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The development and progression of diabetic polyneuropathy (DPN) are due to multiple mechanisms. The creation of reliable animal models of DPN has been challenging and this issue has not yet been solved. However, despite some recognized differences from humans, most of the current knowledge on the pathogenesis of DPN relies on results achieved using rodent animal models. The simplest experimental DPN model reproduces type 1 diabetes, induced by massive chemical destruction of pancreatic beta cells with streptozotocin (STZ). Spontaneous/transgenic models of diabetes are less frequently used, mostly because they are less predictable in clinical course, more expensive, and require a variable time to achieve homogeneous metabolic conditions. Among them, Zucker diabetic fatty (ZDF) rats represent a typical type 2 diabetes model. Both STZ-induced and ZDF rats have been extensively used, but only very few studies have compared the long-term similarities and differences existing between these two models. Moreover, inconsistencies have been reported regarding several aspects of short-term in vivo studies using these models. In this study, we compared the long-term course of DPN in STZ-treated Sprague–Dawley and ZDF rats with a multimodal set of readout measures.

The onset of chemotherapy-induced peripheral neurotoxicity (CIPN) is a leading cause of the dose reduction or discontinuation of cancer treatment due to sensory symptoms. Paclitaxel (PTX) can cause painful peripheral neuropathy, with a negative impact on cancer survivors’ quality of life. While recent studies have shown that neuroinflammation is involved in PTX-induced peripheral neurotoxicity (PIPN), the pathophysiology of this disabling side effect remains largely unclear and no effective therapies are available. Therefore, here we investigated the effects of human intravenous immunoglobulin (IVIg) on a PIPN rat model. PTX-treated rats showed mechanical allodynia and neurophysiological alterations consistent with a severe sensory axonal polyneuropathy. In addition, morphological evaluation showed a reduction of intra-epidermal nerve fiber (IENF) density and evidenced axonopathy with macrophage infiltration, which was more prominent in the distal segment of caudal nerves. Three weeks after the last PTX injection, mechanical allodynia was still present in PTX-treated rats, while the full recovery in the group of animals co-treated with IVIg was observed. At the pathological level, this behavioral result was paralleled by prevention of the reduction in IENF density induced by PTX in IVIg co-treated rats. These results suggest that the immunomodulating effect of IVIg co-treatment can alleviate PIPN neurotoxic manifestations, probably through a partial reduction of neuroinflammation.

Dorsal root ganglia (DRG) sensitive neurons represent the connection between the peripheral sensorial receptors and the central nervous system. These neurons are enwrapped individually by the satellite glial cells (SCGs) from which they receive metabolic support. Together, neuron and SCGs, become a functional unit that, in absence of the blood brain barrier, is easily exposed to external stress and damage insults. This intimate connection/relationship, both morphological and functional, can be partially pictured and studied following traditional slicing 2D histopathological techniques. Indeed, morphological cellular and subcellular alterations and changes in protein expression and/or distribution can be observed using classical techniques. However, a whole-3D approach avoids the serial sectioning required for quantitative results plus is able to show the cyto-architecture of the organ and a more complete picture of the anatomical relationship between cell populations close to physiological conditions. Here we use a 3D imaging technique to show the cyto-architecture of the DRG after “colouring” by immunofluorescence the different DRG cell populations and to assess alterations in DRG of neuropathic rats. CGRP, IB4 and MAP2 markers were useful to study the different neuronal populations. The IB4-MAP2 combination was able to label all neurons while the CGRP-IB4 couple could not but still both settings showed a small subpopulation of neurons where the proteins were co-expressed. Moreover, GFAP, ATF3 and connexin 43 were used as markers of damage in the DRG from neuropathic animals.

Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of the most important side-effect of several anticancer drugs, including Paclitaxel (PTX, taxane family) and Vincristine (VCR, vinca alkaloid family). The mechanisms involved in CIPN onset are not completely understood; several neurotoxic hypotheses have been proposed, among which the role of the neuroinflammation process is emerging. In particular, different studies demonstrated that the role of macrophage infiltration correlated to neurotoxicity and sensory nervous system sensitization. We investigated the presence of macrophage infiltratE in two well-assessed preclinical models of PTX- and VCR- induced peripheral neurotoxicity. Female Wistar rats were divided in control (CTRL), PTX- (10mg/kg i.v. q7dx4 ws) and VCR- (0.2mg/kg i.v. q7dx4 ws) treated groups. The development of CIPN was confirmed by neurophysiological, morphological examinations and behavioral tests, whereas macrophage infiltration and description were obtained by immunoistochemical analyses. PTX and VCR chronic administration induced different degrees of axonal damage and macrophage infiltration in peripheral nerves. In particular, macrophage infiltrate was detected from the first week of treatment in PTX-treated animals, with a progressive increase until the end of treatment. On the contrary, VCR treatment induced a milder macrophage infiltration detected after 2 weeks of treatment, which remained constant until the end of the experiment. Moreover, immunoistochemical analyses evidenced that all the infiltrating cells had a pro-inflammatory phenotype. CIPN was detected from the second week after both anticancer administrations, with a stronger severity in PTX group compared to VCR one. These preliminary results evidence a different amount of macrophage infiltration in CIPN induced by PTX and VCR. Since the detection of inflammatory infiltrate was early and sustained until the end of the drug treatment, it could have a relevant role into the

