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Cisplatin, paclitaxel and bortezomib are effective chemotherapy drugs in cancer treatment. However, they share severe peripheral neurotoxicity (PN) as one of their major dose-limiting side effects, often impairing cancer patients' quality of life and sometimes being permanent. Even if preclinical oncology is largely based on the use of immune-deficient mice, rodent models used to study the chemotherapy-induced PN are available only in immune-competent animals. In this study we characterized for the first time the PN induced by these chemotherapies through neurophysiological, behavioral, morphological and morphometric studies in athymic nude mice, a commonly employed strain in the preclinical oncology. The animals, divided into four groups, were chronically treated with cisplatin, paclitaxel or bortezomib once or twice a week for 4 or 6 weeks or were left untreated. These schedules were tolerated, neurotoxic and in the range of antineoplastic effectiveness. Despite similarities, differences in the features of PN were evident if compared with immune-competent models under comparable regimens of treatment. The results of this study may provide a basis for future combined analysis of antineoplastic and neurotoxic effects of chemotherapy in the same animals., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The proteasome inhibitor bortezomib is an antineoplastic drug mainly used for the treatment of multiple myeloma (MM). Despite its effectiveness, bortezomib clinical use is often limited by the onset of peripheral neuropathy (BiPN). To better understand the mechanisms of BiPN several rat and mice models have been proposed, but no studies in MM-bearing animals allowing to test the antitumor activity of the selected schedules and the role of MM by itself in peripheral nervous system damage have been reported to date. Here, we carried out a study using immunodeficient C.B-17/Prkdcscid (SCID) mice injected with RPMI8266 human MM cells and treated with bortezomib 1 mg/kg once a week for five weeks. Animals were assessed with neurophysiological, behavioral and pathological methods and tumor volume measurement was performed along the study. At the end of the study BiPN was evident in bortezomib-treated animals, and this neurotoxic effect was evident using a schedule able to effectively prevent tumor growth. However, neurophysiological and pathological evidence of MM induced peripheral nervous system damage was also reported. This model based on MM-bearing animals is more reliable in the reproduction of the clinical setting and it is, therefore, more suitable than the previously reported models of BiPN to study its pathogenesis. Moreover, it represents an optimal model to test the efficacy of neuroprotective agents and at the same time their non-interference with bortezomib antineoplastic activity.

The pathogenetic role of vascular endothelial growth factor (VEGF) in long-term retinal and kidney complications of diabetes has been demonstrated. Conversely, little is known in diabetic neuropathy. We examined the modulation of VEGF pathway at mRNA and protein level on dorsal root ganglion (DRG) neurons and Schwann cells (SC) induced by hyperglycaemia. Moreover, we studied the effects of VEGF neutralization on hyperglycemic DRG neurons and streptozotocin-induced diabetic neuropathy. Our findings demonstrated that DRG neurons were not affected by the direct exposition to hyperglycaemia, whereas showed an impairment of neurite outgrowth ability when exposed to the medium of SC cultured in hyperglycaemia. This was mediated by an altered regulation of VEGF and FLT-1 receptors. Hyperglycaemia increased VEGF and FLT-1 mRNA without changing their intracellular protein levels in DRG neurons, decreased intracellular and secreted protein levels without changing mRNA level in SC, while reduced the expression of the soluble receptor sFLT-1 both in DRG neurons and SC. Bevacizumab, a molecule that inhibits VEGF activity preventing the interaction with its receptors, restored neurite outgrowth and normalized FLT-1 mRNA and protein levels in co-cultures. In diabetic rats, it both prevented and restored nerve conduction velocity and nociceptive thresholds. We demonstrated that hyperglycaemia early affected neurite outgrowth through the impairment of SC-derived VEGF/FLT-1 signaling and that the neutralization of SC-secreted VEGF was protective both in vitro and in vivo models of diabetic neuropathy.

