The relationship between circulating neutrophil gelatinase-associated lipocalin and early alteration of metabolic parameters is associated with dietary saturated fat intake in non-diabetic Korean women

Evaluation Between Serum Concentrations of Lipocalin-2 and Metabolic Syndrome and its Components in Korean-Chinese and Han-Chinese Individuals from Yanbian Area

Objectives: To investigate the association between the blood concentration of lipocalin-2 (LCN2) in local multiethnic residents and the increased risk for the development of metabolic syndrome (MS) in the Yanbian Korean Autonomous Prefecture population. Methods: A total of 2078 subjects with (study group) or without (control group) MS (1217 Korean-Chinese and 861 Han-Chinese subjects) were included in this study. MS subjects were divided into five groups according to ethnicity and MS components. They were assessed for smoking history, drinking history, past medical history, general demographic characteristics, and LCN2 concentrations. Results: LCN2 concentrations were higher in all ethnic MS groups than in the control group, and the highest concentrations were detected in Han-Chinese subjects with dyslipidemia. Moreover, LCN2 concentrations were significantly higher in Korean-Chinese individuals with all MS components than in the control group. Logistic regression analyses were conducted. In the unadjusted models, Korean-Chinese and Han-Chinese individuals with high LCN2 concentrations both faced a risk of MS with odds ratios (ORs) of 2.339 (95% confidence interval [CI]: 1.632-3.352) and 1.523 (95% CI: 1.101-2. 108), respectively. After the adjustment, the risk only remained in Korean-Chinese individuals, with an OR of 1.818 (95% CI: 1.031-3.207). Conclusion: Elevated circulating LCN2 was associated with the increased incidence of MS, and the effect in Korean-Chinese individuals was stronger than that in Han-Chinese individuals.

Neutrophil gelatinase-associated lipocalin (NGAL) and inflammatory markers in schizophrenia: A comparative analysis of drug-naive schizophrenia patients, remitted patients, and healthy controls

This study aims to examine the plasma concentrations of NGAL and other inflammatory parameters, including TNF-α, IL-1β, and IFN-γ, in schizophrenia patients and healthy volunteers. It also investigates potential associations between these biomarkers and symptom severity in schizophrenia and the utility of NGAL as a potential diagnostic and monitoring biomarker for schizophrenia. The study included 49 drug-naive schizophrenia patients (DNS), 59 patients with schizophrenia in remission (REM) on antipsychotic treatment, and 58 healthy volunteers (HC). The Positive and Negative Symptoms Evaluation Scale (PANSS) was utilized to assess the severity of symptoms in schizophrenia patients. Plasma levels of TNF-α, IL-1β, IFN-γ, and NGAL were measured for all participants. NGAL levels were significantly lower in the DNS group than in HC. Significantly lower TNF-α levels were observed in both the DNS and REM groups compared to the HC group. Notably, a statistically significant positive correlation was detected between TNF-α and NGAL levels. The findings of this study are noteworthy, as they demonstrate that drug-naive individuals with schizophrenia exhibit significantly diminished levels of NGAL and TNF-α compared to healthy controls. These identified biomarkers hold promise for providing valuable insights into the complex and evolving pathophysiology of schizophrenia.

The Effect of a Comprehensive Life-Style Intervention Program of Diet and Exercise on Four Bone-Derived Proteins, FGF-23, Osteopontin, NGAL and Sclerostin, in Overweight or Obese Children and Adolescents

