Serum 25-hydroxyvitamin D3 Levels and Diabetes in a Japanese Population: The DOSANCO Health Study.

BACKGROUND: Both decreased insulin sensitivity and impaired insulin secretion are common in Asian populations with diabetes, in contrast to Western populations. There is limited evidence regarding the association between insulin response in diabetes in Asian populations and serum 25-hydroxyvitamin D3 (25[OH]D3) insufficiency. METHODS: The present cross-sectional study compared the prevalence of diabetes, defined as a fasting plasma glucose level ≥126 mg/dL and/or a HbA1c level ≥6.5%, among 480 participants aged 35-79 years not taking anti-diabetes medications, based on serum 25(OH)D3 levels. A logistic regression model was used to calculate the odds ratios for diabetes in each serum 25(OH)D3 group. Furthermore, this study examined the association between serum 25(OH)D3 levels and the index of homeostasis model assessment of insulin resistance (HOMA-IR) using a linear regression model. RESULTS: The prevalence of diabetes was 7.29% in the study population, and was higher in lower serum 25(OH)D3 quartile groups. The odds ratios for diabetes in the first, second, and third serum 25(OH)D3 quartile groups (25[OH]D3: ≤18.10, 18.11-22.90, and 22.91-28.17 ng/mL) were 4.02 (95% confidence interval [CI], 1.25-12.92), 2.50 (95% CI, 0.77-8.10), and 1.91 (95% CI, 0.60-6.09), respectively, with the fourth quartile group (⩾28.18 ng/mL) serving as the reference group, after adjusting for sociodemographic, lifestyle, physical and environmental factors. Serum 25(OH)D3 levels showed an inverse association with log-transformed HOMA-IR after adjusting for similar factors (standardized ß = -0.08; 95% CI, -0.14 to -0.02). CONCLUSION: Serum 25(OH)D3 levels were inversely associated with diabetes prevalence in a general Japanese population, with a slight inverse association between serum 25(OH)D3 levels and HOMA-IR.

Feasibility and safety of noncontrast percutaneous coronary intervention in patients with complicated acute coronary syndrome.

OBJECTIVES: This study aimed to examine the feasibility and safety of noncontrast percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS). BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) occurs in 10-20% of ACS patients undergoing PCI, resulting in poor short- and long-term prognoses. Reducing the amount of contrast medium can prevent CI-AKI. METHODS: This was a prospective single-center study. In successful noncontrast PCI, contrast medium was not injected from guiding catheter engagement to wire removal in ad-hoc PCI. Coronary angiography after PCI was permitted once. CI-AKI was defined as an increase in the serum creatinine level of ≥0.5 mg/dl or ≥1.25 times the baseline within 72 hr post PCI. Worsening renal function (WRF) was defined as an increase in the serum creatinine level of ≥0.3 mg/dl from baseline after PCI. RESULTS: This study included 106 lesions from 81 patients. Forty-eight (45%) lesions were Type C lesions. Successful noncontrast PCI was performed in 95 (90%) lesions. CI-AKI, coronary perforation, no/slow flow, and periprocedural death were observed in 4 (5%), 0, 9 (11%), and 0 patients, respectively. The follow-up period was 348 (190-492) days. Six-month WRF was observed in 18 individuals (22%). While successful noncontrast PCI was not associated with the incidence of CI-AKI, successful noncontrast PCI was inversely associated with WRF (hazard ratio, 0.28; 95% confidence interval, 0.09-0.90) after adjustment for renal function. CONCLUSIONS: The present study suggests that noncontrast PCI is feasible and can be safely performed in ACS patients with complex lesions.

Synthetic Studies of Isoschizogamine: Alternative Preparation of the Key Intermediate.

