Electrophysiologic recovery after vitamin E-deficient neuropathy

Nutritional neuropathies

Neuropathies associated with nutritional deficiencies are routinely encountered by the practicing neurologist. Although these neuropathies assume different patterns, most are length-dependent, sensory axonopathies. Cobalamin deficiency neuropathy is the exception, often presenting with a non-length-dependent sensory neuropathy. Patients with cobalamin and copper deficiency neuropathy characteristically have concomitant myelopathy, whereas vitamin E deficiency is uniquely associated with a spinocerebellar syndrome. In contrast to those nutrients for which deficiencies produce neuropathies, pyridoxine toxicity results in a non-length-dependent sensory neuronopathy. Deficiencies occur in the context of malnutrition, malabsorption, increased nutrient loss (such as with dialysis), autoimmune conditions such as pernicious anemia, and with certain drugs that inhibit nutrient absorption. When promptly identified, therapeutic nutrient supplementation may result in stabilization or improvement of these neuropathies.

Vitamin E deficiency begins within 6 months after gastrectomy for gastric cancer

BACKGROUND

To clarify factors related to vitamin E malabsorption after gastric surgery, we evaluated serum vitamin E levels in patients who had undergone gastrectomy for gastric cancer.

METHODS

We studied 39 patients (26 men, 13 women; mean age, 61.7 years) who underwent gastrectomy for early gastric cancer. Surgical procedures included 24 subtotal gastrectomies and 15 total gastrectomies. We measured serum levels of vitamin E before and 3, 6, 9, and 12 months after gastrectomy. A level of less than 0.75 mg/dl was defined as a low vitamin E level.

RESULTS

Serum vitamin E levels decreased to less than 0.75 mg/dl in 6 (15.4%) of the 39 patients within 6 months after gastrectomy and in 7 (17.9%) of the 39 patients within 1 year after gastrectomy. The proportion of patients with a low serum vitamin E level was significantly higher in the total gastrectomy group (p = 0.002). A low vitamin E level was significantly associated with a low total cholesterol level. Total cholesterol levels in low vitamin E levels patients were lower than normal vitamin E levels patients. None of the patients with a low vitamin E level had neuropathy.

CONCLUSIONS

The type of operation performed (total vs. subtotal gastrectomy) may be the major cause of vitamin E malabsorption after gastrectomy for gastric cancer. Vitamin E deficiency probably begins within 6 months after gastrectomy for gastric cancer.

A disease-drug-phenotype matrix inferred by walking on a functional domain network

Protein domains are classified as units of structure, evolution and function, and thus form the molecular backbone of biosphere. Although functional networks at the protein level have been reported to be of value in predicting diseases (phenotypes or drugs), they have not previously been applied at the sub-protein resolution (protein domain in this case). We herein introduce a domain network with a functional perspective. This network has nodes consisting of protein domains (at the superfamily/evolutionary level), with edges weighted by the semantic similarity according to domain-centric Gene Ontology (dcGO) annotations, which henceforth we call "dcGOnet". By globally exploring this network via a random walk, we demonstrate its predictive value on disease, drug, or phenotype-related ontologies. On cross-validation recovering ontology labels for domains, we achieve an overall area under the ROC curve of 89.0% for drugs, 87.3% for diseases, 87.6% for human phenotypes and 88.2% for mouse phenotypes. We show that the performance using global information from this network is significantly better than using local information, and also illustrate that the better performance is not sensitive to network size, or the choice of algorithm parameters, and is universal to different ontologies. Based on the dcGOnet and its global properties, we further develop an approach to build a disease-drug-phenotype matrix. The predicted interconnections are statistically supported using a novel randomization procedure, and are also empirically supported by inspection for biological relevance. Most of the high-ranking predictions recover connections that are well known, but others uncover connections that have only suggestive or obscure support in the literature; we show that these are missed by simpler methods, in particular for drug-disease connections. The value of this work is threefold: we describe a general methodology and make the software available, we provide the functional domain network itself, and the ranked drug-disease-phenotype matrix provides rich targets for investigation. All three can be found at .

