Phospholipid methylation and biological signal transmission

Liposomes have a direct effect on multiple myeloma: a Mendelian randomization study

Background

Multiple myeloma (MM), a malignant disease of plasma cells originating in the bone marrow, is influenced significantly by genetic factors. Although plasma liposomes have been linked to MM, the nature of their potential causal relationship remains to be elucidated. This study aims to explore this relationship using Mendelian randomization (MR) analysis.

Methods

Liposome-associated genetic instrumental variables (IVs) were identified from plasma lipidomics data of 7,174 Finnish individuals within a Genome-Wide Association Study (GWAS) pooled database. A MM pooled dataset was sourced from a GWAS meta-analysis encompassing 150,797 individuals, including 598 MM patients and 218,194 controls. These IVs underwent MR analysis, adhering to strict criteria for correlation, independence, and the exclusion of confounders. The inverse variance weighted (IVW) method, MR-Egger method, weighted median (WM) method, and simple median were utilized for MR analysis assessment, alongside Cochran's Q test, MR-Egger intercept, MR-Pleiotropy Residual Sum and Outlier (MR-RESSO) method, and leave-one-out analysis for evaluating heterogeneity, multiplicity, and instrumental bias.

Results

The study identified 88 significant, independent single nucleotide polymorphisms (SNPs) as IVs for MR analysis, each with an F-statistic value above 10, indicating robustness against weak instrument bias. IVW analysis revealed associations between six plasma liposome components and MM risk (p < 0.05). Phosphatidylinositol (16:0_18:1) serum levels (odds ratio [OR] = 1.769, 95% confidence interval [CI]: 1.132-2.763, p = 0.012) and triacylglycerol (56:4) levels (p = 0.026, OR = 1.417, 95% CI: 1.042-1.926) were positively correlated with the risk of multiple myeloma development. Phosphatidylethanolamine (18:0_20:4) (p = 0.004, 95% CI: 0.621-0.916, OR = 0.754), phosphatidylcholine (18:2_20:4) (p = 0.004, OR = 0.680, 95% CI: 0.519-0.889), sterol ester (27:1/18:3) levels (p = 0.013, OR = 0.677, 95% CI: 0.498-0.922), and phosphatidylcholine (O-18:2_20:4) levels (OR = 0.710, 95% CI: 0.517-0.913, p = 0.033) were negatively associated with the risk of developing multiple myeloma. The Cochran's Q test did not detect statistical method heterogeneity, nor did the MR-RESSO test or the MR-Egger intercept detect horizontal pleiotropy; leave-one-out analyses confirmed the absence of bias from individual SNPs.

Conclusions

Our findings suggest a complex relationship between plasma liposome components and MM risk. Elevated serum levels of triacylglycerol and phosphatidylinositol are positively associated with MM risk, while certain phospholipids and sterol esters offer a protective effect. This study provides valuable insights into the clinical relevance of liposomes in the pathology of multiple myeloma.

Coordination of bilayer properties by an inward-rectifier K+ channel is a cooperative process driven by protein-lipid interaction

Physical properties of biological membranes directly or indirectly govern biological processes. Yet, the interplay between membrane and integral membrane proteins is difficult to assess due to reciprocal effects between membrane proteins, individual lipids, and membrane architecture. Using solid-state NMR (SSNMR) we previously showed that KirBac1.1, a bacterial Inward-Rectifier K+ channel, nucleates bilayer ordering and microdomain formation through tethering anionic lipids. Conversely, these lipids cooperatively bind cationic residues to activate the channel and initiate K+ flux. The mechanistic details governing the relationship between cooperative lipid loading and bilayer ordering are, however, unknown. To investigate, we generated KirBac1.1 samples with different concentrations of 13C-lableded phosphatidyl glycerol (PG) lipids and acquired a full suite of SSNMR 1D temperature series experiments using the ordered all-trans (AT) and disordered trans-gauche (TG) acyl conformations as markers of bilayer dynamics. We observed increased AT ordered signal, decreased TG disordered signal, and increased bilayer melting temperature with increased PG concentration. Further, we identified cooperativity between ordering and direct binding of PG lipids, indicating KirBac1.1-driven bilayer ordering and microdomain formation is a classically cooperative Hill-type process driven by and predicated upon direct binding of PG lipids. Our results provide unique mechanistic insight into how proteins and lipids in tandem contribute to supramolecular bilayer heterogeneity in the lipid membrane.

Rumen-protected methionine supplementation alters lipid profile of preimplantation embryo and endometrial tissue of Holstein cows

Our objective is to evaluate the effects of feeding rumen-protected Met (RPM) throughout the transition period and early lactation on the lipid profile of the preimplantation embryos and the endometrial tissue of Holstein cows. Treatments consisted of feeding a total mixed ration with top-dressed RPM (Smartamine® M, Adisseo, Alpharetta, GA, United States; MET; n = 11; RPM at a rate of 0.08% of DM: Lys:Met = 2.8:1) or not (CON; n = 9, Lys:Met = 3.5:1). Endometrial biopsies were performed at 15, 30, and 73 days in milk (DIM). Prior to the endometrial biopsy at 73 DIM, preimplantation embryos were harvested via flushing. Endometrial lipid profiles were analyzed using multiple reaction monitoring-profiling and lipid profiles of embryos were acquired using matrix assisted laser desorption/ionization mass spectrometry. Relative intensities levels were used for principal component analysis. Embryos from cows in MET had greater concentration of polyunsaturated lipids than embryos from cows in CON. The endometrial tissue samples from cows in MET had lesser concentrations of unsaturated and monounsaturated lipids at 15 DIM, and greater concentration of saturated, unsaturated (specifically diacylglycerol), and monounsaturated (primarily ceramides) lipids at 30 DIM than the endometrial tissue samples from cows in CON. In conclusion, feeding RPM during the transition period and early lactation altered specific lipid classes and lipid unsaturation level of preimplantation embryos and endometrial tissue.

The effects of dietary self-monitoring intervention on anthropometric and metabolic changes via a mobile application or paper-based diary: a randomized trial

BACKGROUND/OBJECTIVES

Weight loss via a mobile application (App) or a paper-based diary (Paper) may confer favorable metabolic and anthropometric changes.

SUBJECTS/METHODS

A randomized parallel trial was conducted among 57 adults whose body mass indices (BMIs) were 25 kg/m2 or greater. Participants randomly assigned to either the App group (n = 30) or the Paper group (n = 27) were advised to record their foods and supplements through App or Paper during the 12-week intervention period. Relative changes of anthropometries and biomarker levels were compared between the 2 intervention groups. Untargeted metabolic profiling was identified to discriminate metabolic profiles.

