Associations between plasma metabolites and heavy metal exposure in residents of environmentally polluted areas

Heavy metals are commonly released into the environment through industrial processes such as mining and refining. The rapid industrialization that occurred in South Korea during the 1960s and 1970s contributed significantly to the economy of the country; however, the associated mining and refining led to considerable environmental pollution, and although mining is now in decline in South Korea, the detrimental effects on residents inhabiting the surrounding areas remain. The bioaccumulation of toxic heavy metals leads to metabolic alterations in human homeostasis, with disruptions in this balance leading to various health issues. This study used metabolomics to explore metabolomic alterations in the plasma samples of residents living in mining and refining areas. The results showed significant increases in metabolites involved in glycolysis and the surrounding metabolic pathways, such as glucose-6-phosphate, phosphoenolpyruvate, lactate, and inosine monophosphate, in those inhabiting polluted areas. An investigation of the associations between metabolites and blood clinical parameters through meet-in-the-middle analysis indicated that female residents were more affected by heavy metal exposure, resulting in more metabolomic alterations. For women, inhabiting the abandoned mine area, metabolites in the glycolysis and pentose phosphate pathways, such as ribose-5-phosphate and 3-phosphoglycerate, have shown a negative correlation with albumin and calcium. Finally, Mendelian randomization(MR) was used to determine the causal effects of these heavy metal exposure-related metabolites on heavy metal exposure-related clinical parameters. Metabolite biomarkers could provide insights into altered metabolic pathways related to exposure to toxic heavy metals and improve our understanding of the molecular mechanisms underlying the health effects of toxic heavy metal exposure.

Blood sphingolipid as a novel biomarker in patients with neuromyelitis optica spectrum disorder

BACKGROUND

Sphingolipids are signaling molecules and structural components of the axolemma and myelin sheath. Plasma sphingolipid levels may reflect disease status of neuromyelitis optica spectrum disorder (NMOSD). We aimed to examine plasma sphingolipids as disease severity biomarkers for NMOSD and compare their characteristics with those of serum neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP).

METHODS

We measured plasma sphingolipids, sNfL, and sGFAP levels in NMOSD cases with anti-aquaporin-4-antibody. An unbiased approach, partial least square discriminant analysis (PLS-DA), was utilized to determine whether sphingolipid profiles differ according to the disease state of NMOSD (presence, moderate-to-severe disability [Expanded Disease Severity Scale, (EDSS) > 3.0], and relapses).

RESULTS

We investigated 81 patients and 10 controls. PLS-DA models utilizing sphingolipids successfully differentiated patients with EDSS > 3.0, but failed to identify the presence of disease and relapses. Ceramide-C14-a significant contributor to differentiating EDSS > 3.0-positively correlated with EDSS, while its levels were independent of age and the presence of relapses. This characteristic was unique from those of sNfL and sGFAP, which were affected by age and relapses as well as EDSS.

CONCLUSION

Plasma sphingolipids may be useful NMOSD biomarkers for disability with distinct characteristics compared to sNfL and sGFAP.

Diagnosis of osteochondral lesions of the talus on Dual-layer spectral detector CT arthrography: clinical feasibility of virtual noncontrast images

AIM

To compare the image quality of virtual noncontrast (VNC) and true noncontrast (TNC) CT images and to evaluate the clinical feasibility of VNC CT images for assessing osteochondral lesions of the talus (OLTs).

MATERIALS AND METHODS

Forty-five OLT patients who underwent ankle CT arthrography (CTA) using dual-layer spectral detector CT were enrolled. Reconstruction of VNC and three-dimensional volume rendering images was performed. Afterward, image noise, the signal-to-noise ratio (SNR), and the contrast-to-noise ratio (CNR) were measured. For the subjective evaluation, two board-certified musculoskeletal radiologists [R2-1] assessed spatial resolution, overall image quality, and lesion conspicuity. The accuracy rate for OLT grading was determined in 23 patients who underwent arthroscopic surgery.

RESULTS

While VNC images showed significantly less noise than TNC images, TNC images showed better SNRs and CNRs (p<.01). In the subjective analysis, TNC images showed better overall image quality (p<.001). For the 3D volume rendering images, VNC images scored significantly higher for lesion conspicuity (p<.001). The accuracy rates of CTA and CTA with VNC images for OLT grading were 79.2% and 83.3%, respectively. Regarding confidence level, when CTA and VNC images were evaluated together, the confidence level was significantly higher than that when only CTA images were evaluated (p<.001).

CONCLUSION

VNC imaging can provide better confidence level of OLT grading and evaluation of the integrity of the subchondral bone plate when combined with conventional CTA without additional radiation dose to the patient. In addition, VNC images-based 3D volume rendering reconstruction would be helpful for preoperative planning in OLT patients.

Metabolomic profiles of ovariectomized mice and their associations with body composition and frailty-related parameters in postmenopausal women

BACKGROUND

Menopause, a dramatical estrogen-deficient condition, is considered the most significant milestone in women's health.

PURPOSE

To investigate the metabolite changes attributed to estrogen deficiency using random forest (RF)-based machine learning (ML) modeling strategy in ovariectomized (OVX) mice as well as determine the clinical relevance of selected metabolites in older women.

METHODS AND RESULTS

Untargeted and targeted metabolomic analyses revealed that metabolites related to TCA cycle, sphingolipids, phospholipids, fatty acids, and amino acids, were significantly changed in the plasma and/or muscle of OVX mice. Subsequent ML classifiers based on RF algorithm selected alpha-ketoglutarate (AKG), arginine, carnosine, ceramide C24, phosphatidylcholine (PC) aa C36:6, and PC ae C42:3 in plasma as well as PC aa 34:1, PC aa C34:3, PC aa C36:5, PC aa C32:1, PC aa C36:2, and sphingosine in muscle as top featured metabolites that differentiate the OVX mice from the sham-operated group. When circulating levels of AKG, arginine, and carnosine, which showed the most significant changes in OVX mice blood, were measured in postmenopausal women, higher plasma AKG levels were associated with lower bone mass, weak grip strength, poor physical performance, and increased frailty risk.

CONCLUSIONS

Metabolomics- and ML-based methods identified the key metabolites of blood and muscle that were significantly changed after ovariectomy in mice, and the clinical implication of several metabolites was investigated by looking at their correlation with body composition and frailty-related parameters in postmenopausal women. These findings provide crucial context for understanding the diverse physiological alterations caused by estrogen deficiency in women.

PIBF1 regulates trophoblast syncytialization and promotes cardiovascular development

Proper placental development in early pregnancy ensures a positive outcome later on. The developmental relationship between the placenta and embryonic organs, such as the heart, is crucial for a normal pregnancy. However, the mechanism through which the placenta influences the development of embryonic organs remains unclear. Trophoblasts fuse to form multinucleated syncytiotrophoblasts (SynT), which primarily make up the placental materno-fetal interface. We discovered that endogenous progesterone immunomodulatory binding factor 1 (PIBF1) is vital for trophoblast differentiation and fusion into SynT in humans and mice. PIBF1 facilitates communication between SynT and adjacent vascular cells, promoting vascular network development in the primary placenta. This process affected the early development of the embryonic cardiovascular system in mice. Moreover, in vitro experiments showed that PIBF1 promotes the development of cardiovascular characteristics in heart organoids. Our findings show how SynTs organize the barrier and imply their possible roles in supporting embryogenesis, including cardiovascular development. SynT-derived factors and SynT within the placenta may play critical roles in ensuring proper organogenesis of other organs in the embryo.

Circulating lumican as a potential biomarker for osteosarcopenia in older adults

In vitro and animal experiments demonstrated that lumican exerts anabolic effects on bone and muscle by stimulating osteoblastogenesis, suppressing osteoclastogenesis and increasing myogenesis. However, the relationship between circulating lumican and musculoskeletal phenotypes in humans remains unclear. We aimed to analyze the relationship between serum lumican levels and osteosarcopenia in older adults. Blood samples were collected from 134 participants (age: 65 years and older) who underwent comprehensive assessment of bone and muscle phenotypes. Osteoporosis and sarcopenia were diagnosed based on World Health Organization and Asian consensus guidelines, respectively. Osteosarcopenia was defined as the simultaneous presence of osteoporosis and sarcopenia. After adjusting for sex, age, and body mass index, older adults with osteosarcopenia had 20.2 % lower serum lumican levels than those without (P = 0.010). The odds ratio (OR) for osteosarcopenia per standard deviation decrease in serum lumican level was 4.17 (P = 0.003). Consistently, higher serum lumican levels were correlated with higher bone mass at all measured sites (P = 0.004 to 0.045) and higher grip strength (P = 0.023). Furthermore, participants in the lowest tertile (T1) had 7.56-fold higher OR for osteosarcopenia (P = 0.024) than those in the highest lumican tertile (T3). In conclusion, these findings clinically validate previous experimental data showing the musculoskeletal protective effects of lumican and suggest that blood lumican levels could be used as a potential biomarker to assess the risk of not only osteosarcopenia but also osteoporosis or sarcopenia in older adults.

