with phosphorylated heavy neurofilament subunit (pNF-H). High levels of CTR1 mRNA were detected in all tissues from healthy control animals, and strong CTR1 immunoreactivity was associated with plasma membranes and vesicular cytoplasmic structures of the cell bodies of larger-sized DRG neurons without co-localization with ATP7A. DRG neurons with strong expression of ATP7A or CTR1 had distinct cell body size profiles with minimal overlap between them. Oxaliplatin treatment did not alter the size profile of strongly ATP7A-immunoreactive neurons but significantly reduced the size profile of strongly CTR1-immunoreactive neurons. ATP7B mRNA was barely detectable, and no specific immunoreactivity for ATP7B was found, in DRG tissue from healthy control animals.

CONCLUSIONS

In conclusion, adult rat DRG tissue exhibits a specific pattern of expression of copper transporters with distinct subsets of peripheral sensory neurons intensely expressing either ATP7A or CTR1, but not both or ATP7B. The neuron subtype-specific and largely non-overlapping distribution of ATP7A and CTR1 within rat DRG tissue may be required to support the potentially differing cuproenzyme requirements of distinct subsets of sensory neurons, and could influence the transport and neurotoxicity of oxaliplatin.

Neurophysiological and neuropathological characterization of new murine models of chemotherapy-induced chronic peripheral neuropathies

Cisplatin, paclitaxel and bortezomib belong to some of the most effective families of chemotherapy drugs for solid and haematological cancers. Epothilones represent a new family of very promising antitubulin agents. The clinical use of all these drugs is limited by their severe peripheral neurotoxicity. Several in vivo rat models have reproduced the characteristics of the peripheral neurotoxicity of these drugs. However, since only a very limited number of cancer types can be studied in immunocompetent rats, these animal models do not represent an effective way to evaluate, at the same time, the antineoplastic activity and the neurotoxic effects of the anticancer compounds. In this study, we characterized the neurophysiological impairment induced by chronic chemotherapy treatment in BALB/c mice, a strain suitable for assessing the activity of anticancer treatments. At the end of a 4-week period of treatment with cisplatin, paclitaxel, epothilone-B or bortezomib, sensory and sensory/motor nerve conduction velocities (NCV) were determined in the caudal and digital nerves and dorsal root ganglia (DRG) and sciatic nerves were collected for histopathological analysis. The electrophysiological studies revealed that all the compounds caused a statistically significant reduction in the caudal NCV, while impairment of the digital NCV was less severe. This functional damage was confirmed by the histopathological observations evidencing axonal degeneration in the sciatic nerve induced by all the drugs associated with pathological changes in DRG induced only by cisplatin and bortezomib. These results confirm the possibility to use our models to combine the study of the antineoplastic activity of anticancer drugs and of their toxic effects on the peripheral nervous system in the BALB/c mouse strain.

Adenovirus vector targeted to dorsal root ganglia as a future tool for the treatment of sensory neuron diseases

Evaluation of: Terashima T, Oka K, Kritz AB, Kojima H, Baker AH, Chan L: DRG-targeted helper-dependent adenoviruses mediate selective gene delivery for therapeutic rescue of sensory neuronopathies in mice. J. Clin. Invest. 119(7), 2101–2112 (2009). In this study, Terashima and colleagues have developed a genetically modified helper adenovirus detargeted for native adenoviral tropism and expressing homing peptides specific for dorsal root ganglia. These helper viruses were used to generate dorsal root ganglia-targeted helper-dependent adenovirus. With an intratechal route, sensory neuron targetting was efficient with minimal immune reaction in mice. This vector transduced the β subunit of β-hexosaminidase gene in the dorsal root ganglia of a mouse model of Sandoff disease, resulting in correction of the enzymatic deficit and electrophysiological and functional improvement. This approach allows for future developments in the treatment of sensory neuronopathies in humans.

Changes in laryngeal sensation evaluated with a new method before and after radiotherapy

Radiotherapy of the laryngopharynx sometimes leads to functional disabilities including swallowing dysfunction. One of the reasons for these disabilities is a deterioration of laryngeal sensation. Laryngeal sensation is an important factor in swallowing, but quantitative evaluation of laryngeal sensation has been difficult. In this study, we evaluated changes in laryngeal sensation before and after radiotherapy for laryngeal and hypopharyngeal cancer, using a flexible laryngoscope and probes. This study was conducted in 12 patients, 8 with laryngeal cancer and 4 with hypopharyngeal cancer, who received radiotherapy alone or chemoradiotherapy at our medical centre. Measurements were performed using a 3.3-mm-diameter flexible laryngoscope with a probe port and four types of probes with 0.06-, 0.13-, 0.20-, and 0.30-mm nylon filaments attached to a wire tip. Sensation was evaluated at the tip of the epiglottis and the arytenoid region. Measurements were performed before radiotherapy, 1, 3 months, and 1 year after completion of radiotherapy. Sensation of the epiglottis and arytenoid deteriorated significantly 1 and 3 months after radiotherapy compared with before radiotherapy. Laryngeal sensation recovered in most cases within 1 year after radiotherapy. The present study clearly demonstrates the deterioration of laryngeal sensation with radiotherapy.

