Spatial dimensions of water quality value in New England river networks.

Households' willingness to pay (WTP) for water quality improvements-representing their economic value-depends on where improvements occur. Households often hold higher values for improvements close to their homes or iconic areas. Are there other areas where improvements might hold high value to individual households, do effects on WTP vary by type of improvement, and can these areas be identified even if they are not anticipated by researchers? To answer these questions, we integrated a water quality model and map-based, interactive choice experiment to estimate households' WTP for water quality improvements throughout a river network covering six New England states. The choice experiment was implemented using a push-to-web survey over a sample of New England households. Voting scenarios used to elicit WTP included interactive geographic information system (GIS) maps that illustrated three water quality measures at various zoom levels across the study domain. We captured data on how respondents maneuvered through these maps prior to answering the value-eliciting questions. Results show that WTP was influenced by regionwide quality improvements and improvements surrounding each respondent's home, as anticipated, but also by improvements in individualized locations identifiable via each respondent's map interactions. These spatial WTP variations only appear for low-quality rivers and are focused around particular areas of New England. The study shows that dynamic map interactions can convey salient information for WTP estimation and that predicting spatial WTP heterogeneity based primarily on home or iconic locations, as typically done, may overlook areas where water quality has high value.

Gastroesophageal reflux disease increases the risk of essential hypertension: results from the Nationwide Readmission Database and Mendelian randomization analysis.

BACKGROUND: The link between gastroesophageal reflux disease (GERD) and essential hypertension (EH) and its causal nature remains controversial. Our study examined the connection between GERD and the risk of hypertension and assessed further whether this correlation has a causal relationship. METHODS: First, we utilized the National Readmission Database including 14 422 183 participants to conduct an observational study. Dividing the population into GERD and non-GERD groups, we investigated the correlation between GERD and EH using multivariate logistic regression. Next, bidirectional two-sample Mendelian randomization was adopted. The summary statistics for GERD were obtained from a published genome-wide association study including 78 707 cases and 288 734 controls. We collected summary statistics for hypertension containing 70 651 cases and 223 663 controls from the FinnGen consortium. We assessed causality primarily by the inverse-variance weighted method with validation by four other Mendelian randomization approaches as well as an array of sensitivity analyses. RESULTS: In the unadjusted model, GERD patients had a higher risk of EH than the non-GERD group, regardless of gender (odds ratio, 1.43; 95% confidence interval: 1.42-1.43; P < .001). Further adjusting for critical confounders did not change this association. For Mendelian randomization, we found that genetically predicted GERD was causally linked to an enhanced risk of EH in inverse-variance weighted technique (odds ratio, 1.52; 95% confidence interval: 1.39-1.67; P = 3.51 × 10-18); conversely, EH did not raise the risk of GERD causally. CONCLUSIONS: GERD is a causal risk factor for EH. Further research is required to probe the mechanism underlying this causal connection.

Base-promoted cyclization reaction of o-isothiocyanato arylacetylenes and aroylacetonitriles: easy access to benzo[d][1,3]thiazines.

A green and efficient synthesis of benzo[d][1,3]thiazines through a base-promoted cyclization reaction of o-isothiocyanato arylacetylenes with aroylacetonitriles has been developed. This protocol features high step economy and efficiency, and tolerates various functional groups. The reaction was scalable and applied for the post-modification of drugs.

Ageing attenuates bone healing by mesenchymal stem cells in a microribbon hydrogel with a murine long bone critical-size defect model.

BACKGROUND: Despite the high incidence of fractures and pseudoarthrosis in the aged population, a potential role for the use of mesenchymal stem cells (MSCs) in the treatment of bone defects in elderly patients has not been elucidated. Inflammation and the innate immune system, including macrophages, play crucial roles in the differentiation and activation of MSCs. We have developed lentivirus-transduced interleukin 4 (IL4) over-expressing MSCs (IL4-MSCs) to polarize macrophages to an M2 phenotype to promote bone healing in an established young murine critical size bone defect model. In the current study, we explore the potential of IL4-MSCs in aged mice. METHODS: A 2 mm femoral diaphyseal bone defect was created and fixed with an external fixation device in 15- to 17-month-old male and female BALB/c mice. Microribbon (µRB) scaffolds (Sc) with or without encapsulation of MSCs were implanted in the defect sites. Accordingly, the mice were divided into three treatment groups: Sc-only, Sc + MSCs, and Sc + IL4-MSCs. Mice were euthanized six weeks after the surgery; subsequently, MicroCT (µCT), histochemical and immunohistochemical analyses were performed. RESULTS: µCT analysis revealed that bone formation was markedly enhanced in the IL4-MSC group. Compared with the Sc-only, the amount of new bone increased in the Sc + MSCs and Sc + IL4-MSC groups. However, no bridging of bone was observed in all groups. H&E staining showed fibrous tissue within the defect in all groups. Alkaline phosphatase (ALP) staining was increased in the Sc + IL4-MSC group. The Sc + IL4-MSCs group showed a decrease in the number of M1 macrophages and an increase in the number of M2 macrophages, with a significant increase in the M2/M1 ratio. DISCUSSION: IL4 promotes macrophage polarization to an M2 phenotype, facilitating osteogenesis and vasculogenesis. The addition of IL4-MSCs in the µRB scaffold polarized macrophages to an M2 phenotype and increased bone formation; however, complete bone bridging was not observed in any specimens. These results suggest that IL4-MSCs are insufficient to heal a critical size bone defect in aged mice, as opposed to younger animals. Additional therapeutic strategies are needed in this challenging clinical scenario.