Bortezomib (BTZ) is the first proteasome inhibitor entered in clinical practice. Peripheral neuropathy is likely to be a class side effect of these drugs, although its severity is largely variable, and it deserves to be further investigated, since the mechanisms of BTZ-induced peripheral neurotoxicity (BiPN) are still unknown.   In our study, we investigated in vivo and in vitro possible pathogenic events relevant to BiPN using a well-established rat model, with particular reference to the extent of proteasome inhibition and the effects on α-tubulin polymerization in sciatic nerves and dorsal root ganglia specimens obtained from animals treated with chronic regimens at a dose of 0.2 mg/kg intravenously. The same assessments were also performed after a single injection. Moreover, these studies were replicated in vitro using embryonic DRG neurons exposed to 100 nM BTZ and adult DRG neurons exposed to 10-50 nM BTZ for 24 h and 48 h. A significant increase in the polymerized fraction of α-tubulin and prolonged proteasome inhibition were observed after the chronic BTZ treatment in vivo. Recovery to physiological levels was observed after a 4-week follow-up post-treatment period. Proteasome inhibition and increased α-tubulin polymerization were also observed following BTZ treatment of both embryonic and adult DRG neurons in vitro. Our in vivo results suggest that proteasome inhibition and alteration of tubulin dynamics contribute to BiPN. The in vitro systems here described reliably replicate the in vivo results, and might therefore be used for further mechanistic studies on the effects of proteasome inhibitors on neurons.

Background: Bortezomib is an anti-neoplastic drug acting against multiple myeloma but its use is associated with the onset of painful peripheral neuropathy. Tumor necrosis factor-α (TNFα) is associated with the development of neuropathic pain; several models have shown that the inactivation of TNFα leads to a reduction in pain stimuli perception. The aim of the present study was to analyze if the administration of an antibody against TNFα is able to prevent the development of bortezomib-induced neuropathic pain., Materials and Methods: Nerve conduction velocity was measured and a histopathological examination was performed to assess the extent of peripheral neuropathy. To study the onset of painful neuropathy, the response to mechanical or thermal stimuli was evaluated., Results: This study demonstrated that co-administration of an antibody against TNFα is able to prevent allodynia induced by bortezomib but does not reduce neuropathy., Conclusion: Targeting TNFα might be useful in limiting patients' discomfort during bortezomib therapy.

Islet transplantation is a poorly investigated long-term strategy for insulin replacement and for treatment of complications in patients with diabetes. We investigated whether islet transplantation and insulin treatment can relieve diabetic neuropathy and rescue the residual endogenous pancreatic β cells. We used a multimodal approach, with five groups of Sprague-Dawley rats studied for 8 months: control rats, diabetic rats, insulin-treated diabetic rats with moderate or mild hyperglycemia, and diabetic rats transplanted with microencapsulated islets. Islet transplantation normalized glycemia and increased body and muscle weight; it was also effective in reducing proteinuria and altered liver function. Transplantation significantly improved tail nerve conduction velocity, Na(+)-K(+)-ATPase activity, and morphological alterations in the sciatic nerve as evidenced by decrease in g-ratio; it also restored thermal and ameliorated mechanical nociceptive thresholds. Morphometric analysis of pancreas indicated a significant β-cell volume increase in transplanted rats, compared with mildly and moderately hyperglycemic rats. Thus, allogeneic islet transplantation had a positive systemic effect in diabetic rats and induced regression of the established neuropathy and restitution of the typical characteristics of the islets. These findings strongly reinforce the need for improving glycemic control, not only to reverse established diabetic complications but also to improve β-cell status in diabetic pancreas., (Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Since peripheral sensory neuropathy is the major, clinically relevant side effect of sagopilone we investigated the general and peripheral neurotoxicity of sagopilone administered intravenously with different doses (1.2 and 2.4 mg/kg) and schedules in 48 Wistar rats and we performed in parallel a pharmacokinetic/pharmacodynamic (PK/PD) study. A trend toward a different peripheral neurotoxicity could be assessed after 2 weeks of treatment (bolus > 30-min infusion > 3-h infusion) with both doses of sagopilone. Although sagopilone concentrations in peripheral nerve tissue above 100 ng/g were associated with a reduction in nerve conduction velocity (NCV), a clear dose-dependence of this reduction on the level of systemic exposure to sagopilone was not observed. The PK/PD evaluation revealed no consistent effect of the infusion duration on serum PK parameters or the PD read-out NCV. Sagopilone concentrations in brain, sciatic nerve, liver, and kidney were higher after bolus compared to infusion, but there were no influence of infusion duration on these concentrations. No correlation between sagopilone concentrations in any organ/tissue with NCV changes was detected. This study evidences that the PD of sagopilone is not the main determinant of the onset and severity of sagopilone-induced peripheral neurotoxicity in the investigated clinically-relevant dose range, thus indicating that further investigation might identify neuronal-specific mechanisms of action able to drive a focused strategy to prevent peripheral neurotoxicity without reducing the anticancer effectiveness of the epothilones.

