Sensitive ex vivo human skin transdermal assay testing method with mass spectrometric analysis for cosmetics application.

BACKGROUND: Cosmetics manufacturers are focused on cosmetic delivery systems into the skin, but the level of diffusion of the systems in the skin tissues is not well understood. The current methods, such as Franz diffusion, assess analyte diffusion in the whole skin or artificial membranes, which has limitations for understanding skin delivery systems. AIMS: Our study aimed to create a transdermal delivery method which is based on dermal-epidermal separation of human skin, allowing us to assess each layer of skin separately for its efficacy. MATERIALS AND METHODS: During the experiment, resveratrol was used as the target analyte by applying it to the skin and then separating it into dermis and epidermis. Each layer is treated individually and subjected to a high-resolution mass spectrometry analysis to detect resveratrol levels. As a result, the efficiency of resveratrol diffusion in the dermal and epidermal layers of the skin can be evaluated. RESULTS: We found that resveratrol was detected in both the dermal and epidermal layers using our method. CONCLUSIONS: Hence, we developed a sensitive method for transdermal delivery testing that can be used to evaluate skin delivery systems for cosmetic or pharmaceutical purposes.

Exacerbation of cardiovascular ageing by diabetes mellitus and its associations with acyl-carnitines.

OBJECTIVE: To demonstrate differences in cardiovascular structure and function between diabetic and non-diabetic older adults. To investigate associations between acyl-carnitines and cardiovascular function as indexed by imaging measurements. METHODS: A community-based cohort of older adults without cardiovascular disease underwent current cardiovascular imaging and metabolomics acyl-carnitines profiling based on current and archived sera obtained fifteen years prior to examination. RESULTS: A total of 933 participants (women 56%, n=521) with a mean age 63±13 years were studied. Old diabetics compared to old non-diabetics had lower myocardial relaxation (0.8±0.2 vs 0.9±0.3, p=0.0039); lower left atrial conduit strain (12±4.3 vs 14±4.1, p=0.045), lower left atrial conduit strain rate (-1.2±0.4 vs -1.3±0.5, p=0.042) and lower ratio of left atrial conduit strain to left atrial booster strain (0.5±0.2 vs 0.7±0.3, p=0.0029). Higher levels of archived short chain acyl-carnitine were associated with present-day impairments in myocardial relaxation (C5:1; OR 1.03, p=0.011), worse left atrial conduit strain function (C5:1; OR 1.03, p=0.037). Increases in hydroxylated acyl-carnitines were associated with worse left atrial conduit strain [(C4-OH; OR 1.05, p=0.0017), (C16:2-OH; OR 1.18, p=0.037)]. Current, archived and changes in long chain acyl-carnitines were associated with cardiovascular functions [(C16; OR 1.02, p=0.002), (C20:3; OR 1.01, p=0.014), (C14:3; OR 1.12, p=0.033), (C18:1; OR 1.01, p=0.018), (C18:2; OR 1.01, p=0.028), (C20:4; OR 1.10, p=0.038)] (all p<0.05). CONCLUSION: Older diabetic adults had significant impairments in left ventricular myocardial relaxation and left atrial strain, compared to older non-diabetic adults. Short chain and long chain, di-carboxyl and hydroxylated acyl-carnitines were associated with these cardiovascular functional differences.

Metabolic stress is a primary pathogenic event in transgenic Caenorhabditis elegans expressing pan-neuronal human amyloid beta.

Alzheimer's disease (AD) is the most common neurodegenerative disease affecting the elderly worldwide. Mitochondrial dysfunction has been proposed as a key event in the etiology of AD. We have previously modeled amyloid-beta (Aß)-induced mitochondrial dysfunction in a transgenic Caenorhabditis elegans strain by expressing human Aß peptide specifically in neurons (GRU102). Here, we focus on the deeper metabolic changes associated with this Aß-induced mitochondrial dysfunction. Integrating metabolomics, transcriptomics and computational modeling, we identify alterations in Tricarboxylic Acid (TCA) cycle metabolism following even low-level Aß expression. In particular, GRU102 showed reduced activity of a rate-limiting TCA cycle enzyme, alpha-ketoglutarate dehydrogenase. These defects were associated with elevation of protein carbonyl content specifically in mitochondria. Importantly, metabolic failure occurred before any significant increase in global protein aggregate was detectable. Treatment with an anti-diabetes drug, Metformin, reversed Aß-induced metabolic defects, reduced protein aggregation and normalized lifespan of GRU102. Our results point to metabolic dysfunction as an early and causative event in Aß-induced pathology and a promising target for intervention.

