A method for human health impact assessment in social LCA: lessons from three case studies

Purpose

Improving human health is a long-lasting endeavour of mankind. In the field of social life cycle assessment (SLCA), the importance of human health is often highlighted, and further development of impact assessment methods has been recommended. The purpose of this article is to present a method for assessing human health impacts within SLCA.

Methods

By using a systematic combining approach, knowledge and experience about assessing human health impacts were obtained from three previously conducted case studies. The first case study was about an airbag system, the second about a catalytic converter and the third about gold jewellery. The disability-adjusted life years (DALY) indicator was used for impact assessment in all three case studies.

Results and discussion

Both positive and negative human health impacts associated with the products were identified and assessed in the three case studies. For the airbag system, avoided health impacts in the use phase outweighed health impacts during production. For the catalytic converter, whether health impacts avoided exceeded health impacts caused or not depended on which time perspective regarding impacts was employed. Gold jewellery does not help avoiding any health impacts but caused considerable health impacts when produced at a certain location. Based on experience from these case studies, a generic human health impact assessment method was developed, and a life cycle human health typology for products was developed based on the method. The method provides a basis for analysis and interpretation of health impacts along product life cycles, and it is therefore important to report both positive and negative health impacts separately for different actors.

Conclusions

The developed human health impact assessment method involves the assessment and comparison of both positive and negative human health impacts along product life cycles. In addition to the products assessed in the three case studies, we suggest additional products that could be particularly interesting to assess with the developed method, including medicines, seat belts, other conflict minerals, alcoholic beverages and products with a high chemical impact.

     

Nutrition in the life cycle assessment of foods—function or impact?

Purpose

This work provides an unambiguous conceptual framework for inclusion of nutrition in Life Cycle Assessments (LCAs) of food that enables the distinction between two different roles of nutrition, namely serving as the basis of food comparisons via the functional unit and as an impact pathway that links food ingestion with human health effects.

Methods

We compare how nutritional aspects have been considered in the functional unit of published LCAs of food with the procedural requirements for ensuring comparability of the functional units. We consider the relevance of nutrient profiling models for assessing food- and diet-related health damages and benefits in the context of LCAs of food. We finally recommend a method that will enable a systematic, comparative, and holistic assessment of the marginal health effect of food products on human health.

Results and discussion

Satiety is proposed as a central attribute for comparisons of food products, while weighted measures of nutrient content are suggested to be largely misplaced as part of the functional unit. In contrast, nutritional measures have a large role to play in assessing the human health impacts of the marginal ingestion of specific food products. Such measures should enable a direct quantification of human health effect and benefits and should take advantage of robust epidemiological evidence.

Conclusions

Nutritional measures enter into both the functional unit in the form of satiety measures and into the calculation of impacts in the form of the marginal influence of the specific food item on the human health impact of the overall diet. To enhance the differentiation of health impacts at the level of individual food items, it is recommended to combine the nutrient balance indicator with the DALY Nutritional Index (DANI) in each specific dietary context.

     

Life-LCA: assessing the environmental impacts of a human being—challenges and perspectives

Purpose

The life-cycle assessment (LCA) method is typically applied to products, but the potential and demand for extending its use also to other applications are high. In this respect, this paper proposes an LCA concept to be used for the assessment of human beings as new study objects, namely Life-LCA. Key challenges of such a new approach and potential solutions for those are identified and discussed.

Methods

The Life-LCA concept was developed based on a detailed desktop research. Several Life-LCA-specific challenges were identified and categorized under three research questions. One of these questions focusses on the conceptual design of a Life-LCA method while the others are addressing operational issues, which are the definition of the new study system and the practical assessment of complex human consumption behaviors. Methodological solutions are proposed, e.g., based on suggestions provided in the existing methods product LCA and organizational LCA (O-LCA).

Results and discussion

Conceptual challenges arise from the general diversity, complexity, and temporal development of human lives and consumption behaviors. We introduce Life-LCA as a two-dimensional method that covers both, the new human life cycle (dimension 1) and the life cycle of the consumed products (dimension 2). Furthermore, the two types Individual Life-LCA and Lifestyle-LCA are differentiated. Especially, the definition of a general system boundary for Life-LCA and data collection and evaluation face many operational challenges. For example, the social behavior of human beings is a new factor to be considered which causes new allocation problems in LCA. Moreover, the high demand for aggregated LCA data requires specific rules for data collection and evaluation as well as a new bottom-up product clustering scheme.