An alternative synthetic route toward a key intermediate in the total synthesis of isoschizogamine is described. The Claisen-Johnson rearrangement stereoselectively constructed a quaternary carbon. Trifluoroperacetic acid mediated the Baeyer-Villiger oxidation to form a bicyclic lactone. The Mukaiyama-Matsuo protocol converted the lactone into an α,ß-unsaturated lactone, that was used as the substrate for the rhodium-mediated 1,4-addition of an arylboronic acid.

Brain Microdialysis Study of Vancomycin in the Cerebrospinal Fluid After Intracerebroventricular Administration in Mice.

Vancomycin (VCM) is an important antibiotic for treating methicillin-resistant Staphylococcus aureus (MRSA) infections. To treat bacterial meningitis caused by MRSA, it is necessary to deliver VCM into the meninges, but the rate of VCM translocation through the blood-brain barrier is poor. Additionally, high doses of intravascularly (i.v.) administered VCM may cause renal impairments. Thus, VCM is sometimes administered intracerebroventricularly (i.c.v.) for clinical treatment. However, information on the VCM pharmacokinetics in cerebrospinal fluid (CSF) after i.c.v. administration is lacking. In the present study, we evaluated the VCM pharmacokinetics in the CSF and systemic circulation after i.c.v. compared to that after i.v. administration, using the brain microdialysis method in mice. VCM administered via i.c.v. showed a highly selective distribution in the CSF, without migration to systemic circulation. Moreover, to assess renal impairments after i.c.v. administration of VCM, we histologically evaluated damage to the mouse kidney by hematoxylin and eosin staining. No significant morphological change in the kidney was observed in the i.c.v. administration group compared to that in the i.v. administration group. Our results demonstrate that i.c.v. administration of VCM can be partially prevented from entering the systemic circulation to prevent renal impairments caused by VCM.

Profiling of cardiolipins and their hydroperoxides in HepG2 cells by LC/MS.

Cardiolipin (CL) exists as crucial functional phospholipid in mitochondria. The oxidation of CL is concerned with mitochondrial dysfunction and various diseases. As main oxidation products, CL hydroperoxide (CL-OOH) plays a key role in intermediating oxidative reaction. Thus, direct analysis of CL-OOH is of great interest. In the present study, CL and CL-OOH profiles were analyzed in oxidized HepG2 cell lipid via HPLC-Orbitrap MS/MS. Furthermore, the contents of individual molecular species were compared between intact and AAPH-oxidized HepG2 cells. In total, 46 CL and 18 CL-OOH were identified from oxidized cell lipids, while 21 CL and 9 CL-OOH were detected in AAPH-treated cells. Most CL depleted significantly after AAPH inducement, with percentages varying from 8.3% (CL70:7) to 73.7% (CL72:4), depending on fatty acyl composition. While almost all the CL-OOH remarkably increased, among them 68:6-, 72:6-, and 72:7-OOHs were only detected in AAPH-treated cells. CL68:5- and CL68:4-OOH were the most abundant species, while CL70:5-OOH among all the species expressed the highest oxidation percentage of the corresponding CL. Our results showed practical separation, identification, and semi-quantitation of CL-OOH species, which could contribute to approaches to lipidomic analysis of CL and CL-OOH, as well as tracing biomarkers in mitochondrial oxidative stress diagnosis. Graphical abstract Illustration represents cardiolipin hydroperoxide structure and its content increasing in AAPH-treated HepG2 cells by LC/MS analysis.

Identification of molecular species of oxidized triglyceride in plasma and its distribution in lipoproteins.