The adipose and bone tissues demonstrate considerable interconnected endocrine function. In the present study, we determined the concentrations of fibroblast growth factor-23 (FGF-23), osteopontin, neutrophil gelatinase-associated lipocalin (NGAL) and sclerostin in 345 children and adolescents who were overweight or obese (mean age ± SD mean: 10.36 ± 0.16 years; 172 males, 173 females; 181 prepubertal; and 164 pubertal) before and after their participation in a comprehensive life-style intervention program of diet and exercise for one year. Following the one-year life-style interventions, there was a significant decrease in BMI (p < 0.01), FGF-23 (p < 0.05), osteopontin (p < 0.01) and NGAL (p < 0.01), and an increase in sclerostin (p < 0.01) concentrations. BMI z-score (b = 0.242, p < 0.05) and fat mass (b = 0.431, p < 0.05) were the best positive predictors and waist-to-height ratio (WHtR) (b = −0.344, p < 0.05) was the best negative predictor of the change of osteopontin. NGAL concentrations correlated positively with HbA1C (b = 0.326, p < 0.05), WHtR (b = 0.439, p < 0.05) and HOMA-IR (b = 0.401, p < 0.05), while BMI (b = 0.264, p < 0.05), fat mass (b = 1.207, p < 0.05), HDL (b = 0.359, p < 0.05) and waist circumference (b = 0.263, p < 0.05) were the best positive predictors of NGAL. These results indicate that FGF-23, osteopontin, NGAL and sclerostin are associated with being overweight or obese and are altered in relation to alterations in BMI. They also indicate a crosstalk between adipose tissue and bone tissue and may play a role as potential biomarkers of glucose metabolism. Further studies are required to delineate the physiological mechanisms underlying this association in children and adolescents.

Short-term Effects of Eating Behavior Modification on Metabolic Syndrome-Related Risks in Overweight and Obese Korean Adults

Background

We investigated whether eating behavior modification improves metabolic syndrome (MetS)-related risks in overweight/obese Korean adults, and identified dietary factors that improve metabolic status.

Methods

Among 159 volunteers, 71 with a body mass index ≥23 kg/m² and without other chronic diseases participated in the 8-week intervention, among which 54 participants who completed the intervention were included in the analyses. At baseline, patients were categorized either metabolically healthy obese (MHO; <3 MetS risk factors, n=42) or metabolically unhealthy obese (MUHO; ≥3 MetS risk factors, n=12), and then educated regarding how to choose healthy foods and meals.

Results

Lipid profiles and anthropometric and glycemic parameters were significantly improved among all participants after the intervention. Changes in waist circumference (P=0.025), and glycemic parameters (glucose, P=0.046, insulin, P=0.005, C-peptide, P=0.041) were positively correlated with changes in calorie intake from snacks. Changes in visceral fat area were negatively correlated with changes in total calorie intake (P=0.046), and positively correlated with those in calorie intake from dietary fats (P=0.039). In addition, changes in insulin (P=0.013) and C-peptide (P=0.008) concentrations were negatively correlated with changes in dietary fiber intake at dinner. After the intervention, 83.3% of initially MUHO participants became MHO and 16.7% of MHO participants became MUHO.

Conclusion

Eating behavior modification may be an important strategy to improve metabolic factors in overweight/obese people.

Increased lipocalin 2 levels in adolescents with type 2 diabetes mellitus

OBJECTIVES

Bone can act as an endocrine organ through the secretion of bone-specific hormones, i.e., osteokines. Recent research has demonstrated that lipocalin 2 (LCN2) secreted by osteoblasts are part of an important endocrine system that is finely tuned with other organs to ensure homeostatic balance and health. The aim of this study was to explore the association between bone and glucose metabolism in adolescents with obesity and type 2 diabetes mellitus (DM2).

METHODS

The participants were 8 adolescents with DM2 (5 males, 3 females; age: 17.0 (14.0-20.0) years, median (interquartile range)), 14 adolescents with simple obesity (9 males, 5 females; age: 13.5 (12.4-15.5) years), and 15 controls (6 males, 9 females; age: 13.3 (11.0-15.0) years). Serum LCN2 and under-carboxylated osteocalcin (un-OC) levels were measured using enzyme-linked immunosorbent assays.

RESULTS

The LCN2 levels were higher in patients with DM2 (58.1 (34.2-95.0) ng/mL; median (interquartile range)), but not in those with obesity (30.8 (23.1-38.3) ng/mL), when compared to the controls (18.2 (9.8-25.7) ng/mL). In the whole study group overall, serum LCN2 was positively correlated with the Model Assessment of Insulin Resistance score (r=0.339, p=0.046) and body mass index (r=0.580, p<0.0001), and negatively correlated with adiponectin (r=-0.462, p=0.005). A multiple stepwise regression model showed that serum adiponectin was an independent predictor of serum LCN2.