Conclusions

Life-LCA, either used for the assessment of individual lives or lifestyles, has the potential to raise environmental awareness of people by making their specific environmental impacts comprehensively measurable and thus, tangible. However, many challenges need to be solved in future interdisciplinary research to develop a robust and applicable method. This paper conceptualizes such an approach and proposes solutions that can serve as a framework for ongoing method development.

     

Offshore refuges support higher densities and show slower population declines of wintering Ruddy Turnstones Arenaria interpres

ABSTRACT

Capsule: Wintering Ruddy Turnstones Arenaria interpres occur in higher densities and their populations decline less on, or close to, offshore refuges than on mainland sites subject to greater levels of human disturbance.

Aim: To compare wintering densities of Ruddy Turnstones and changes in counts across time from sites with differing levels of human disturbance.

Methods: Long-term counts of Ruddy Turnstones (1998/1999 to 2015/2016) were used from 19 sites (two offshore refuges and 17 mainland sites subject to higher levels of human disturbance) in northeast England. No direct measure of human disturbance was available for our mainland sites; instead we used questionnaires (n?=?690) to understand how far people travelled to visit the coast and then used this distance with human population densities in a buffer around each site as a proxy for human disturbance levels.

Results: After controlling for the extent of their preferred habitat at each site (rocky shore) we found: (i) the closer each of the 19 sites was to the nearest offshore refuge the higher the density of Ruddy Turnstones and (ii) bird counts were stable at the two refuge sites, whereas, on average, counts declined at the 17 mainland sites. However, no relationship was found between Ruddy Turnstone counts from 17 mainland sites and human population densities within differing distances from each site (up to 10?km).

Conclusions: Our work suggests that Ruddy Turnstones made greater use of relatively undisturbed areas (offshore refuges) than those subject to greater disturbance by humans (mainland sites). Although the use of refuges and mainland in our study area was not well known, observations from 11 radio-tagged Ruddy Turnstones suggest that individual birds did use both locations. In a broader context, our work concurs with other studies that highlight the need for refuges with limited or no human access.     

Environmental improvement of lead refining: a case study of water footprint assessment in Jiangxi Province,China

Purpose

China is currently facing water scarcity due to its large national population and rapid economic development. Lead is a typical non-ferrous metal. The lead industry is one of the top 10 water-consuming industries in China and suffers from the heavy burden of properly managing discharged wastewater containing heavy metals and organic pollutants. Accordingly, a water footprint analysis of lead refining was conducted in this study to enhance the water management in China’s lead industry. This study is part 2 of the environmental improvement for lead-refining series.

Methods

In accordance with the ISO 14046 standard, life cycle assessment-based water footprint analysis was applied to a lead-refining enterprise in Jiangxi Province, China. Five midpoint (i.e., water scarcity, aquatic eutrophication, carcinogens, non-carcinogens, and freshwater ecotoxicity) and two endpoint (i.e., human health and ecosystem quality) indicators are utilized to assess the water footprint impact results.

Results and discussion

Direct pollutant emissions are a major contributor to ecosystem quality and freshwater ecotoxicity, whereas indirect processes (i.e., industrial hazardous waste landfill, transport, and chemicals) contribute considerably to human health, aquatic eutrophication, and carcinogen categories. Chromium, copper, arsenic, and zinc were the key substances in the lead production chain, and their emissions exerted a significant impact on human health and ecosystem quality.

Conclusions

Reducing direct copper emission was the most important key to minimizing ecosystem quality decline in China’s lead industry, and optimizing indirect processes was effective in mitigating the impact on human health. Enhancing wastewater treatment, increasing chemical consumption efficiency, optimizing transport and industrial hazardous waste disposal, improving supervision, issuing relevant governmental regulations, and adopting advanced wastewater treatment technologies are urgently needed to control the water footprint.

