Pathological inclusions containing fibrillar aggregates of hyperphosphorylated tau protein are a characteristic feature in tauopathies, which include Alzheimer's disease (AD). Tau is a microtubule-associated protein whose transcript undergoes alternative splicing in the brain. Exon 10 encodes one of four microtubule-binding repeats. Exon 10 inclusion gives rise to tau protein isoforms containing four microtubule-binding repeats (4R) whereas exclusion leads to isoforms containing only three repeats (3R). The ratio between 3R and 4R isoforms is tightly controlled via alternative splicing in the human adult nervous system and distortion of this balance results in neurodegeneration. Previous studies showed that several splicing regulators, among them hTRA2-beta1 and CLK2, regulate exon 10 alternative splicing. Like most splicing factors, htra2-beta and clk2 pre-mRNAs are regulated by alternative splicing. Here, we investigated whether human postmortem brain tissue of AD patients reveal differences in alternative splicing patterns of the tau, htra2-beta, presenilin 2 and clk2 genes when compared with age-matched controls. We found that the splicing patterns of all four genes are altered in affected brain areas of sporadic AD patients. In these affected areas, the amount of mRNAs of tau isoforms including exon 10, the htra2-beta1 isoform and an inactive form of clk2 are significantly increased. These findings suggest that a misregulation of alternative splicing seems to contribute to sporadic AD.

Validation of an LC-MS/MS method for the quantitative analysis of 1P-LSD and its tentative metabolite LSD in fortified urine and serum samples including stability tests for 1P

1‐Propanoyl‐lysergic acid diethylamide (1P‐LSD) appeared as a non‐controlled alternative to LSD a few years ago. Although evidence is beginning to emerge from in vitro and animal studies that 1P‐LSD might serve as a prodrug for LSD, an equivalent evaluation in humans is unavailable. Controlled oral and intravenous self‐administrations of 100 μg 1P‐LSD hemitartrate are reported in two human volunteers followed by analyses of urine and serum samples using a fully validated LC–MS/MS method. Psychometric evaluations included assessment of selected subjective drug effects and administration of the Five‐Dimensions of Altered States of Consciousness rating scale (5D‐ASC). In serum and urine, oral administrations of 1P‐LSD only led to the detection of LSD reflecting biphasic elimination with a terminal elimination half‐life of approx. t1/2 = 6.4 h. 1P‐LSD could be detected for only up to 4.16 h in serum and 2.7 h in urine following intravenous administration, whereas LSD was detected in all serum samples (last sampling after approx. 24 h) and up to 80 h in urine. LSD showed first order elimination kinetics with an approx. t1/2 = 5.7 h, whereas 1P‐LSD showed a rapid decrease in concentration within the first hour followed by a slower decrease, most probably due to hydrolysis. The bioavailability of LSD after oral ingestion of 1P‐LSD was close to 100%. The psychosensory effects of 1P‐LSD and their time course were comparable to those seen after uptake of LSD in other studies which further supports the prodrug hypothesis. The 5D‐ASC scores were higher after oral compared with intravenous administration of 1P‐LSD.

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