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a significant complication in the successful treatment of many cancers. For several antineoplastic agents neurotoxicity is common, severe, usually doselimiting, and clinically reflected in an axonal peripheral neuropathy with glove-and-stocking distribution of sensory loss, often associated with neuropathic pain. These symptoms may be disabling, adversely affecting activities of daily living and thereby quality of life of cancer patients. In particular, we have focused on bortezomib, a first-in-class proteasome inhibitor used for the treatment of multiple myeloma, which is associated with a relatively high incidence of CIPN. The pathogenesis of CIPN has not been completely understood, and there are no effective strategies to prevent this side effect, with limited evidence of effective drugs for treating established neurotoxicity. Among possible pharmacological treatments of CIPN, modulation of the endocannabinoid system might be particularly promising. To investigate this hypothesis, we performed electrophysiological, behavioral and pathological analyses in a rat model of painful CIPN induced by treatment with bortezomib. The animals were intravenously injected with bortezomib 0.20 mg/kg, 3 times a week for 8 weeks. Moreover, localization of CB1R/CB2R-like immunoreactivity and protein quantification for CB1R/CB2R were performed in dorsal root ganglion (DRG) and in the spinal cord. In addition, CD68 positive macrophages in the peripheral nerve as well as resident macrophages (Iba-1) positive cells or microglia were also evaluated in the DRG and spinal cord dorsal horn, respectively. Bortezomib induced significant alterations in rat electrophysiological endpoints and behavioral studies of pain associated with a significant reduction in IENF density if compared to control rats. Moreover, huge M1 proinflammatory infiltrating cells in caudal nerves and increased Iba-1 positive cells in DRG and microglia in the spina

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a common complication in the successful treatment of cancer. This side effect is dose-limiting and clinically reflects in an axonal peripheral neuropathy with sensory loss, combined often with neuropathic pain. These symptoms may be disabling, dversely affecting the quality of life of patients. Here we focussed on bortezomib (BTZ), a first-in-class proteasome inhibitor used for the treatment of ultiple myeloma, which is associated with a relatively high incidence of CIPN. The pathogenesis of CIPN has not been completely understood, and there are no effective strategies or drugs to prevent or treat this side effect. Among possible pharmacological treatments of CIPN, modulation of the endocannabinoid system might be particularly promising. To investigate this hypothesis, we performed electrophysiological, behavioral and pathological analyses in a rat model of painful CIPN induced by BTZ-treatment. Animals were intravenously injected with BTZ 0.20 mg/kg, 3 times a week for 8 weeks. Moreover, localization of CB1R/CB2R-like immunoreactivity (LI) and protein quantification for CB1R/CB2R were performed in dorsal root ganglia (DRG) nd in the spinal cord. In addition, cd68-LI macrophages in the peripheral nerve as well as resident Iba-1 positive cells, macrophages or microglia, were lso evaluated in the DRG and spinal cord dorsal horn (DH), respectively. BTZ induced alterations in rat electrophysiological endpoints and behavioral tudies of pain associated with a reduction in intraepidermal nerve fiber density if compared to control rats. Moreover, huge M1 proinflammatory nfiltrating cells in caudal nerves and increased Iba-1 positive cells in DRG and microglia in the DH of rats after 8 weeks of treatment were also observed. In addition, BTZ induced an increase in the number of CB1Rand CB2R-LI DRG neurons, as well as an increase in CB1R and CB2R protein expression in dRG. The densitometric analysis on BTZ-treated DH show