     

The pathogenicity,structural and functional exploration of human HMGB1 single nucleotide polymorphisms using in silico study

Abstract

The human HMGB1 gene mutations have a major impact on several immune-related diseases and cancer. The detrimental effect of non-synonymous mutations of HMGB1 has not been investigated yet, hence the present study aims to examine single nucleotide polymorphisms and their implications on the structure-function of human HMGB1. The multifaceted HMGB1 protein acts as pleiotropic cytokine and regulates essential genes for coordinated cellular functions. The mutational effect on HMGB1 was analyzed by sequence-based homology methods, supervised learning methods, and structure-based methods. The study identified 58 non-synonymous mutations in human HMGB1, out of which only 2 mutations; R10T (rs61742222) and F103C (rs61733675) were classified as the SNPs with highest deleterious and disease-causing mutants. The effect of these mutations in structure of HMGB1 was scrutinized and the R10T mutant found to have a distinct structural behaviour in the B-box domain. In addition, R10T mutant predicted that it affects the MoRF function of HMGB1 and it could disrupt the DNA binding or/and protein partner interaction activity by HMGB1. F103C mutation takes place at the TLR binding and cytokine inducing region of HMGB1, hence it could affect the protein binding activity which involves in many cellular signaling. The study identified potent mutations R10T (a cancer-causing somatic mutation) and F103C (a novel mutation) and these mutations either directly or indirectly hinder DNA binding activity and TLR and cytokine binding of HMGB1. These findings will help in understanding the molecular basis of these promising mutations and functional role of human HMGB1 in cancer and immunological diseases.

Abbreviations AGER Advanced glycosylation end product-specific receptor

CXCL Chemokine (C-X-C motif) ligand

dbSNP The single nucleotide polymorphism database

HMGB1 High mobility group box 1

LINCS LINear Constraint Solver

MDS Molecular dynamics simulation

MoRF Molecular recognition features

NPT Number of particle, Pressure and Temperature

NVT Number of particle, Volume and Temperature

nsSNP Non-synonymous SNP

PBC Partial boundary condition

PCA Principal component analysis

PME Partial mesh Ewald

RMSD Root mean square deviation

RMSF Root mean square fluctuation

SNP Single nucleotide polymorphism

SPC Single-point charge

TLR Toll-like receptor

UTR Un-translated Region

Communicated by Ramaswamy H. Sarma     

Metabolic phenotyping to monitor chronic enteritis canceration

Introduction

Untargeted metabolomics intends to objectively analyze a wide variety of compounds. Their diverse physicochemical properties make it difficult to choose an appropriate reconstitution solvent after sample evaporation without influencing the chromatography or hamper column sorbent integrity.

Objectives

The study aimed to identify the most appropriate reconstitution solvent for blood plasma samples in terms of feature recovery, four endogenous compounds, and one selected internal standard.

Methods

We investigated several reconstitution solvent mixtures containing acetonitrile and methanol to resolve human plasma extract and evaluated them concerning the peak areas of tryptophan-d₅, glucose, creatinine, palmitic acid, and the phophatidylcholine PC(P-16:0/P-16:0), as well as the total feature count

Results

Results indicated that acetonitrile containing 30% methanol was best suited to match all tested criteria at least for human blood plasma samples.

Conclusion

Despite identifying the mixture of acetonitrile and methanol being suitable as solvent for human blood plasma extracts, we recommend to systematically test for an appropriate reconstitution solvent for each analyzed biomatrix.

     

Economic importance,taxonomic representation and scientific priority as drivers of genome sequencing projects

Background

Of the approximately two hundred sequenced plant genomes, how many and which ones were sequenced motivated by strictly or largely scientific considerations, and how many by chiefly economic, in a wide sense, incentives? And how large a role does publication opportunity play?

Results

In an integration of multiple disparate databases and other sources of information, we collect and analyze data on the size (number of species) in the plant orders and families containing sequenced genomes, on the trade value of these species, and of all the same-family or same-order species, and on the publication priority within the family and order. These data are subjected to multiple regression and other statistical analyses. We find that despite the initial importance of model organisms, it is clearly economic considerations that outweigh others in the choice of genome to be sequenced.

Conclusions

This has important implications for generalizations about plant genomes, since human choices of plants to harvest (and cultivate) will have incurred many biases with respect to phenotypic characteristics and hence of genomic properties, and recent genomic evolution will also have been affected by human agricultural practices.