RESULTS

Out of the 57 participants, 54 participants completed the trial. Changes in body weight and BMI were not significantly different between the 2 groups (P = 0.11). However, body fat and low-density lipoprotein (LDL)-cholesterol levels increased in the App group but decreased in the Paper group, and the difference was statistically significant (P = 0.03 for body fat and 0.02 for LDL-cholesterol). In the metabolomics analysis, decreases in methylglyoxal and (S)-malate in pyruvate metabolism and phosphatidylcholine (lecithin) in linoleic acid metabolism from pre- to post-intervention were observed in the Paper group.

CONCLUSIONS

In the 12-week randomized parallel trial of weight loss through a App or a Paper, we found no significant difference in change in BMI or weight between the App and Paper groups, but improvement in body fatness and LDL-cholesterol levels only in the Paper group under the circumstances with minimal contact by dietitians or health care providers.

Trial Registration

Clinical Research Information Service Identifier: KCT0004226.

The effect of methylated phosphatidylethanolamine derivatives on the ionization properties of signaling phosphatidic acid

Phosphatidylethanolamine (PE) and Phosphatidylcholine (PC) are the most abundant glycerophospholipids in eukaryotic membranes. The differences in the physicochemical properties of their headgroups have contrasting modulatory effects on their interaction with intracellular macromolecules. As such, their overall impact on membrane structure and function differs significantly. Enzymatic methylation of PE's amine headgroup produces two methylated derivatives namely monomethyl PE (MMPE) and dimethyl PE (DMPE) which have physicochemical properties that generally range between that of PE and PC. Additionally, their influence on membrane properties differs from both PE and PC. Although variations in headgroup methylation have been reported to affect signaling pathways, the direct influence that these differences exert on the ionization properties of signaling phospholipids have not been investigated. Here, we briefly review membrane function and structure that are mediated by the differences in headgroup methylation between PE, MMPE, DMPE and PC. In addition, using ³¹P MAS NMR, we investigate the effect of these four phospholipids on the ionization properties of the ubiquitous signaling anionic lipid phosphatidic acid (PA). Our results show that PA's ionization properties are differentially affected by changes in phospholipid headgroup methylation. This could have important implications for PA-protein binding and hence physiological functions in cells where signaling events lead to changes in abundance of methylated PE derivatives in the membrane.

A Permissive Amide N-Methyltransferase for Dithiolopyrrolones

Amide N-methylation is important for the activity and permeability of bioactive compounds but can be challenging to perform selectively. The broad-spectrum antimicrobial natural products thiolutin and holomycin differ only by an N-methyl group at the endocyclic amide of thiolutin, but only thiolutin exhibits antifungal activity. The enzyme responsible for amide N--methylation in thiolutin biosynthesis has remained elusive. Here, we identified and characterized the amide N-methyltransferase DtpM that is encoded >400 kb outside of the thiolutin gene cluster. DtpM catalyzes efficient conversion of holomycin to thiolutin, exhibits broad substrate scope toward dithiolopyrrolones, and has high thermal stability. In addition, sequence similarity network analysis suggests DtpM is more closely related to phenol O-methyltransferases than some amide methyltransferases. This study expands the limited examples of amide N-methyltransferases and may facilitate chemoenzymatic synthesis of diverse dithiolopyrrolone compounds as potential therapeutics.

Epigenetic Modifications and Their Potential Contribution to Traumatic Brain Injury Pathobiology and Outcome

Epigenetic information is not permanently encoded in the DNA sequence, but rather consists of reversible, heritable modifications that regulate the gene expression profile of a cell. Epigenetic modifications can result in cellular changes that can be long lasting and include DNA methylation, histone methylation, histone acetylation, and RNA methylation. As epigenetic modifications are reversible, the enzymes that add (epigenetic writers), the proteins that decode (epigenetic readers), and the enzymes that remove (epigenetic erasers) these modifications can be targeted to alter cellular function and disease biology. While epigenetic modifications and their contributions are intense topics of current research in the context of a number of diseases, including cancer, inflammatory diseases, and Alzheimer disease, the study of epigenetics in the context of traumatic brain injury (TBI) is in its infancy. In this review, we will summarize the experimental and clinical findings demonstrating that TBI triggers epigenetic modifications, with a focus on changes in DNA methylation, histone methylation, and the translational utility of the universal methyl donor S-adenosylmethionine (SAM). Finally, we will review the evidence for using methyl donors as possible treatments for TBI-associated pathology and outcome.

The Role of Human Chorionic Gonadotropin Beta (hCGβ) in HPV-Positive and HPV-Negative Oropharyngeal Squamous Cell Carcinoma

Background: This study was carried out to observe the upregulation of the free β-subunit of human chorionic gonadotropin (hCGβ) and its prognostic significance in human papillomavirus (HPV)-positive and HPV-negative oropharyngeal squamous cell carcinoma (OPSCC). Materials and methods: A total of 90 patients with OPSCC treated with curative intent at the Helsinki University Hospital (HUS), Helsinki, Finland, during 2012−2016 were included. Serum samples were collected prospectively, and their hCGβ concentrations (S-hCGβ) were determined by an immunofluorometric assay. The expression of hCGβ in tumor tissues was defined by immunohistochemistry (IHC). HPV determination was performed by combining p16-INK4 IHC and HPV DNA PCR genotyping. Overall survival (OS) and disease-specific survival (DSS) were used as survival endpoints. Results: S-hCGβ positivity correlated with poor OS in the whole patient cohort (p < 0.001) and in patients with HPV-negative OPSCC (p < 0.001). A significant correlation was seen between S-hCGβ and poor DSS in the whole cohort (p < 0.001) and in patients with HPV-negative OPSCC (p = 0.007). In a multivariable analysis, S-hCGβ was associated with poor DSS. Of the clinical characteristics, higher cancer stage and grade were associated with S-hCGβ positivity. No statistically significant correlation with tissue positivity of hCGβ was seen in these analyses. Conclusion: S-hCGβ may be a potential independent factor indicating poor prognosis, notably in HPV-negative OPSCC.

The reliability of biomedical science: A case history of a maturing experimental field

There is much discussion in the media and some of the scientific literature of how many of the conclusions from scientific research should be doubted. These critiques often focus on studies, typically in non-experimental spheres of biomedical and social sciences - that search large datasets for novel correlations, with a risk that inappropriate statistical evaluations might yield dubious conclusions. By contrast, results from experimental biological research can often be interpreted largely without statistical analysis. Typically: novel observation(s) are reported, and an explanatory hypothesis is offered; multiple labs undertake experiments to test the hypothesis; interpretation of the results may refute the hypothesis, support it or provoke its modification; the test/revise sequence is reiterated many times; and the field moves forward. I illustrate this experimental/non-experimental dichotomy by examining the contrasting recent histories of: (a) our remarkable and growing understanding of how several inositol-containing phospholipids contribute to the lives of eukaryote cells; and (b) the difficulty of achieving any agreed mechanistic understanding of why consuming dietary supplements of inositol is clinically beneficial in some metabolic diseases.

