Dimethylsulphoxide-induced encephalopathy

Recurrent seizure and sustained encephalopathy associated with dimethylsulfoxide-preserved stem cell infusion

We report the case of a patient who received two infusions of dimethylsulfoxide (DMSO) cryopreserved autologous peripheral blood progenitor cells (PBPCs) after myeloablative chemotherapy for a relapsing lymphoma. A 49-year-old man presented an episode of tonic-clonic seizure over a few minutes after the start of each infusion and developed a profound and sustained but reversible encephalopathy with coma after the second infusion. The patient's neurological condition correlated well with the electrophysiological findings (electroencephalogram and multimodality evoked potentials) and, to a lesser extent, with the radiological abnormalities (magnetic resonance imaging). Severe but reversible neurological complications may occur with the infusion of PBPCs cryopreserved with DMSO.

Preclinical evaluation of an automated closed fluid management device: Cytomate, for washing out DMSO from hematopoietic stem cell grafts after thawing

Infusion of dimethylsulfoxide (DMSO) contained in cryopreserved and thawed hematopoietic stem cell (HSC) grafts is frequently associated with mild or moderate adverse reactions, and occasionally with more severe events including neurological symptoms. The severity of these complications is related to the amount of residual DMSO. We evaluated a recently available, closed, automated and 'cgmp (current good manufacturing practice) compliant' device (CytoMate) for its ability to wash out DMSO at the expense of a limited loss of viable CD34(+) cells. A total of 16 procedures were carried out with 39 blood HSC bags intended for destruction. Mean amounts of DMSO for each cellular product (one, two or three bags) were between 12.2 and 39.6 g before thawing; after the washing procedure, residual DMSO quantities were between 0.1 and 3.7 g. When set up to reproducibly allow for a more than 96% elimination of DMSO, processing of thawed cells with the CytoMate cell processor resulted in a mean recovery of viable total cells, CD34(+) cells and lymphocyte subsets above 60%. We conclude that this simple and efficient washing technique is suitable for routine processing of HSC grafts. Clinical studies will demonstrate whether a reduction in the incidence of adverse effects associated with DMSO infusion is observed.

Neurological events associated with the infusion of cryopreserved bone marrow and/or peripheral blood progenitor cells

Reports of neurological toxicity of cryopreserved stem cell infusion are infrequent. Three of 179 consecutive patients experienced significant neurological events in this context. Transient global amnesia developed following infusion in one patient and in the other two, cerebral infarction occurred. Profound hypotension, bradyarrhythmias or hypoxia were not associated with any of these episodes. These events may have been related to infused DMSO, which in the non-transplant setting has been associated with neurological toxicity and local infusion of which has resulted in acute vasospasm in animal models. These cases suggest that infusion of cryopreserved stem cells may result in cerebrovascular ischaemia. Bone Marrow Transplantation (2000) 25, 1285-1287.

Posttranslational elevation of cytochrome P450 3A levels and activity by dimethyl sulfoxide

The molecular mechanisms by which dimethyl sulfoxide (DMSO) enhances CYP3A protein in phenobarbital-treated primary cultured rat hepatocytes were examined. DMSO treatment rapidly increased CYP3A protein levels in the absence of an increase in CYP3A mRNA levels or an increase in CYP2B protein or mRNA levels. CYP3A levels were increased approximately 3.7- and 9-fold following 0.1% DMSO treatment for 6 and 48 h, respectively. Analyses of the polysomal distribution of CYP3A mRNA suggested that DMSO treatment did not significantly alter the translational efficiency of the CYP3A mRNA. Comparative analyses of immunodetectable protein levels following treatment with cycloheximide showed that DMSO clearly decreased the rate of CYP3A protein turnover but not that of CYP2B. Examination of testosterone metabolism in hepatocyte cultures revealed that DMSO pretreatment increased CYP3A-catalyzed 2 beta- and 6 beta-testosterone hydroxylation. When DMSO was in the culture medium, no inhibitory affect on CYP3A-catalyzed testosterone metabolism was observed, although a slight (15-21%) inhibitory effect was noted for CYP2B-catalyzed 16 alpha- and 16 beta-testosterone hydroxylation. These data provide evidence that DMSO increased CYP3A protein levels as a result of decreased protein degradation. DMSO increased both immunodetectable CYP3A protein levels and catalytic activity, in contrast to compounds that have been reported to stabilize CYP3A protein and inhibit activity.

Posttranscriptional elevation of cytochrome P450 3A expression

Human CYP3A, the most abundant hepatic and intestinal cytochrome P450, catalyzes the metabolism of a diverse array of xenobiotics. Dimethyl sulfoxide is a commonly used solvent which has been used therapeutically. Dimethyl sulfoxide effects on CYP3A, CYP2E1, CYP2B and NADPH cytochrome P450 reductase expression in rat liver and in primary cultured rat hepatocytes were examined. Dimethyl sulfoxide increased immunodetectable hepatic CYP3A and CYP2E1 levels approximately 2.5 to 3-fold in the absence of any change in the respective mRNA levels. No change in CYP2B or P450 reductase expression was observed, indicating that dimethyl sulfoxide effects were selective. Dimethyl sulfoxide also increased CYP3A protein in rats pretreated with dexamethasone. In primary cultured rat hepatocytes, dimethyl sulfoxide increased CYP3A and CYP2E1 protein without increasing the respective mRNA levels. These results show that dimethyl sulfoxide, at levels relevant to human exposure, enhances CYP3A and CYP2E1 expression by posttranscriptional mechanisms.

Reversible encephalopathy after cryopreserved peripheral blood stem cell infusion

We report two patients who experienced severe reversible encephalopathy following infusion of peripheral blood stem cells cryopreserved in 10% dimethylsulfoxide (DMSO). In one patient, reduction of DMSO level with plasmapheresis resulted in marked improvement in encephalopathy. Infusion of large volumes of cryopreserved stem cells may result in a significant toxic reaction. Plasmapheresis may be a treatment option for patients with significant toxicity related to DMSO.