Clinical and preclinical features of eribulin-related peripheral neuropathy.

Different microtubule-targeting agents (MTAs) possess distinct modes of action and their clinical use in cancer treatment is often limited by chemotherapy-induced peripheral neurotoxicity (CIPN). Eribulin is a member of the halichondrin class of antineoplastic drugs, which is correlated with a high antimitotic activity against metastatic breast cancer and liposarcoma. Current clinical evidence suggests that eribulin treatment, unlike some of the other MTAs, is associated with a relatively low incidence of severe peripheral neuropathy. This suggests that different MTAs possess unique mechanisms of neuropathologic induction. Animal models reliably reproduced eribulin-related neuropathy providing newer insights in CIPN pathogenesis, and they are highly suitable for in vivo functional, symptomatic and morphological characterizations of eribulin-related CIPN. The purpose of this review is to discuss the most recent literature on eribulin with a focus on both clinical and preclinical data, to explain the molecular events responsible for its favorable neurotoxic profile.

Ghrelin agonist HM01 attenuates chemotherapy-induced neurotoxicity in rodent models.

Chemotherapy-Induced Peripheral Neurotoxicity (CIPN) is often dose-limiting and impacts life quality and survival of cancer patients. Ghrelin agonists have neuroprotectant effects and may have a role in treating or preventing CIPN. We evaluated the CNS-penetrant ghrelin agonist HM01 in three experimental models of CIPN at doses of 3-30 mg/kg p.o. daily monitoring orexigenic properties, nerve conduction, mechanical allodynia, and intra-epidermal nerve fiber density (IENFD). In a cisplatin-based study, rats were dosed daily for 3 days (0.5 mg/kg i.p.) + HM01. Cisplatin treatment induced mechanical hypersensitivity which was significantly reduced by HM01. In a second study, oxaliplatin was administered to mice (6 mg/kg i.p. 3 times/week for 4 weeks) resulting in significant digital nerve conduction velocity (NCV) deficits and reduction of IENFD. Concurrent HM01 dose dependently prevented the decline in NCV and attenuated the reduction in IENFD. Pharmacokinetic studies showed HM01 accumulation in the dorsal root ganglia and sciatic nerves which reached concentrations > 10 fold that of plasma. In a third model, HM01 was tested in preventive and therapeutic paradigms in a bortezomib-based rat model (0.2 mg/kg i.v., 3 times/week for 8 weeks). In the preventive setting, HM01 blocked bortezomib-induced hyperalgesia and IENFD reduction at all doses tested. In the therapeutic setting, significant effect was observed, but only at the highest dose. Altogether, the robust peripheral nervous system penetration of HM01 and its ability to improve multiple oxaliplatin-, cisplatin-, and bortezomib-induced neurotoxicities suggest that HM01 may be a useful neuroprotective adjuvant for CIPN.

Lowering plasma 1-deoxysphingolipids improves neuropathy in diabetic rats.

1-Deoxysphingolipids (1-deoxySLs) are atypical neurotoxic sphingolipids that are formed by the serine-palmitoyltransferase (SPT). Pathologically elevated 1-deoxySL concentrations cause hereditary sensory and autonomic neuropathy type 1 (HSAN1), an axonal neuropathy associated with several missense mutations in SPT. Oral L-serine supplementation suppressed the formation of 1-deoxySLs in patients with HSAN1 and preserved nerve function in an HSAN1 mouse model. Because 1-deoxySLs also are elevated in patients with type 2 diabetes mellitus, L-serine supplementation could also be a therapeutic option for diabetic neuropathy (DN). This was tested in diabetic STZ rats in a preventive and therapeutic treatment scheme. Diabetic rats showed significantly increased plasma 1-deoxySL concentrations, and L-serine supplementation lowered 1-deoxySL concentrations in both treatment schemes (P < 0.0001). L-serine had no significant effect on hyperglycemia, body weight, or food intake. Mechanical sensitivity was significantly improved in the preventive (P < 0.01) and therapeutic schemes (P < 0.001). Nerve conduction velocity (NCV) significantly improved in only the preventive group (P < 0.05). Overall NCV showed a highly significant (P = 5.2E-12) inverse correlation with plasma 1-deoxySL concentrations. In summary, our data support the hypothesis that 1-deoxySLs are involved in the pathology of DN and that an oral L-serine supplementation could be a novel therapeutic option for treating DN.