     

Exploring toxicity of perfluorinated compounds through complex network and pathway modeling

Abstract

Perfluorinated compounds (PFCs) have serious impacts on human health, which could interfere with the body's signal pathways and affect the normal hormone balance of humans. PFCs were reported to bind to many proteins causing a series of biological effects. It was quite possible that the in vivo action of PFCs was not a single target or a single pathway, suggesting the toxic effect was due to the disturbance of protein or gene network, not limited to the modification of a single target protein or gene. Thus, a PFCs-targets interaction network was constructed and the significant differences in the characteristics of complex networks between the branched PFCs and linear PFCs were observed. A molecular dynamics simulation proved that binding ability of the branched PFCs to the target protein was much weaker than that of the linear PFCs, explaining why the branched PFCs presented significantly difference from the linear PFCs in terms of complex network characteristics. In addition, four target genes were identified as the central node genes of the network. The four target genes were proved to present certain influences on some diseases, which suggested a high correlation between PFCs to these diseases, including obesity, hepatocellular carcinoma and diabetes. The present work was helpful to develop new approaches to identify the key toxic targets of compounds and to explore the toxicity effects on pathways. Abbreviations AR androgen receptor

BPA bisphenol A

ESR1 estrogen receptor 1

ESR2 estrogen receptor 2

GLTP glycolipid transfer protein

HbF the fetal hemoglobin

HBG1 hemoglobin subunit γ-1

hERα human ERα

HSD17B1 hydroxysteroid 17-β dehydrogenase 1

KEGG Kenya encyclopedia of genes and genomes

MD molecular dynamics simulation

PFCs perfluorinated compounds

PFOA perfluorooctanoic acid

PFOS perfluorooctane sulfonate

POPs persistent organic pollutants

RMSD root-mean-square deviation

SHBG sex hormone binding globulin

SPC/E extended simple point charge model

TR thyroid hormone receptor

Communicated by Ramaswamy H. Sarma     

Microcystins: measuring human exposure and the impact on human health

Abstract

Context: Freshwater cyanobacterial toxins, microcystins, may be a contributing factor to the development of hepatocellular cancer and colorectal cancer.

Objectives: This review summarizes the toxicity data, exposure routes and the methodologies available to determine exposure to elucidate the relationship to liver and colorectal cancer.

Methods: Literature searches were conducted using Medline, PubMed and Web of Science.

Results: There is evidence of human poisonings resulting from exposure to microcystins, however current methods rely on targeted approaches only suitable for acute exposure. No methods exist for the determination of chronic exposure to microcystins.

Conclusions: With the growing evidence of exposure to microcystins and the possible links to cancer, methods to measure medium to long-term human exposure are needed. The identification and validation of candidate biomarkers are key to undertaking urgently required epidemiological studies.     

Characterization of Corticotropin-Releasing Hormone Binding Sites in the Human Placenta

Abstract

The human placenta synthesizes and secretes large amounts of corticotropin-releasing hormone (CRH) which has been implicated in the triggering of parturition. The placental CRH was found to act in a paracrine manner to stimulate secretion of ACTH and β-endorphin. In view of this we sought to characterize CRH binding sites in the human placenta.

The specific binding of ¹²⁵I-tyrosyl-ovine CRH (¹²⁵I-oCRH) to placental membranes was dependent on time, temperature, pH, divalent cations and was reversible on addition of excess oCRH. Scatchard analysis revealed a high affinity binding site with a dissociation constant of ?0.7 nmol/L and maximum number of binding sites ?44 fmol/mg protein.

Disuccinimidyl suberate, a chemical cross-linker, was used to covalently attach ¹²⁵I-oCRH to placental membranes. The labelled placental membranes were analyzed by SDS-PAGE and autoradiography. A major radioactively labelled band with a molecular weight of 55,000 Da was identified.

In this study we have identified placental binding sites for CRH with properties similar to CRH receptors described in a number of human and animal tissues and with a molecular weight similar to that of the brain CRH receptor. These binding sites may be involved in the regulation of the placental CRH/ACTH - β-endorphin axis during pregnancy and parturition.     

Factors affecting breeding distribution of Storm-petrels Hydrobates pelagicus in Orkney and Shetland

Capsule The main factors are past and present human activities, especially the introduction of rats to islands.

Aims To assess factors that influence breeding distribution and abundance of Storm-petrel.

Methods We used a database for 142 islands in Shetland and Orkney. Breeding status of Storm-petrel was related to data for each island on introduced and indigenous predators, other human-related features, and aspects of island geography.

Results Although 92% of the total land area of the archipelagos comprised islands with rats present, Storm-petrel colonies were almost totally restricted to rat-free islands. They also occurred more frequently on islands with cliffs, far from neighbouring islands with humans, and on islands with a low rate of human visits. Colony size was smaller on the smallest occupied islands. Breeding numbers of Great Skuas Stercorarius skua, Great Black-backed Gulls Larus marinus, and Storm-petrels all correlated, as each increased with island size.