Urine Tricarboxylic Acid Cycle Metabolites Predict Progressive Chronic Kidney Disease in Type 2 Diabetes.

Context: Metabolites in the tricarboxylic acid (TCA) cycle are not only involved in energy metabolism but also play important roles in non-energy production activities. Objective: To study whether baseline urine key TCA cycle metabolites (lactate, pyruvate, citrate, α-ketoglutaric acid, succinate, fumarate, and malate) independently predict risk of chronic kidney disease (CKD) progression [fast estimated glomerular filtration rate (eGFR) decline] in individuals with type 2 diabetes mellitus (T2DM). Design: One discovery and one validation nested case-control studies in two independent T2DM cohorts. Setting and Participants: Subjects with T2DM were recruited and followed in a regional hospital and at a primary care facility. Main Outcome Measures: eGFR trajectory (slope) was estimated by linear regression. Progressive CKD was defined as eGFR decline of ≥5 mL/min/1.73 m2 per year. Results: As compared with those with stable renal function (n = 271), participants who experienced progressive CKD (n = 116) had a lower level of urine citrate but significantly higher levels of lactate, fumarate, and malate levels at baseline. Both fumarate and malate predicted progressive CKD independent of traditional cardio-renal risk factors, including eGFR and albuminuria. Fumarate interacted with sex (P for interaction = 0.03) and independently predicted progressive CKD in male but not female participants. All these findings were reproducible in a validation study (case n = 96, control n = 402). Exploratory analysis suggested that fumarate might partially mediate the effect of oxidative stress on CKD progression. Conclusions: Key TCA cycle metabolites, especially fumarate, may be involved in the pathophysiologic pathway independent of traditional cardio-renal risk factors, leading to CKD progression in patients with T2DM.

Electroenhanced solid-phase microextraction of methamphetamine with commercial fibers.

Electroenhanced solid-phase microextraction (EE-SPME) method with gas chromatographic mass spectrometric analysis was investigated for the determination of methamphetamine in urine sample with commercial fibers. In this approach, commercial SPME fibers were used in direct immersion mode with an applied potential to extract methamphetamine. EE-SPME was more effective in the extraction compared to conventional SPME (i.e. application of potential). The method was simple to use, and avoided the need for alkalization and derivatization of methamphetamine. Experimental conditions were optimized to achieve better extraction performance. Various conditions including applied potential, sample pH, extraction and desorption time were investigated. Based on the optimized conditions, EE-SPME achieved a higher enrichment factor of 159-fold than conventional SPME. The calibration plot under the best selected parameters was linear in the range of 0.5-15ng/mL (r=0.9948). The feasibility of EE-SPME was demonstrated by applying it to the analysis of human urine samples. The limit of detection of methamphetamine was 0.25ng/mL with a satisfactory relative standard deviation of 6.12% (n=3) in human urine.

Electro membrane extraction of biological anions with ion chromatographic analysis.

A simple and sensitive single step electro membrane extraction (EME) procedure was demonstrated for biological organic anions with determination by ion chromatography (IC). Nitrite, adipate, oxalate, iodide, fumarate, thiocyanate and perchlorate were extracted from aqueous donor solutions, across a supported liquid membrane (SLM) consisting of methanol impregnated in the walls of a porous polypropylene membrane bag and into an alkaline aqueous acceptor solution in the lumen of the propylene envelope by the application of potential of 12V applied across the SLM. The acceptor solution was analyzed by IC. Parameters affecting the extraction performance such as type of SLM, extraction time, pH of the donor and acceptor solution, and extraction voltage were studied. The most favorable EME conditions were methanol as the SLM, extraction time of 5min, pH of acceptor and sample solutions of 12 and 4, respectively, and a voltage of 12V. Portable 12V batteries were used in the study. Under these optimized conditions, all anions had enrichment factors ranging from 3.6 to 36.2 with relative standard deviations (n=3) of between 6.6 and 17.5%. Good linearity ranging from 0.1 to 10µgmL(-1) with coefficients of correlation (r) of between 0.9981 and 0.9996 were obtained. The limits of detection of the EME-IC method were from 0.01 to 0.14µgmL(-1). The developed methodology was applied to amniotic fluid samples to evaluate the feasibility of the method for real applications.