Higher Plasma Stromal Cell-Derived Factor 1 Is Associated with Lower Risk for Sarcopenia in Older Asian Adults

BACKGRUOUND

Despite the protective effects of stromal cell-derived factor 1 (SDF-1) in stimulating muscle regeneration shown in experimental research, there is a lack of clinical studies linking circulating SDF-1 concentrations with muscle phenotypes. In order to elucidate the role of SDF-1 as a potential biomarker reflecting human muscle health, we investigated the association of plasma SDF-1 levels with sarcopenia in older adults.

METHODS

This cross-sectional study included 97 community-dwelling participants who underwent a comprehensive geriatric assessment at a tertiary hospital in South Korea. Sarcopenia was defined by specific cutoff values applicable to the Asian population, whereas plasma SDF-1 levels were determined using an enzyme immunoassay.

RESULTS

After accounting for sex, age, and body mass index, participants with sarcopenia and low muscle mass exhibited plasma SDF-1 levels that were 21.8% and 18.3% lower than those without these conditions, respectively (P=0.008 and P=0.009, respectively). Consistently, higher plasma SDF-1 levels exhibited a significant correlation with higher skeletal muscle mass index (SMI) and gait speed (both P=0.043), and the risk of sarcopenia and low muscle mass decreased by 58% and 55% per standard deviation increase in plasma SDF-1 levels, respectively (P=0.045 and P=0.030, respectively). Furthermore, participants in the highest SDF-1 tertile exhibited significantly higher SMI compared to those in the lowest tertile (P=0.012).

CONCLUSION

These findings clinically corroborate earlier experimental discoveries highlighting the muscle anabolic effects of SDF- 1 and support the potential role of circulating SDF-1 as a biomarker reflecting human muscle health in older adults.

Reduced Ceramides Are Associated with Acute Rejection in Liver Transplant Patients and Skin Graft and Hepatocyte Transplant Mice, Reducing Tolerogenic Dendritic Cells

We set up this study to understand the underlying mechanisms of reduced ceramides on immune cells in acute rejection (AR). The concentrations of ceramides and sphingomyelins were measured in the sera from hepatic transplant patients, skin graft mice and hepatocyte transplant mice by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Serum concentrations of C24 ceramide, C24:1 ceramide, C16:0 sphingomyelin, and C18:1 sphingomyelin were lower in liver transplantation (LT) recipients with than without AR. Comparisons with the results of LT patients with infection and cardiac transplant patients with cardiac allograft vasculopathy in humans and in mouse skin graft and hepatocyte transplant models suggested that the reduced C24 and C24:1 ceramides were specifically involved in AR. A ceramide synthase inhibitor, fumonisin B1 exacerbated allogeneic immune responses in vitro and in vivo, and reduced tolerogenic dendritic cells (tDCs), while increased P3-like plasmacytoid DCs (pDCs) in the draining lymph nodes from allogeneic skin graft mice. The results of mixed lymphocyte reactions with ceranib-2, an inhibitor of ceramidase, and C24 ceramide also support that increasing ceramide concentrations could benefit transplant recipients with AR. The results suggest increasing ceramides as novel therapeutic target for AR, where reduced ceramides were associated with the changes in DC subsets, in particular tDCs.

Gut microbiota composition and metabolite profiling in smokers: a comparative study between emphysema and asymptomatic individuals with therapeutic implications

BACKGROUND

Diet has a crucial role in the gut microbiota, and dysbiosis in the gut and lungs has been suggested to be associated with chronic obstructive pulmonary disease. We compared the diet, microbiome and metabolome between asymptomatic smokers and those with emphysema.

METHODS

We enrolled 10 asymptomatic smokers with preserved lung function and 16 smokers with emphysema with severe airflow limitation. Dietary intake information was gathered by a self-reported questionnaire. Sputum and faecal samples were collected for microbial and metabolomics analysis. A murine model of emphysema was used to determine the effect of metabolite supplementation.

RESULTS

Despite having a similar smoking history with emphysema patients, asymptomatic smokers had higher values of body mass index, fibre intake and faecal acetate level. Linear discriminant analysis identified 17 microbial taxonomic members that were relatively enriched in the faeces of asymptomatic smokers. Analysis of similarity results showed dissimilarity between the two groups (r=0.287, p=0.003). Higher acetate level was positively associated with forced expiratory volume in one second in the emphysema group (r=0.628, p=0.012). Asymptomatic smokers had a greater number of species associated with acetate and propionate (r>0.6) than did those with emphysema (30 vs 19). In an emphysema mouse model, supplementation of acetate and propionate reduced alveolar destruction and the production of proinflammatory cytokines, and propionate decreased the CD3+CD4+IL-17+ T-cell population in the lung and spleen.

CONCLUSION

Smokers with emphysema showed differences in diet, microbiome and short-chain fatty acids compared with asymptomatic smokers. Acetate and propionate showed therapeutic effects in a smoking-induced murine model of emphysema.

Aquaporin-4 Deficiency is Associated with Cognitive Impairment and Alterations in astrocyte-neuron Lactate Shuttle

Cognitive impairment refers to notable declines in cognitive abilities including memory, language, and emotional stability leading to the inability to accomplish essential activities of daily living. Astrocytes play an important role in cognitive function, and homeostasis of the astrocyte-neuron lactate shuttle (ANLS) system is essential for maintaining cognitive functions. Aquaporin-4 (AQP-4) is a water channel expressed in astrocytes and has been shown to be associated with various brain disorders, but the direct relationship between learning, memory, and AQP-4 is unclear. We examined the relationship between AQP-4 and cognitive functions related to learning and memory. Mice with genetic deletion of AQP-4 showed significant behavioral and emotional changes including hyperactivity and instability, and impaired cognitive functions such as spatial learning and memory retention. 18 F-FDG PET imaging showed significant metabolic changes in the brains of AQP-4 knockout mice such as reductions in glucose absorption. Such metabolic changes in the brain seemed to be the direct results of changes in the expression of metabolite transporters, as the mRNA levels of multiple glucose and lactate transporters in astrocytes and neurons were significantly decreased in the cortex and hippocampus of AQP-4 knockout mice. Indeed, AQP-4 knockout mice showed significantly higher accumulation of both glucose and lactate in their brains compared with wild-type mice. Our results show that the deficiency of AQP-4 can cause problems in the metabolic function of astrocytes and lead to cognitive impairment, and that the deficiency of AQP4 in astrocyte endfeet can cause abnormalities in the ANLS system.

Systemic antibiotics cause deterioration of emphysema associated with exaggerated inflammation and autophagy

The interaction between the microbial environment and the host is important for immune homeostasis. Recent research suggests that microbiota dysbiosis can be involved in respiratory diseases. Emphysema is a chronic inflammatory disease, but it is unclear whether dysbiosis caused by antibiotics can affect disease progression. Here, we tried to elucidate the effect of systemic antibiotics on smoking-exposed emphysema models. In this study, the antibiotic mixture caused more alveolar destruction and airspace expansion in the smoking group than in the smoking only or control groups. This emphysema aggravation as a result of antibiotic exposure was associated with increased levels of inflammatory cells, IL-6, IFNγ and protein concentrations in bronchoalveolar lavage fluid. Proteomics analysis indicated that autophagy could be involved in antibiotic-associated emphysema aggravation, and increased protein levels of LC3B, atg3, and atg7 were identified by Western blotting. In microbiome and metabolome analyses, the composition of the gut microbiota was different with smoking and antibiotic exposure, and the levels of short-chain fatty acids (SCFAs), including acetate and propionate, were reduced by antibiotic exposure. SCFA administration restored emphysema development with reduced inflammatory cells, IL-6, and IFNγ and decreased LC3B, atg3, and atg7 levels. In conclusion, antibiotics can aggravate emphysema, and inflammation and autophagy may be associated with this aggravation. This study provides important insight into the systemic impact of microbial dysbiosis and the therapeutic potential of utilizing the gut microbiota in emphysema.

The alternative bile acid pathway can predict food allergy persistence in early childhood

BACKGROUND

Mechanisms underlying persistent food allergy (FA) are not well elucidated. The intestinal mucosa is the primary exposure route of food allergens. However, no study has examined intestinal metabolites associated with FA persistence. The goal of this study was to investigate intestinal metabolites and associated microbiomes in early life that aid in determining the development and persistence of FA.

METHODS

We identified metabolomic alterations in the stool of infants according to FA by mass spectrometry-based untargeted metabolome profiling. The targeted metabolomic analysis of bile acid metabolites and stool microbiome was performed. Bile acid metabolite composition in infancy was evaluated by characterizing the subjects at the age of 3 into FA remission and persistent FA.

RESULTS

In untargeted metabolomics, primary bile acid biosynthesis was significantly different between subjects with FA and healthy controls. In targeted metabolomics for bile acids, intestinal bile acid metabolites synthesized by the alternative pathway were reduced in infants with FA than those in healthy controls. Subjects with persistent FA were also distinguished from healthy controls and those with FA remission by bile acid metabolites of the alternative pathway. These metabolites were negatively correlated with specific IgE levels in egg white. The abundance of intestinal Clostridia was decreased in the FA group and was correlated with ursodeoxycholic acid.

CONCLUSION

Intestinal bile acid metabolites of the alternative pathway could be predictive biomarkers for persistent FA in early childhood. These findings require replication in future studies.

