A rapid UHPLC-QDa method for quantification of human salivary amino acid profiles.

Abnormal salivary amino acid (AA) levels may indicate dysfunction of the body. Being noninvasive, sampling easily and cost-effective of saliva, a rapid, precise and simple analysis method has become very important for quantitative salivary AA profiles. After one-step to precipitate protein, the resultant extraction was derived with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) within 10 min. Quantitation of AA profile was achieved within 6 min in a single run by ultra-high performance liquid chromatography coupled with a single quadrupole mass spectrometry (UHPLC-QDA detector). The method was validated with acceptable accuracy ranging from 80.33 % to 122.31 %, appropriate linearity with the coefficient (R2) more than 0.991, good intra- and inter-day precision, repeatability and stability (RSD < 15 %). The recoveries at three different spiked concentrations ranged over 79.18 %-125.36 % while the matrix effect was from -19.86 % to 11.95 %. This simple, rapid and robust method was successfully applied to quantify human salivary 30 amino acids, in which the levels of taurine, γ-aminobutyric acid, methionine and tryptophan in healthy people were close to the LOQs. Besides, the levels of histidine and cystine were not able to be measured due to their relatively high LOQs, which were considered as the limitations of this developed method.

Saliva 1,5-anhydroglucitol is associated with early-phase insulin secretion in Chinese patients with type 2 diabetes.

INTRODUCTION: Saliva collection is a non-invasive test and is convenient. 1,5-anhydroglucitol (1,5-AG) is a new indicator reflecting short-term blood glucose levels. This study aimed to explore the relationship between saliva 1,5-AG and insulin secretion function and insulin sensitivity. RESEARCH DESIGN AND METHODS: Adult patients with type 2 diabetes who were hospitalized were enrolled. Based on blood glucose and C-peptide, homeostasis model assessment 2 for ß cell secretion function, C-peptidogenic index (CGI), △2-hour C-peptide (2hCP)/△2-hour postprandial glucose (2hPG), ratio of 0-30 min area under the curve for C-peptide and area under the curve for glucose (AUCCP30/AUCPG30), and AUC2hCP/AUC2hPG were calculated to evaluate insulin secretion function, while indicators such as homeostasis model assessment 2 for insulin resistance were used to assess insulin sensitivity. RESULTS: We included 284 subjects (178 men and 106 women) with type 2 diabetes aged 20-70 years. The saliva 1,5-AG level was 0.133 (0.089-0.204) µg/mL. Spearman's correlation analysis revealed a significantly negative correlation between saliva 1,5-AG and 0, 30, and 120 min blood glucose, glycated hemoglobin A1c, and glycated albumin (all p<0.05), and a significantly positive association between saliva 1,5-AG and CGI (r=0.171, p=0.004) and AUC CP30 /AUC PG30 (r=0.174, p=0.003). The above correlations still existed after adjusting for age, sex, body mass index, and diabetes duration. In multiple linear regression, saliva 1,5-AG was an independent factor of CGI (standardized ß=0.135, p=0.015) and AUC CP30 /AUC PG30 (standardized ß=0.110, p=0.020). CONCLUSIONS: Saliva 1,5-AG was related to CGI and AUCCP30/AUCPG30 in patients with type 2 diabetes. TRIAL REGISTRATION NUMBER: ChiCTR-SOC-17011356.

Association Between Neck Circumference and Microalbuminuria in Community Residents.

OBJECTIVE: Neck circumference (NC) represents the subcutaneous fat deposition in the neck and is an effective indicator for evaluating metabolic disorders, such as metabolic syndrome, subclinical atherosclerosis, and non-alcoholic fatty liver disease. Microalbuminuria (MAU) is regarded as a potential sign of systemic endothelial dysfunction and microvascular abnormalities. The aim of this study was to elucidate the association of NC with urine albumin-to-creatinine ratio (UACR) and MAU. METHODS: A total of 1882 Shanghai community residents were enrolled (816 men and 1066 women), with age ranging from 40 to 80 years. Anthropometric parameters, including NC, and biochemical indices were measured. MAU was determined if 30 mg/g ≤ UACR < 300 mg/g. An elevated NC was defined as NC ≥ 38.5 cm for men and NC ≥ 34.5 cm for women. RESULTS: Individuals with an elevated NC had significantly higher prevalence of MAU and UACR values than those with normal NC in both men and women (all P < 0.05). The logistic regression analysis showed that there were significant and positive associations between elevated NC and the increasing risk of MAU after adjusting for lipid profile and glycemic indices (P = 0.007 for men and P = 0.009 for women). After further adjusting for blood pressure, elevated NC caused an 69.3% additional risk of MAU in men (P = 0.037) and the positive correlation in women disappeared (P = 0.131). CONCLUSION: There was an independent and positive association between elevated NC and the risk of MAU in men in the Chinese community population. CHINESE CLINICAL TRIAL REGISTRY WWWCHICTRORGCN REGISTRATION NUMBER: ChiCTR1900024011.