BACKGROUND: The role of triglycerides carried in the triglyceride-rich lipoproteins (TRL) in the progression of atherosclerosis is uncertain. Identification of oxidized triglycerides and its possible association with atherosclerosis were largely ignored. Here we applied mass spectrometric approach to detect and identify triglyceride hydroperoxides (TGOOH) in human plasma and lipoproteins. METHODS: EDTA plasma was collected from healthy human volunteers (n=9) after 14-16 h of fasting. Very low-density lipoprotein (VLDL) (d<1.006) and intermediate-density lipoprotein (IDL) (d=1.006-1.019) were isolated from the plasma (n=6) by sequential ultracentrifugation in KBr, followed by the isolation of LDL and high-density lipoprotein (HDL) using size-exclusion high-performance liquid chromatography (HPLC). Total lipids from the plasma and isolated lipoproteins were extracted, and analyzed for the detection and identification of TGOOH using liquid chromatography/LTQ ion trap Orbitrap mass spectrometry. All the processes, from specimen collection to the mass spectrometric analysis, were carried out at 4 °C in the presence of antioxidant to prevent oxidation of lipoproteins. RESULTS: We identified 11 molecular species of TGOOH in either plasma or VLDL and IDL, of which TGOOH-18:1/18:2/16:0, TGOOH-18:1/18:1/16:0, TGOOH-16:0/18:2/16:0, TGOOH-18:1/18:1/18:1, and TGOOH-16:0/20:4/16:0 were most dominant. These TGOOH molecules are carried by TRL but not by LDL and HDL. Mean concentration of TGOOH in plasma, VLDL and IDL were, respectively, 56.1 ± 25.6, 349.8 ± 253.6 and 512.5 ± 173.2 µmol/mol of triglycerides. CONCLUSIONS: This is the first report to identify several molecular species of oxidized triglycerides in TRL. Presence of oxidized triglyceride may contribute to the atherogenicity of TRL. Further work is needed to elucidate the association of the oxidized triglyceride in atherosclerosis.

Random walk and cell morphology dynamics in Naegleria gruberi.

Amoeboid cell movement and migration are wide-spread across various cell types and species. Microscopy-based analysis of the model systems Dictyostelium and neutrophils over the years have uncovered generality in their overall cell movement pattern. Under no directional cues, the centroid movement can be quantitatively characterized by their persistence to move in a straight line and the frequency of re-orientation. Mathematically, the cells essentially behave as a persistent random walker with memory of two characteristic time-scale. Such quantitative characterization is important from a cellular-level ethology point of view as it has direct connotation to their exploratory and foraging strategies. Interestingly, outside the amoebozoa and metazoa, there are largely uncharacterized species in the excavate taxon Heterolobosea including amoeboflagellate Naegleria. While classical works have shown that these cells indeed show typical amoeboid locomotion on an attached surface, their quantitative features are so far unexplored. Here, we analyzed the cell movement of Naegleria gruberi by employing long-time phase contrast imaging that automatically tracks individual cells. We show that the cells move as a persistent random walker with two time-scales that are close to those known in Dictyostelium and neutrophils. Similarities were also found in the shape dynamics which are characterized by the appearance, splitting and annihilation of the curvature waves along the cell edge. Our analysis based on the Fourier descriptor and a neural network classifier point to importance of morphology features unique to Naegleria including complex protrusions and the transient bipolar dumbbell morphologies.

Dictyostelium Differentiation-inducing Factor Derivatives Reduce the Glycosylation of PD-L1 in MDA-MB-231 Human Breast Cancer Cells.

Objectives: Triple-negative breast cancer (TNBC) is a metastatic and intractable cancer with limited treatment options. Refractory cancer cells often express the immune checkpoint molecules programmed death-ligand 1 (PD-L1) and PD-L2, which inhibit the anticancer effects of T cells. Differentiation-inducing factors, originally found in Dictyostelium discoideum, and their derivatives possess strong antiproliferative activity, at least in part by reducing cyclin D1 expression in various cancer cells, but their effects on PD-L1/PD-L2 have not been examined. In this study, we investigate the effects of six DIF compounds (DIFs) on the expression of PD-L1/PD-L2 and cyclin D1/D3 in MDA-MB-231 cells, a model TNBC cell line. Methods: MDA-MB-231 cells were incubated for 5 or 15 h with or without DIFs, and the mRNA expression of cyclin D1, PD-L1, and PD-L2 were assessed by quantitative polymerase chain reaction (qPCR). Whereas, MDA-MD-231 cells were incubated for 12 or 24 h with or without DIFs, and the protein expression of cyclins D1 and D3, PD-L1, and PD-L2 were assessed by Western blotting. Results: As expected, some DIFs strongly reduced cyclin D1/D3 protein expression in MDA-MB-231 cells. Contrary to our expectation, DIFs had little effect on PD-L1 mRNA expression or increased it transiently. However, some DIFs partially reduced glycosylated PD-L1 and increased non-glycosylated PD-L1 in MDA-MB-231 cells. The level of PD-L2 was very low in these cells. Conclusions: Since PD-L1 glycosylation plays an important role in preventing T cells from attacking cancer cells, such DIFs may promote T cell attack on cancer cells in vivo.