Preventing paclitaxel-induced peripheral neuropathy: a phase II trial of vitamin E supplementation

A randomized, controlled trial was performed to assess the efficacy and safety of vitamin E supplementation for prophylaxis against paclitaxel-induced peripheral neuropathy (PIPN). Thirty-two patients undergoing six courses of paclitaxel-based chemotherapy were randomly assigned to receive either chemotherapy with vitamin E (300 mg twice a day, Group I) or chemotherapy without vitamin E supplementation (Group II). A detailed neurological examination and electrophysiological study was performed during and 3 months after chemotherapy. The severity of PIPN was summarized by means of a modified Peripheral Neuropathy (PNP) score. The incidence of neurotoxicity differed significantly between groups, occurring in 3/16 (18.7%) patients assigned to the vitamin E supplementation group and in 10/16 (62.5%) controls (P=0.03). The relative risk (RR) of developing PIPN was significantly higher in controls than in vitamin E group patients (RR=0.3, 95% confidence interval (CI)=0.1-0.9). Mean PNP scores were 2.25+/-5.1 (range 0-15) for patients in Group I and 11+/-11.63 (range 0-32) for those in Group II (P=0.01). Vitamin E supplementation was well tolerated and showed an excellent safety profile. This study shows that vitamin E effectively and safely protects patients with cancer from the occurrence of paclitaxel-induced peripheral nerve damage. A double-blind, placebo-controlled trial is needed to confirm these results.

A randomized controlled trial evaluating the efficacy and safety of vitamin E supplementation for protection against cisplatin-induced peripheral neuropathy: final results

AIM

A randomized, open label with blind assessment, controlled trial was performed to assess efficacy and adverse-event profile of vitamin E, given as supplementation for prophylaxis against cisplatin-induced peripheral neuropathy (CIPN).

PATIENTS AND METHODS

A total of 30 patients scheduled to receive six courses of cumulative cisplatin-based regimens were randomly allocated to treatment and control groups and were then studied by means of neurological examination and electrophysiological study. Patients assigned to group I (n=14) orally received vitamin E at a daily dose of 600 mg/day during chemotherapy and 3 months after its cessation were compared to patients of group II (n=16), who received no vitamin E supplementation and served as controls. The severity of neurotoxicity was summarized by means of a modified Peripheral Neuropathy (PNP) score.

RESULTS

The incidence of neurotoxicity differed significantly between groups, occurring in 3/14 (21.4%) of patients assigned to the vitamin E supplementation group and in 11/16 (68.5%) of controls (p=0.026). The relative risk (RR) of developing neurotoxicity was significantly higher in case of controls, RR=2.51, 95% C.I.=1.16-5.47. Mean PNP scores were 4.99+/-1.33 for patients of group I and 10.47+/-10.62 for controls, (p=0.023). None of the adverse events or deaths occurred, were judged as likely to be related to the vitamin E supplementation.

CONCLUSION

Vitamin E effectively and safely protects patients with cancer from occurrence of cisplatin neurotoxicity.

Isolated vitamin E deficiency with demyelinating neuropathy

A 22-year-old man, with a past history of generalized tonic-clonic seizures treated with phenobarbital, presented with spinocerebellar ataxia. The electrophysiological studies revealed a demyelinating motor-sensory neuropathy. The serum vitamin E level was low. Sural nerve biopsy revealed loss of large myelinated fibers with evidence of remyelination. Vitamin E supplementation led to clinical and electrophysiological recovery of sensory conduction and evoked potentials. Motor nerve conduction, however, showed only partial recovery. Vitamin E deficiency leading to a demyelinating neuropathy, as in the present case, suggests that the full spectrum of the disease entity is not fully defined.