A targeted metabolomics approach for sepsis-induced ARDS and its subphenotypes

BACKGROUND

Acute respiratory distress syndrome (ARDS) is etiologically and clinically a heterogeneous disease. Its diagnostic characteristics and subtype classification, and the application of these features to treatment, have been of considerable interest. Metabolomics is becoming important for identifying ARDS biology and distinguishing its subtypes. This study aimed to identify metabolites that could distinguish sepsis-induced ARDS patients from non-ARDS controls, using a targeted metabolomics approach, and to identify whether sepsis-induced direct and sepsis-induced indirect ARDS are metabolically distinct groups, and if so, confirm their metabolites and associated pathways.

METHODS

This study retrospectively analyzed 54 samples of ARDS patients from a sepsis registry that was prospectively collected from March 2011 to February 2018, along with 30 non-ARDS controls. The cohort was divided into direct and indirect ARDS. Metabolite concentrations of five analyte classes (energy metabolism, free fatty acids, amino acids, phospholipids, sphingolipids) were measured using liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry by targeted metabolomics.

RESULTS

In total, 186 metabolites were detected. Among them, 102 metabolites could differentiate sepsis-induced ARDS patients from the non-ARDS controls, while 14 metabolites could discriminate sepsis-induced ARDS subphenotypes. Using partial least-squares discriminant analysis, we showed that sepsis-induced ARDS patients were metabolically distinct from the non-ARDS controls. The main distinguishing metabolites were lysophosphatidylethanolamine (lysoPE) plasmalogen, PE plasmalogens, and phosphatidylcholines (PCs). Sepsis-induced direct and indirect ARDS were also metabolically distinct subgroups, with differences in lysoPCs. Glycerophospholipid and sphingolipid metabolism were the most significant metabolic pathways involved in sepsis-induced ARDS biology and in sepsis-induced direct/indirect ARDS, respectively.

CONCLUSION

Our study demonstrated a marked difference in metabolic patterns between sepsis-induced ARDS patients and non-ARDS controls, and between sepsis-induced direct and indirect ARDS subpheonotypes. The identified metabolites and pathways can provide clues relevant to the diagnosis and treatment of individuals with ARDS.

Lack of association between serum myonectin levels and sarcopenia in older Asian adults

Myonectin is a muscle-secreted factor that helps maintain homeostasis in the body by regulating several functions, including lipid metabolism. Previous studies suggested that myonectin may play a role in muscle health in an autocrine manner, but its impact on human skeletal muscle is still unclear. We aimed to investigate the relationship of serum myonectin levels with sarcopenia and related muscle parameters. We conducted a cross-sectional study of 142 older adults whose muscle mass, grip strength, gait speed, chair stands, and short physical performance battery (SPPB) were evaluated in the geriatric clinic of a tertiary medical center. Sarcopenia was defined based on Asian-specific cutoff values, and circulating myonectin levels were measured using an enzyme immunoassay. Before and after adjusting for age, sex, and body mass index, the serum myonectin level was not significantly different when the patients were stratified by status of sarcopenia, muscle mass, muscle strength, and physical performance. Furthermore, whether given as a continuous variable or divided into quartile groups, the serum myonectin level had no association with the skeletal muscle mass, grip strength, gait speed, chair stand test, or SPPB score. Our findings did not confirm the potential role of myonectin in muscle metabolism observed in experimental research. Thus, serum myonectin levels cannot predict the risk of sarcopenia in older Asian adults.

Fatty acid amides as potential circulating biomarkers for sarcopenia

BACKGROUND

Sarcopenia is characterized by a progressive decrease in skeletal muscle mass and function with age. Given that sarcopenia is associated with various metabolic disorders, effective metabolic biomarkers for its early detection are required. We aimed to investigate the metabolic biomarkers related to sarcopenia in elderly men and perform experimental studies using metabolomics.

METHODS

Plasma metabolites from 142 elderly men, comprising a sarcopenia group and an age-matched control group, were measured using global metabolome profiling. Muscle and plasma samples from an aging mouse model of sarcopenia, as well as cell media and cell lysates during myoblast differentiation, were analysed based on targeted metabolome profiling. Based on these experimental results, fatty acid amides were quantified from human plasma as well as human muscle tissues. The association of fatty acid amide levels with sarcopenia parameters was evaluated.

RESULTS

Global metabolome profiling showed that fatty acid amide levels were significantly different in the plasma of elderly men with sarcopenia (all Ps < 0.01). Consistent with these results in human plasma, targeted metabolome profiling in an aging mouse model of sarcopenia showed decreased levels of fatty acid amides in plasma but not in muscle tissue. In addition, the levels of fatty acid amides increased in cell lysates during muscle cell differentiation. Targeted metabolome profiling in men showed decreased docosahexaenoic acid ethanolamide (DHA EA) levels in the plasma (P = 0.016) but not in the muscle of men with sarcopenia. DHA EA level was positively correlated with sarcopenia parameters such as skeletal muscle mass index (SMI) and handgrip strength (HGS) (P = 0.001, P = 0.001, respectively). The area under the receiver-operating characteristic curve (AUC) for DHA EA level ≤ 4.60 fmol/μL for sarcopenia was 0.618 (95% confidence interval [CI]: 0.532-0.698). DHA EA level ≤ 4.60 fmol/μL was associated with a significantly greater likelihood of sarcopenia (odds ratio [OR]: 2.11, 95% CI: 1.03-4.30), independent of HGS. The addition of DHA EA level to age and HGS significantly improved the AUC from 0.620 to 0.691 (P = 0.0497).

CONCLUSIONS

Our study demonstrated that fatty acid amides are potential circulating biomarkers in elderly men with sarcopenia. DHA EA, in particular, strongly related to muscle mass and strength, can be a key metabolite to become a reliable metabolic biomarker for sarcopenia. Further research on fatty acid amides will provide insights into the metabolomic changes relevant to sarcopenia from an aging perspective.

Vitreous Fatty Amides and Acyl Carnitines Are Altered in Intermediate Age-Related Macular Degeneration

Purpose

Age-related macular degeneration (AMD) is the leading cause of visual impairment worldwide. In this study, we aimed to investigate the vitreous humor metabolite profiles of patients with intermediate AMD using untargeted metabolomics.

Methods

We performed metabolomics using high-resolution liquid chromatography mass spectrometry on the vitreous humor of 31 patients with intermediate AMD and 30 controls who underwent vitrectomy for epiretinal membrane with or without cataract surgery. Univariate analyses after false discovery rate correction were performed to discriminate the metabolites and identify the significant metabolites of intermediate AMD. For biologic interpretation, enrichment and pathway analysis were conducted using MetaboAnalyst 5.0.

Results

Of the 858 metabolites analyzed in the vitreous humor, 258 metabolites that distinguished patients with AMD from controls were identified (P values < 0.05). Ascorbic acid and uric acid levels increased in the AMD group (all P values < 0.05). The acyl carnitines, such as acetyl L-carnitine (1.37-fold), and fatty amides, such as anandamide (0.9-fold) and docosanamide (0.67-fold), were higher in patients with intermediate AMD. In contrast, nicotinamide (-0.55-fold), and succinic acid (-1.69-fold) were lower in patients with intermediate AMD. The metabolic pathway related oxidation of branched chain fatty acids and carnitine synthesis showed enrichment.

Conclusions

Multiple metabolites related to fatty amides and acyl carnitine were found to be increased in the vitreous humor of patients with intermediate AMD, whereas succinic acid and nicotinamide were reduced, suggesting that altered metabolites related to fatty amides and acyl carnitines and energy metabolism may be implicated in the etiology of AMD.

Metabolomics Reveals Dysregulated Sphingolipid and Amino Acid Metabolism Associated with Chronic Obstructive Pulmonary Disease

Purpose

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease presenting as multiple phenotypes, such as declining lung function, emphysema, or persistent airflow limitation caused by several risk factors, including cigarette smoking and air pollution. The inherent complexity of COPD phenotypes propounds difficulties for accurate diagnosis and prognosis. Although metabolomic profiles on COPD have been reported, the role of metabolism in COPD-related phenotypes is yet to be determined. In this study, we investigated the association between plasma sphingolipids and amino acids, and between COPD and COPD-related phenotypes in a Korean cohort.

Patients and Methods

Blood samples were collected from 120 patients with COPD and 80 control participants who underwent spirometry and quantitative computed tomography. The plasma metabolic profiling was carried out using LC-MS/MS analysis.

Results

Among the evaluated plasma sphingolipids, an increase in the metabolism of two specific sphingomyelins, SM (d18:1/24:0) and SM (d18:1/24:1) were significantly associated with COPD. There was no significant correlation between any of the SMs and the emphysema index, FVC and FEV₁ in the COPD cohort. Meanwhile, Cer (d18:1/18:0) and Cer (d18:1/24:1) were significantly associated with reduced FEV₁. Furthermore, the levels of several amino acids were altered in the COPD group compared to that in the non-COPD group; glutamate and alpha AAA were substantial associated with emphysema in COPD. Kynurenine was the only amino acid significantly associated with reduced FEV₁ in COPD. In contrast, there was no correlation between FVC and the elevated metabolites.

Conclusion

Our results provide dysregulated plasma metabolites impacting COPD phenotypes, although more studies are needed to explore the underlying mechanism related to COPD pathogenesis.