Although bortezomib (BTZ) is the frontline treatment for multiple myeloma, its clinical use is limited by the occurrence of painful peripheral neuropathy, whose treatment is still an unmet clinical need. Previous studies have shown chronic BTZ administration (0.20 mg/kg intravenously three times a week for 8 weeks) to female Wistar rats induced a peripheral neuropathy similar to that observed in humans. In this animal model of BTZ-induced neurotoxicity, the present authors evaluated the efficacy of CR4056, a novel I2 ligand endowed with a remarkable efficacy in several animal pain models. CR4056 was administered in a wide range of doses (0.6-60 mg/kg by gavage every day for 2-3 weeks) in comparison with buprenorphine (Bupre) (28.8 μg/kg subcutaneously every day for 2 weeks) and gabapentin (Gaba) (100 mg/kg by gavage every day for 3 weeks). Chronic administration of BTZ reduced nerve conduction velocity and induced allodynia. CR4056, Bupre, or Gaba did not affect the impaired nerve conduction velocity. Conversely, CR4056 dose-dependently reversed BTZ-induced allodynia (minimum effective dose 0.6 mg/kg). The optimal dose found, 6 mg/kg, provided a constant pain relief throughout the treatment period and without rebound after suspension, being effective when coadministered with BTZ, starting before or after allodynia was established, or when administered alone after BTZ cessation. A certain degree of tolerance was seen after 7 days of administration, but only at the highest doses (20 and 60 mg/kg). Bupre was effective only acutely, since tolerance was evident from the fourth day onwards. Gaba showed a significant activity only at the fourth day of treatment. CR4056, over the range of concentrations of 3-30 μM, was unable to hinder BTZ cytotoxicity on several tumor cell lines, which could indicate that this substance does not directly interfere with BTZ antitumor activity. Therefore, CR4056 could represent a new treatment option for BTZ-induced neuropathic pain.

Purpose: Alterations in mRNA for myelin proteins are reported in animal models of chemotherapy-induced peripheral neuropathies (CIPN); however, ultrastructural changes in aldehyde-fixed and plastic-embedded myelin are not evident by electron microscopy. Therefore, we used X-ray diffraction (XRD) to investigate more subtle changes in myelin sheath structure from unfixed nerves., Experimental Design: We used in vivo chronic animal models of CIPN in female Wistar rats, administering cisplatin (CDDP 2mg/kg, i.p. twice/week), paclitaxel (PT 10mg/kg, i.v. once/week) or bortezomib (0.20mg/kg, i.v. three times/week) over a total period of 4weeks. Animal weights were monitored, and tail nerve conduction velocity (NCV) was determined at the end of the treatments to assess the occurrence of peripheral neuropathy. Sciatic nerves were collected and the myelin structure was analyzed using electron microscopy (EM) and XRD., Results: All the rats treated with the chemotherapy agents developed peripheral neuropathy, as indicated by a decrease in NCV values; however, light and electron microscopy indicated no severe pathological alterations of the myelin morphology. XRD also did not demonstrate significant differences between sciatic nerves in treated vs. control rats with respect to myelin period, relative amount of myelin, membrane structure, and regularity of membrane packing., Conclusions: These results indicate that experimental peripheral neuropathy caused by CDDP, PT, and bortezomib-which are among the most widely used chemotherapy agents-does not significantly affect the structure of internodal myelin in peripheral nerve., (Copyright © 2011 Elsevier Inc. All rights reserved.)