Emerging Role of Phospholipids and Lysophospholipids for Improving Brain Docosahexaenoic Acid as Potential Preventive and Therapeutic Strategies for Neurological Diseases

Docosahexaenoic acid (DHA, 22:6n-3) is an omega-3 polyunsaturated fatty acid (PUFA) essential for neural development, learning, and vision. Although DHA can be provided to humans through nutrition and synthesized in vivo from its precursor alpha-linolenic acid (ALA, 18:3n-3), deficiencies in cerebral DHA level were associated with neurodegenerative diseases including Parkinson’s and Alzheimer’s diseases. The aim of this review was to develop a complete understanding of previous and current approaches and suggest future approaches to target the brain with DHA in different lipids’ forms for potential prevention and treatment of neurodegenerative diseases. Since glycerophospholipids (GPs) play a crucial role in DHA transport to the brain, we explored their biosynthesis and remodeling pathways with a focus on cerebral PUFA remodeling. Following this, we discussed the brain content and biological properties of phospholipids (PLs) and Lyso-PLs with omega-3 PUFA focusing on DHA’s beneficial effects in healthy conditions and brain disorders. We emphasized the cerebral accretion of DHA when esterified at sn-2 position of PLs and Lyso-PLs. Finally, we highlighted the importance of DHA-rich Lyso-PLs’ development for pharmaceutical applications since most commercially available DHA formulations are in the form of PLs or triglycerides, which are not the preferred transporter of DHA to the brain.

Dissymmetrical tails-regulated helical nanoarchitectonics of amphiphilic ornithines: nanotubes, bundles and twists

How dissymmetrical tails (i.e. tails of different lengths) in one lipid molecule exert an impact on the structure and properties of the resulting assembly is an intriguing issue in both biological and material senses. However, the underlying mechanism that engenders such phenomena is still obscure, which prompted us to unmask it by exploring the self-assembly behaviours of artificial building blocks comprising dissymmetrical tails. Here, a series of Fmoc-protected ornithine lipids with dissymmetrical alkyl tails was designed and the dissymmetry of the two tails was found to hierarchically tune the self-assembled nanostructures from nanotubes to bundles and nanotwists. With the Fmoc-headgroup employed as a chromophorous probe, it was revealed that the alkyl chain dissymmetry controlled the interacting modes of van der Waals interactions between alkyl tails, π-π stacking between Fmoc motifs and hydrogen bonding formed by the three amide bonds in lipid bilayers. The counterbalance between those noncovalent interactions was responsible for such remarkable tuning ability towards self-assembly and emissive behaviours of the lipids, including circularly polarized light emission. This work provides insight into dissymmetrical tails-regulated biological structures and functions of natural lipids, and also sets up a novel strategy of rationally modulating chiral and emissive properties of supramolecular materials, i.e., tunable CPL materials, by exploitation of the tail dissymmetry.

Methylation as a key regulator of Tau aggregation and neuronal health in Alzheimer's disease

Neurodegenerative diseases like Alzheimer's, Parkinson's and Huntington's disease involves abnormal aggregation and accumulation of toxic proteins aggregates. Post-translational modifications (PTMs) of the causative proteins play an important role in the etiology of disease as they could either slow down or accelerate the disease progression. Alzheimer disease is associated with the aggregation and accumulation of two major protein aggregates-intracellular neurofibrillary tangles made up of microtubule-associated protein Tau and extracellular Amyloid-β plaques. Post-translational modifications are important for the regulation of Tau`s function but an imbalance in PTMs may lead to abnormal Tau function and aggregation. Tau methylation is one of the important PTM of Tau in its physiological state. However, the methylation signature on Tau lysine changes once it acquires pathological aggregated form. Tau methylation can compete with other PTMs such as acetylation and ubiquitination. The state of PTM at these sites determines the fate of Tau protein in terms of its function and stability. The global methylation in neurons, microglia and astrocytes are involved in multiple cellular functions involving their role in epigenetic regulation of gene expression via DNA methylation. Here, we have discussed the effect of methylation on Tau function in a site-specific manner and their cross-talk with other lysine modifications. We have also elaborated the role of methylation in epigenetic aspects and neurodegenerative conditions associated with the imbalance in methylation metabolism affecting global methylation state of cells. Video abstract.

Effects of Folic Acid Combined with DHA Supplementation on Cognitive Function and Amyloid-β-Related Biomarkers in Older Adults with Mild Cognitive Impairment by a Randomized, Double Blind, Placebo-Controlled Trial

BACKGROUND

The neuroprotective benefits of combined folic acid and docosahexaenoic acid (DHA) on cognitive function in mild cognitive impairment (MCI) patients are suggested but unconfirmed.

OBJECTIVE

To explore the effects of 6-month folic acid + DHA on cognitive function in patients with MCI.

METHODS

Our randomized controlled trial (trial number ChiCTR-IOR-16008351) was conducted in Tianjin, China. We divided 160 MCI patients aged > 60 years into four regimen groups randomly: folic acid (0.8 mg/day) + DHA (800 mg/day), folic acid (0.8 mg/day), DHA (800 mg/day), and placebo, for 6 months. Cognitive function and blood amyloid-β peptide (Aβ) biomarker levels were measured at baseline and 6 months. Cognitive function was also measured at 12 months.

RESULTS

A total of 138 patients completed this trial. Folic acid improved the full-scale intelligence quotient (FSIQ), arithmetic, and picture complement scores; DHA improved the FSIQ, information, arithmetic, and digit span scores; folic acid + DHA improved the arithmetic (difference 1.67, 95% CI 1.02 to 2.31) and digital span (1.33, 0.24 to 2.43) scores compared to placebo. At 12 months, all scores declined in the intervention groups. Folic acid and folic acid + DHA increased blood folate (folic acid + DHA: 7.70, 3.81 to 11.59) and S-adenosylmethionine (23.93, 1.86 to 46.00) levels and reduced homocysteine levels (-6.51, -10.57 to -2.45) compared to placebo. DHA lower the Aβ40 levels (-40.57, -79.79 to -1.35) compared to placebo (p < 0.05), and folic acid + DHA reduced the Aβ42 (-95.59, -150.76 to -40.43) and Aβ40 levels (-45.75, -84.67 to -6.84) more than DHA (p < 0.05).