Oxaliplatin (OHP) is an antineoplastic compound able to induce peripheral neurotoxicity. Oxidative stress has been suggested to be a key factor in the development of OHP‐related peripheral neurotoxicity. Mangafodipir, a contrast agent possessing mitochondrial superoxide dismutase (MnSOD)‐mimetic activity, has been tested as a cytoprotector in chemotherapy‐induced peripheral neurotoxicity (CIPN). Calmangafodipir (PledOx®) has even better therapeutic activity. We investigated a BALB/c mouse model of OHP‐related CIPN and the effects of the pre‐treatment of calmangafodipir (2.5, 5, or 10 mg/kg intravenously) on sensory perception, and we performed a pathological study on skin biopsies to assess intraepidermal nerve fiber (IENF) density. At the end of the treatments, OHP alone or in pre‐treatment with calmangafodipir 2.5 and 10 mg/kg, induced mechanical allodynia and cold thermal hyperalgesia, but calmangafodipir 5 mg/kg prevented these effects. Accordingly, OHP alone or in pre‐treatment with calmangafodipir 2.5 and 10 mg/kg, induced a significant reduction in IENF density, but calmangafodipir 5 mg/kg prevented this reduction. These results confirm a protective effect of calmangafodipir against OHP‐induced small fiber neuropathy. Interestingly, these results are in agreement with previous observations suggesting a U‐shaped effect of calmangafodipir, with the 10 mg/kg dose less effective than the lower doses.

Chemotherapy-induced peripheral neurotoxicity represents one of the most relevant dose-limiting side effects that can affect cancer patients treated with the common antineoplastic agents. Since the severity of neurotoxicity often leads to dose reduction or early cessation of chemotherapy, the investigation of molecular mechanisms underlying chemotherapy-induced peripheral neurotoxicity is an urgent clinical need in order to better understand its physiopathology and find effective strategies for neuroprotection. Several in vivo preclinical models of chemotherapy-induced peripheral neurotoxicity have been developed but a great variability in mouse strain, dose, route of administration of the drug, treatment schedule and assessment of neurotoxicity is observed between the different published studies making difficult the comparison and interpretation of their results. In many of these studies only behavioural tests are used as outcome measures, while possible neurophysiological and neuropathological changes are not evaluated. In this study, focused on experimental oxaliplatin-induced peripheral neurotoxicity, we reproduced and compared four mouse models with very different drug dose (low or high dose-intensity) and treatment schedules (short or long-term treatment), selected from the literature. Using a multimodal assessment based on behavioural, neurophysiological and neuropathological methods, we evidenced remarkable differences in the results obtained in the selected animal models. This work suggests the importance of a multimodal approach including extensive pathological investigation to confirm the behavioural results.

Oxaliplatin (OHP) Induced Peripheral Neurotoxicity (OIPN) is one of the dose-limiting toxicities of the drug and these adverse effects limit cancer therapy with L-OHP, used for colorectal cancer treatment. Acute neurotoxicity consists of symptoms that are the hallmarks of a transient axonal hyperexcitability; chronic neurotoxicity has a clinical picture compatible with a length-dependent sensory neuropathy. Acute OIPN pathogenesis has been linked to sodium voltage-operated channels (Na + VOC) dysfunction and it has been advocated as a possible predisposing factor to chronic neurotoxicity. We tested if topiramate (TPM), a well-known Na + VOC modulator, was able to modify acute as well as chronic OIPN. The project was divided into two parts. In Experiment 1 we tested by means of Nerve Excitability Testing (NET) a cohort of female Wistar rats to assess TPM effects after a single OHP administration (5 mg/kg, iv). In Experiment 2 we assessed TPM effects after chronic OHP treatment (5 mg/kg, 2qw4ws, iv) using NET, nerve conduction studies (NCS), behavioral tests and neuropathology (caudal nerve morphometry and morphology and Intraepidermal Nerve Fiber [IENF] density). In Experiment 1 TPM was able to prevent OHP effects on Na + VOC: OHP treatment induced a highly significant reduction of the sensory nerve's threshold, during the superexcitability period (p-value = 0.008), whereas TPM co-administration prevented this effect. In Experiment 2 we verified that TPM was able to prevent not only acute phenomena, but also to completely prevent chronic OIPN. This latter observation was supported by a multimodal approach: in fact, only OHP group showed altered findings compared to CTRL group at a neurophysiological (proximal caudal nerve sensory nerve action potential [SNAP] amplitude, p-value = 0.001; distal caudal nerve SNAP amplitude, p-value<0.001, distal caudal nerve sensory conduction velocity, p-value = 0.04), behavioral (mechanical threshold, p-value 0.003) and neuropatho