Lipid signatures reflect the function of the murine primary placentation

The placenta regulates maternal-fetal communication, and its defect leads to significant pregnancy complications. The maternal and embryonic circulations are primitively connected in early placentation, but the function of the placenta during this developmentally essential period is relatively unknown. We thus performed a comparative proteomic analysis of the placenta before and after primary placentation and found that the metabolism and transport of lipids were characteristically activated in this period. The placental fatty acid (FA) carriers in specific placental compartments were upregulated according to gestational age, and metabolomic analysis also showed that the placental transport of FAs increased in a time-dependent manner. Further analysis of two mutant mice models with embryonic lethality revealed that lipid-related signatures could reflect the functional state of the placenta. Our findings highlight the importance of the nutrient transport function of the primary placenta in the early gestational period and the role of lipids in embryonic development.

Sphingomyelin synthase 1 mediates hepatocyte pyroptosis to trigger non-alcoholic steatohepatitis

OBJECTIVE

Lipotoxic hepatocyte injury is a primary event in non-alcoholic steatohepatitis (NASH), but the mechanisms of lipotoxicity are not fully defined. Sphingolipids and free cholesterol (FC) mediate hepatocyte injury, but their link in NASH has not been explored. We examined the role of free cholesterol and sphingomyelin synthases (SMSs) that generate sphingomyelin (SM) and diacylglycerol (DAG) in hepatocyte pyroptosis, a specific form of programmed cell death associated with inflammasome activation, and NASH.

DESIGN

Wild-type C57BL/6J mice were fed a high fat and high cholesterol diet (HFHCD) to induce NASH. Hepatic SMS1 and SMS2 expressions were examined in various mouse models including HFHCD-fed mice and patients with NASH. Pyroptosis was estimated by the generation of the gasdermin-D N-terminal fragment. NASH susceptibility and pyroptosis were examined following knockdown of SMS1, protein kinase Cδ (PKCδ), or the NLR family CARD domain-containing protein 4 (NLRC4).

RESULTS

HFHCD increased the hepatic levels of SM and DAG while decreasing the level of phosphatidylcholine. Hepatic expression of Sms1 but not Sms2 was higher in mouse models and patients with NASH. FC in hepatocytes induced Sms1 expression, and Sms1 knockdown prevented HFHCD-induced NASH. DAG produced by SMS1 activated PKCδ and NLRC4 inflammasome to induce hepatocyte pyroptosis. Depletion of Nlrc4 prevented hepatocyte pyroptosis and the development of NASH. Conditioned media from pyroptotic hepatocytes activated the NOD-like receptor family pyrin domain containing 3 inflammasome (NLRP3) in Kupffer cells, but Nlrp3 knockout mice were not protected against HFHCD-induced hepatocyte pyroptosis.

CONCLUSION

SMS1 mediates hepatocyte pyroptosis through a novel DAG-PKCδ-NLRC4 axis and holds promise as a therapeutic target for NASH.

The arachidonic acid metabolite 11,12-epoxyeicosatrienoic acid alleviates pulmonary fibrosis

Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid that are rapidly metabolized into diols by soluble epoxide hydrolase (sEH). sEH inhibition has been shown to increase the biological activity of EETs, which are known to have anti-inflammatory properties. However, the role of EETs in pulmonary fibrosis remains unexplored. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used to analyze EETs in the lung tissues of patients with idiopathic pulmonary fibrosis (IPF, n = 29) and controls (n = 15), and the function of 11,12-EET was evaluated in in vitro and in vivo in pulmonary fibrosis models. EET levels in IPF lung tissues, including those of 8,9-EET, 11,12-EET, and 14,15-EET, were significantly lower than those in control tissues. The 11,12-EET/11,12-DHET ratio in human lung tissues also differentiated IPF from control tissues. 11,12-EET significantly decreased transforming growth factor (TGF)-β1-induced expression of α-smooth muscle actin (SMA) and collagen type-I in MRC-5 cells and primary fibroblasts from IPF patients. sEH-specific siRNA and 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU; sEH inhibitor) also decreased TGF-β1-induced expression of α-SMA and collagen type-I in fibroblasts. Moreover, 11,12-EET and TPPU decreased TGF-β1-induced p-Smad2/3 and extracellular-signal-regulated kinase (ERK) expression in primary fibroblasts from patients with IPF and fibronectin expression in Beas-2B cells. TPPU decreased the levels of hydroxyproline in the lungs of bleomycin-induced mice. 11,12-EET or sEH inhibitors could inhibit pulmonary fibrosis by regulating TGF-β1-induced profibrotic signaling, suggesting that 11,12-EET and the regulation of EETs could serve as potential therapeutic targets for IPF treatment.

Signaling molecules called eicosanoids, which are derived from fatty acids, can suppress lung damage in idiopathic pulmonary fibrosis (IPF), a chronic, progressive disease in which scar tissue builds up in the lungs, making it hard to breathe. The causes of IPF are unknown. Eicosanoids, which have anti-inflammatory properties, have been studied in various lung diseases. Jin Woo Song at the University of Ulsan College of Medicine in Seoul, South Korea, and co-workers investigated how they might affect IPF. They found that eicosanoid levels were lower in lung tissues from patients with IPF than in healthy tissues. Further investigation showed eicosanoid levels could be boosted by suppressing an enzyme called sEH that degrades them. Thus, suppression of sEH and boosting of eicosanoid levels show promise as therapeutic targets for IPF.

Butyrate Prevents TGF-β1-Induced Alveolar Myofibroblast Differentiation and Modulates Energy Metabolism

Idiopathic pulmonary fibrosis (IPF) is a serious lung disease characterized by excessive collagen matrix deposition and extracellular remodeling. Signaling pathways mediated by fibrotic cytokine transforming growth factor β1 (TGF-β1) make important contributions to pulmonary fibrosis, but it remains unclear how TGF-β1 alters metabolism and modulates the activation and differentiation of pulmonary fibroblasts. We found that TGF-β1 lowers NADH and NADH/NAD levels, possibly due to changes in the TCA cycle, resulting in reductions in the ATP level and oxidative phosphorylation in pulmonary fibroblasts. In addition, we showed that butyrate (C4), a short chain fatty acid (SCFA), exhibits potent antifibrotic activity by inhibiting expression of fibrosis markers. Butyrate treatment inhibited mitochondrial elongation in TGF-β1-treated lung fibroblasts and increased the mitochondrial membrane potential (MMP). Consistent with the mitochondrial observations, butyrate significantly increased ADP, ATP, NADH, and NADH/NAD levels in TGF-β1-treated pulmonary fibroblasts. Collectively, our findings indicate that TGF-β1 induces changes in mitochondrial dynamics and energy metabolism during myofibroblast differentiation, and that these changes can be modulated by butyrate, which enhances mitochondrial function.

High-fiber diets attenuate emphysema development via modulation of gut microbiota and metabolism

Dietary fiber functions as a prebiotic to determine the gut microbe composition. The gut microbiota influences the metabolic functions and immune responses in human health. The gut microbiota and metabolites produced by various dietary components not only modulate immunity but also impact various organs. Although recent findings have suggested that microbial dysbiosis is associated with several respiratory diseases, including asthma, cystic fibrosis, and allergy, the role of microbiota and metabolites produced by dietary nutrients with respect to pulmonary disease remains unclear. Therefore, we explored whether the gut microbiota and metabolites produced by dietary fiber components could influence a cigarette smoking (CS)-exposed emphysema model. In this study, it was demonstrated that a high-fiber diet including non-fermentable cellulose and fermentable pectin attenuated the pathological changes associated with emphysema progression and the inflammatory response in CS-exposed emphysema mice. Moreover, we observed that different types of dietary fiber could modulate the diversity of gut microbiota and differentially impacted anabolism including the generation of short-chain fatty acids, bile acids, and sphingolipids. Overall, the results of this study indicate that high-fiber diets play a beneficial role in the gut microbiota-metabolite modulation and substantially affect CS-exposed emphysema mice. Furthermore, this study suggests the therapeutic potential of gut microbiota and metabolites from a high-fiber diet in emphysema via local and systemic inflammation inhibition, which may be useful in the development of a new COPD treatment plan.

Treatment of chemotherapy-induced cachexia with BST204: a multimodal validation study

INTRODUCTION

Chemotherapy is a major etiology of cachexia. Ginseng products are known to have various anti-cachectic and health-promoting effects, such as inhibiting inflammation and promoting energy production. In particular, BST204, purified ginseng dry extract, contains multiple ginsenosides that can reduce chemotherapy-related fatigue and toxicity.

OBJECTIVES

To investigate the effects of BST204 on the alleviation of chemotherapy-induced cachexia using a multimodal approach.

METHODS

In a CT26 mouse syngeneic colon cancer model, cachexia was predominantly induced by chemotherapy with 5-fluorouracil (5-FU) than by tumor growth. BST204 at a dose of 100 or 200 mg/kg was administered to 5-FU-treated mice.

RESULTS

BST204 significantly mitigated the decrease in tumor-excluded body weight (change in 5-FU group and BST204 groups: - 13% vs. - 6% on day 7; - 30% vs. - 20% on day 11), muscle volume (- 19% vs. - 11%), and fat volume (- 91% vs. - 56%). The anti-cachectic effect of BST204 was histologically demonstrated by an improved balance between muscle regeneration and degeneration and a decrease in muscle cross-sectional area reduction.