1-[(2-adamantyl)amino]acetyl-2-cyano-(S)-pyrrolidine, monohydrochloride (PKF275-055), a vildagliptin analog, is a novel, selective, potent, orally bioavailable, and long-acting dipeptidyl peptidase IV inhibitor. We studied the effect of PKF275-055 administration on the prevention, protection, and treatment of diabetic neuropathy in the streptozotocin-induced diabetic rat. PKF275-055 improved body and muscle weight. Oral glucose tolerance tests showed a marked improvement in glucose metabolism under all treatment schedules. When tested in prevention and protection experiments, PKF275-055 completely averted the decrease of Na⁺/K⁺-ATPase activity and partially counteracted the nerve conduction velocity (NCV) deficit observed in untreated diabetic rats but had no effects on abnormal mechanical and thermal sensitivity. When used in a therapeutic setting, PKF275-055 induced a significant correction in the alteration in Na⁺,K⁺-ATPase activity and NCV present in untreated diabetics. Diabetic rats developed mechanical hyperalgesia within 2 weeks after streptozotocin injection and exhibited significantly longer thermal response latencies. It is noteworthy that PKF275-055 treatment restored mechanical sensitivity thresholds by approximately 50% (p < 0.01) and progressively improved the alteration in thermal responsiveness. In conclusion, PKF275-055 showed an anabolic effect, improved oral glucose tolerance, and counteracted the alterations in Na⁺,K⁺-ATPase activity, NCV, and nociceptive thresholds in diabetic rats. The present data support a potential therapeutic effect of PKF275-055 in the treatment of rodent diabetic neuropathy.

Purpose: Cisplatin is one of the most effective cytotoxic agents in the treatment of solid malignancies, but its use is limited by several side effects. Among them, peripheral neurotoxicity can be dose limiting. A liposomal formulation of cisplatin, Lipoplatin™, was developed to reduce the systemic toxicity of cisplatin but without preventing its efficacy. The aim of this study was to use an animal model to establish, through a multimodal approach, whether chronic treatment with two different schedules of Lipoplatin™, selected within the range of its anticancer effective dose, is less neurotoxic than cisplatin administration., Methods: Female Wistar rats were treated intraperitoneally with cisplatin at a dose of 4 mg/kg or with Lipoplatin™ at doses delivering 12 or 24 mg/kg of cisplatin once weekly for 4 weeks. General toxicity was assessed by daily observation, body weight change, hematological and blood chemistry analysis, and histopathology of liver and kidney. The onset of peripheral neurotoxicity was assessed by measuring tail nerve conduction velocity (NCV), morphological and morphometric analysis of dorsal root ganglia (DRG), and morphological analysis of the sciatic nerve., Results: Cisplatin induced a statistically significant reduction in body weight, the development of renal failure, and impairment in NCV with pathological alterations in the DRG and sciatic nerve. By contrast, Lipoplatin™ was markedly less nephrotoxic, and no significant weight gain reduction was observed in animals treated with both doses of the drug. Moreover, the lowest dose induced less severe damage to the peripheral nervous system with a moderate decrease in NCV and mild pathological alterations in DRG and the sciatic nerve., Conclusions: The results suggest that Lipoplatin™ 12 mg/kg is less neurotoxic than cisplatin 4 mg/kg, thus opening up the possibility of using this new formulation in future studies where its anticancer activity and the peripheral neurotoxicity will be assessed in parallel.

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., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Bortezomib is a proteasome inhibitor showing strong antitumor activity against many tumors, primarily multiple myeloma. Bortezomib-induced neuropathic pain is the main side effect and the dose-limiting factor of the drug in clinical practice. In order to obtain a pre-clinical model to reproduce the characteristic pain symptoms in bortezomib-treated patients, we developed an animal model of bortezomib-induced nociceptive sensory neuropathy. In this study, bortezomib (0.15 or 0.20mg/kg) was administered to Wistar rats three times/week for 8 weeks, followed by a 4 week follow-up period. At the end of the treatment period a significant decrease in weight gain was observed in the treated groups vs. controls, and hematological and histopathological parameters were evaluated. After the treatment period, both doses of bortezomib induced a severe reduction in nerve conduction velocity and demonstrated a dose-cumulative effect of the drug. The sensory behavioral assessment showed the onset of mechanical allodynia, while no effect on thermal perception was observed. Sciatic nerves and dorsal root ganglia (DRG) were collected at the end of the 8-week treatment and at the end of the follow-up period. The pathological examination revealed a dose-dependent axonopathy of the unmyelinated fibers in nerves of treated animals. No pathological alteration in most of DRG satellite cells and neurons was observed. Therefore, this animal model may be useful for studying the neurotoxicity and pain onset mechanisms related to bortezomib treatment., (Copyright (c) 2009 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.)

