Inhibition of monoacylglycerol lipase mediates a cannabinoid 1-receptor dependent delay of kindling progression in mice.

Endocannabinoids, including 2-arachidonoylglycerol (2-AG), activate presynaptic cannabinoid type 1 receptors (CB1R) on inhibitory and excitatory neurons, resulting in a decreased release of neurotransmitters. The event-specific activation of the endocannabinoid system by inhibition of the endocannabinoid degrading enzymes may offer a promising strategy to selectively activate CB1Rs at the site of excessive neuronal activation with the overall goal to prevent the development epilepsy. The aim of this study was to investigate the impact of monoacylglycerol lipase (MAGL) inhibition on the development and progression of epileptic seizures in the kindling model of temporal lobe epilepsy. Therefore, we selectively blocked MAGL by JZL184 (8mg/kg, i.p.) in mice to analyze the effects of increased 2-AG levels on kindling acquisition and to exclude an anticonvulsive potential. Our results showed that JZL184 treatment significantly delayed the development of generalized seizures (p=0.0066) and decreased seizure (p<0.0001) and afterdischarge duration (p<0.001) in the kindling model of temporal lobe epilepsy, but caused only modest effects in fully kindled mice. Moreover, we proved that JZL184 treatment had no effects in conditional CB1R knockout mice lacking expression of the receptor in principle neurons of the forebrain. In conclusion, the data demonstrate that indirect CB1R agonism delays the development of generalized epileptic seizures but has no relevant acute anticonvulsive effects. Furthermore, we confirmed that the effects of JZL184 on kindling progression are CB1R mediated. Thus, the data indicate that the endocannabinoid 2-AG might be a promising target for an anti-epileptogenic approach.

Analysis in conditional cannabinoid 1 receptor-knockout mice reveals neuronal subpopulation-specific effects on epileptogenesis in the kindling paradigm.

The endocannabinoid system serves as a retrograde negative feedback mechanism. It is thought to control neuronal activity in an epileptic neuronal network. The purpose of this study was to evaluate the impact of the endocannabinoid and endovanilloid systems on both epileptogenesis and ictogenesis. Therefore, we modulated the endocannabinoid and endovanilloid systems genetically and pharmacologically, and analyzed the subsequent impact on seizure progression in the kindling model of temporal lobe epilepsy in mice. In addition, the impact of seizures on associated cellular alterations was evaluated. Our principal results revealed that the endocannabinoid system affects seizure and afterdischarge duration dependent on the neuronal subpopulation being modulated. Genetic deletion of CB1-receptors (CB1Rs) from principal neurons of the forebrain and pharmacological antagonism with rimonabant (5 mg/kg) caused longer seizure duration. Deletion of CB1R from GABAergic forebrain neurons resulted in the opposite effect. Along with these findings, the CB1R density was elevated in animals with repetitively induced seizures. However, neither genetic nor pharmacological interventions had any impact on the development of generalized seizures. Other than CB1, genetic deletion or pharmacological blockade with SB366791 (1 mg/kg) of transient receptor potential vanilloid receptor 1 (TRPV1) had no effect on the duration of behavioral or electrographic seizure activity in the kindling model. In conclusion, we demonstrate that endocannabinoid, but not endovanilloid, signaling affects termination of seizure activity, without influencing seizure severity over time. These effects are dependent on the neuronal subpopulation. Thus, the data argue that the endocannabinoid system plays an active role in seizure termination but does not regulate epileptogenesis.

Membranoproliferative glomerulonephritis in two siblings: report and literature review.

There is evidence of a genetic basis in some cases of idiopathic membranoproliferative glomerulonephritis (MPGN) types I and III, particularly those occurring in families. The clinical and morphological features and disease course in two siblings with MPGN are described. In the male sibling, both clinical and morphological features as well as serum complement profile suggested type I MPGN; electron microscopy appearance in the female sibling was consistent with type III MPGN. Both patients had treatment-resistant nephrotic syndrome which evolved into renal insufficiency in the girl. No hereditary complement deficiencies were found in siblings or their parents. Both children exhibited HLA-A24; -B27, w4; -DR11, 52; -DQ3 antigens. Between 1981 and 1996, 18 patients from eight families with unequivocal diagnosis of MPGN I or III had been described. The mode of inheritance appeared to be autosomal dominant or X-linked in four of these families. In 11 patients, including our 2, in whom HLA typing was performed, eight had the HLA-A2 antigen. Similarities and discrepancies regarding clinical and morphological features and outcomes were evident in these intrafamilial cases, suggesting either a similar genetic background or a multigenic origin of MPGN. The familial occurrence of the MPGN, highlighted by our report, supports the concept that genetically determined factors may be involved in the pathogenesis of the disease.

