Cisplatin-induced alterations in the blood-nerve barrier: effects of combination of vitamin B1, B6 and B12.

BACKGROUND: Cisplatin is a chemotherapeutic agent against solid cancers. However, neuropathy is a major side effect and has no effective treatment so far. Emerging evidence suggests that cisplatin might damage nerve capillaries leading to impaired blood-nerve barrier (BNB). This study aimed to investigate the ultrastructural changes of the BNB in the sciatic nerves and dorsal root ganglia of rats with cisplatin neuropathy and the effects of B1-6-12. MATERIALS AND METHODS AND RESULTS: The results showed that cisplatin 2 mg/kg injected intraperitoneally twice a week for 5 consecutive weeks caused thermal hypoalgesia and structural abnormalities of nerves and ganglia. Co-treatment with oral B1-6-12 (100:100:1) 100, 300 and 600 mg/kg/day for 5 weeks reduced the sensory deficit and structural alterations. Electron microscopic analysis demonstrated the higher frequencies and wider distances of pericyte detachment in the capillaries of cisplatin than control groups. Vitamin B1, B6 and B12 especially the medium dose, reversed these abnormalities. Culture of endothelial cells and pericytes with cisplatin demonstrated reduced cell viability, increased caspase-3 activity, lower transendothelial electrical resistance and decreased expression of tight junction proteins, occludin and zonula occluden-2. CONCLUSIONS: Vitamin B1, B6 and B12 could correct these toxic effects of cisplatin. These data confirm that cisplatin causes pathological alterations in the components of BNB which correlate with the severity of neuropathy. Furthermore, B1-6-12 is effective against these abnormalities and deserves further investigations as potential treatment for cisplatin-induced neuropathy.

Curcumin reduces blood-nerve barrier abnormalities and cytotoxicity to endothelial cells and pericytes induced by cisplatin.

BACKGROUND: Cisplatin is a platinum-based antineoplastic agent used to treat cancers of solid organs. Neuropathy is one of its major side effects, necessitating dose reduction or cessation. Previous studies suggested that cisplatin causes microvascular toxicity, including pericyte detachment. This study aimed to clarify whether these alterations occurred in the blood-nerve barrier (BNB) of capillaries after cisplatin treatment. MATERIALS AND METHODS AND RESULTS: Electron microscopic analysis of rat sciatic nerves with cisplatin neuropathy showed increased frequency and severity of pericyte detachment. Moreover, the vascular basement membrane did not tightly encircle around the endothelial cells and pericytes. Cultured human umbilical vein endothelial cells and human brain vascular pericytes showed reduced viability, increased caspase-3 activity and enhanced oxidative stress following cisplatin treatment. In addition, cisplatin decreased transendothelial electrical resistance (TEER) and the expression of the tight junction proteins occludin and zonula occludens-1. Curcumin, a polyphenol found in the root of Curcuma longa, had favourable effects on cisplatin neuropathy in previous work. Therefore, curcumin was tested to determine whether it had any effect on these abnormalities. Curcumin alleviated pericyte detachment, cytotoxicity, oxidative stress, TEER reduction and tight junction protein expression. CONCLUSIONS: These data indicate that cisplatin causes BNB disruption in the nerves and might result in neuropathy. Curcumin might improve neuropathy via the restoration of BNB. Whether alterations in the BNB occur and curcumin is effective in patients with cisplatin neuropathy remain to be investigated.