The pattern and diagnostic criteria of sensory neuronopathy: a case-control study

Acquired sensory neuronopathies encompass a group of paraneoplastic, dysimmune, toxic or idiopathic disorders characterized by degeneration of peripheral sensory neurons in dorsal root ganglia. As dorsal root ganglia cannot easily be explored, the clinical diagnosis of these disorders may be difficult. The question as to whether there exists a common clinical pattern of sensory neuronopathies, allowing the establishment of validated and easy-to-use diagnostic criteria, has not yet been addressed. In this study, logistic regression was used to construct diagnostic criteria on a retrospective study population of 78 patients with sensory neuronopathies and 56 with other sensory neuropathies. For this, sensory neuronopathy was provisionally considered as unambiguous in 44 patients with paraneoplastic disorder or cisplatin treatment and likely in 34 with a dysimmune or idiopathic setting who may theoretically have another form of neuropathy. To test the homogeneity of the sensory neuronopathy population, likely candidates were compared with unambiguous cases and then the whole population was compared with the other sensory neuropathies population. Criteria accuracy was checked on 37 prospective patients referred for diagnosis of sensory neuropathy. In the study population, sensory neuronopathy showed a common clinical and electrophysiological pattern that was independent of the underlying cause, including unusual forms with only patchy sensory loss, mild electrical motor nerve abnormalities and predominant small fibre or isolated lower limb involvement. Logistic regression allowed the construction of a set of criteria that gave fair results with the following combination: ataxia in the lower or upper limbs + asymmetrical distribution + sensory loss not restricted to the lower limbs + at least one sensory action potential absent or three sensory action potentials <30% of the lower limit of normal in the upper limbs + less than two nerves with abnormal motor nerve conduction study in the lower limbs.

Neuronal expression of copper transporter 1 in rat dorsal root ganglia: association with platinum neurotoxicity

PURPOSE

We report the neuronal expression of copper transporter 1 (CTR1) in rat dorsal root ganglia (DRG) and its association with the neurotoxicity of platinum-based drugs.

METHODS

CTR1 expression was studied by immunohistochemistry and RT-PCR. The toxicity of platinum drugs to CTR1-positive and CTR1-negative neurons was compared in DRG from animals treated with maximum tolerated doses of oxaliplatin (1.85 mg/kg), cisplatin (1 mg/kg) or carboplatin (8 mg/kg) twice weekly for 8 weeks.

RESULTS

Abundant CTR1 mRNA was detected in DRG tissue. CTR1 immunoreactivity was associated with plasma membranes and cytoplasmic vesicular structures of a subpopulation (13.6 +/- 3.1%) of mainly large-sized (mean cell body area, 1,787 +/- 127 microm(2)) DRG neurons. After treatment with platinum drugs, the cell bodies of these CTR1-positive neurons became atrophied, with oxaliplatin causing the greatest percentage reduction in the mean cell body area relative to controls (42%; P < 0.05), followed by cisplatin (18%; P < 0.05) and carboplatin causing the least reduction (3.2%; P = NS). CTR1-negative neurons, with no immunoreactivity or only diffuse cytoplasmic staining, showed less treatment-induced cell body atrophy than CTR1-positive neurons.

CONCLUSIONS

CTR1 is preferentially expressed by a subset of DRG neurons that are particularly vulnerable to the toxicity of platinum drugs. These findings, together with its neuronal membrane localization, are suggestive of CTR1-related mechanisms of platinum drug neuronal uptake and neurotoxicity.

Chemotherapy-induced peripheral neuropathy

Recent advances in the development and administration of chemotherapy for malignant diseases have led to prolonged survival of patients and the promise of a return to normal lives. This progress comes with a price, however, and the nervous system is frequently the target of therapy-induced toxicity. Unlike more immediate toxicities that affect the gastrointestinal tract and bone marrow, chemotherapy-induced neurotoxicity is frequently delayed in onset and may progress over time. In the peripheral nervous system, the major brunt of the toxic attack is directed against the peripheral nerve, targeting the neuronal cell body, the axonal transport system, the myelin sheath, and glial support structures, resulting in chemotherapy-induced peripheral neuropathy.