CONCLUSION

Chemotherapy-induced cachexia was biochemically and metabolically characterized by activated inflammation, enhanced oxidative stress, increased protein degradation, decreased protein stabilization, reduced glucose-mediated energy production, and deactivated glucose-mediated biosynthesis. These adverse effects were significantly improved by BST204 treatment. Overall, our multimodal study demonstrated that BST204 could effectively alleviate chemotherapy-induced cachexia.

High Phosphoglycerate Dehydrogenase Expression Induces Stemness and Aggressiveness in Thyroid Cancer

Background: We examined the changes in glucose metabolites of papillary thyroid cancer (PTC) and identified phosphoglycerate dehydrogenase (PHGDH) as a potential target. The role of PHGDH in the proliferation and tumorigenesis of thyroid cancer cells and its clinical significance were analyzed. Methods: Glucose metabolites of various thyroid tissues were analyzed via targeted metabolomics analysis. In vitro experiments using shPHGDHs, inhibitor (NCT503), or PHGDH overexpression in thyroid cell lines (BCPAP, 8505C, and Nthy-Ori) were performed. In vivo experiments were performed by using shPHGDH. Human tissue samples and The Cancer Genome Atlas (TCGA) data were used to validate the experimental findings. Results:PHGDH knockdown in BCPAP and 8505c cell lines significantly inhibited cell viability, colony formation, and tumor spheroid formation compared with the control. In addition, treatment with NCT503 showed similar results. PHGDH inhibition by both knockdown and treatment with NCT503 significantly inhibited the expression of embryonic cancer stemness markers (Oct4, Sox2, KLF4, and Nanog). PHGDH overexpression in Nthy-Ori cells significantly increased cell viability and colony formation. The stemness markers were significantly increased after PHGDH overexpression. PHGDH knockdown significantly inhibited tumor growth in an in vivo mouse xenograft study using 8505c cells. The protein expression of Oct4 in tumors was significantly reduced after PHGDH knockdown. The associations between PHGDH expression and stemness markers were confirmed in the TCGA data and human thyroid tissue samples. Positive PHGDH protein expression was associated with metastases of PTC. Conclusions:PHGDH expression is induced in thyroid cancer and is associated with stemness and aggressiveness of PTC.

Effect of Pioglitazone on Perihematomal Edema in Intracerebral Hemorrhage Mouse Model by Regulating NLRP3 Expression and Energy Metabolism

Objective

Cerebral edema is the predominant mechanism of secondary inflammation after intracerebral hemorrhage (ICH). Pioglitazone, peroxisome proliferator-activated receptor gamma agonist has been shown to play a role in regulation of central nervous system inflammation. Here, we examined the pharmacological effects of pioglitazone in an ICH mouse model and investigated its regulation on NLRP3 inflammasome and glucose metabolism.

Methods

The ICH model was established in C57 BL/6 mice by the stereotactical inoculation of blood (30 µL) into the right frontal lobe. The treatment group was administered i.p. pioglitazone (20 mg/kg) for 1, 3, and 6 days. The control group was administered i.p. phosphate-buffered saline for 1, 3, and 6 days. We investigated brain water contents, NLRP3 expression, and changes in the metabolites in the ICH model using liquid chromatography-tandem mass spectrometry.

Results

On day 3, brain edema in the mice treated with pioglitazone was decreased more than that in the control group. Expression levels of NLRP3 in the ICH model treated with pioglitazone were decreased more than those of the control mice on days 3 and 7. The pioglitazone group showed higher levels of glycolytic metabolites than those in the ICH mice. Lactate production was increased in the ICH mice treated with pioglitazone.

Conclusion

Our results demonstrated less brain swelling following ICH in mice treated with pioglitazone. Pioglitazone decreased NLRP3-related brain edema and increased anaerobic glycolysis, resulting in the production of lactate in the ICH mice model. NLRP3 might be a therapeutic target for ICH recovery.

Stearic acid attenuates profibrotic signalling in idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE

Lipid metabolism dysregulation has been implicated in the pathogenesis of IPF; however, the roles of most lipid metabolites in lung fibrosis remain unexplored. Therefore, we aimed to identify changes in lipid metabolites in the lung tissues of IPF patients and determine their roles in pulmonary fibrosis.

METHODS

Free fatty acids in the lung tissues of IPF patients and controls were quantified using a metabolomic approach. The roles of free fatty acids in fibroblasts or epithelial cells treated with TGF-β1 were evaluated using fibrotic markers. The antifibrotic role of stearic acid was also assessed in a bleomycin-induced lung fibrosis mouse model. Protein levels in cell lysates or tissues were measured by western blotting.

RESULTS

The levels of stearic acid were lower in IPF lung tissues than in control lung tissues. Stearic acid significantly reduced TGF-β1-induced α-SMA and collagen type 1 expression in MRC-5 cells. Furthermore, stearic acid decreased the levels of p-Smad2/3 and ROS in MRC-5 cells treated with TGF-β1 and disrupted TGF-β1-induced EMT in Beas-2B cells. Stearic acid reduced the levels of bleomycin-induced hydroxyproline in a mouse model.

CONCLUSION

Changes in the free fatty acid profile, including low levels of stearic acid, were observed in IPF patients. Stearic acid may exert antifibrotic activity by regulating profibrotic signalling.

Diversity in the Extracellular Vesicle-Derived Microbiome of Tissues According to Tumor Progression in Pancreatic Cancer

This study was conducted to identify the composition and diversity of the microbiome in tissues of pancreatic cancer and to determine its role. First, extracellular vesicles (EVs) were obtained from the paired tumor and normal tissues, and 16s rRNA gene sequencing was performed. We identified the microbiomes, compared the diversity between groups, and found that Tepidimonas was more abundant in tumors. Second, larger tumors resulted in lower levels of Leuconostoc and Sutterella, and increased lymph node metastasis resulted in higher levels of Comamonas and Turicibacter in tumor tissues. Moreover, in the case of tumor recurrence, the levels of Streptococcus and Akkermansia were decreased in tumor tissues. Finally, with the supernatant of Tepidimonasfonticaldi, proliferation and migration of cells increased, and epithelial-mesenchymal transition and the Tricarboxylic Acid (TCA) cycle-related metabolites were enhanced. The composition and diversity of EV-derived microbiomes are important for providing novel insights into theragnostic approaches in pancreatic cancer.

Inhibition of Ceramide Accumulation in Podocytes by Myriocin Prevents Diabetic Nephropathy

BACKGROUND

Ceramides are associated with metabolic complications including diabetic nephropathy in patients with diabetes. Recent studies have reported that podocytes play a pivotal role in the progression of diabetic nephropathy. Also, mitochondrial dysfunction is known to be an early event in podocyte injury. Thus, we tested the hypothesis that ceramide accumulation in podocytes induces mitochondrial damage through reactive oxygen species (ROS) production in patients with diabetic nephropathy.

METHODS

We used Otsuka Long Evans Tokushima Fatty (OLETF) rats and high-fat diet (HFD)-fed mice. We fed the animals either a control- or a myriocin-containing diet to evaluate the effects of the ceramide. Also, we assessed the effects of ceramide on intracellular ROS generation and on podocyte autophagy in cultured podocytes.

RESULTS

OLETF rats and HFD-fed mice showed albuminuria, histologic features of diabetic nephropathy, and podocyte injury, whereas myriocin treatment effectively treated these abnormalities. Cultured podocytes exposed to agents predicted to be risk factors (high glucose, high free fatty acid, and angiotensin II in combination [GFA]) showed an increase in ceramide accumulation and ROS generation in podocyte mitochondria. Pretreatment with myriocin reversed GFA-induced mitochondrial ROS generation and prevented cell death. Myriocin-pretreated cells were protected from GFA-induced disruption of mitochondrial integrity.

CONCLUSION

We showed that mitochondrial ceramide accumulation may result in podocyte damage through ROS production. Therefore, this signaling pathway could become a pharmacological target to abate the development of diabetic kidney disease.

Association of circulating levels of total and protein-bound sphingosine 1-phosphate with osteoporotic fracture

The biological activity and effects of circulating sphingosine 1-phosphate (S1P) might be dependent on the carrier protein. Although S1P is known to be a biomarker for osteoporotic fracture (OF), its role according to its carrier protein (high-density lipoprotein (HDL), low-density lipoprotein (LDL), or albumin) has not yet been studied. We measured the protein-bound S1P levels and bone mineral density (BMD) in 58 postmenopausal women with OF and 58 age-matched and body mass index–matched postmenopausal women without OF. Albumin-bound S1P was the most abundant. Before adjustment, women with OF had higher total S1P (p=0.046) and albumin-bound S1P (p=0.026) levels than those without OF, but there was no difference in the levels of HDL-bound or LDL-bound S1P. After adjustment for confounders including BMD, women with OF had only higher levels of total S1P than those without OF (p=0.047). Before adjustment, the OR for OF was higher in subjects in the highest quartile for total S1P (OR 5.36, 95% CI 1.22 to 23.63) or albumin-bound S1P (OR 4.48, 95% CI 1.22 to 16.42). After adjustment for confounders including BMD, statistical significance persisted only for total S1P (OR 2.23, 95% CI 1.12 to 4.81). These findings suggest that the positive association of S1P with OF is mainly due to level of total plasma S1P and not due to the differing contributions from specific carrier protein-bound fractions.