CONCLUSION

Folic acid and DHA improve cognitive function and reduce blood Aβ production in MCI patients. Combination therapy may be more beneficial in reducing blood Aβ-related biomarkers.

Modes of Calcium Regulation in Ischemic Neuron

Calcium (Ca2+) dysregulation is a major catalytic event. Ca2+ dysregulation leads to neuronal cell death and brain damage result in cerebral ischemia. Neurons are unable in maintaining calcium homeostasis. Ca2+ homeostasis imbalance results in increased calcium influx and impaired calcium extrusion across the plasma membrane. Ca2+ dysregulation is mediated by different cellular and biochemical mechanism, which leads to neuronal loss resulting stroke/cerebral ischemia. A better understanding of the Ca2+ dysregulation might help in the development of new treatments in order to reduce ischemic brain injury. An optimal concentration of Ca2+ does not lead to neurotoxicity in the ischemic neuron. Intracellular Ca2+ act as a trigger for acute neurotoxicity and this cause induction of long-lasting processes leading to necrotic and/or apoptotic post-ischemic delayed neuronal death or of compensatory, neuroprotective mechanisms has increased considerably. Moreover, routes of ischemic Ca2+ influx to neurons, involvement of intracellular Ca2+ stores and Ca2+ buffers, spatial and temporal relations between ischemia-induced increases in intracellular Ca2+ concentration and neurotoxicity will further increase our understanding about underlying mechanism and they can act as a target for the development of drugs. Here, in our article we are trying to provide a brief overview of various Ca2+ influx pathways involve in ischemic neuron and how ischemic neuron attempts to counterbalance this calcium overload.

Application of Docking Analysis in the Prediction and Biological Evaluation of the Lipoxygenase Inhibitory Action of Thiazolyl Derivatives of Mycophenolic Acid

5-LOX inhibition is among the desired characteristics of anti-inflammatory drugs, while 15-LOX has also been considered as a drug target. Similarity in inhibition behavior between soybean LOX-1 and human 5-LOX has been observed and soybean LOX (sLOX) type 1b has been used for the evaluation of LOX inhibition in drug screening for years. After prediction of LOX inhibition by PASS and docking as well as toxicity by PROTOX and ToxPredict sixteen (E)-N-(thiazol-2-yl)-6-(4-hydroxy-6-methoxy-7-methyl-3-oxo-1,3-dihydroisobenzofuran-5-yl)-4-methylhex-4-enamide derivatives with lengths varying from about 15⁻20 Å were evaluated in vitro for LOX inhibitory action using the soybean lipoxygenase sLOX 1b. Docking analysis was performed using soybean LOX L-1 (1YGE), soybean LOX-3 (1JNQ), human 5-LOX (3O8Y and 3V99) and mammalian 15-LOX (1LOX) structures. Different dimensions of target center and docking boxes and a cavity prediction algorithm were used. The compounds exhibited inhibitory action between 2.5 μΜ and 165 μΜ. Substituents with an electronegative atom at two-bond proximity to position 4 of the thiazole led to enhanced activity. Docking results indicated that the LOX structures 1JNQ, 3V99 and 1LOX can effectively be used for estimation of LOX inhibition and amino acid interactions of these compounds.

Traumatic Brain Injury Alters Methionine Metabolism: Implications for Pathophysiology

Methionine is an essential proteinogenic amino acid that is obtained from the diet. In addition to its requirement for protein biosynthesis, methionine is metabolized to generate metabolites that play key roles in a number of cellular functions. Metabolism of methionine via the transmethylation pathway generates S-adenosylmethionine (SAM) that serves as the principal methyl (−CH₃) donor for DNA and histone methyltransferases (MTs) to regulate epigenetic changes in gene expression. SAM is also required for methylation of other cellular proteins that serve various functions and phosphatidylcholine synthesis that participate in cellular signaling. Under conditions of oxidative stress, homocysteine (which is derived from SAM) enters the transsulfuration pathway to generate glutathione, an important cytoprotective molecule against oxidative damage. As both experimental and clinical studies have shown that traumatic brain injury (TBI) alters DNA and histone methylation and causes oxidative stress, we examined if TBI alters the plasma levels of methionine and its metabolites in human patients. Blood samples were collected from healthy volunteers (HV; n = 20) and patients with mild TBI (mTBI; GCS > 12; n = 20) or severe TBI (sTBI; GCS < 8; n = 20) within the first 24 h of injury. The levels of methionine and its metabolites in the plasma samples were analyzed by either liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry (LC-MS or GC-MS). sTBI decreased the levels of methionine, SAM, betaine and 2-methylglycine as compared to HV, indicating a decrease in metabolism through the transmethylation cycle. In addition, precursors for the generation of glutathione, cysteine and glycine were also found to be decreased as were intermediate metabolites of the gamma-glutamyl cycle (gamma-glutamyl amino acids and 5-oxoproline). mTBI also decreased the levels of methionine, α-ketobutyrate, 2 hydroxybutyrate and glycine, albeit to lesser degrees than detected in the sTBI group. Taken together, these results suggest that decreased levels of methionine and its metabolic products are likely to alter cellular function in multiple organs at a systems level.

Effect of dietary combination of methionine and fish oil on cellular immunity and plasma fatty acids in infectious bursal disease challenged chickens

This study was carried out to investigate the modulatory effects of dietary methionine and fish oil on immune response, plasma fatty acid profile, and blood parameters of infectious bursal disease (IBD) challenged broiler chickens. A total of 300 one-day-old male broiler chicks were assigned to one of six dietary treatment groups in a 3 × 2 factorial arrangement. There were three levels of fish oil (0, 2.5 and 5.5%), and two levels of methionine (NRC recommendation and twice NRC recommendation). The results showed that the birds fed with 5.5% fish oil had higher total protein, white blood cell count, and IL-2 concentration than those of other groups at 7 days after IBD challenge. Inclusion of fish oil in diet had no effect on IFN- γ concentration. However, supplementation of methionine twice the recommendation enhanced the serum IFN- γ and globulin concentration. Neither of fish oil nor methionine supplementation affected the liver enzymes concentration. It can be suggested that a balance of moderate level of fish oil (2.5%) and methionine level (twice NRC recommendation) might enhance immune response in IBD challenged broiler chickens.