Mice with cisplatin and oxaliplatin-induced painful neuropathy develop distinct early responses to thermal stimuli

Background

Cisplatin has been in use for 40 years for treatment of germ line and other forms of cancer. Oxaliplatin is approved for treatment of metastatic colorectal cancer. Thirty to forty percent of cancer patients receiving these agents develop pain and sensory loss. Oxaliplatin induces distinctive cold-associated dysesthesias in up to 80% of patients.

Results

We have established mouse models of cisplatin and oxaliplatin-induced neuropathy using doses similar to those used in patients. Adult male C57BL6J mice were treated with daily intraperitoneal injection for 5 days, followed by 5 days of rest, for two cycles. Total cumulative doses of 23 mg/kg cisplatin and 30 mg/kg oxaliplatin were used. Behavioral evaluations included cold plate, von Frey, radiant heat, tail immersion, grip strength and exploratory behavior at baseline and at weekly intervals for 8 weeks. Following two treatment cycles, mice in the cisplatin and oxaliplatin treatment groups demonstrated significant mechanical allodynia compared to control mice. In addition, the cisplatin group exhibited significant thermal hyperalgesia in hind paws and tail, and the oxaliplatin group developed significant cold hyperalgesia in hind paws.

Conclusion

We have therefore established a model of platinum drug-induced painful peripheral neuropathy that reflects the differences in early thermal pain responses that are observed in patients treated with either cisplatin or oxaliplatin. This model should be useful in studying the molecular basis for these different pain responses and in designing protective therapeutic strategies.

Reversibility of symptomatic peripheral neuropathy with bortezomib in the phase III APEX trial in relapsed multiple myeloma: impact of a dose-modification guideline

The frequency, characteristics and reversibility of bortezomib-associated peripheral neuropathy were evaluated in the phase III APEX (Assessment of Proteasome Inhibition for Extending Remissions) trial in patients with relapsed myeloma, and the impact of a dose-modification guideline on peripheral neuropathy severity and reversibility was assessed. Patients received bortezomib 1.3 mg/m(2) (days 1, 4, 8, 11, eight 21-d cycles, then days 1, 8, 15, 22, three 35-d cycles); bortezomib was held, dose-reduced or discontinued depending on peripheral neuropathy severity, according to a protocol-specified dose-modification guideline. Overall, 124/331 patients (37%) had treatment-emergent peripheral neuropathy, including 30 (9%) with grade >or=3; incidence and severity were not affected by age, number/type of prior therapies, baseline glycosylated haemoglobin level, or diabetes history. Grade >or=3 incidence appeared lower versus phase II trials (13%) that did not specifically provide dose-modification guidelines. Of patients with grade >or=2 peripheral neuropathy, 58/91 (64%) experienced improvement or resolution to baseline at a median of 110 d, including 49/72 (68%) who had dose modification versus 9/19 (47%) who did not. Efficacy did not appear adversely affected by dose modification for grade >or=2 peripheral neuropathy. Bortezomib-associated peripheral neuropathy is manageable and reversible in most patients with relapsed myeloma. Dose modification using a specific guideline improves peripheral neuropathy management without adversely affecting outcome.

Neuropathies in the context of malignancies

PURPOSE OF REVIEW

To conduct a critical review of recent data pertaining to the clinical and therapeutic aspects of peripheral neuropathies in the setting of malignancies, with the exception of paraproteinemic neuropathies. Our search extended to the past 2 years, using a PubMed search strategy.

RECENT FINDINGS

In the field of neuropathies linked with the development of the cancer, recent works have focused on lymphoma and cancer-associated vasculitides. In paraneoplastic syndromes, the major fact of the past 2 years is the issue of guidelines for diagnosis and treatment of these disorders, under the aegis of the paraneoplastic syndromes Euronetwork and of the European Federation of Neurological Sciences. When considering chemotherapy, neurotoxicity is becoming increasingly better known. Finally, the spectrum of late-delayed complications of irradiation further increases with a better clinical characterization of radiotherapy-induced dropped head syndrome.

SUMMARY

This article successively reviews the results of the recent studies in these various fields. In the field of chemotherapy, we will particularly focus on some new data concerning oxaliplatin, bortezomib, the albumin-bound form of paclitaxel and lenalidomide.

Chemotherapy-induced peripheral neuropathy

Recent advances in the development and administration of chemotherapy for malignant diseases have led to prolonged survival of patients and the promise of a return to normal lives. The cost of progress comes with a price, however, and the nervous system is frequently the target of therapy-induced toxicity. Unlike more immediate toxicities that affect the gastrointestinal tract and bone marrow, chemotherapy-induced neurotoxicity is frequently delayed in onset and may progress over time. In the peripheral nervous system, the major brunt of the toxic attack is directed against the peripheral nerve, targeting the neuronal cell body, the axonal transport system, the myelin sheath, and glial support structures, resulting in chemotherapy-induced peripheral neuropathy.