Macrophages Modulate the Function of MSC- and iPSC-Derived Fibroblasts in the Presence of Polyethylene Particles.

Fibroblasts in the synovial membrane secrete molecules essential to forming the extracellular matrix (ECM) and supporting joint homeostasis. While evidence suggests that fibroblasts contribute to the response to joint injury, the outcomes appear to be patient-specific and dependent on interactions between resident immune cells, particularly macrophages (Mφs). On the other hand, the response of Mφs to injury depends on their functional phenotype. The goal of these studies was to further explore these issues in an in vitro 3D microtissue model that simulates a pathophysiological disease-specific microenvironment. Two sources of fibroblasts were used to assess patient-specific influences: mesenchymal stem cell (MSC)- and induced pluripotent stem cell (iPSC)-derived fibroblasts. These were co-cultured with either M1 or M2 Mφs, and the cultures were challenged with polyethylene particles coated with lipopolysaccharide (cPE) to model wear debris generated from total joint arthroplasties. Our results indicated that the fibroblast response to cPE was dependent on the source of the fibroblasts and the presence of M1 or M2 Mφs: the fibroblast response as measured by gene expression changes was amplified by the presence of M2 Mφs. These results demonstrate that the immune system modulates the function of fibroblasts; furthermore, different sources of differentiated fibroblasts may lead to divergent results. Overall, our research suggests that M2 Mφs may be a critical target for the clinical treatment of cPE induced fibrosis.

Newly identified peptide hormone inhibits intestinal fat absorption and improves NAFLD through its receptor GPRC6A.

BACKGROUND & AIMS: Circulating peptides and G protein-coupled receptors (GPCRs) have gained much attention because of their biofunctions in metabolic disorders including obesity and non-alcoholic fatty liver disease (NAFLD). Herein, we aimed to characterize the role and therapeutic potential of a newly identified peptide hormone in NAFLD. METHODS: Using bioinformatics, we identified a murine circulating pentadecapeptide flanked by potential convertase cleavage sites of osteocalcin (OCN), which we named 'metabolitin (MTL)'. We used ligand-receptor binding, receptor internalization, bioluminescence resonance energy transfer and Nano isothermal titration calorimetry assays to study the binding relationship between MTL and GPRC6A. For in vivo biological studies, wild-type mice kept on a high-fat diet (HFD) were injected or gavaged with MTL to study its function in NAFLD. RESULTS: We confirmed that MTL binds to GPRC6A and OCN interacts with GPRC6A using in vitro biological studies. Both intraperitoneal and oral administration of MTL greatly improved NAFLD and insulin resistance in a mouse model. Interacting with GPRC6A expressed in intestines, MTL can significantly inhibit intestinal neurotensin secretion, which in turn inhibits triglyceride but not cholesterol gut absorption, mediated by the 5'AMP-activated protein kinase pathway. In addition, glucagon like peptide-1 secretion was induced by MTL treatment. CONCLUSIONS: Oral or intraperitoneal MTL significantly improves the symptoms of NAFLD by inhibiting lipid absorption and insulin resistance. MTL could be a potential therapeutic candidate for the treatment of NAFLD. LAY SUMMARY: A novel murine peptide hormone, herein named 'metabolitin', inhibits fatty acid absorption and improves systemic insulin resistance in a murine model of obesity and non-alcoholic fatty liver disease. Thus, metabolitin has therapeutic potential for the treatment of patients with non-alcoholic fatty liver disease.

Trained murine mesenchymal stem cells have anti-inflammatory effect on macrophages, but defective regulation on T-cell proliferation.

