L-Cysteine-induced up-regulation of the low-density lipoprotein receptor is mediated via a transforming growth factor-alpha signalling pathway

Simultaneous extraction and quantitative analysis of S-Methyl-l-Cysteine Sulfoxide, sulforaphane and glucosinolates in cruciferous vegetables by liquid chromatography mass spectrometry

Sulfur containing compounds including glucosinolates (GLS), sulforaphane (SFN) and S-methyl-l-cysteine sulfoxide (SMCSO) have been proposed to be partly responsible for the beneficial health effects of cruciferous vegetables. As such, greater understanding of their measurements within foods is important to estimate intake in humans and to inform dietary intervention studies. Herein is described a simple and sensitive method for simultaneous analysis of 20 GLS, SFN and SMCSO by liquid chromatography mass spectrometry. Analytes were effectively retained and resolved on an Xbridge C18 column. Detection can be achieved using high resolution or unit resolution mass spectrometry; the latter making the method more applicable to large studies. Quantitative analysis using calibration standards was demonstrated for 10 GLS, SFN and SMCSO. A further 10 GLS were tentatively identified using high resolution mass spectrometry. The use of surrogate GLS standards was shown to be unreliable, with closely related GLS displaying significantly different ionisation efficiencies.

S-methyl cysteine sulfoxide and its potential role in human health: a scoping review

Higher intakes of cruciferous and allium vegetables are associated with a lower risk of cardiometabolic-related outcomes in observational studies. Whilst acknowledging the many healthy compounds within these vegetables, animal studies indicate that some of these beneficial effects may be partially mediated by S-methyl cysteine sulfoxide (SMCSO), a sulfur-rich, non-protein, amino acid found almost exclusively within cruciferous and alliums. This scoping review explores evidence for SMCSO, its potential roles in human health and possible mechanistic action. After systematically searching several databases (EMBASE, MEDLINE, SCOPUS, CINAHL Plus Full Text, Agricultural Science), we identified 21 original research articles meeting our inclusion criteria. These were limited primarily to animal and in vitro models, with 14/21 (67%) indicating favorable anti-hyperglycemic, anti-hypercholesterolemic, and antioxidant properties. Potential mechanisms included increased bile acid and sterol excretion, altered glucose- and cholesterol-related enzymes, and improved hepatic and pancreatic β-cell function. Raising antioxidant defenses may help mitigate the oxidative damage observed in these pathologies. Anticancer and antibacterial effects were also explored, along with one steroidogenic study. SMCSO is frequently overlooked as a potential mediator to the benefits of sulfur-rich vegetables. More research into the health benefits of SMCSO, especially for cardiometabolic and inflammatory-based pathology, is warranted. Human studies are especially needed.

The LDL-Receptor and its Molecular Properties: From Theory to Novel Biochemical and Pharmacological Approaches in Reducing LDL-cholesterol

BACKGROUND

The Low-Density Lipoprotein (LDL) Receptor (LDL-R) is a transmembrane protein playing a crucial role in effective lipid homeostasis. Various therapeutic agents have been used in the management of dyslipidemias, however, the outcome of therapeutic target is debated.

OBJECTIVE

The aim of this review is to summarize and fully understand the current concept regarding LDL-R and its molecular properties, metabolic pathway, factors affecting LDL-R activity and all available pharmacological interventions. Additionally, non-lipid related properties of LDL-R are also referred.

METHODS

Literature from the PubMed database was extracted to identify papers between 1984 to 2017 regarding LDL-R and therapeutic agents on dyslipidemia management.

RESULTS

We analyzed basic data regarding agents associated with LDL-R (Sterol Regulating Element-Binding Proteins - SREBPs, Protein ARH, IDOL, Thyroid Hormones, Haematologic Disorders, Protein convertase subtilisin kexintype 9 - PCSK-9, ApoC-III) as well as non-lipid related properties of LDL-R, while all relevant (common and novel) pharmacological interventions (statins, fibrates, cholesterol absorption inhibitors, bile acid sequestrants and PCSK- 9) are also referred.

CONCLUSION

LDL-R and its molecular properties are involved in lipid homeostasis, so potentially sets the therapeutic goals in cardiovascular patients, which is usually debated. Further research is needed in order to fully understand its properties, as well as to find the potential pharmacological interventions that could be beneficial in cholesterol homeostasis and various morbidities in order to reach the most appropriate therapeutic goal.

Leptin concentrations and SCD-1 indices in classical homocystinuria: Evidence for the role of sulfur amino acids in the regulation of lipid metabolism

BACKGROUND

We describe body composition, lipid metabolism and Stearoyl-CoA desaturase-1 (SCD-1) indices in patients with classical homocystinuria (HCU).

METHODS

Eleven treated HCU patients and 16 healthy controls were included. Body composition and bone mineral density were assessed by dual X-ray absorptiometry. Sulfur amino acids (SAA) and their derivatives (total homocysteine, cysteine, methionine, S-adenosylmethionine, S-adenosylhomocysteine, and glutathione), lipids (free fatty acids, acylcarnitines, triglycerides and lipoproteins), glucose, insulin, leptin, adiponectin, and isoprostanes were measured in plasma. Insulin resistance was evaluated by HOMA-IR. To estimate liver SCD-1 activity, SCD-16 [16:1(n-7)/16:0] and SCD-18 [18:1(n-9)/18:0] desaturation indices were determined.

RESULTS

In HCU patients, SCD-16 index was significantly reduced (p=0.03). A trend of an association of SCD-16 index with cysteine was observed (r=0.624, p=0.054). HCU patients displayed lower lean mass (p<0.05), with no differences in fat mass percentage. Leptin and low-density lipoprotein concentrations were lower in HCU patients (p<0.05). Femur bone mineral density Z-scores were correlated with plasma cysteine (r=0.829; p=0.04) and total homocysteine (r=-0.829; p=0.04) in HCU patients.

CONCLUSIONS

We report alterations in leptin and SCD-1 in HCU patients. These results agree with previous findings from epidemiologic and animal studies, and support a role for SAA on lipid homeostasis.