Davor Sporiš

The influence of C3435T polymorphism of ABCB1 gene on penetration of phenobarbital across the blood-brain barrier in patients with generalized epilepsy.

BACKGROUNDnEpilepsy is refractory to medical treatment in about one-third of the patients. The exact pathological mechanism of epilepsy pharmacoresistance is still unclear, but a decreased antiepileptic drug (AED) uptake into the brain is suspected to play a role. P-glycoprotein (Pgp), a transmembrane transporter encoded by ABCB1 gene and located at the endothelial cells of the blood-brain barrier (BBB), has been associated with epilepsy pharmacoresistance.nnnOBJECTIVEnTo analyze the effect of two ABCB1 gene polymorphisms, C3435T and G2677T/A, on phenobarbital (PB) concentrations in the cerebrospinal fluid (CSF) and serum (S) and to assess the relationship of ABCB1 polymorphisms to phenobarbital penetration across BBB in vivo and seizure frequency.nnnMETHODSnCSF PB and S PB concentrations were measured in 60 patients with idiopathic primary generalized epilepsy receiving phenobarbital monotherapy. CSF/S PB concentration ratio was calculated as an index of phenobarbital penetration across BBB. The patients were genotyped for the ABCB1 gene C3435T and G2677T/A polymorphisms. Seizure frequency was recorded during the 6-month phenobarbital monotherapy.nnnRESULTSnPatients with different C3435T polymorphism had significantly different CSF PB concentrations and CSF/S PB concentration ratio. In comparison with CT heterozygotes and TT homozygotes, CC homozygotes had a significantly lower CSF PB concentration (p=0.006) and CSF/PB concentration ratio (p<0.001). G2677T/A polymorphism showed no such effect (p=0.466). CC genotype and low CSF/S PB concentration ratio correlated with increased seizure frequency.nnnCONCLUSIONSnC3435T polymorphism of ABCB1 gene was demonstrated in vivo to significantly influence the CSF/S PB concentration ratio and seizure frequency.

Association of refractory complex partial seizures with a polymorphism of ApoE genotype.

Apolipoprotein E (ApoE) is a constituent of many types of lipoproteins that play a role in metabolism of cholesterol and lipids in the body as well as in the brain. ApoE is synthesised in astrocytes and microglia and enter to neurons through LDL, LRP and VLDL receptors. Recently it was shown that ApoE is also produced in neurons. ApoE has a role in modulating learning and memory, structural plasticity, mobilization of cholesterol in repair, growth and maintenance of myelin and neuronal membranes during development and aging, and cell death after ischemic, convulsive, or other type of brain injury. The aim of this research was to investigate the possible association of ApoE gene polymorphism with the development of resistance to pharmacological therapy in patients with partial complex seizures with or without secondary generalization. In this prospective matched‐pair controlled study, 60 patients with cryptogenic epilepsy with complex partial seizures, with or without secondary generalization, who have been suffering for five or more years, were studied. The first group comprised 30 patients refractory to the current therapy, while the second group consisted of patients with well‐controlled seizures. The refractory and non‐refractory groups of patients differed significantly in their phenotypes. Phenotype E3/4 was six times more frequent in refractory group than among non‐refractory group. The lack of response was shown to be significantly associated with the presence of β allele. This study provided evidence that the presence of β4 allele is more often associated with a lack of response to current antiepileptic drugs as compared to β2 and β3 alleles.

Association between lamotrigine concentrations and ABCB1 polymorphisms in patients with epilepsy.