Background Multiple cell signaling pathways are implicated in the development, progression, and persistence of cisplatin-induced peripheral neuropathy. Although advances have been made in terms of understanding specific neurotoxic mechanisms, there are few predictive factors identified that can help inform the clinician approach to symptom prevention or management. Objective We investigate the differential sensitivity to cisplatin-induced peripheral neuropathy and examine the contribution of dorsal root ganglion (DRG) transcriptional profiles across two inbred strains of mice. Methods Cisplatin (4 mg/kg intraperitoneal or vehicle control) was administered twice a week for 4 weeks to adult female C57BL/6J and A/J mice - the C57BL/6J strain of mice characterized by a robust mechanical allodynia and the A/J with a mild largely resistant allodynia phenotype. Peripheral nerve conduction velocities (NCVs), electrophysiological evaluation of wide dynamic range (WDR) neurons, morphological examination of DRG neurons, and microarray analysis of spinal cord tissues were compared across the 4 weeks. Results The A/J strain presents with an early, mild nocifensive response to cisplatin with reduced neuronal activity in WDR neurons and small changes in cross-sectional nucleus size in DRG neurons at 4 weeks. The more nocifensive-sensitive C57BL/6J strain presents with no early changes in WDR neuron responsiveness; however, there were significant changes in DRG size. Both strains demonstrate a drop in NCV after 4 weeks of treatment, with the greatest reduction present in the A/J strain. Transcriptome data implicate neuroimmune modulation in the differential response to cisplatin in the DRGs of A/J and C57BL/6J mice. Discussion Nocifensive responses in both strains implicate involvement of small myelinated and unmyelinated fibers in neurotoxic cisplatin response, whereas reductions in NCV reflect involvement of the largest myelinated fibers in the peripheral nerves. Microarray data

Background: Chemotherapy-induced peripheral neurotoxicity (CIPN) is a severe adverse effect in patients receiving antitumor agents, and no effective treatment is available. Although the mechanisms responsible for the development of CIPN are poorly understood, recent findings make neuroinflammation an attractive target to be investigated, particularly when neuropathic pain is a prominent feature such as after bortezomib administration. The aim of our study was to evaluate the effect of intravenous immunoglobulins (IVIg) delivery in chronic CIPN. The related neuro-immune aspects were investigated in a well-characterized rat model of bortezomib-induced peripheral neurotoxicity (BIPN). Methods: After determination of a suitable schedule based on a preliminary pharmacokinetic pilot study, female Wistar rats were treated with IVIg 1g/kg every 2weeks. IVIg treatment was started at the beginning of bortezomib administration ("preventive" schedule), or once BIPN was already ensued after 4weeks of treatment ("therapeutic" schedule). Neurophysiological and behavioral studies were performed to assess the extent of painful peripheral neurotoxicity induced by bortezomib, and these functional assessments were completed by pathologic examination of peripheral nerves and intraepidermal nerve fiber quantification (IENF). The role of the innate immune response in BIPN was investigated by immunochemistry characterization of macrophage infiltration in peripheral nerves. Results: Both schedules of IVIg administration were able to significantly reduce bortezomib-induced heat and mechanical allodynia. Although these changes were not evidenced at the neurophysiological examination of peripheral nerves, they behavioral effects were paralleled in the animals treated with the preventive schedule by reduced axonopathy in peripheral nerves and significant protection from loss of IENF. Moreover, IVIg administration was very effective in reducing infiltration in peripheral nerves of macrophages wi

Type-1 Diabetes is generally treated with exogenous insulin administration. Despite treatment, a very common long term consequence of diabetes is the development of a disabling and painful peripheral neuropathy. The transplantation of pancreatic islets is an advanced alternative therapeutic approach, but its clinical application is still very limited, mainly because of the great number of islets required to complete the procedure and of their short-term survival. An intriguing method to improve the performance of pancreatic islets transplantation is the co-transplantation of Mesenchymal Stem Cells (MSCs), adult stem cells already known to support the survival of different cellular populations. In this proof-of-concept study, we demonstrated using an in vivo model of diabetes, the ability of allogenic MSCs to reduce the number of pancreatic islets necessary to achieve glycemic control in diabetic rats, and overall their positive effect on diabetic neuropathy, with the reduction of all the neuropathic signs showed after disease induction. The cutback of the pancreatic islet number required to control glycemia and the regression of the painful neuropathy make MSC co-transplantation a very promising tool to improve the clinical feasibility of pancreatic islet transplantation for diabetes treatment

This study is aimed at describing the changes occurring in the entire peripheral nervous system sensory pathway along a 2-year observation period in a cohort of C57BL/6 mice. The neurophysiological studies evidenced significant differences in the selected time points corresponding to childhood, young adulthood, adulthood, and aging (i.e., 1, 7, 15, and 25 months of age), with a parabolic course as function of time. The pathological assessment allowed to demonstrate signs of age-related changes since the age of 7 months, with a remarkable increase in both peripheral nerves and dorsal root ganglia at the subsequent time points. These changes were mainly in the myelin sheaths, as also confirmed by the Rotating-Polarization Coherent-Anti-stokes-Raman-scattering microscopy analysis. Evident changes were also present at the morphometric analysis performed on the peripheral nerves, dorsal root ganglia neurons, and skin biopsies. This extensive, multimodal characterization of the peripheral nervous system changes in aging provides the background for future mechanistic studies allowing the selection of the most appropriate time points and readouts according to the investigation aims.