Dietary cellulose prevents gut inflammation by modulating lipid metabolism and gut microbiota

A Western diet comprising high fat, high carbohydrate, and low fiber content has been suggested to contribute to an increased prevalence of colitis. To clarify the effect of dietary cellulose (an insoluble fiber) on gut homeostasis, for 3 months mice were fed a high-cellulose diet (HCD) or a low-cellulose diet (LCD) based on the AIN-93G formulation. Histologic evaluation showed crypt atrophy and goblet cell depletion in the colons of LCD-fed mice. RNA-sequencing analysis showed a higher expression of genes associated with immune system processes, especially those of chemokines and their receptors, in the colon tissues of LCD-fed mice than in those of HCD-fed mice. The HCD was protective against dextran sodium sulfate-induced colitis in mice, while LCD exacerbated gut inflammation; however, the depletion of gut microbiota by antibiotic treatment diminished both beneficial and non-beneficial effects of the HCD and LCD on colitis, respectively. A comparative analysis of the cecal contents of mice fed the HCD or the LCD showed that the LCD did not influence the diversity of gut microbiota, but it resulted in a higher and lower abundance of Oscillibacter and Akkermansia organisms, respectively. Additionally, linoleic acid, nicotinate, and nicotinamide pathways were most affected by cellulose intake, while the levels of short-chain fatty acids were comparable in HCD- and LCD-fed mice. Finally, oral administration of Akkermansia muciniphila to LCD-fed mice elevated crypt length, increased goblet cells, and ameliorated colitis. These results suggest that dietary cellulose plays a beneficial role in maintaining gut homeostasis through the alteration of gut microbiota and metabolites.

An RNA-binding-protein, NONO governs energy metabolism by regulating NAMPT in lung cancer

The RNA binding proteins (RBPs) have multiple roles in human cancer. However, their molecular target and function have not been clearly identified. Our genomic analysis derived from patients reveals that NONO is a potential oncogenic gene in lung cancer. NONO is highly expressed in lung cancer tissues compared with normal tissues, and its expression has been correlated with the prognosis of lung cancer patients. We found that NONO significantly influences cancer cell proliferation in lung cancer. Gene expression profiles with NONO-depleted cells revealed that the sirtuin signaling pathway is highly correlated with NONO. Thus, NONO-silenced cells caused reduction of the TCA cycle and glycolysis metabolism. We identified that NONO regulated NAMPT, which is a well-known gene involved in sirtuin signaling, and NONO has a significant correlation with NAMPT in lung cancer patients. We propose that NONO modulates energy metabolism by direct interaction with NAMPT and suggest that a functional relationship between NONO and NAMPT contributes to lung cancer cell survival. Targeting the axis can be a promising approach for patient treatment in lung cancer.

Activation of Factor XII and Kallikrein-Kinin System Combined with Neutrophil Extracellular Trap Formation in Diabetic Retinopathy

BACKGROUND

In diabetic retinopathy (DR), neutrophil extracellular traps (NET) and kallikrein-kinin system are considered as contributing factors. However, the detail activation mechanisms has not been fully understood. Since the NET could provide negative-charged surface for factor XII activation and the activated factor XII (XIIa) can initiate kallikrein-kinin system, this study investigated whether patients with DR show activation of NET, factor XII and kallikrein-kinin system.

METHODS

The markers related to NET (DNA-histone complex) and kallikrein-kinin system (high-molecular-weight kininogen, prekallikrein, bradykinin) and factor XIIa were measured in 253 patients with diabetes. To access ex vivo effect of glucose, DNA-histone complex and factor XIIa were measured in whole blood stimulated by glucose.

RESULTS

The circulating level of DNA-histone complex and factor XIIa were significantly higher in patients with DR than those without DR. In logistic regression analysis, DNA-histone complex, factor XIIa, and high-molecular-weight kininogen were the risk factors of DR. In recursive partitioning analysis, among patients with diabetes duration less than 10 years, patients with high level of DNA-histone complex (>426 AU) showed high risk of DR. In ex vivo experiment, glucose significantly elevated both DNA-histone complex and factor XIIa.

CONCLUSION

Our findings suggest that activation of factor XII and kallikrein-kinin system combined with NET formation actively occur in patients with DR and circulating levels of DNA-histone complex, factor XIIa and HMWK can be potential biomarkers to estimate the risk of DR. Strategies against factor XII activation may be beneficial to inhibit DR.

The Detrimental Effects of Kynurenine, a Tryptophan Metabolite, on Human Bone Metabolism

CONTEXT

Studies in aged mice support a role for kynurenine, a tryptophan metabolite, in age-induced bone loss; however, the role of kynurenine in human bone metabolism is not well understood.

OBJECTIVE

To assess whether the kynurenine level in bone marrow (BM) aspirates, directly reflecting the bone microenvironment, is associated with osteoporosis-related phenotypes and bone biochemical markers.

DESIGN AND SETTING

A case-control study conducted in a clinical unit.

PARTICIPANTS AND MAIN OUTCOME MEASURES

BM samples were collected from 72 patients at the time of hip surgery for either fragility hip fracture (HF) (n = 27) or for other causes (n = 45). In these samples, kynurenine was measured by liquid chromatography-tandem mass spectrometry, and the levels of tartrate-resistant acid phosphatase 5b (TRAP5b), bone-specific alkaline phosphatase (BSALP), receptor activator of nuclear factor-κB ligand (RANKL), and osteoprotegerin (OPG) were measured by immunoassay.

RESULTS

Age was positively correlated with BM kynurenine level. After adjustment for confounders, subjects with fragility HF had a 39.7% higher BM kynurenine level than those without, and the OR per SD increment in BM kynurenine level for fragility HF was 3.80. The BM kynurenine level was inversely associated with bone mass at the total femur. Higher kynurenine concentrations were significantly associated with higher TRAP-5b and RANKL levels, but not with BSALP and OPG levels, in BM plasma.

CONCLUSION

These results suggest that increased kynurenine levels during aging may contribute to the bone fragility seen in the elderly through increased bone resorption, with a resultant imbalance in bone remodeling.

V232M substitution restricts a distinct O-glycosylation of PLD3 and its neuroprotective function

The link between Val232Met variant of phospholipase D3 (PLD3) and late-onset Alzheimer's disease (AD) is still obscure. While it may not affect directly the amyloid precursor protein function, PLD3 could be regulating multiple cellular compartments. Here, we investigated the function of wild-type human PLD3 (PLD3^WT) and the Val232Met variant (PLD3^VM) in the presence of β-amyloid (Aβ) in a Drosophila melanogaster model of AD. We expressed PLD3^WT in CNS of the Aβ-model flies and monitored its effect on the ER stress, cell apoptosis and recovery the Aβ-induced cognitive impairment. The expression reduced ER stress and neuronal apoptosis, which resulted in normalized antioxidative phospholipids levels and brain protection. A specific O-glycosylation at pT271 in PLD3 is essential for its normal trafficking and cellular localization. The V232 M substitution impairs this O-glycosylation, leading to enlarged lysosomes and plausibly aberrant protein recycling. PLD3^VM was less neuroprotective, and while, PLD3^WT expression enhances the lysosomal functions, V232 M attenuated PLD3's trafficking to the lysosomes. Thus, the V232 M mutation may affect AD pathogenesis. Further understanding of the mechanistic role of PLD3 in AD could lead to developing novel therapeutic agents.

Association of blood n-3 fatty acid with bone mass and bone marrow TRAP-5b in the elderly with and without hip fracture

The plasma n-3 fatty acid level was 26.2% lower in patients with osteoporotic hip fracture than in those with osteoarthritis. In all patients, n-3 fatty acid was positively associated with bone mineral density and inversely associated with tartrate-resistant acid phosphatase-5b level in bone marrow aspirates, reflecting the bone microenvironment.

INTRODUCTION

Despite the potential beneficial role of n-3 fatty acid (FA) on bone metabolism, the specific mechanisms underlying these effects in humans remain unclear. Here, we assessed whether the plasma n-3 level, as an objective indicator of its status, is associated with osteoporosis-related phenotypes and bone-related markers in human bone marrow (BM) samples.

METHODS

This was a case-control and cross-sectional study conducted in a clinical unit. n-3 FA in the blood and bone biochemical markers in the BM aspirates were measured by gas chromatography/mass spectrometry and immunoassay, respectively. BM fluids were collected from 72 patients who underwent hip surgery because of either osteoporotic hip fracture (HF; n = 28) or osteoarthritis (n = 44).

RESULTS

After adjusting for confounders, patients with HF had 26.2% lower plasma n-3 levels than those with osteoarthritis (P = 0.006), and each standard deviation increment in plasma n-3 was associated with a multivariate-adjusted odds ratio of 0.40 for osteoporotic HF (P = 0.010). In multivariate analyses including all patients, a higher plasma n-3 level was associated with higher bone mass at the lumbar spine (β = 0.615, P = 0.002) and total femur (β = 0.244, P = 0.045). Interestingly, the plasma n-3 level was inversely associated with the tartrate-resistant acid phosphatase-5b level (β = - 0.633, P = 0.023), but not with the bone-specific alkaline phosphatase level, in BM aspirates.