Aims/hypothesis: Type 1 diabetes is a chronic disease leading to complications such as peripheral neuropathies, nephropathy and cardiovascular disease. Pancreatic islet transplantation is being extensively investigated for blood glucose control in animals and in human type 1 diabetic patients, but the question of whether it can reverse long-term diabetic complications has not been fully explored. We investigated the effects of islet transplantation on diabetic complications in a rat model of streptozotocin-induced diabetes., Methods: Three groups of rats were used: healthy controls, diabetic and diabetic rats transplanted with microencapsulated islets at 2 months after diabetes induction, when neuropathy was detectable by a decrease in tail nerve conduction velocity (NCV) and impaired nociceptive thresholds. Blood glucose levels and body weight were measured weekly. The variables considered were: thermal (hot plate test) and mechanical sensitivity (Randal-Selitto paw withdrawal test), NCV and Na+, K+-ATPase activity in the sciatic nerve. At the end of the experiments hearts were removed for morphometric determination and myocyte number, and kidneys removed for histological examination., Results: Islet transplantation in diabetic rats induced normoglycaemia in a few days, accompanied by a rapid rise in body weight and amelioration of impaired nociceptive thresholds, as well as normalisation of NCV and Na(+), K(+)-ATPase, which were both about 25% below normal in diabetic rats. Myocyte loss was reduced (-34%) by islet transplantation and the observed mild kidney damage of diabetic rats was prevented., Conclusions/interpretation: Besides controlling glycaemia, transplantation of microencapsulated pancreatic islets induced almost complete regression of neuropathy and prevented cardiovascular alterations.

Epothilones are a novel class of microtubule-targeting anticancer agents that are neurotoxic. In this study, we investigated the epothilone B toxic effect in vitro and we characterized in vivo the general and neurological side effects of epothilone B administration in Wistar and Fischer rats. The in vitro experiments made it possible to explore a wide concentration range (0.1 nM-1 muM) and evidenced a dose-dependent effect of epothilone B exposure on neuron neurite elongation. This dose-dependent neurotoxic effect was confirmed in both in vivo studies performed on two different rat strains at the neurophysiological, behavioral and pathological levels in the dose range 0.25-1.5 mg/kg iv weekly x 4 weeks and tubulin hyper-polymerization was demonstrated in sciatic nerve specimens. These are the first studies of the neurological effects of epothilone B and they can provide a basis for extending pre-clinical investigation to other members of the epothilone family.

We have characterised for the first time the general and neurological side effects experienced when using a series of chronic non-lethal cisplatin + paclitaxel schedules in Wistar rats, selected according to our previous experience and the animals' maximum tolerated dose. At the pathological level, the use of combination schedules was definitely more toxic at the kidney and sternal bone marrow level than the single-agent schedules. At the neurophysiological examination based on the assessment of the nerve conduction velocity measurement in the tail nerve, we identified only one combination schedule that was more neurotoxic than the similar schedules based on single-agent administration. This observation was confirmed by the neuropathological examination performed on the sciatic nerve, dorsal root ganglia, ventral and dorsal roots. Our study supports the hypothesis that the general and, to a lesser extent, neurological effects of a combination of cisplatin and paclitaxel are different from those of the administration of both drugs as single agents. We believe that these models may be useful for testing neuroprotective strategies.

Actively induced Lewis rat Experimental Autoimmune Encephalomyelitis (EAE) is a highly reproducible model for portraying the acute phase of multiple sclerosis. Our aim was to get more information about this model by means of flow cytometry looking at potential markers for tracing new treatments' efficacy. Thus we characterized the changes occurring in encephalitogenic TCR Vbeta8.2(+) frequency and the adhesion molecule alpha4 integrin expression in both spleen and spinal cord T cells. The increase in both these parameters was observed only in spinal cord infiltrating T cells while relevant changes in spleen cell composition were observed as early as disease onset.