Conclusions The presence or absence of rats is the single most important influence on Storm-petrel breeding distribution in Orkney and Shetland. However, geographical and human-related effects, such as the presence of cliffs or the occurrence of human visits, also appear to influence the distribution of Storm-petrels, whereas avian predators appear to have had little effect until now.     

Purification and Characterization of a Cytostatic Factor with Anti-Viral Activity from the Bitter Melon

Abstract

We have previously reported that a crude aqueous extract of the bitter melon (Momordica charantia) has both cytostatic and cytotoxic activi-ties ^1,2, and is a competitive inhibitor of guanylate cyclase activity³. This crude preparation kills human leukemic lymphocytes in a dose-dependent manner while not affecting the viability of normal human lymphocytes at these same doses¹.

In this report we describe the purification and characterization of one of these cytostatic factors which also exhibits anti-viral activity.

The partially purified factor was both cytostatic to BHK-21 cells and inhibitory to VSV plaque formation in a dose-dependent manner. This pre-paration was inhibitory to both viral and host cell RNA and protein synthesis as early as 30 min after addition to these samples. As determined by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), this purified factor is a single component with a molecular weight corresponding to 40,000 daltons.

The factor is sensitive to boiling and to pre-treatments with trypsin, but not ribonuclease (RNAse), or deoxyribonuclease (DNAse).

As determined by radioactive precursor uptake and incorporation studies, the purified factor inhibits both RNA and protein synthesis in intact tissue culture cells and inhibits protein synthesis in a cell-free wheat germ system⁴. DNA synthesis was slightly stimulated.

The purified factor is cytostatic for both BHK-21 and for the IM9 leukemic cell lines for at least 120 h.

The cytostatic component had no effect on cellular cyclic GMP metabolism.     

Genome-wide analysis of epigenetic dynamics across human developmental stages and tissues

Background

Epigenome is highly dynamic during the early stages of embryonic development. Epigenetic modifications provide the necessary regulation for lineage specification and enable the maintenance of cellular identity. Given the rapid accumulation of genome-wide epigenomic modification maps across cellular differentiation process, there is an urgent need to characterize epigenetic dynamics and reveal their impacts on differential gene regulation.

Methods

We proposed DiffEM, a computational method for differential analysis of epigenetic modifications and identified highly dynamic modification sites along cellular differentiation process. We applied this approach to investigating 6 epigenetic marks of 20 kinds of human early developmental stages and tissues, including hESCs, 4 hESC-derived lineages and 15 human primary tissues.

Results

We identified highly dynamic modification sites where different cell types exhibit distinctive modification patterns, and found that these highly dynamic sites enriched in the genes related to cellular development and differentiation. Further, to evaluate the effectiveness of our method, we correlated the dynamics scores of epigenetic modifications with the variance of gene expression, and compared the results of our method with those of the existing algorithms. The comparison results demonstrate the power of our method in evaluating the epigenetic dynamics and identifying highly dynamic regions along cell differentiation process.

     

Identifying micro-inversions using high-throughput sequencing reads

Background

The identification of inversions of DNA segments shorter than read length (e.g., 100 bp), defined as micro-inversions (MIs), remains challenging for next-generation sequencing reads. It is acknowledged that MIs are important genomic variation and may play roles in causing genetic disease. However, current alignment methods are generally insensitive to detect MIs. Here we develop a novel tool, MID (Micro-Inversion Detector), to identify MIs in human genomes using next-generation sequencing reads.

Results

The algorithm of MID is designed based on a dynamic programming path-finding approach. What makes MID different from other variant detection tools is that MID can handle small MIs and multiple breakpoints within an unmapped read. Moreover, MID improves reliability in low coverage data by integrating multiple samples. Our evaluation demonstrated that MID outperforms Gustaf, which can currently detect inversions from 30 bp to 500 bp.

Conclusions

To our knowledge, MID is the first method that can efficiently and reliably identify MIs from unmapped short next-generation sequencing reads. MID is reliable on low coverage data, which is suitable for large-scale projects such as the 1000 Genomes Project (1KGP). MID identified previously unknown MIs from the 1KGP that overlap with genes and regulatory elements in the human genome. We also identified MIs in cancer cell lines from Cancer Cell Line Encyclopedia (CCLE). Therefore our tool is expected to be useful to improve the study of MIs as a type of genetic variant in the human genome. The source code can be downloaded from: http://cqb.pku.edu.cn/ZhuLab/MID.