[Familial membranoproliferative glomerulonephritis]. / Familijarni membranoproliferacioni glomerulonefritis.

INTRODUCTION: Idiopathic membranoproliferative (mesangiocapillary) glomerulonephritis (MPGN) is a chronic, often progressive renal disease with variable clinical expression divided into three distinct morphological formes, now designated types I, II, and III, on the basis of immunofluorescent (IF) and ultrastructural appearances and complement profiles [1-5]. Several lines of evidences suggest a genetic basis for at least some cases of MPGN I and III. The extended haplotypes HLA-B8, DR3, SCO1, GLO2 were found to constitute 13% of the disease-associated haplotypes and 1% of control hyplotypes [8]. Significantly high percentage of those with MPGN I and III have inherited defects of the complement system [9]. Additional evidence for genetic factors is the rarity of the disease in blacks [10] and examples of MPGN occurring in families. The disease has been reported in siblings as well as in families with affected members spanning more than one generation [11-16]. Here we describe clinical and morphological features in two siblings affected by MPGN and present complement and HLA typing studies done in patients and their parents. A review of familial MPGN I and III cases reported between 1981 and 1996 is made, and genetic susceptibility factors for MPGN are discussed. SUBJECTS AND METHODS: Between 1976 and 1996 diagnosis of idiopathic MPGN was made in 24 patients, aged 516.5 years. The diagnosis was established after excluding systemic, liver and infectious disorders and malignant neoplasms. The MPGN type was confirmed by light microscopy, IF and electron microscopy studies of the renal biopsy tissues processed by standard techniques. One family with two siblings having MPGN was identified in our series. This family was examined for the presence of renal disease and an inherited complement defect. Laboratory evaluations of the patients and parents included complete urinalysis, serum protein, albumin, urea, creatinine and cholesterol levels and glomerular filtration rate (GFR) estimation. ANA, rheumatoid factors, cryoglobulins, immune complexes, HBV antigens and antibodies and anti-HCV antibodies were also determined. Haemolytic tests for CHSO (classical and alternative pathways) were carried out using standard techniques. The measurement of the various complement factors was carried out using a radial immunodiffusion technique with monospecific antisera (CIq, C2, C4, C3, C5, B, H). HLA-A, B, DR and DQ haplotypes were determined by microcytotoxicity assay of peripheral blood lymphocytes. RESULTS: Patient 1 (SC, male). Renal disease presented at the age of his five years with nephrotic syndrome resistant to corticosteroid treatment. Morphological features and serum complement profile suggested type I MPGN. Treatment consisted of alternate-day prednisone, followed by cyclosporine and then by cyclophosphamide. At the end of the follow-up lasting 5.5 years he had only moderate proteinuria. Patient 2 (MC, female). Proteinuria was revealed at the age of 3 years becoming progressive and leading to the nephrotic syndrome resistant to corticosteroids at the age of 6 years. Electronmicroscopy features were consistent with type III MPGN, although serum C3 and C4 levels remained normal all the time. The same treatment as in her brother was given but she remained persistently nephrotic and anaemic; hypertension developed when she was 6 years old and her renal function became to declaine at the age of 7.5 years. Detailed family studies failed to reveal any evidence of complement deficiencies or secondary cause of MPGN. Siblings had in common HLA-A24, B27, Bw4, DRI1, DRS2, and DQ3 antigens. DISCUSSION: In our patients clinical and morphological features are very similar and are consistent with diagnosis of MPGN, i.e. probably type I in the boy and type III in the girl. Although some extended haplotypes HLA-B8, DR3, SCO1, GLO2, were significantly more frequent (13%) than in controls (1%), and the patients with MPGN having this extended haplotype had