CONCLUSIONS

These findings provide clinical evidence that n-3 FA is a potential inhibitor of osteoclastogenesis that favors human bone health.

Potential involvement of Drosophila flightless-1 in carbohydrate metabolism

A previous study of ours indicated that Drosophila flightless-1 controls lipid metabolism, and that there is an accumulation of triglycerides in flightless-1 (fliI)-mutant flies, where this mutation triggers metabolic stress and an obesity phenotype. Here, with the aim of characterizing the function of FliI in metabolism, we analyzed the levels of gene expression and metabolites in fliI-mutant flies. The levels of enzymes related to glycolysis, lipogenesis, and the pentose phosphate pathway increased in fliI mutants; this result is consistent with the levels of metabolites corresponding to a metabolic pathway. Moreover, high-throughput RNA sequencing revealed that Drosophila FliI regulates the expression of genes related to biological processes such as chromosome organization, carbohydrate metabolism, and immune reactions. These results showed that Drosophila FliI regulates the expression of metabolic genes, and that dysregulation of the transcription controlled by FliI gives rise to metabolic stress and problems in the development and physiology of Drosophila.

Perilipin 1 (Plin1) deficiency promotes inflammatory responses in lean adipose tissue through lipid dysregulation

Lipid droplets are specialized cellular organelles that contain neutral lipid metabolites and play dynamic roles in energy homeostasis. Perilipin 1 (Plin1), one of the major lipid droplet-binding proteins, is highly expressed in adipocytes. In mice, Plin1 deficiency impairs peripheral insulin sensitivity, accompanied with reduced fat mass. However, the mechanisms underlying insulin resistance in lean Plin1 knockout (Plin1^-/-) mice are largely unknown. The current study demonstrates that Plin1 deficiency promotes inflammatory responses and lipolysis in adipose tissue, resulting in insulin resistance. M1-type adipose tissue macrophages (ATMs) were higher in Plin1^-/- than in Plin1^+/+ mice on normal chow diet. Moreover, using lipidomics analysis, we discovered that Plin1^-/- adipocytes promoted secretion of pro-inflammatory lipid metabolites such as prostaglandins, which potentiated monocyte migration. In lean Plin1^-/- mice, insulin resistance was relieved by macrophage depletion with clodronate, implying that elevated pro-inflammatory ATMs might be attributable for insulin resistance under Plin1 deficiency. Together, these data suggest that Plin1 is required to restrain fat loss and pro-inflammatory responses in adipose tissue by reducing futile lipolysis to maintain metabolic homeostasis.

Matrine suppresses KRAS-driven pancreatic cancer growth by inhibiting autophagy-mediated energy metabolism

Matrine is a natural compound extracted from the herb Sophora flavescens Ait which is widely used in traditional Chinese medicine for treating various diseases. Recently, matrine was reported to have antitumor effects against a variety of cancers without any obvious side effects; however, the molecular mechanisms of its antiproliferative effects on cancer are unclear. Here, we report that matrine inhibits autophagy-mediated energy metabolism, which is necessary for pancreatic cancer growth. We found that matrine significantly reduces pancreatic cancer growth in vitro and in vivo by insufficiently maintaining mitochondrial metabolic function and energy level. We also found that either pyruvate or α-ketoglutarate supplementation markedly rescues pancreatic cancer cell growth following matrine treatment. Inhibition of mitochondrial energy production results from matrine-mediated autophagy inhibition by impairing the function of lysosomal protease. Matrine-mediated autophagy inhibition requires stat3 downregulation. Furthermore, we found that the antitumor effect of matrine on pancreatic cancer growth depends on the mutation of the KRAS oncogene. Together, our data suggest that matrine can suppress the growth of KRAS-mutant pancreatic cancer by inhibiting autophagy-mediated energy metabolism.

Gemigliptin, a novel dipeptidyl peptidase-IV inhibitor, exerts a synergistic cytotoxicity with the histone deacetylase inhibitor PXD101 in thyroid carcinoma cells

PURPOSE

The influence of the dipeptidyl peptidase-IV inhibitor gemigliptin alone or in combination with the histone deacetylase inhibitor PXD101 on survival of thyroid carcinoma cells was investigated.

METHODS

SW1736, TPC-1, 8505C and BCPAP human thyroid carcinoma cells were used. To assess cell survival, cell viability, the percentage of viable cells and dead cells, cytotoxic activity, ATP levels and FACS analysis were measured. To validate the impact of gemigliptin combined with PXD101, the interactions were estimated by obtaining combination index in cells treated with two agents.

RESULTS

In cells treated with gemigliptin or PXD101, cell viability, the percentage of viable cells and ATP levels were reduced, and the percentage of dead cells and cytotoxic activity were elevated. In cells treated with both gemigliptin and PXD101, compared with PXD101 alone, cell death was augmented, and all of the combination index values were lower than 1.0, suggesting the synergism between gemigliptin and PXD101. The percentage of apoptotic cells, and the protein levels of Bcl2 and cleaved poly (ADP-ribose) polymerase were elevated, and the protein levels of xIAP and survivin were reduced. The protein levels of phospho-Akt and phospho-AMPK were elevated, and cell migration was reduced.

CONCLUSIONS

Our results demonstrate that gemigliptin induces cytotoxicity in thyroid carcinoma cells. Moreover, gemigliptin has a synergistic activity with PXD101 in the induction of cell death through involvement of Bcl2 family proteins, xIAP and survivin as well as mediation of Akt and AMPK in thyroid carcinoma cells.

Benefits of Thromboelastography and Thrombin Generation Assay for Bleeding Prediction in Patients With Thrombocytopenia or Hematologic Malignancies

Background

Thromboelastography (TEG) provides comprehensive information on the whole blood clot formation phases, whereas thrombin generation assay (TGA) reveals the endogenous thrombin levels in plasma. We investigated the potential significance of TEG and TGA parameters for prediction of clinical bleeding in hematologic patients on the basis of the patient's platelet levels.

Methods

TEG and TGA were performed in 126 patients with thrombocytopenia or hematologic malignancies. The bleeding tendencies were stratified on the basis of the World Health Organization bleeding grade.

Results

Maximum amplitude (MA) and clot formation in TEG and endogenous thrombin potential (ETP) in TGA showed significant associations with high bleeding grades (P=0.001 and P=0.011, respectively). In patients with platelet counts ≤10×10⁹/L, low MA values were strongly associated with a high bleeding risk. For bleeding prediction, the area under the curve (AUC) of MA (0.857) and ETP (0.809) in patients with severe thrombocytopenia tended to be higher than that of platelets (0.740) in all patients. Patients with platelet counts ≤10×10⁹/L displayed the highest AUC of the combined MA and ETP (0.929).

Conclusions

Both TEG and TGA were considered to be good predictors of clinical bleeding in patients with severe thrombocytopenia. Combination of the ETP and MA values resulted in a more sensitive bleeding risk prediction in those with severe thrombocytopenia.

Thrombin Generation Assay Detects Moderate-Intensity Statin-Induced Reduction of Hypercoagulability in Diabetes

Statins not only have a lipid-lowering effect but also reduce inflammation and have an antithrombotic effect. Since hypercoagulability assessed by thrombin generation assay (TGA) and increased formation of neutrophil extracellular traps (NET) were demonstrated in diabetes, we investigated whether statin therapy in diabetes modifies coagulation status and NET formation. Twenty-five consecutive patients with diabetes were recruited. Global coagulation assays (prothrombin time [PT], activated partial thromboplastin time [aPTT], and TGA) and NET markers (DNA–histone complex, cell-free DNA, and neutrophil elastase) were measured before and after 3-month moderate-intensity statin therapy. In addition, all coagulation factors and 3 anticoagulation factors were measured. Statin therapy significantly reduced endogenous thrombin potential (ETP) value and blood lipids but did not change the PT and aPTT values or NET formation markers. Statin significantly decreased not only coagulation factors (II, V, VIII, IX, and X) but also the anticoagulation factor antithrombin. Statin-induced reduction of factor V and X significantly contributed to the reduction of ETP value. The extent of reduction in coagulation factors correlated with that of anticoagulation factors, but not that of cholesterol. It is possible to use TGA as a global coagulation assay that can detect coagulation status modified by statin therapy. Additional studies are needed to evaluate the clinical implications of statin-induced simultaneous reduction of coagulation and anticoagulation factors.

Biochemical and molecular analyses of infantile sialic acid storage disease in a patient with nonimmune hydrops fetalis

Nonimmune hydrops fetalis is the most severe clinical manifestation of lysosomal storage diseases (LSDs). Around 14 different LSDs have been accounted for as 1-15% of the cause of nonimmune hydrops fetalis. We report a Korean infant affected by an extremely rare but severe form of sialic acid storage disease. The patient presented with nonimmune hydrops fetalis, dysmorphic facial features, hepatosplenomegaly, and dysostosis multiplex and died at 39 days of age due to persistent pulmonary hypertension. LSD was suspected based on the presence of diffuse vacuolation of syncytiotrophoblast, villous stromal cells, and intermediate trophoblast in placental biopsy. Increased excretion of urinary free sialic acid was detected by liquid chromatography-tandem mass spectrometry. The patient was compound heterozygous of the c.908G>A (p.Trp303Ter) and the splicing mutation c.1259+5G>T (IVS9+5 G>T) in the SLC17A5 gene.