CONCLUSIONS

The results of this study indicate that further investigations are warranted to determine whether LCN2 may act as a sensitive indicator of early-stage insulin resistance.

Effect of Breakfast Consumption and Meal Time Regularity on Nutrient Intake and Cardiometabolic Health in Korean Adults

Objective

Dietary factors are important contributors to obesity and related metabolic disorders. Few studies have evaluated the impact of dietary habits (e.g., breakfast consumption frequency and meal regularity) on metabolic health. We investigated the effects of breakfast consumption frequency and meal time regularity on nutrient intake and cardiometabolic status in Korean adults.

Methods

Participants without diagnosed diseases (n=217) were examined for anthropometric and biochemical parameters, lifestyle, dietary habits, and nutrient intake. They were categorized into 4 groups by breakfast consumption frequency (≥6 or <6 times/week) and meal time regularity (regular or irregular): breakfast ≥6 times/week and regular eating (HBRE), breakfast ≥6 times/week and irregular eating (HBIE), breakfast <6 times/week and regular eating (LBRE) and breakfast <6 times/week and irregular eating (LBIE).

Results

Participants in the LBIE group were the youngest, had higher waist circumference, body mass index, triglyceride levels, and inflammation, and consumed the highest daily total caloric intake (TCI), the highest proportion of fats, and the lowest proportion of carbohydrates. The LBIE group also had the lowest proportion of energy intake at breakfast and the highest proportion at dinner. The LBIE group consumed the lowest amounts of fiber, beta-carotene, vitamin K, folate, calcium and iron, and had the highest prevalence of inadequate nutrient intake for TCI, protein, vitamins A, C, B6, and B12, folate, calcium, iron, zinc, and copper.

Conclusion

Regular breakfast consumption and meal times are related to healthy lifestyle habits and adequate nutrient intake, which affect metabolic health, thereby helping prevent obesity and related metabolic disorders.

The gonadal expression pattern of lipocalin‑2 and 24p3 receptor is modified in the gonads of the offspring of obese rats

Obesity represents a global health and economic burden, affecting millions of individuals worldwide. This pathology is associated with a chronic low-grade inflammatory state that is partially responsible for the development of other cardiometabolic complications. Clinical studies have reported an association between high circulating levels of lipocalin-2 (Lcn2) and increased body weight. Additionally, there is scientific evidence demonstrating the impact of maternal obesity on fetal programming. The latter and the fact that the authors previously found that Lcn2 and its receptor (24p3R) are expressed in the gonads of wild-type rats, led to the analysis of their mRNA profile and cellular localization in gonads collected from the offspring of obese rats at 21 days postconception (dpc), and 0, 2, 4, 6, 12, 20 and 30 days postnatal (dpn) in the present study. Semi-quantitative PCR revealed a statistically significant downregulation of Lcn2 and 24p3R mRNA at 21 dpc in the ovaries (P<0.01) and testicles (P<0.001) of the offspring of obese mothers. At 30 dpn, the relative expression of Lcn2 mRNA decreased significantly in the ovaries of the experimental group (P<0.05), while Lcn2 mRNA expression was not detectable in testicles. Regarding 24p3R, its mRNA was only significantly decreased at 21 dpc in ovaries of pups of obese mothers. At 30 dpn, the change in females was not significant. Conversely, in testicles, 24p3R mRNA levels increased slightly in the experimental group at 30 dpn. The Lcn2 protein signal was less intense in gonadal tissue sections from 30 dpn offspring of obese rats (P<0.001), whereas the 24p3R signal was downregulated in ovaries (P<0.001) and slightly upregulated in testicles. It was concluded that maternal obesity changes the expression of Lcn2 and 24p3R in the gonads of the offspring of obese rats, possibly through fetal programming. The consequences of this dysregulation for the offspring's gonadal function remains to be determined.

Serum Levels and Placental Expression of NGAL in Gestational Diabetes Mellitus

OBJECTIVES

The aim was to investigate neutrophil gelatinase-associated lipocalin (NGAL) levels in the serum and term placentas and its potential role in gestational diabetes mellitus (GDM).