Background: Epilepsy is treated with a variety of anticonvulsants that are often used concomitantly. Therefore, therapeutic drug monitoring is often necessary. Along with clinical and environmental factors, genetic predisposition has been recognized to be relevant for interindividual variability in drug response. Polymorphic transporter proteins such as P-glycoprotein significantly influence pharmacokinetics and bioavailability of many structurally unrelated drugs. The aim of the study was to evaluate the impact of polymorphisms in the P-glycoprotein–encoding gene ABCB1 (C1236T, G2677T/A, C3435T) on antiepileptic drug disposition. Methods: We recruited 222 patients with epilepsy who were prescribed lamotrigine in monotherapy or polytherapy. Lamotrigine plasma concentrations were analyzed and compared with ABCB1 gene variants. The ABCB1 genotyping was performed by real-time polymerase chain reaction methods. The therapeutic drug monitoring was performed by high-performance liquid chromatography–diode array detector (DAD) and immunoassay. Results: A significant correlation was confirmed between lamotrigine concentration and additional drugs (P < 0.001). In the whole group, statistical analysis showed correlations between lamotrigine concentrations and ABCB1 C1236T variants: 10.1 and 6.5 &mgr;mol/L for CC versus CT + TT, respectively (P = 0.021), and for dose corrected lamotrigine 0.068 and 0.053 &mgr;mol·L−1·mg−1, for CC versus CT + TT, respectively (P = 0.017). Analysis of a specific haplotype showed that 1236C–2677G–3435C carriers had higher lamotrigine concentrations than 1236T–2677G–3435T carriers (P < 0.001), followed by 1236T–2677T–3435C carriers (P < 0.001). Conclusions: ABCB1 C1236T, G2677T/A, C3435T polymorphisms have an influence on lamotrigine serum concentrations.

Patient with neuromyelitis optica and inflammatory demyelinating lesions comprising whole spinal cord from C2 level till conus: case report

BackgroundNeuromyelitis optica (NMO) is an idiopathic, severe, inflammatory demyelinating disease of the central nervous system, that causes severe optic neuritis and myelitis attacks. Early discrimination between multiple sclerosis (MS) and NMO is important, as optimum treatment for both diseases may differ considerably.Case PresentationWe report a case of a patient who initially presented as longitudinally extensive transverse myelitis (LETM), having spastic upper extremities diparesis and spastic paraplegia, C2/C3 sensory level and urinary incontinence, as well as extensive inflammatory spinal cord lesions from C2 level to conus. After 5 months the patient had another attack of transverse myelitis, had electrophysiological findings consistent with optic neuritis, was seropositive for NMO-IgG (aquaporin-4 IgG) and thus fulfilled NMO diagnostic criteria. Following treatment of disease attacks with pulse corticosteroid therapy and intravenous immunoglobulins, we included oral azathioprine in a combination with oral prednisone in the therapy. Since there was no significant clinical improvement, we decided to use cyclophosphamide therapy, which resulted in good clinical improvement and gradual decrease of cord swelling.ConclusionIn this NMO case report we wanted to emphasize the extensiveness of inflammatory spinal cord changes in our patient, from C2 level to conus. In the conclusion it is important to say that accurate, early diagnosis and distinction from MS is critical to facilitate initiation of immunosuppressive therapy for attack prevention.

Povezanost apolipoproteina E ε2 s kasnijim početkom epilepsije temporalnog režnja

The aim of the study was to evaluate the possible association between Apo E polymorphisms and age at seizure onset in patients with non-lesional temporal lobe epilepsy. Eighty patients with non-lesional temporal lobe epilepsy with or without bilateral tonic-clonic propagation were analyzed. Age at seizure onset was defined as age at the first unequivocal seizure (excluding febrile convulsions). ApoE alleles were determined by a procedure where genome DNA was amplified by chain reaction along with polymerase, using the LightCycler kit (Roche) for ApoE mutations on codons 112 and 158. There was a statistically significant difference between the groups of patients with ApoE ε2/3 and ε3/4 genotypes (p=0.03), but not between patients with ApoE, ε2/3 and ε3/3, and those with ApoE ε3/4 and ε3/3. In conclusion, the results of our study suggested positive association of a specific ApoE genotype and onset of non-lesional temporal lobe epilepsy.