Effect of lead on lipid peroxidation, phospholipids composition, and methylation in erythrocyte of human

Lead (Pb) is one of the most abundant heavy metals on earth considered as number one environmental persistent toxin and health hazard affecting millions of people in all age groups. After entering bloodstream, 99% of Pb is accumulated in erythrocytes and causes poisoning. Toxic Pb effects on erythrocytes membrane's composition of phosphatidyl serine (PS), phosphatidyl ethanolamine (PE), phosphatidyl choline (PC), and sphingomyelin (SM), and phospholipids transmethylation were determined. Lipid peroxidation in Pb-exposed erythrocytes was evaluated as malondialdehyde (MDA) formation in presence of Fe and vitamin E to understand severity of Pb toxicity and its mitigation. Pb (0.5-5.0 μM) degraded PS (12 to 31%, P < 0.05-0.001) and elevated SM (19-51%, P < 0.05-0.001). Composition of PC and PE were diminished (22%) and elevated (29%), respectively, with higher Pb exposure (5.0 μM, P < 0.001). Pb toxicity suppressed (P < 0.001) transmethylation of phospholipids in membranes (34, 41, and 50%, respectively, with 0.5, 2.5, and 5.0 μM). Pb-induced dose-related MDA production (P < 0.05-0.001) in erythrocytes was obtained, which was accentuated in presence of Fe (P < 0.05-0.001). The vitamin E mitigated (P < 0.05-0.01) the severity of Pb-induced lipid peroxidation. The ratio PS/SM showed maximum change of -27 (P < 0.01), -30 (P < 0.01), and -54% (P < 0.001), respectively at 0.5, 2.5, and 5.0 μM Pb exposures. Ratios PC/SM and PS/PE were at the second, whereas PE/PS at the third order. The study suggests that the mechanisms underlying distortion of compositional phospholipids, inhibition of transmethylation, and exasperated phospholipid peroxidative damage are the active phenomena of Pb toxicity in erythrocytes.

Phospholipid metabolites in recurrent glioblastoma: in vivo markers detect different tumor phenotypes before and under antiangiogenic therapy

Purpose

Metabolic changes upon antiangiogenic therapy of recurrent glioblastomas (rGBMs) may provide new biomarkers for treatment efficacy. Since in vitro models showed that phospholipid membrane metabolism provides specific information on tumor growth we employed in-vivo MR-spectroscopic imaging (MRSI) of human rGBMs before and under bevacizumab (BVZ) to measure concentrations of phosphocholine (PCho), phosphoethanolamine (PEth), glycerophosphocholine (GPC), and glyceroethanolamine (GPE).

Methods

¹H and ³¹P MRSI was prospectively performed in 32 patients with rGBMs before and under BVZ therapy at 8 weeks intervals until tumor progression. Patients were dichotomized into subjects with long overall survival (OS) (>median OS) and short OS (<median OS) survival time from BVZ-onset. Metabolite concentrations from tumor tissue and their ratios were compared to contralateral normal-appearing tissue (control).

Results

Before BVZ, ¹H-detectable choline signals (total GPC and PCho) in rGBMs were elevated but significance failed after dichotomizing. For metabolite ratios obtained by ³¹P MRSI, the short-OS group showed higher PCho/GPC (p = 0.004) in rGBMs compared to control tissue before BVZ while PEth/GPE was elevated in rGBMs of both groups (long-OS p = 0.04; short-OS p = 0.003). Under BVZ, PCho/GPC and PEth/GPE in the tumor initially decreased (p = 0.04) but only PCho/GPC re-increased upon tumor progression (p = 0.02). Intriguingly, in normal-appearing tissue an initial PEth/GPE decrease (p = 0.047) was followed by an increase at the time of tumor progression (p = 0.031).

Conclusion

An elevated PCho/GPC ratio in the short-OS group suggests that it is a negative predictive marker for BVZ efficacy. These gliomas may represent a malignant phenotype even growing under anti-VEGF treatment. Elevated PEth/GPE may represent an in-vivo biomarker more sensitive to GBM infiltration than MRI.

S-adenosylmethionine (SAMe) therapy in liver disease: a review of current evidence and clinical utility

S-adenosyl-L-methionine (SAMe; AdoMet) is an important, metabolically pleiotropic molecule that participates in multiple cellular reactions as the precursor for the synthesis of glutathione and principle methyl donor required for methylation of nucleic acids, phospholipids, histones, biogenic amines, and proteins. SAMe synthesis is depressed in chronic liver disease and so there has been considerable interest in the utility of SAMe to ameliorate disease severity. Despite encouraging pre-clinical data confirming that SAMe depletion can exacerbate liver injury and supporting a hepatoprotective role for SAMe therapy, to date no large, high-quality randomised clinical trials have been performed that establish clinical utility in specific disease states. Here, we offer an in-depth review of the published scientific literature relating to the physiological and pathophysiological roles of SAMe and its therapeutic use in liver disease, critically assessing implications for clinical practice and offering recommendations for further research.

One-carbon metabolism in psychiatric illness

The cost of psychiatric illness to the UK economy was recently estimated at pound77 billion annually. Despite years of research no firm aetiological explanation exists, and with no physiological or biochemical markers diagnosis is made entirely on a behavioural basis. All current pharmacological therapies are associated with serious long-term side effects. Substantial evidence supports the involvement of one-carbon cycle dysregulation in psychiatric illness, but this is not currently used as a basis for diagnosis or treatment. The present paper reviews the evidence for one-carbon cycle dysregulation in schizophrenic, bipolar, depressed and autistic patients. Also presented are novel findings from the field of epigenetics, which demonstrate how the one-carbon cycle-derived methyl donor S-adenosylmethionine influences the expression of key genes in the brain affecting memory, learning, cognition and behaviour, genes whose expression is reduced to varying degrees in these patient groups. Clinical evidence that nutritional supplements can rectify one-carbon cycle activity, and restore normal gene expression, suggests a novel approach to the development of biochemical tests and simple, non-harmful treatments for some psychiatric patients. Conversely, evidence from animal studies highlights the dangers of exposing the unborn fetus to very high dietary levels of folic acid, a one-carbon cycle cofactor. Fetal adaptations to a high-folate environment may interfere with folate metabolism postnatally, with serious consequences for the epigenetic regulation of gene expression. The public health implications of these diverse scenarios indicate an urgent need for further research in this field.