METHODS

A total of 49 GDM subjects and 39 age-matched women with normal pregnancies were recruited. We examined serum concentrations of NGAL and tumor necrosis factor-α (TNF-α) in maternal blood and cord blood and their expression levels in the term placentas and umbilical cord.

RESULTS

Serum NGAL levels were significantly higher in GDM patients than in normal pregnant controls both in the maternal blood (4.80 ± 1.99 vs. 3.66 ± 1.13, P=0.001) and the cord blood (4.70 ± 2.08 vs. 3.85 ± 1.44, P=0.027). Moreover, serum NGAL levels exhibited a positive correlation with various parameters of insulin resistance. Maternal serum NGAL levels positively correlated with the NGAL levels found in the cord blood of the control (r = 0.399, P=0.012) and the GDM subjects (r = 0.349, P=0.014). Finally, the expression of NGAL protein levels in the placenta (1.22 ± 0.39 vs. 0.65 ± 0.23, P < 0.001) and umbilical cord (0.65 ± 0.23 vs. 0.25 ± 0.10, P < 0.001) were higher in GDM women than those noted in the control subjects. In the GDM group, maternal serum NGAL levels exhibited a positive correlation with placental NGAL mRNA and protein levels (r = 0.848, P=0.008; r = 0.636, P=0.011, respectively).

CONCLUSIONS

NGAL may be an important adipokine involved in GDM and fetal development. The oversecretion of NGAL from the placenta may contribute to the elevated levels of serum NGAL in gestational diabetes mellitus.

The role of osteoblasts in energy homeostasis

Osteoblasts are specialized mesenchymal cells that synthesize bone matrix and coordinate the mineralization of the skeleton. These cells work in harmony with osteoclasts, which resorb bone, in a continuous cycle that occurs throughout life. The unique function of osteoblasts requires substantial amounts of energy production, particularly during states of new bone formation and remodelling. Over the last 15 years, studies have shown that osteoblasts secrete endocrine factors that integrate the metabolic requirements of bone formation with global energy balance through the regulation of insulin production, feeding behaviour and adipose tissue metabolism. In this article, we summarize the current understanding of three osteoblast-derived metabolic hormones (osteocalcin, lipocalin and sclerostin) and the clinical evidence that suggests the relevance of these pathways in humans, while also discussing the necessity of specific energy substrates (glucose, fatty acids and amino acids) to fuel bone formation and promote osteoblast differentiation.

Perinatal lipocalin-2 profile at the extremes of fetal growth

BACKGROUND

Lipocalin-2 (LCN-2) has been identified as an osteoblast-secreted hormone regulating immunity, inflammation and metabolic homeostasis and has emerged as a diagnostic and prognostic biomarker for acute kidney injury in neonates. We investigated the impact of fetal growth on antepartum maternal serum, cord serum and breast milk LCN-2 concentrations and the associations of the latter with perinatal parameters.

METHODS

Maternal serum, cord serum and breast milk LCN-2 concentrations were measured by ELISA in samples from 80 mothers who delivered 40 appropriate (AGA), 20 large for gestational age (LGA) and 20 intrauterine growth restricted (IUGR) neonates, classified by customized weight centiles. LCN-2 concentrations were associated with birth weight, customized centile, gender, maternal age and delivery mode.

RESULTS

Antepartum maternal serum LCN-2 concentrations were significantly higher in women delivering AGA infants compared to the other two groups. Cord blood LCN-2 concentrations were significantly higher compared to maternal ones; furthermore, they were significantly elevated in the IUGR group compared to the LGA one (p = .019). Lowest concentrations were detected in breast milk, which did not differ between the three growth groups. A negative correlation was documented between cord blood LCN-2 concentrations and customized centiles (r: -0.304, p = .007).

CONCLUSIONS

The higher cord serum LCN-2 concentrations, compared to maternal ones, may point to its fetal origin and potential role in intrauterine growth. The negative correlation of cord LCN-2 concentrations with customized centiles, possibly implies reduced nephron endowment/subclinical kidney damage in IUGR neonates. The extremely low LCN-2 breast milk concentrations could imply that the secretion of LCN-2 from maternal circulation to breast milk is not influenced by factors leading to intrauterine growth pathology.