Meal-related oscillations in the serum serotonin levels in healthy young men

CONTEXT

Serotonin acts as a neurotransmitter in the central and enteric nervous systems, modulating psychological, metabolic and gastrointestinal functions. Serotonin is also found in the serum or plasma, indicating its potential role as a hormone.

OBJECTIVE

We aimed to assess the 24-hour diurnal profile of serum serotonin in relation to meal ingestion in healthy adult men.

METHODS

Ten healthy (5 lean and 5 obese) male subjects were enrolled in this study. Blood samples were drawn every 30-60 minutes throughout a 24-hour period to determine the serotonin levels. Three meals were provided on a fixed schedule. To confirm the effect of meal intake on serum serotonin levels, 4 subjects underwent fasting until 1500 h and were then provided a meal without notice.

RESULTS

Serum serotonin levels had distinct diurnal variations, with the highest levels early in the morning and the lowest levels in the midafternoon and during sleep. Notably, these diurnal oscillations were markedly reduced in obese subjects. Fluctuations in serum serotonin levels were associated with meal intake, and the levels peaked 30 minutes before meals and exhibited a trough during the postprandial period. Fasting blunted the meal-related oscillations in serum serotonin levels. Moreover, unexpected meal intake did not lead to a premeal increase in serum serotonin levels.

CONCLUSIONS

Serum serotonin levels displayed meal-related diurnal oscillations, which were disrupted by fasting and obesity. These findings suggest the possibility that circulating serotonin modulates metabolic function in humans.

microRNA-155 positively regulates glucose metabolism via PIK3R1-FOXO3a-cMYC axis in breast cancer

MicroRNA is an endogenous, small RNA controlling multiple target genes and playing roles in various biological processes including tumorigenesis. Here, we addressed the function of miR-155 using LC-MS/MS-based metabolic profiling of miR-155 deficient breast cancer cells. Our results revealed the loss of miR-155 hampers glucose uptake and glycolysis, via the down-regulation of glucose transporters and metabolic enzymes including HK2, PKM2, and LDHA. We showed this is due to the down-regulation of cMYC, controlled through phosphoinositide-3-kinase regulatory subunit alpha (PIK3R1)-PDK1/AKT-FOXO3a pathway. UTR analysis of the PIK3R1 and FOXO3a indicated miR-155 directly represses these genes. A stable expression of miR-155 in patient-derived cells (PDCs) showed activated glucose metabolism whereas a stable inhibition of miR-155 reduced in vivo tumor growth with retarded glucose metabolism. Furthermore, analysis of 50 triple-negative breast cancer (TNBC) specimens and specific uptake value (SUV) of PET images revealed a positive correlation between miR-155 level and glucose usage in human breast tumors via PIK3R1-PDK/AKT-FOXO3a-cMYC axis. Collectively, these data demonstrate the miR-155 is a key regulator of glucose metabolism in breast cancer.

Associations among FADS1 rs174547, eicosapentaenoic acid/arachidonic acid ratio, and arterial stiffness in overweight subjects

We aimed to evaluate the longitudinal interaction effects between the minor allele of FADS1 rs174547 and overweight on n-3 and n-6 long-chain polyunsaturated fatty acid (PUFA) levels and pulse wave velocity (PWV). Plasma PUFA levels were measured via GC-MS, and arterial stiffness was determined as brachial-ankle PWV (ba-PWV) at baseline and after a mean follow-up of 3 years. The FADS1 rs174547 T > C genotype was analyzed. At 3-years of follow-up, after adjustment for age, sex, smoking and drinking, there were interaction effects between the FADS1 rs174547 T > C genotype and baseline BMI on the changes (from baseline) in plasma arachidonic acid (AA) levels, in the eicosapentaenoic acid (EPA)/AA ratio, and in ba-PWV (p for interaction = 0.036, 0.022, and 0.001, respectively). There were smaller increases in AA levels from baseline among normal-weight C allele carriers (n = 112) and overweight TT subjects (n = 47) than among normal-weight TT subjects (n = 91). Overweight C allele carriers (n = 37) showed greater reductions in the plasma EPA/AA ratio and greater increases in ba-PWV than the 3 other populations studied. The minor allele of the FADS1 rs174547 polymorphism is associated with age-related decreases in the EPA/AA ratio and increases in ba-PWV among overweight subjects.

Genetic and metabolic comparison of orthotopic and heterotopic patient-derived pancreatic-cancer xenografts to the original patient tumors

Tumors from 25 patients with pancreatic cancer were used to establish two patient-derived xenograft (PDX) models: orthotopic PDX (PDOX) and heterotopic (subcutaneous) PDX (PDHX). We compared gene expression by immunohistochemistry, single-nucleotide polymorphism (SNP), DNA methylation, and metabolite levels. The 4 cases, of the total of 13 in which simultaneous PDHX & PDOX models were established, were randomly selected. The molecular-genetic characteristics of the patient's tumor were well maintained in the two PDX models. SNP analysis demonstrated that both groups were more than 90% identical to the original patient's tumor, and there was little difference between the two models. DNA methylation of most genes was similar among the two models and the original patients tumor, but some gene sets were hypermethylated the in PDOX model and hypomethylated in the PDHX model. Most of the metabolites had a similar pattern to those of the original patient tumor in both PDX tumor models, but some metabolites were more prominent in the PDOX and PDHX models. This is the first simultaneous molecular-genetic and metabolite comparison of patient tumors and their tumors established in PDOX and PDHX models. The results indicate high fidelity of these critical properties of the patient tumors in the two models.

Interferon Potentiates Toll-Like Receptor-Induced Prostaglandin D2 Production through Positive Feedback Regulation between Signal Transducer and Activators of Transcription 1 and Reactive Oxygen Species

Prostaglandin D₂ (PGD₂) is a potent lipid mediator that controls inflammation, and its dysregulation has been implicated in diverse inflammatory disorders. Despite significant progress made in understanding the role of PGD₂ as a key regulator of immune responses, the molecular mechanism underlying PGD₂ production remains unclear, particularly upon challenge with different and multiple inflammatory stimuli. Interferons (IFNs) potentiate macrophage activation and act in concert with exogenous inflammatory mediators such as toll-like receptor (TLR) ligands to amplify inflammatory responses. A recent study found that IFN-γ enhanced lipopolysaccharide-induced PGD₂ production, indicating a role of IFNs in PGD₂ regulation. Here, we demonstrate that TLR-induced PGD₂ production by macrophages was significantly potentiated by signaling common to IFN-β and IFN-γ in a signal transducer and activators of transcription (STAT)1-dependent mechanism. Such potentiation by IFNs was also observed for PGE₂ production, despite the differential regulation of PGD synthase and PGE synthase isoforms mediating PGD₂ and PGE₂ production under inflammatory conditions. Mechanistic analysis revealed that the generation of intracellular reactive oxygen species (ROS) was remarkably potentiated by IFNs and required for PGD₂ production, but was nullified by STAT1 deficiency. Conversely, the regulation of STAT1 level and activity by IFNs was largely dependent on ROS levels. Using a model of zymosan-induced peritonitis, the relevance of this finding in vivo was supported by marked inhibition of PGD₂ and ROS produced in peritoneal exudate cells by STAT1 deficiency. Collectively, our findings suggest that IFNs, although not activating on their own, are potent amplifiers of TLR-induced PGD₂ production via positive-feedback regulation between STAT1 and ROS.

Urinary desmosine is associated with emphysema severity and frequent exacerbation in patients with COPD

BACKGROUND AND OBJECTIVE

Matrix degradation is a key feature of chronic obstructive pulmonary disease (COPD). Desmosine and isodesmosine (desmosines) are excreted in urine following matrix degradation. The main purpose of this study was to investigate the association between computed tomography (CT) emphysema indices and urinary desmosines in patients with COPD.

METHODS

A total of 152 subjects were selected from the Korean Obstructive Lung Disease cohort. Their urine samples were assayed for desmosines using liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. The cohort was divided into emphysema-dominant (n = 80) and non-emphysema dominant- (n = 72) groups according to the CT emphysema index.

RESULTS

The level of urinary desmosines was significantly higher in the emphysema-dominant group. Significant differences were also observed between the two groups for body mass index and lung function. Multivariate analysis indicated that a high level of urinary desmosines was a significant independent predictor of emphysema (relative risk: 2.6; 95% CI: 1.11-6.09; P = 0.028). The percentage of frequent exacerbators was significantly higher in the high urinary desmosine group in the first year of follow-up (P = 0.041). The mean number of exacerbations was higher in the high urinary desmosine group, although this difference was not statistically significant (P = 0.067). The changes in emphysema index did not differ between the two urinary desmosine groups over 3 years of follow-up.

CONCLUSION

This study indicates that the level of urinary desmosines measured by LC-MS/MS methods is associated with the CT emphysema index. Urinary desmosine can be a useful predictor in identifying frequent exacerbators.