No Association between Neck Circumference and Free Triiodothyronine in Euthyroid Men.

OBJECTIVE: Neck circumference (NC) is a simple anthropometric index for the assessment of upper body obesity. Thyroid hormones are closely related to obesity, body fat distribution indicators, and metabolic parameters. However, there are currently no reports on the association between NC and thyroid hormones in the Chinese population. This study aimed to explore the relationship between NC and thyroid hormones in men with normal thyroid function. METHODS: A total of 737 euthyroid men from Shanghai communities were enrolled. Anthropometric parameters, including NC and waist circumference (WC), were measured. Serum thyroid hormones were measured by electrochemical luminescence immunoassay. RESULTS: NC, WC, and body mass index (BMI) were significantly positively correlated with serum free triiodothyronine (FT3) (all P < 0.05). FT3 levels all presented significant upward trends with the increase in NC, WC, or BMI quartiles (all P for trend < 0.05), whereas there were no significant correlations between the three obesity indices and free thyroxine or thyroid-stimulating hormone (both P > 0.05). After adjustment for metabolic confounding factors such as age, blood pressure, blood glucose, lipid profiles, and CRP in multiple linear regression analysis, the correlation between FT3 and NC disappeared (standardized ß = -0.015, P=0.705), and FT3 remained significantly associated with WC (standardized ß = 0.103, P=0.012) and BMI (standardized ß = 0.082, P=0.047). CONCLUSIONS: In euthyroid men from Shanghai communities, there was no independent correlation between serum FT3 levels and NC. The trial was registered with ChiCTR1900024011.

Comparison of neck and waist circumferences for identifying subclinical atherosclerosis in a community-based population.

AIMS: Recently, neck circumference (NC) has been proposed as a new anthropometric index for assessing upper body fat, which has a close relationship with cardiovascular diseases (CVDs) and their risk factors. The purpose of this study was to explore the role of NC in identifying subclinical atherosclerosis, an early stage of CVD, in a Shanghai community population. MATERIALS AND METHODS: We enrolled 1387 subjects (486 men and 901 women) from the Shanghai community. Anthropometric measurements, including NC and waist circumference (WC), were taken for all subjects. Carotid intima media thickness (C-IMT) was determined by carotid ultrasonography. Elevated NC was defined as NC ≥ 38.5 cm in men and NC ≥ 34.5 cm in women. RESULTS: There was a positive correlation between NC and C-IMT, and this association remained significant even after adjustment for BMI (P = .015; P = .038). After adjusting for confounding factors, the additional risks of elevated C-IMT were 58% and 33% for each SD increase in NC in men and women, respectively (P = .003; P = .009). The NC cutoffs could identify 53.38% of men and 43.07% of women with elevated C-IMT, which was comparable to the identification of 56.08% of men and 42.57% of women with elevated C-IMT using WC cutoffs (P = .218; P = .920). CONCLUSIONS: NC was significantly and positively correlated with C-IMT. The cutoffs of NC could be helpful to identifying subclinical atherosclerosis in a community-based population, and the identification showed no difference compared to that using WC cutoffs.

Correlations between neck circumference and serum thyroid hormones levels in postmenopausal women with euthyroid and subclinical hypothyroidism.