Background: Antineoplastic drugs, such as cisplatin (CDDP), induce disabling peripheral neuropathies, representing a hindrance to effective cancer treatments. The exact pathogenesis of CDDP-induced neuropathy is not yet understood, and the dysregulation of gene expression has been proposed. Valproate (VPA) is an antiepileptic drug recently discovered to remodel gene expression, with hypothetically putative neuroprotective effects., Materials and Methods: VPA was tested in both, in vitro and in vivo models of CDDP-neurotoxicity., Results: VPA administered in combination with CDDP promoted dorsal root ganglia (DRG) neurons survival. Moreover, this treatment induced in Wistar rats an improvement of body weight, sensory nerve conduction velocity, and DRG morphometric analysis. In contrast, VPA was not able to rescue CDDP pre-treated rats., Conclusion: When used in combination with CDDP, VPA displays a protective action against neuropathy, in our models, suggesting possible future clinical applications.

Anthracyclines and anthracenediones are important oncotherapeutics; however, their use is associated with irreversible and cumulative cardiotoxicity. A novel aza-anthracenedione, pixantrone (BBR 2778), was developed to reduce treatment-related cardiotoxicity while retaining efficacy. This study evaluates the cumulative cardiotoxic potential of pixantrone compared with equiactive doses of doxorubicin and mitoxantrone in both doxorubicin-pretreated and doxorubicin-naïve mice. CD1 female mice were given doxorubicin 7.5 mg/kg (once weekly for 3 weeks) followed 6 weeks later by either sterile 0.9% saline, doxorubicin 7.5 mg/kg, pixantrone 27 mg/kg, or mitoxantrone 3 mg/kg (once weekly for 3 weeks). A second group of CD1 female mice were given 2 cycles of either sterile 0.9% saline, pixantrone 27 mg/kg, doxorubicin 7.5 mg/kg, or mitoxantrone 3 mg/kg (once weekly for 3 weeks). Animals were sacrificed at different time points for histopathologic examination of the heart. In the doxorubicin-pretreated mice, further exposure to doxorubicin or mitoxantrone resulted in a significant worsening of pre-existing degenerative cardiomyopathy. In contrast, pixantrone did not worsen pre-existing cardiomyopathy in these animals. Only minimal cardiac changes were observed in mice given repeated cycles of pixantrone, while 2 cycles of doxorubicin or mitoxantrone resulted in marked or severe degenerative cardiomyopathy. These animal studies demonstrate the reduced cardiotoxic potential of pixantrone compared with doxorubicin and mitoxantrone. Exposure to pixantrone did not worsen pre-existing cardiomyopathy in doxorubicin-pretreated mice, suggesting that pixantrone may be useful in patients pretreated with anthracyclines.

This study examined the dose-dependent efficacy of erythropoietin (EPO) for preventing and/or treating cisplatin (CDDP) induced peripheral neurotoxicity (CINP), and its influence on tumour treatment and growth. Rats received eight intraperitoneal (ip) injections of 2 mg/kg CDDP twice weekly. EPO co-administered (50 or 10 microg/kg ip, three times/week) had a dose-dependent effect, partially preventing CINP, but 0.5 microg/kg ip was not effective. The neuroprotective effect lasted at least 5 weeks after the last dose of EPO and CDDP. In addition, EPO (50 microg/kg ip three times/week) after the last injection of CDDP still induced a significant recovery of CINP. In a separate experiment in rats bearing mammary carcinoma EPO treatment (50 microg/kg ip) given concurrently with CDDP (1.0 and 1.5 mg/kg twice a week for four weeks) was neuroprotective without influencing the effectiveness of the treatment or tumour growth. EPO thus appears to be an effective neuroprotectant that does not interfere with tumour treatment.