Synthesis and SAR study of 4,5-diaryl-1H-imidazole-2(3H)-thione derivatives, as potent 15-lipoxygenase inhibitors

A series of 4,5-diaryl-1H-imidazole-2(3H)-thione was synthesized and their inhibitory potency against soybean 15-lipoxygenase and free radical scavenging activities were determined. Compound 11 showed the best IC(50) for 15-LOX inhibition (IC(50) = 4.7 μM) and free radical scavenging activity (IC(50) = 14 μM). Methylation of SH at C(2) position of imidazole has dramatically decreased the 15-LOX inhibition and radical scavenging activity as it can be observed in the inactive compound 14 (IC(50) >250 μM). Structure activity similarity (SAS) showed that the most important chemical modification in this series was methylation of SH group and Docking studies revealed a proper orientation for SH group towards Fe core of the 15-LOX active site. Therefore it was concluded that iron chelating could be a possible mechanism for enzyme inhibition in this series of compounds.

Effects of S-adenosylmethionine augmentation of serotonin-reuptake inhibitor antidepressants on cognitive symptoms of major depressive disorder

BACKGROUND

Major depressive disorder (MDD) is often accompanied by significant cognitive impairment, and there are limited interventions specific to this particular symptom. S-adenosyl methionine (SAMe), a naturally occurring molecule which serves as a major methyl-donor in human cellular metabolism, is required for the synthesis and maintenance of several neurotransmitters that have been implicated in the pathophysiology and treatment of cognitive dysfunction in MDD.

METHODS

This study is a secondary analysis of a clinical trial involving the use of adjunctive SAMe for MDD. Forty-six serotonin-reuptake inhibitor (SRI) non-responders with MDD enrolled in a 6-week, double-blind, randomized trial of adjunctive oral SAMe were administered the self-rated cognitive and physical symptoms questionnaire (CPFQ), a validated measure of cognitive as well as physical symptoms of MDD, before and after treatment.

RESULTS

There was a greater improvement in the ability to recall information (p=0.04) and a trend toward statistical significance for greater improvement in word-finding (p=0.09) for patients who received adjunctive SAMe than placebo. None of the remaining five items reached statistical significance.

CONCLUSION

These preliminary data suggest that SAMe can improve memory-related cognitive symptoms in depressed patients, and warrant replication.

Synthesis of phosphatidylcholine through phosphatidylethanolamine N-methylation in tissues of the mussel Mytilus galloprovincialis

We previously demonstrated the importance of upregulation of phosphatidylethanolamine N-methylation pathway in euryhaline fish and crustaceans facing hyperosmotic conditions. In marine molluscs phosphatidylcholine synthesis through N-methylation of phosphatidylethanolamine has not been described until now. In vivo labeling of the mussel Mytilus galloprovincialis with [1-(3)H]-ethanolamine showed that the digestive gland is the tissue expressing the highest incorporation into lipids. A sustained increase in lipid labeling was observed up to 72 h following label injection with 79-92% of radioactivity concentrated into phosphatidylethanolamine and phosphatidylcholine. A direct correlation (r = 0.47, p < 0.01) between the specific radioactivities of phosphatidylcholine in plasma and the digestive gland was observed. Moreover, the phosphatidylcholine fatty acid compositions of plasma and the digestive gland were similar but differed from those of phosphatidylcholine purified from other tissues. In vitro incubation of tissues with [1-(3)H]-ethanolamine or L-[3-(3)H]-serine showed that a significant labeling of the choline moiety of phosphatidylcholine was observed in the digestive gland and hemocytes. Pulse-chase experiments with [1-(3)H]-ethanolamine also demonstrated that hemocytes are exchanging the newly formed phospholipids with plasma. Finally, phosphatidylethanolamine N-methyltransferase assays demonstrated salinity-dependent activities in the digestive gland and hemocytes. We conclude that in M. galloprovincialis an active phosphatidylcholine synthesis through N-methylation of phosphatidylethanolamine occurs in the digestive gland and hemocytes and that this newly formed phosphatidylcholine is partly exchanged with plasma.

Effects of S-adenosylmethionine augmentation of serotonin-reuptake inhibitor antidepressants on cognitive symptoms of major depressive disorder

Major depressive disorder (MDD) is often accompanied by significant cognitive impairment, and there are limited interventions specific to this particular symptom. S-adenosylmethionine (SAMe), a naturally occurring molecule which serves as a major methyl-donor in human cellular metabolism, is required for the synthesis and maintenance of several neurotransmitters that have been implicated in the pathophysiology and treatment of cognitive dysfunction in MDD.

OBJECTIVES

This study is a secondary analysis of a clinical trial involving the use of adjunctive SAMe for MDD.

METHODS

Forty-six serotonin-reuptake inhibitor (SRI) non-responders with MDD enrolled in a 6-week, double-blind, randomized trial of adjunctive oral SAMe were administered the self-rated cognitive and physical symptoms questionnaire (CPFQ), a validated measure of cognitive as well as physical symptoms of MDD, before and after treatment.

RESULTS

There was a greater improvement in the ability to recall information (P=0.04) and a trend towards statistical significance for greater improvement in word-finding (P=0.09) for patients who received adjunctive SAMe than placebo. None of the remaining five items reached statistical significance.

CONCLUSIONS

These preliminary data suggest that SAMe can improve memory-related cognitive symptoms in depressed patients, and warrant replication.

Insulin-resistant brain state (IRBS) changes membrane composition of fatty acids in temporal and entorhinal brain cortices of rats: relevance to sporadic Alzheimer's disease?

An insulin-resistant brain state (IRBS) was induced by intracerebroventricular application of the diabetogenic substance streptozotocin (STZ) to investigate changes in cerebral fatty acids. Six weeks after the first STZ injection, increases were found in the concentrations of palmitic and stearic acid in temporal cortex; and of palmitic acid in entorhinal cortex indicative of membrane phospholipid breakdown, and damage of the membrane structure. The relevance of these changes is discussed in relation to sporadic Alzheimer's disease.

The interactivities with lipid membranes differentially characterize selective and nonselective beta1-blockers

BACKGROUND AND OBJECTIVE

beta-Adrenoceptor-blocking agents have been used for perioperative management during anaesthesia, in which selective beta1-blockers are advantageous over nonselective beta-blockers. Apart from the different affinity for beta-adrenoceptors, beta1-blockers were differentially characterized in light of their different interaction with lipid membranes.

METHODS

Selective (atenolol, metoprolol and esmolol) and nonselective (alprenolol, oxprenolol and propranolol) beta1-blockers were reacted at 0.2-1 mmol l with 1,2-dipalmitoylphosphatidylcholine liposomes and biomimetic membranes consisting of phospholipids, sphingolipid and cholesterol. Their membrane interactivities were comparatively determined using the potency to modify membrane fluidity by measuring fluorescence polarization. Their relative hydrophobicities were evaluated by reversed-phase liquid chromatography.