Pathogen Profiles in Outpatients with Non-COVID-19 during the 7th Prevalent Period of COVID-19 in Gunma, Japan.

The identification of pathogens associated with respiratory symptoms other than the novel coronavirus disease 2019 (COVID-19) can be challenging. However, the diagnosis of pathogens is crucial for assessing the clinical outcome of patients. We comprehensively profiled pathogens causing non-COVID-19 respiratory symptoms during the 7th prevalent period in Gunma, Japan, using deep sequencing combined with a next-generation sequencer (NGS) and advanced bioinformatics technologies. The study included nasopharyngeal swabs from 40 patients who tested negative for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) using immuno-chromatography and/or quantitative reverse transcription polymerase chain reaction (qRT-PCR) methods. Comprehensive pathogen sequencing was conducted through deep sequencing using NGS. Additionally, short reads obtained from NGS were analyzed for comprehensive pathogen estimation using MePIC (Metagenomic Pathogen Identification Pipeline for Clinical Specimens) and/or VirusTap. The results revealed the presence of various pathogens, including respiratory viruses and bacteria, in the present subjects. Notably, human adenovirus (HAdV) was the most frequently detected virus in 16 of the 40 cases (40.0%), followed by coryneforms, which were the most frequently detected bacteria in 21 of the 40 cases (52.5%). Seasonal human coronaviruses (NL63 type, 229E type, HKU1 type, and OC43 type), human bocaviruses, and human herpesviruses (human herpesvirus types 1-7) were not detected. Moreover, multiple pathogens were detected in 50% of the subjects. These results suggest that various respiratory pathogens may be associated with non-COVID-19 patients during the 7th prevalent period in Gunma Prefecture, Japan. Consequently, for an accurate diagnosis of pathogens causing respiratory infections, detailed pathogen analyses may be necessary. Furthermore, it is possible that various pathogens, excluding SARS-CoV-2, may be linked to fever and/or respiratory infections even during the COVID-19 pandemic.

Total synthesis of (-)-isoschizogamine.

A first asymmetric total synthesis of (-)-isoschizogamine has been accomplished. Our synthesis features the facile construction of the carbon framework of the natural product through a Wagner-Meerwein rearrangement, a tandem metathesis, a stereoselective rhodium-mediated 1,4-addition of an arylboronic acid, and a ring-closing metathesis via a hemiaminal ether.

Fenestration Using a Novel Cutting Balloon for Acute Vessel Occlusion Secondary to Intramural Hematoma Following Stent Implantation.

Intramural hematoma after percutaneous coronary angioplasty is associated with adverse events and requires immediate bail out; however, the optimal treatment approach has not yet been established. Herein, we describe a case of coronary occlusion due to an intramural hematoma following stent implantation in the mid left anterior descending (LAD) coronary artery. Intravascular ultrasound revealed a massive intramural hematoma from the distal edge of the stent to the distal segment of the LAD, and the true lumen was completely compressed. By performing fenestration with a Wolverine™ Cutting Balloon™ (Boston Scientific, Massachusetts, United States), we were able to bail out without additional stenting. In conclusion, a cutting balloon with improved crossability can be an effective management strategy for intramural hematoma.