Bortezomib is a new proteasome inhibitor with a high antitumor activity, but also with a potentially severe peripheral neurotoxicity. To establish a preclinical model and to characterize the changes induced on the peripheral nerves, dorsal root ganglia (DRG) and spinal cord, bortezomib was administered to Wistar rats (0.08, 0.15, 0.20, 0.30 mg/kg/day twice [2q7d] or three times [3q7d] weekly for a total of 4 weeks). At baseline, on days 14, 21 and 28 after the beginning the treatment period and during a 4-week follow-up period sensory nerve conduction velocity (SNCV) was determined in the tail of each animal. Sciatic nerve, DRG and spinal cord specimens were processed for light and electron microscope observations and morphometry. At the maximum tolerated dose bortezomib induced a significant reduction in SNCV, with a complete recovery at the end of the follow-up period. Sciatic nerve examination and morphometric determinations demonstrated mild to moderate pathological changes, involving predominantly the Schwann cells and myelin, although axonal degeneration was also observed. Bortezomib-induced changes were also observed in DRG and they were represented by satellite cell intracytoplasmatic vacuolization due to mitochondrial and endoplasmic reticulum damage, closely resembling the changes observed in sciatic nerve Schwann cells. Only rarely did the cytoplasm of DRG neurons has a dark appearance and clear vacuoles occurring in the cytoplasm. Spinal cord was morphologically normal. This model is relevant to the neuropathy induced by bortezomib in the treatment of human malignancies and it could be useful in increasing our knowledge regarding the mechanisms underlying bortezomib neurotoxicity.

Purpose: Antineoplastic drugs, such as cisplatin (CDDP), are severely neurotoxic, causing disabling peripheral neuropathies with clinical signs known as chemotherapy-induced peripheral neurotoxicity. Cotreatment with neuroprotective agents and CDDP has been proposed for preventing or reversing the neuropathy. Erythropoietin given systemically has a wide range of neuroprotective actions in animal models of central and peripheral nervous system damage. However, the erythropoietic action is a potential cause of side effects if erythropoietin is used for neuroprotection. We have successfully identified derivatives of erythropoietin, including carbamylated erythropoietin, which do not raise the hematocrit but retain the neuroprotective action exerted by erythropoietin., Experimental Design: We have developed previously an experimental chemotherapy-induced peripheral neurotoxicity that closely resembles CDDP neurotoxicity in humans. The present study compared the effects of erythropoietin and carbamylated erythropoietin (50 microg/kg/d thrice weekly) on CDDP (2 mg/kg/d i.p. twice weekly for 4 weeks) neurotoxicity in vivo., Results: CDDP given to Wistar rats significantly lowered their growth rate (P < 0.05), with slower sensory nerve conduction velocity (P < 0.001) and reduced intraepidermal nerve fibers density (P < 0.001 versus controls). Coadministration of CDDP and erythropoietin or carbamylated erythropoietin partially but significantly prevented the sensory nerve conduction velocity reduction. Both molecules preserved intraepidermal nerve fiber density, thus confirming their neuroprotective effect at the pathologic level. The protective effects were not associated with any difference in platinum concentration in dorsal root ganglia, sciatic nerve, or kidney specimens., Conclusions: These results widen the spectrum of possible use of erythropoietin and carbamylated erythropoietin as neuroprotectant drugs, strongly supporting their effectiveness.

Pixantrone is less cardiotoxic and is similarly effective to mitoxantrone (MTX) as an antineoplastic drug. In our study, pixantrone reduced the severity of acute and decreased the relapse rate of chronic relapsing experimental allergic encephalomyelitis (EAE) in rats. A marked and long-lasting decrease in CD3+, CD4+, CD8+ and CD45RA+ blood cells and reduced anti-MBP titers were observed with both pixantrone and MTX. In vitro mitogen- and antigen-induced T-cell proliferation tests of human and rodents cells evidenced that pixantrone was effective at concentrations which can be effectively obtained after i.v. administration in humans. Cardiotoxicity was present only in MTX-treated rats. The effectiveness and the favorable safety profile makes pixantrone a most promising immunosuppressant agent for clinical use in multiple sclerosis (MS).

Extra corporeal photochemotherapy (ECP) is an immunomodulating procedure used in several nonneurological diseases which, similarly to multiple sclerosis, are likely to be due to T-cell-mediated autoimmunity and it is probable that ECP can modulate the normal activity of peripheral blood mononuclear cells (PBMC). Using the Lewis rat experimental allergic encephalomyelitis (EAE) model of human multiple sclerosis (MS) we examined the effect of extracorporeal UV-A irradiation on psoralen-activated PBMC. In our experiment the comparison between the two groups of animals (ECP or sham-treatment) evidenced that the ECP treatment reduced the severity of EAE on clinical grounds and this result was confirmed by the pathological examination. The changes in the titers of anti-myelin antigen antibodies typical of EAE were also modulated by the procedure. Ex vivo examination evidenced a significant reduction in tumor-necrosis factor-alpha (TNF-alpha) released by PBMC after lipopolysaccharides (LPS) stimulation in culture. We conclude that ECP modifies the normal activity of PBMC during the course of EAE and it is possible that one of the anti-inflammatory mechanisms of action of ECP is correlated to a down-regulation of T-helper 1 lymphocytes activity.