RESULTS

The chromatographic evaluation divided the tested drugs into more hydrophobic ones containing nonselective beta-blockers and less hydrophobic ones containing selective beta1-blockers. Nonselective beta-blockers, but not selective beta1-blockers, fluidized liposomal membranes, with the potency being oxprenolol < alprenolol < propranolol. Membrane-active alprenolol preferentially acted on the hydrophobic deeper regions of phospholipid bilayers. The potency of nonselective beta-blockers to fluidize biomimetic membranes was greatest in propranolol, followed by alprenolol and oxprenolol, whereas all selective beta1-blockers were inactive.

CONCLUSION

The membrane-fluidizing effects of beta-blockers are correlated with their relative hydrophobicities and their respective conformations to perturb the alignment of phospholipid acyl chains. The membrane-interacting characteristics differentiate beta-blockers as nonselective propranolol, alprenolol and oxprenolol vs. beta1-selective atenolol, metoprolol and esmolol. Such differentiation reflects not only the structural difference but also the beta-adrenoceptor-blocking difference. The membrane fluidization may be partly responsible for the nonselective blockade of beta-adrenoceptors.

L-methylfolate, methylcobalamin, and N-acetylcysteine in the treatment of Alzheimer's disease-related cognitive decline

Neuroinflammatory oxidative stress occurs early in AD pathology. Elevated blood Hcy is a useful marker for such neuroinflammation. Hcy contributes to pathological cascades involving AP and NFTs. In AD, Hcy should be lowered by B-vitamin supplements and NAC.

Choline attenuates immune inflammation and suppresses oxidative stress in patients with asthma

Asthma is a chronic immune inflammatory disease characterized by variable airflow obstruction and increased bronchial hyperreactivity (BHR). Therapeutic interventions reduce airway inflammation and relieve symptoms but associated with potential side effects that limit their usefulness. The present study was undertaken to assess the effect of choline on immune inflammation and BHR in asthma subjects. The patients of asthma (n=76) were recruited and treated with choline supplement (1500 mg twice) or standard pharmacotherapy for 6 months in two groups. The patients were evaluated by clinical, immunologic and biochemical parameters. The treatment with choline showed significant reduction in symptom/drug score and improvement in PC(20) FEV1 compared to baseline or standard pharmacotherapy (p<0.01). Choline therapy significantly reduced IL-4, IL-5 and TNF-alpha level as compared to baseline or standard pharmacotherapy after 6 months (p<0.01). Blood eosinophil count and total IgE levels were reduced in both the treatment groups. Cysteinyl leukotriene and leukotriene B4 were suppressed significantly by choline treatment (p<0.01). This was accompanied by decreased 8-isoprostanes, a biomarker for oxidative stress after choline treatment (p<0.01). Choline therapy modulates immune inflammation and suppresses oxidative stress in asthma patients. It can be used as an adjunct therapy for asthma patients.

Pharmacologic therapy of non-alcoholic steatohepatitis

Specific therapy for non-alcoholic steatohepatitis (NASH) is needed because of the potential severity of this liver disease. NASH is a recognized cause of cryptogenic cirrhosis and, increasingly, of hepatocellular carcinoma. Therefore, there is an unmet medical need for the therapy of NASH. This article discusses this therapy, with particular emphasis on pharmacologic therapy.

Folate nutrition is related to neuropsychological functions in the elderly

We investigated the nutritional state of B vitamins and the neuropsychological functions in 25 subjects, aged 63.1 +/- 6.3 years, residing in rural areas of Korea. Nutritional states of thiamin, riboflavin, and pyridoxine were assessed enzymatically in the erythrocytes, and folate concentrations were measured microbiologically in the plasma and erythrocytes. A battery of composite neuropsychological test was administered to the subjects. Plasma folate was correlated with the total intelligence score (p=0.049). Folate levels in the erythrocytes were correlated with the performance intelligence scores such as block design (p=0.017) and picture arrangement (p=0.016). The red cell folate was correlated with memory scores such as general memory (p=0.009) and delayed recall (p=0.000). Although it did not reach statistical significance, verbal memory (p=0.053) was highly correlated with the red cell folate. The red cell folate was also correlated positively with the percent of conceptual level response number score (p=0.029), and negatively with the grooved pegboard test score for the non-dominant hand (p=0.010). Fine motor coordination was also influenced by folate nutrition, as finger tapping scores in both hands were significantly correlated with red cell folate (dominant hand; p=0.026, non-dominant hand; p=0.004). Other B vitamins such as thiamin, riboflavin, and vitamin B(6) were not as strongly correlated with neuropsychological function test scores as folate was. These results suggest that folate nutrition influences neuropsychological function test scores significantly in humans. Further studies are needed to explore the relationship between folate or other vitamin B nutrition and neuropsychological functions and the implications thereof.

Methotrexate-associated alterations of the folate and methyl-transfer pathway in the CSF of ALL patients with and without symptoms of neurotoxicity

BACKGROUND

Severe neurotoxicity has been observed after systemic high-dose and intrathecal methotrexate (MTX) treatment. The role of biochemical MTX-induced alterations of the folate and methyl-transfer pathway in the development of neurotoxic symptoms is not yet fully elucidated.

PROCEDURE

MTX, 5-methyltetrahydrofolate, calcium folinate, S-adenosylmethionine, and S-adenosylhomocysteine were measured in the cerebrospinal fluid (CSF) of 29 patients with acute lymphoblastic leukemia (ALL) who were treated with high-dose MTX (5 g/m(2)) followed by calcium folinate rescue (3 x 15 mg/m(2)) and/or intrathecal (8-12 mg) MTX. Two patients developed subacute MTX-associated neurotoxicity. CSF was obtained by lumbal puncture 1-3 weeks after administration of MTX and shortly after the occurrence of neurotoxicity. The analytes were measured using HPLC assays with UV and/or fluorescence detection.

RESULTS

In non-toxic patients, CSF concentrations of 5-methyltetrahydrofolate and S-adenosylmethionine were in the normal range 2 weeks after administration of high-dose and intrathecal MTX followed by rescue. In contrast, when these patients received intrathecal MTX without rescue, 5-methyltetrahydrofolate concentrations were significantly decreased 12 days after the first MTX administration. S-adenosylmethionine concentrations were significantly decreased up to 45 days. The two patients suffering from neurotoxicity had decreased levels of 5-methyltetrahydrofolate and S-adenosylmethionine during or following toxicity. S-adenosylhomocysteine was determined in all samples of neurotoxic patients but was below the limit of quantification in most samples of non-toxic patients. Calcium folinate was not detected; MTX was present only in samples obtained during its infusion.

CONCLUSION

Intrathecal MTX without folinate rescue as well as MTX-associated neurotoxicity are likely to be associated with specific alterations of the folate and methyl-transfer pathway.