Middle-aged and elderly women are at a higher risk of subclinical hypothyroidism (SHypo). Menopause is an important period of metabolic change in women and thyroid hormones are closely related to metabolic status. Neck circumference (NC) is a simple anthropometric index that reflects upper body fat accumulation. Therefore, this study aimed to explore the relationship between NC and thyroid hormones in postmenopausal women. A total of 1050 postmenopausal women were enrolled from Shanghai Zhabei communities (888 euthyroid subjects and 162 SHypo patients). Anthropometric parameters, including NC, were measured. The measurements of serum thyroid hormones were performed by electrochemical luminescence immunoassay. The results showed NC was positively correlated with thyroid-stimulating hormone (TSH) (r = .064, P = .039). TSH and the proportion of SHypo patients increased significantly in those with elevated NC (both P < .05). In logistic regression analysis, the risk of SHypo increased by 46.4% in those with elevated NC (OR = 1.464 [1.035-2.071], P = .031). After adjusting for metabolic confounding factors, the positive association disappeared (P = .112). Multiple linear regression analysis showed there were no significant correlations between NC and TSH in either univariate or multivariate model in the total population (both P > .05). And in the subgroup analysis of euthyroid and SHypo individuals, NC was also not related to TSH (all P > .05). In conclusion, there was no independent association between NC, a simple anthropometric index for upper body fat accumulation, and serum TSH levels in Chinese euthyroid and SHypo postmenopausal women.

Neck Circumference is an Effective Supplement for Nonalcoholic Fatty Liver Disease Screening in a Community-Based Population.

BACKGROUND: Accumulating evidence has shown that neck circumference (NC) is associated with obesity-related metabolic abnormalities. Nonalcoholic fatty liver disease (NAFLD) is regarded as a liver manifestation of metabolic syndrome. This study aimed to investigate the relationship between NC and liver fat content (LFC) and NAFLD. METHODS: A total of 1698 subjects (577 men and 1121 women) from the Shanghai community were enrolled. All the subjects underwent NC measurement and biochemical measurements. LFC was calculated using the parameters from abdominal ultrasound images. Elevated NC was defined as NC ≥38.5 cm in men and NC ≥34.5 cm in women. RESULTS: Subjects with NAFLD based on the LFC measurement had higher values of NC, liver enzyme profiles, homoeostasis model assessment-insulin resistance index, and LFC than those without NAFLD (all P < 0.05), irrespective of sex. NC showed an upward trend with the increase of LFC in both men and women (both P < 0.05). An elevated NC could identify 55.22% of men and 50.29% of women with NAFLD based on quantitative ultrasonography. The positive correlation between NC and LFC remained significant even after adjustment for central obesity (both P < 0.05). After adjusting for confounding factors, the risk of NAFLD in subjects with an elevated NC was 1.52-fold higher in men (P=0.036) and 2.31-fold higher in women (P < 0.001). CONCLUSIONS: There was a significant and positive correlation between NC and LFC. The risk of NAFLD increased significantly in subjects with an elevated NC.

Diabetes Screening: Detection and Application of Saliva 1,5-Anhydroglucitol by Liquid Chromatography-Mass Spectrometry.

CONTEXT: Unlike other commonly used invasive blood glucose-monitoring methods, saliva detection prevents patients from suffering physical uneasiness. However, there are few studies on saliva 1,5-anhydroglucitol (1,5-AG) in patients with diabetes mellitus (DM). OBJECTIVE: This study aimed to evaluate the effectiveness of saliva 1,5-AG in diabetes screening in a Chinese population. DESIGN AND PARTICIPANTS: This was a population-based cross-sectional study. A total of 641 subjects without a valid diabetic history were recruited from September 2018 to June 2019. Saliva 1,5-AG was measured with liquid chromatography-mass spectrometry. MAIN OUTCOME MEASURES: DM was defined per American Diabetes Association criteria. The efficiency of saliva 1,5-AG for diabetes screening was analyzed by receiver operating characteristic curves, and the optimal cutoff point was determined according to the Youden index. RESULTS: Saliva 1,5-AG levels in subjects with DM were lower than those in subjects who did not have DM (both P < .05). Saliva 1,5-AG was positively correlated with serum 1,5-AG and negatively correlated with blood glucose and glycated hemoglobin (HbA1c) (all P < .05). The optimal cutoff points of saliva 1,5-AG0 and 1,5-AG120 for diabetes screening were 0.436 µg/mL (sensitivity: 63.58%, specificity: 60.61%) and 0.438 µg/mL (sensitivity: 62.25%, specificity: 60.41%), respectively. Fasting plasma glucose (FPG) combined with fasting saliva 1,5-AG reduced the proportion of people who required an oral glucose tolerance test by 47.22% compared with FPG alone. CONCLUSION: Saliva 1,5-AG combined with FPG or HbA1c improved the efficiency of diabetes screening. Saliva 1,5-AG is robust in nonfasting measurements and a noninvasive and convenient tool for diabetes screening.