     

OXR1 signaling pathway as a possible mechanism of elastase-induced oxidative damage in pulmonary cells: the protective role of ellagic acid

Background and objective

Oxidative stress is a process that occurs through free radicals on the cell membranes which causes damage to the cell and intracellular organelles, especially mitochondria membranes. H2O2 induced oxidative stress in human cells is of interest in toxicological research since oxidative stress plays a main role in the etiology of several pathological conditions. Neutrophil Elastase (Serine proteinase) is involved in the pathology process of emphysema as a respiratory disease through lung inflammation, and destruction of alveolar walls. The present study investigated the direct oxidative stress effects of Elastase in comparison with H2O2 on human lung epithelial cells (A549 cells) concerning the generation of reactive oxygen species (ROS) and modulation of oxidation resistance 1 (OXR1) and its downstream pathway using the well-known antioxidant Ellagic acid as an activator of antioxidant genes.

Materials and methods

The human pulmonary epithelial cells (A549) were divided into the nine groups including Negative control, Positive control (H2O2), Elastase (15, 30, and 60 mU/mL), Ellagic acid (10 μmol/L), and Elastase?+?Ellagic acid. Cytotoxicity, ROS generation, oxidative stress profile, level of reactive metabolites, and gene expression of OXR1 and its downstream genes were measured in all groups.

Results

The obtained data demonstrated that Elastase exposure caused oxidative stress damage in a dose-depended manner which was associated with decreases in antioxidant defense system genes. Conversely, treatment with Ellagic acid as a potent antioxidant showed improved antioxidant enzyme activity and content which was in line with the upregulation of OXR1 signaling pathway genes.

Conclusions

The present findings can highlight the novel mechanism underlying the oxidative stress induced by Neutrophil Elastase through OXR1 and related genes. Moreover, the benefit of Ellagic acid on cytoprotection, resulting from its antioxidant properties was documented.

     

Comparative reactivity of human IgE to cynomolgus monkey and human effector cells and effects on IgE effector cell potency

Background: Due to genetic similarities with humans, primates of the macaque genus such as the cynomolgus monkey are often chosen as models for toxicology studies of antibody therapies. IgE therapeutics in development depend upon engagement with the FcεRI and FcεRII receptors on immune effector cells for their function. Only limited knowledge of the primate IgE immune system is available to inform the choice of models for mechanistic and safety evaluations.

Methods: The recognition of human IgE by peripheral blood lymphocytes from cynomolgus monkey and man was compared. We used effector cells from each species in ex vivo affinity, dose-response, antibody-receptor dissociation and potency assays.

Results: We report cross-reactivity of human IgE Fc with cynomolgus monkey cells, and comparable binding kinetics to peripheral blood lymphocytes from both species. In competition and dissociation assays, however, human IgE dissociated faster from cynomolgus monkey compared with human effector cells. Differences in association and dissociation kinetics were reflected in effector cell potency assays of IgE-mediated target cell killing, with higher concentrations of human IgE needed to elicit effector response in the cynomolgus monkey system. Additionally, human IgE binding on immune effector cells yielded significantly different cytokine release profiles in each species.

Conclusion: These data suggest that human IgE binds with different characteristics to human and cynomolgus monkey IgE effector cells. This is likely to affect the potency of IgE effector functions in these two species, and so has relevance for the selection of biologically-relevant model systems when designing pre-clinical toxicology and functional studies.     

N-Acetylcysteine affects obesity-related protein expression in 3T3-L1 adipocytes

Abstract

Objectives

Oxidative stress plays critical roles in the pathogeneses of diabetes, hypertension, and atherosclerosis, but its effect on fat accumulation is still unclear. In this study, we analyzed the role of the well-known antioxidant and a glutathione (GSH) precursor N-acetylcysteine (NAC) in fat accumulation and the expression of obesity-associated proteins.

Methods

We studied the effects of 10 µM NAC on obesity-related protein expression in cultured 3T3-L1 preadipocytes, which are able to differentiate into mature adipocytes and accumulate lipids.

Results

NAC treatment inhibited fat accumulation and reduced the expression of obesity-related proteins, including monoamine oxidase A, heat shock protein 70 (HSP70), aminoacylase -1 (ACY-1), and transketolase.

Discussion

Our results suggest that the effects of NAC on triglycerides (Tgs) and protein expression are correlated. In support of this, we showed that NAC treatment affected both the Tg synthesis pathway and the expression levels of proteins implicated in human obesity.