Clinical impact of noncontrast percutaneous coronary intervention in patients with acute coronary syndrome.

PURPOSE: Contrast-induced acute kidney injury (CI-AKI) is one of the common serious complications of percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS). This study aimed to assess the significance of noncontrast strategy in the setting of ACS. METHODS: CI-AKI was defined as an increase in serum creatinine of ?0.5 mg/dL or ?1.25 times from the baseline. One-year worsening renal function (WRF) was defined as an increase of ?0.3mg/dL in serum creatinine from the baseline after PCI. RESULTS: Of 250 ACS patients, 81 were treated with noncontrast PCI. The average doses of contrast medium in the noncontrast and conventional groups were 17 (9?22) ml and 150 (120?200) ml, respectively. CI-AKI was observed in 4 patients (5%) in the noncontrast group and 29 patients (17%) in the conventional group. Noncontrast PCI was associated with a lower incidence of CI-AKI (adjusted odds ratio, 0.26;95% confidence interval [CI], 0.08?0.82). The bootstrap method and inverse probability weighting led to similar results. CI-AKI was associated with a higher incidence of 1-year WRF (adjusted hazard ratio, 2.30;95% CI, 1.12?4.69), while noncontrast PCI was not. CONCLUSIONS: Noncontrast PCI was associated with the lower incidence of CI-AKI in ACS patients. J. Med. Invest. 69 : 57-64, February, 2022.

Association of Potassium Level at Discharge with Long-Term Mortality in Hospitalized Patients with Heart Failure.

Dyskalemia (hypokalemia and hyperkalemia) is a common comorbidity of heart failure (HF). Although dyskalemia is associated with poor prognosis, different prognostic impacts of hypo- and hyperkalemia remain vastly unclear. This study investigated the association of dyskalemia with prognosis in HF patients, especially the mode of death and left ventricular ejection fraction (LVEF). The multicenter study included 3398 patients hospitalized for HF. Patients were divided into three groups based on serum potassium levels at discharge: hypokalemia (<3.5 mEq/L; n = 115 (3.4%)), normokalemia (3.5−5.0 mEq/L; n = 2960 (87.1%)), and hyperkalemia (≥5.0 mEq/L; n = 323 (9.5%)). Two-year all-cause, cardiac, and non-cardiac mortality was evaluated. Association of serum potassium with two-year mortality demonstrated a U-shaped curve, with a worse prognosis for patients with hypokalemia. All-cause mortality at two-years did not differ among the three groups. Hypokalemia was associated with 2-year cardiac death (adjusted hazard ratio (HR), 2.60; 95% confidence interval (CI), 1.20−5.64) in HF with reduced ejection fraction (HFrEF; LVEF < 40%), but not in non-HFrEF. Regardless of LVEF, hyperkalemia was not independently associated with any mortality. Hypokalemia was independently associated with cardiac death, particularly in HFrEF patients. Such an association was not observed in hyperkalemia regardless of LVEF.

Comparison of dimension reduction methods on fatty acids food source study.

Serum fatty acids (FAs) exist in the four lipid fractions of triglycerides (TGs), phospholipids (PLs), cholesteryl esters (CEs) and free fatty acids (FFAs). Total fatty acids (TFAs) indicate the sum of FAs in them. In this study, four statistical analysis methods, which are independent component analysis (ICA), factor analysis, common principal component analysis (CPCA) and principal component analysis (PCA), were conducted to uncover food sources of FAs among the four lipid fractions (CE, FFA, and TG + PL). Among the methods, ICA provided the most suggestive results. To distinguish the animal fat intake from endogenous fatty acids, FFA variables in ICA and factor analysis were studied. ICA provided more distinct suggestions of FA food sources (endogenous, plant oil intake, animal fat intake, and fish oil intake) than factor analysis. Moreover, ICA was discovered as a new approach to distinguish animal FAs from endogenous FAs, which will have an impact on epidemiological studies. In addition, the correlation coefficients between a published dataset of food FA compositions and the loading values obtained in the present ICA study suggested specific foods as serum FA sources. In conclusion, we found that ICA is a useful tool to uncover food sources of serum FAs.

