Loss of function and reduced levels of sphingolipid desaturase DEGS1 variants are both relevant in disease mechanism

The last step of ex novo ceramide biosynthesis consists of the conversion of dihydroceramide into ceramide catalyzed by sphingolipid Δ4-desaturase DEGS1. DEGS1 variants were found to be responsible for heterogeneous clinical pictures belonging to the family of hypomyelinating leukodystrophies. To investigate the mechanisms making such variants pathogenic, we designed a procedure for the efficient detection of desaturase activity in vitro using LC-MS/MS and prepared a suitable cell model knocking out DEGS1 in HEK-293T cells through CRISPR-Cas9 genome editing (KO-DES-HEK). Transfecting KO-DES-HEK cells with DEGS1 variants, we found that their transcripts were all overexpressed as much as the WT transcripts, while the levels of cognate protein were 40%-80% lower. In vitro desaturase activity was lost by many variants except L175Q and N255S, which maintain a catalytic efficiency close to 12% of the WT enzyme. Metabolic labeling of KO-DES-HEK with deuterated palmitate followed by LC-MS/MS analysis of the formed sphingolipids revealed that the ceramide/dihydroceramide and sphingomyelin/dihydrosphingomyelin ratios were low and could be reverted by the overexpression of WT DEGS1 as well as of L175Q and N255S variants, but not by the overexpression of all other variants. Similar analyses performed on fibroblasts from a patient heterozygous for the N255S variant showed very low variant DEGS1 levels and a low ratio between the same unsaturated and saturated sphingolipids formed upon metabolic labeling, notwithstanding the residual activity measured at high substrate and homogenate protein concentrations. We conclude that loss of function and reduced protein levels are both relevant in disease pathogenesis.

Medicinal Cannabis: Extended Stability of Cannabis Extracts Produced Using a New Ethanol-based Extraction Method

Cannabis as a therapeutic agent is increasing in popularity all around the globe, particularly in Western countries, and its potential is now well assessed. On the other hand, each country has its own regulation for the preparation of cannabis macerated oils; in Italy, there are only a few preparation methods allowed. With this work, we aim to perform a stability study of cannabis oils produced with a novel method for the extraction of cannabinoids from cannabis inflorescence. Three different varieties of cannabis were used, with and without the adding of tocopherol acetate as an antioxidant. Cannabinoids were extracted using ethanol at room temperature; then, the solvent was evaporated under reduced pressure and the preparations reconstituted with olive oil. In this work, we assessed the stability of both cannabinoids and terpenes in these formulas over 8 months. Cannabinoid stability was assessed by monitoring the concentrations of THC and CBD, while terpene stability was assessed by monitoring β-Caryophyllene and α-Humulene concentrations. Stability of the extracts was not influenced by the presence of tocopherol acetate, though refrigeration seems to be detrimental for a long storage of products, especially regarding THC concentrations. The improvements offered by this method reside in the flexibility in controlling the concentration of the extract and the ability to produce highly concentrated oils, alongside the possibility to produce standardized oils despite the variability of the starting plant material.

Assessment of quality of life in recently post-menopausal women on dopaminergic therapy for pathological hyperprolactinaemia

BACKGROUND

Psychological distress has been reported in pre-menopausal hyperprolactinaemic women. The aim of this study was to assess quality of life in a group of recently post-menopausal women with a long-term history of hyperprolactinaemia.

METHODS

Thirty-one recently post-menopausal hyperprolactinaemic women (age range 46-59 years) and 37 control women matched for age and menopausal status. Hyperprolactinaemia had been diagnosed 2-22 years before the study. All hyperprolactinaemic women were on dopaminergic therapy. The self-rating Kellner Symptom Questionnaire (KSQ) and the Hamilton Depression Scale (HDS) were used to evaluate psychiatric profile. Evaluation of climacteric symptoms was performed with the ad-hoc self-rating 21-item Menopausal Rating Scale (MRS). Serum PRL, E2, LH, FSH, and free-thyroid hormones were evaluated.

RESULTS

Hyperprolactinaemic women showed normal PRL on dopaminergic therapy. No difference was noted in PRL, LH, FSH, free-T4, and E2 levels between groups. Free-T3 was significantly (p = 0.001) lower in hyperprolactinaemic than in control women. There was no difference in overall scores on the MRS between the groups. Only the item "rapid and strengthened heart-beat" was significantly (p = 0.04) lower in hyperprolactinaemic than in control women. Control women showed a significant correlation between the score for this item and free-thyroid hormone levels. Overall KSQ scores and subsection analysis of items did not show significant differences between groups. On HDS evaluation, depressive symptoms were similar in hyperprolactinaemic and control women.

CONCLUSIONS

Quality of life seems unchanged in recently post-menopausal women with a long-term history of hyperprolactinaemia currently on dopaminergic therapy. The present study does not therefore support the differences in psychological profile reported in literature between untreated hyperprolactinaemic and control women unselected for age.

Toxicologic profile of iobitridol, a new nonionic low-osmolality contrast medium

PURPOSE

The toxicologic profile of iobitridol, a new nonionic low-osomolality contrast medium, was evaluated in compliance with the current regulatory requirements in Europe, the USA and Canada.

MATERIAL AND METHODS

The toxicity of iobitridol was tested following acute or repeated i.v. administration in several different species (mouse, rat, dog); single oral administration in the mouse and intracisternal injection in the rat. Furthermore, teratogenicity and mutagenicity were evaluated in the rat and rabbit. Local perivenous toxicity was assessed in the rabbit.

RESULTS

The acute toxicity of iobitridol in the mouse is equivalent to that of iohexol, a reference product tested under the same conditions. Chronic administration (daily injections i.v. injection over 4 weeks) in the rat and dog did not demonstrate any particular toxicity for iobitridol. It should be noted that, unlike iohexol, iobitridol did not provoke any vacuolization of the renal tubular cells in the rat following repeated injections. Furthermore, this contrast agent did not show any teratogenic or mutagenic potential. The typical local inflammatory signs observed following perivenous injection in the rabbit were low in intensity and reversible.

CONCLUSION

The toxicologic profile of iobitridol appears to be favorable and does not show any particular risk for clinical use under the usual indications of water soluble iodinated contrast agents.