Experimental allergic encephalomyelitis (EAE) is a well-established model of human multiple sclerosis that is commonly used to evaluate the possible effectiveness of new treatments in this disease. Extracorporeal photochemotherapy (ECP) is an immunomodulating procedure currently used in several non-neurological diseases that, like multiple sclerosis, are likely to be due to T-cell-mediated autoimmunity. In this study we examined the effect of ECP using the EAE paradigm in the Lewis rat. In our model, ECP induced a significant modulation in peripheral blood T-cell distribution, changes which are typical of EAE. Remarkably, this effect was closely correlated with the clinical and pathological results, which showed reduced severity of the disease in the ECP-treated EAE animals vs. the EAE alone rats. We conclude that ECP induces modifications in the immunological events that occur during the course of EAE in rats, thus giving support to the hypothesis that it could be used in the treatment of multiple sclerosis.

The distribution of paclitaxel (Taxol) within the central and peripheral nervous system after repeated administration of this antineoplastic agent is still largely unknown. In this study we determined for the first time paclitaxel tissue concentration in the brain, spinal cord, dorsal root ganglia (DRG) and sciatic nerve using an experimental paradigm in the rat which reproduces the features of paclitaxel peripheral neurotoxicity in humans. Pathological confirmation of the onset of paclitaxel-induced peripheral neurotoxicity was performed. In order to achieve reliable results even with low concentrations of paclitaxel, a newly reported analytical method (high-performance liquid chromatography with tandem mass spectrometry) was used. We demonstrated that paclitaxel has easy access to the DRG, where it accumulates, while the lowest concentrations of the drug were measured in the brain. The intermediate concentrations of paclitaxel observed in the sciatic nerve and spinal cord may be due to paclitaxel transport along the centrifugal and centripetal branches of the DRG neuron axons.

The effectiveness of paclitaxel (Taxol) in the treatment of different tumors is well-known but, on the other hand, there is little information regarding its neurotoxicity and the mechanism(s) underlying this potentially severe side effect. In this study, using behavioral, neurophysiological, morphological and morphometric methods, we evaluated the effect of intravenous administration of paclitaxel on the rat nervous system. After 2 pilot studies, 40 female Wistar rats were treated with intravenous paclitaxel via a catheter placed in the jugular vein, while 20 animals were used as controls. Paclitaxel dissolved in ethanol/Tween 80/saline (5/5/90%) was administered 5 times over a period of 10 days. At the end of the experiment half the surviving animals in each group were evaluated and sacrificed (day 11), while the rest of the rats were evaluated and sacrificed on day 25. On day 11 the treated animals had significant impairment in pain perception (tail-flick test), coordination (rota-rod test) and nerve conduction velocity in the tail nerve. At the light microscope minimal axonal damage and Schwann cell activation were observed in the sciatic nerve. At the electron microscope microtubular accumulation was present within the axon in dorsal and ventral spinal roots and in the sciatic nerve. On day 25 the behavioral tests were normal in treated rats, while the nerve conduction velocity was still moderately reduced in comparison with the controls. At the electron microscope a morphological examination evidenced that microtubular accumulation was less severe, but still evident, especially in the sciatic nerve. Morphometric determinations performed on days 11 and 25 did not evidence differences between paclitaxel-treated rats and controls. The results of this study, the first in which an extended examination of the nervous system of animals treated intravenously with paclitaxel has been carried out, suggest that short-term administration of the drug induces mainly reversible changes in the peripheral nerves and spinal roots. Microtubules seem to be the main target of paclitaxel neurotoxicity, in much the same way as has been described for its antineoplastic activity. Finally, no pathological changes were seen in the neuronal bodies of the spinal cord and dorsal root ganglia. This model may be used for further studies with combination treatments with other antineoplastic or neuroprotective agents.