Impaired mental health status following intensive care unit admission in a patient with COVID-19.

Background: Severe respiratory failure patients with coronavirus disease (COVID-19) sometimes do not receive post-intensive care syndrome prevention bundles. No detailed report has been published on the practical observations of mental impairments in these patients. Case presentation: A 33-year-old man was admitted with COVID-19 pneumonia. On day 6, he was admitted to the intensive care unit (ICU). Considering the risk of nosocomial infection, as per the hospital policy, early rehabilitation could not be initiated for COVID-19 patients at that time and family visits were not allowed. Thereafter, his respiratory condition gradually improved; he was discharged on day 19. When the ICU nurse called to assess his medical condition, the patient complained of insomnia after ICU discharge. Therefore, we called him for an outpatient visit 28 days after discharge and scored his mental health status. Conclusion: Careful follow-up is required to treat mental impairment in patients with COVID-19.

Synthetic Studies on Pactamycin: A Synthesis of Johnson's Intermediate.

A formal total synthesis of pactamycin (1) has been accomplished by face-selective and regioselective nitroso Diels-Alder (NDA) reaction of acyl nitroso compound 14, which contains a camphorsultam chiral auxiliary, and chiral cyclopentadiene 12. Construction of the chiral secondary alcohol of 12 was performed by (S,S)-Ts-DENEB catalyst-mediated reduction, and the NDA adduct 15a was readily converted to Johnson's intermediate 21.

Multivariate Analysis for Molecular Species of Cholesteryl Ester in the Human Serum.

Cholesteryl ester (CE) is an ester of cholesterol and fatty acid (FA). Plasma CE reflects complicated metabolisms of cholesterol, phospholipids, lipoproteins, and dietary FAs. An informatics approach could be useful for analysis of the CE species. In this study, two basic dimension reduction methods, principal component analysis (PCA) and factor analysis, were applied to serum CE species determined by LC-MS/MS in a Japanese population (n = 545). PCA and factor analysis both reflected the size (concentration), food source, fat solubility, and biological aspect of the CE species. In a comparison between PCA (PC4) and factor analysis (factor 4), the latter was found to be more suggestive from a biological aspect of n-6 FAs. Cholesteryl docosahexaenoate (DHA) was found to be unique by a factor analysis, possibly relevant to the unique accumulation of DHA in the brain. An informatics approach, especially factor analysis, might be useful for the analysis of complicated metabolism of CE species in the serum.

Application of Direct Sonoporation from a Defined Surface Area of the Peritoneum: Evaluation of Transfection Characteristics in Mice.

In the present study, we developed a sonoporation system, namely "direct sonoporation", for transfecting the peritoneum from a defined surface area to avoid systematic side effects. Here, the transfection characteristics are explained because there is less information about direct sonoporation. Naked pDNA and nanobubbles were administered to diffusion cell attached to the visceral and parietal peritoneum from the liver and peritoneal wall surface, respectively. Then, ultrasound was irradiated. Direct sonoporation showed a higher transfection efficacy at the applied peritoneum site from the liver surface while other sites were not detected. Moreover, transgene expression was observed in the peritoneal mesothelial cells (PMCs) at the applied peritoneum site. No abnormality was observed in the inner part of the liver. Although transgene expression of the visceral peritoneum was tenfold higher than that of the parietal peritoneum, transgene expression was observed in the PMCs on both the applied peritoneum sites. These results suggest that direct sonoporation is a site-specific transfection method of the PMCs on the applied peritoneum site without transgene expression at other sites and show little toxicity in the inner tissues at the applied site via cavitation energy. This information is valuable for the development of an intraperitoneal sonoporation device for treatment of peritoneal diseases such as peritoneal fibrosis.