Correlations between serum concentration of three bone-derived factors and obesity and visceral fat accumulation in a cohort of middle aged men and women

BACKGROUND

The aim of this study was to investigate the interrelationships between three bone-derived factors [serum osteocalcin (OCN), fibroblast growth factor (FGF) 23, and neutrophil gelatinase-associated lipocalin (NGAL) levels] and body fat content and distribution, in order to reveal the potential endocrine function of bone in the development of obesity.

METHODS

We recruited 1179 people (aged 59.5 ± 6.2 years) from communities in Shanghai. Serum OCN levels were determined using an electrochemiluminescence immunoassay. Serum FGF23 and NGAL levels were determined using a sandwich enzyme-linked immunosorbent assay. The abdominal fat distribution, including visceral fat area (VFA), was assessed by magnetic resonance imaging. Visceral obesity was defined as a VFA ≥ 80 cm².

RESULTS

Serum OCN levels were inversely correlated with body fat parameters, while FGF23 and NGAL were positively correlated (P < 0.05). After adjusting for confounders, waist circumference (W) and VFA had a closer relationship with serum OCN, FGF23, and NGAL levels than body mass index (BMI) and body fat percentage (fat%, all P < 0.05). The risk of visceral obesity significantly increased with higher FGF23 and/or NGAL levels, as well as with reduced OCN levels (all P < 0.05). In addition, serum OCN, FGF23, and NGAL levels were independently associated with visceral obesity (all P < 0.01). The relationships persisted among subjects with normal glucose tolerance or subjects with hyperglycaemia (both P < 0.05).

CONCLUSIONS

Compared to the indicators of overall adiposity such as BMI or fat%, visceral adiposity indicators (W or VFA) were more closely related to serum OCN, FGF23 and NGAL levels. There was no interaction among the relationship of three bone-derived factors with visceral obesity, which revealed the independent relationship of endocrine function of skeleton with body fat.

Impact of Blood or Erythrocyte Membrane Fatty Acids for Disease Risk Prediction: Focusing on Cardiovascular Disease and Chronic Kidney Disease

Fatty acids (FAs) are essential nutrients and main constituents of cell membranes that are involved in the signaling pathway and associated with health conditions. We investigated if blood or erythrocyte membrane FAs can predict the risk of cardiovascular disease (CVD), chronic kidney disease (CKD), and related complications. Omega-3 (n-3) FAs are important predictors for metabolic syndrome, diabetes, CVD, and CKD risks, and the n-3 index is also a good biomarker for sudden cardiac death in coronary artery disease. Linoleic acid, which is one of the major n-6 FAs reflecting recent dietary FA intake, may predict CVD risk and mortality in the general population and patients with CKD. Monounsaturated FAs (MUFAs) are also related to diabetes or diabetic nephropathy. Oleic acid, a major MUFA, is an emerging marker that is related to acute coronary syndrome, low glomerular filtration rate, and vascular calcification in patients with CKD, and can be modified by n-3 FA supplementation. Saturated FAs, trans-FAs, and FA desaturation/elongation are associated with CVD risk; however, few studies have been conducted on patients with CKD. In summary, blood or erythrocyte membrane FA measurements are important for CVD and CKD risk prediction and management. Further studies are needed to elucidate the FAs for their risk predictions.

Perspectives in Lipocalin-2: Emerging Biomarker for Medical Diagnosis and Prognosis for Alzheimer's Disease

Lipocalin-2 (LCN2), a secreted glycoprotein belonging to the lipocalin superfamily was reported to participate in various biological processes including cell migration, cell survival, inflammatory responses, and insulin sensitivity. LCN2 is expressed in the multiple tissues such as kidney, liver, uterus, and bone marrow. The receptors for LCN2 were additionally found in microglia, astrocytes, epithelial cells, and neurons, but the role of LCN2 in the central nervous system (CNS) has not been fully understood yet. Recently, in vitro, in vivo, and clinical studies reported the association between LCN2 and the risk of Alzheimer's disease (AD). Here, we reviewed the significant evidences showing that LCN2 contributes to the onset and progression of AD. It may suggest that the manipulation of LCN2 in the CNS would be a crucial target for regulation of the pathogenesis and risk of AD.