Cognitive impairment in folate-deficient rats corresponds to depleted brain phosphatidylcholine and is prevented by dietary methionine without lowering plasma homocysteine

Poor folate status is associated with cognitive decline and dementia in older adults. Although impaired brain methylation activity and homocysteine toxicity are widely thought to account for this association, how folate deficiency impairs cognition is uncertain. To better define the role of folate deficiency in cognitive dysfunction, we fed rats folate-deficient diets (0 mg FA/kg diet) with or without supplemental L-methionine for 10 wk, followed by cognitive testing and tissue collection for hematological and biochemical analysis. Folate deficiency with normal methionine impaired spatial memory and learning; however, this impairment was prevented when the folate-deficient diet was supplemented with methionine. Under conditions of folate deficiency, brain membrane content of the methylated phospholipid phosphatidylcholine was significantly depleted, which was reversed with supplemental methionine. In contrast, neither elevated plasma homocysteine nor brain S-adenosylmethionine and S-adenosylhomocysteine concentrations predicted cognitive impairment and its prevention by methionine. The correspondence of cognitive outcomes to changes in brain membrane phosphatidylcholine content suggests that altered phosphatidylcholine and possibly choline metabolism might contribute to the manifestation of folate deficiency-related cognitive dysfunction.

The effects of phosphatidylserine on endocrine response to moderate intensity exercise

Background

Previous research has indicated that phosphatidylserine (PS) supplementation has the potential to attenuate the serum cortisol response to acute exercise stress. Equivocal findings suggest that this effect might be dose dependent. This study aimed to examine the influence of short-term supplementation with a moderate dose of PS (600 mg per day) on plasma concentrations of cortisol, lactate, growth hormone and testosterone before, during, and following moderate intensity exercise in healthy males.

Methods

10 healthy male subjects participated in the study. Each subject was assigned to ingest 600 mg PS or placebo per day for 10 days using a double-blind, placebo-controlled, crossover design. Serial venous blood samples were taken at rest, after a 15 minute moderate intensity exercise protocol on a cycle ergometer that consisted of five 3-minute incremental stages beginning at 65% and ending at 85% VO_{2 max}, and during a 65 minute passive recovery. Plasma samples were assessed for cortisol, growth hormone, testosterone, lactate and testosterone to cortisol ratio for treatment (PS or placebo).

Results

Mean peak cortisol concentrations and area under the curve (AUC) were lower following PS (39 ± 1% and 35 ± 0%, respectively) when compared to placebo (p < 0.05). PS increased AUC for testosterone to cortisol ratio (184 ± 5%) when compared to placebo (p < 0.05). PS and placebo supplementation had no effect on lactate or growth hormone levels.

Conclusion

The findings suggest that PS is an effective supplement for combating exercise-induced stress and preventing the physiological deterioration that can accompany too much exercise. PS supplementation promotes a desired hormonal status for athletes by blunting increases in cortisol levels.

Problems in the congenital lactic acidoses

The congenital lactic acidosis form a heterogeneous group of inborn errors that includes defects of gluconeogenesis, the pyruvate dehydrogenase complex, the Krebs cycle and the respiratory chain. These disorders are not easily classified because of the absence of specific metabolites, difficulties in providing suitable tissue specimens and technical problems with the enzyme assays. The commonest causes of lactic acidosis due to inborn errors are the deficiencies of glucose-6-phosphatase and fructose bisphosphatase, which present with hypoglycaemia, lactic acidosis and hepatomegaly. Pyruvate carboxylase and phosphoenolpyruvate deficiencies vary considerably in both clinical expression and biochemical findings. Neurological symptoms predominate in defects of the pyruvate dehydrogenase complex, and some cases of the spinocerebellar ataxias may be due to partial defects of the pyruvate and 2-oxoglutarate dehydrogenase complexes.

Steroid and peptide control mechanisms in membrane of Xenopus laevis oocytes resuming meiotic division

Stage 5-6 Xenopus laevis oocytes are arrested in prophase of the first meiotic division, and can be studied in vitro after removal from their follicle cell environment. While they do not mature spontaneously, they demonstrate germinal vesicle (nucleus) breakdown (GVBD) if exposed to approximately 1 microM-progesterone (the hormone released in vivo at the time of ovulation and maturation). The oocytes' then become eggs ready to be fertilized. The progesterone-oocyte interaction, contrary to what is observed in all endocrine steroid target organs so far studied, takes place at the surface membrane level and is not narrowly progesterone-specific, since other hormones such as cortisol or testosterone can also cause resumption of meiosis in vitro. This is the first description of such a paracrine steroid system, which depends however on a receptor mechanism, as indicated by physicochemical experiments, studies with antagonistic (competitive) steroids, and cell-free specific inhibitory effects on membrane-bound adenylate cyclase. It was found that insulin and related growth factors (mitosis-stimulating activity, MSA; insulin-like growth factor, IGF) are also reinitiators of meiosis. Insulin also potentiates the effects of low progesterone concentration (approximately 1 nM) in completely denuded oocytes (free of the vitelline membrane). From these observations it is suggested that there may be a physiological, cooperative involvement of a steroid (progesterone) and an insulin-like peptide factor within the ovaries which promotes oocyte maturation in vivo. The molecular mechanisms of the hormone-dependent changes in cyclic AMP and Ca2+ remain to be elucidated in detail, as well as the respective roles of these two sets of metabolic events.

Folate, vitamin b(12), and homocysteine as risk factors for cognitive decline in the elderly

OBJECTIVE

Cross-sectional studies have shown that the dysregulation of one-carbon metabolism is associated with cognitive impairment. However, the findings of longitudinal studies investigating this association have been inconsistent. This study investigated the prospective associations between cognitive decline and the levels of folate, vitamin B(12) and homocysteine both at baseline and over course of the study period.

METHODS

A total of 607 (83%) elderly individuals were selected from a group of 732 elderly individuals without dementia at baseline and followed over a 2.4-year study period. The Mini-Mental State Examination (MMSE) was administered to the subjects, and the serum levels of folate, vitamin B(12) and homocysteine were assayed both at baseline and at follow-up examinations. Covariates included demographic data, disability, depression, alcohol consumption, physical activity, vascular risk factors, serum creatinine level, vitamin intake, and apolipoprotein E genotype.

RESULTS

Cognitive decline was associated with decreasing quintiles of folate at baseline, a relative decline in folate and an increase in homocysteine across the two examinations after adjustment for relevant covariates.

CONCLUSION

These results suggest that folate and homocysteine are involved in the etiology of cognitive decline in the elderly.