Clinical impact of visceral-to-subcutaneous fat ratio in patients with acute aortic dissection.

BACKGROUND: Obesity has increased worldwide. Although the visceral-to-subcutaneous fat ratio (VS ratio) is an established risk factor for cardiovascular disease, its clinical impact on the long-term prognosis of patients with acute aortic dissection (AAD) remains unclear. MATERIALS AND METHODS: This retrospective study included 111 patients with AAD admitted to our hospital from 2013 to 2016. Patients who died during hospitalization, and those diagnosed with Marfan's syndrome were excluded. Visceral and subcutaneous fat accumulation (VFA, SFA) at umbilical level were calculated on a dedicated workstation. Major Adverse Cardiovascular and Cerebrovascular Events (MACCE) and worsening renal function (WRF) at 3 years were evaluated. RESULTS: Patient characteristics were as below: age, 73 ± 13; male, 55%; Stanford type A, 53%. Average VFA, SFA, and VS ratio on admission were 98 (52-145) cm2, 141 (90-185) cm2, and 0.75 (0.47-0.97), respectively. VFA was higher in male than in female (male, 134 [84-179] cm2; female, 71 [46-99] cm2; p < 0.001), whereas SFA was similar (male, 141 [91-174] cm2: female, 134 [90-205] cm2; p = 0.687). VS ratio was also higher in male (male, 0.88 [0.75-1.17]; female, 0.49 [0.39-0.65]; p < 0.001). Both MACCE and WRF at 3 years were observed in 17 (15%) and 32 (29%) patients, respectively. Multivariate Cox regression analysis demonstrated that VS ratio tended to be associated with the 3-year MACCE (HR for an increase of 0.5 unit, 1.49; 95% CI, 0.99-2.24; p = 0.056). This result persisted in male (HR for an increase of 0.5 unit, 1.54; 95% CI, 0.96-2.48; p = 0.073) but not female. The VS ratio was not related to the 3-year WRF. CONCLUSION: The VS ratio tends to be associated with the 3-year MACCE in patients with AAD. This finding is inconclusive owing to a small sample and low incidence of adverse events. Further studies with larger samples are needed to confirm the clinical significance of VS ratio.

Determination of total, free and esterified short-chain fatty acid in human serum by liquid chromatography-mass spectrometry.

BACKGROUND: Short-chain fatty acids are primarily absorbed through the portal vein during lipid digestion, which is utilized as the energy source, as well as prevent type 2 diabetes and some cancers. However, reports on the determination of these short-chain fatty acids in human serum are limited. METHODS: Blood samples from human subjects ( n = 547, male/female = 246/301, age 58.85 ± 12.57) were collected. Saponification was applied to obtain total fatty acid. After derivatization by 2-nitrophenylhydrazine, fatty acid 4:0 and fatty acid 6:0 were measured by liquid chromatography-mass spectrometry. RESULTS: The developed method exhibited good linearity (R2 = 0.9996 for both). All the coefficients of variation of reproducibility and accuracy for fatty acid 4:0 and fatty acid 6:0 ranged 3.0%-6.1%, with the average recoveries of 87.8%-102.4% and 92.2%-98.2%, respectively. In all the samples, the concentration of fatty acid 4:0 (162.4 ± 76.4 µmol/L) was significantly higher than fatty acid 6:0 (2.0 ± 2.5 µmol/L, P < 0.001). Furthermore, the esterified form was predominant in both fatty acid 4:0 and fatty acid 6:0 (98.2% and 82.4% of total fatty acids, respectively). Besides, short-chain fatty acids showed no significant differences with regard to sex or age differences. CONCLUSION: This developed liquid chromatography-mass spectrometry method is convenient and reliable, which might be useful for monitoring the variations of short-chain fatty acids in blood.