Mesenchymal stem cell (MSC)-mediated immunomodulation affects both innate and adaptive immune systems. These responses to environmental cues, such as pathogen-associated molecular patterns, damage-associated molecular patterns, or proinflammatory cytokines, are crucial for resolution of inflammation, as well as successful tissue healing and regeneration. We observed that intermittent, repeated exposure of MSCs to LPS induced stronger NF-κB activation than singular stimulation. A similar phenomenon, named innate immune memory or trained immunity, has been reported with macrophages. However, the potential regulation of "immune memory" in nonclassic immune cells, such as MSCs, has not been reported. In the current study, we chose IFN-γ plus TNF-α restimulation-induced iNOS expression as a model of MSC activation, because IFN-γ and TNF-α play crucial roles in MSC-mediated immunomodulation. The iNOS expression was enhanced in LPS-trained MSCs, 3 d after a washout period following primary stimulation. LPS-trained MSCs enhanced the anti-inflammatory (arginase 1 and CD206) marker expression, but decreased the proinflammatory marker (TNF-α, IL-1ß, iNOS, and IL-6) expression using an MSC-macrophage coculture model. In contrast, LPS-trained MSCs demonstrated a defective regulation on CD4 T-cell proliferation. Mechanistic studies suggested that histone methylation and the JNK pathway are involved in LPS-trained immunomodulation in MSCs. Our results demonstrate differential immunomodulatory effects of trained MSCs on macrophages and T cells. These immunomodulatory consequences are critical, because they will have a major impact on current MSC-based cell therapies.-Lin, T., Pajarinen, J., Kohno, Y., Huang, J.-F., Maruyama, M., Romero-Lopez, M., Nathan, K., Yao, Z., Goodman, S. B. Trained murine mesenchymal stem cells have anti-inflammatory effect on macrophages, but defective regulation on T-cell proliferation.

Regulation of C-reactive protein conformation in inflammation.

C-reactive protein (CRP) is a non-specific diagnostic marker of inflammation and an evolutionarily conserved protein with roles in innate immune signaling. Natural CRP is composed of five identical globular subunits that form a pentamer, but the role of pentameric CRP (pCRP) during inflammatory pathogenesis remains controversial. Emerging evidence suggests that pCRP can be dissociated into monomeric CRP (mCRP) that has major roles in host defenses and inflammation. Here, we discuss our current knowledge of the dissociation mechanisms of pCRP and summarize the stepwise conformational transition model to mCRP to elucidate how CRP dissociation contributes to proinflammatory activity. These discussions will evoke new understanding of this ancient protein.

Ablation of prolactin receptor increases hepatic triglyceride accumulation.

Increasing prevalence of non-alcoholic fatty liver disease (NAFLD) worldwide has necessitated a more thorough understanding of it and expanded the scope of research in this field. Women are more resistant to NAFLD than men despite equal exposure to major risk factors, such as obesity or hyperlipidemia. Female resistance is hormone-dependent, as evidenced by the sharp increase in NAFLD incidence in post-menopausal women who do not take hormone replacement therapy. Here, we found that the estrogen-responsive pituitary hormone prolactin (PRL), through specific PRL receptor (PRLR), down-regulates hepatic triglyceride (TG) accumulation. PRL was demonstrated to significantly down-regulate hepatic TG accumulation in female mice and protect male mice from liver steatosis induced by high-fat diet. Interestingly, Ad-shPRLR injected mice, whose hepatic PRLR abundance was effectively decreased at the protein levels, exhibited significantly aggravated liver steatosis. PRL could decrease the expression of stearoyl-coenzyme A desaturase 1 (SCD1), the rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids, in animal models and multiple hepatic cell lines. Following knockdown of PRLR, the changes to PRL-triggered SCD1 expression disappeared. Thus, PRL acted as a previously unrecognized master regulator of liver TG metabolism, indicating that modification of PRL via PRLR might serve as a potential therapeutic target for NAFLD.

Transplanted interleukin-4--secreting mesenchymal stromal cells show extended survival and increased bone mineral density in the murine femur.

BACKGROUND: Mesenchymal stromal cell (MSC)-based therapy has great potential to modulate chronic inflammation and enhance tissue regeneration. Crosstalk between MSC-lineage cells and polarized macrophages is critical for bone formation and remodeling in inflammatory bone diseases. However, the translational application of this interaction is limited by the short-term viability of MSCs after cell transplantation. METHODS: Three types of genetically modified (GM) MSCs were created: (1) luciferase-expressing reporter MSCs; (2) MSCs that secrete interleukin (IL)-4 either constitutively; and (3) MSCs that secrete IL-4 as a response to nuclear factor kappa-light-chain-enhancer of activated B cell (NFκB) activation. Cells were injected into the murine distal femoral bone marrow cavity. MSC viability and bone formation were examined in vivo. Cytokine secretion was determined in a femoral explant organ culture model. RESULTS: The reporter MSCs survived up to 4 weeks post-implantation. No difference in the number of viable cells was found between high (2.5 × 106) and low (0.5 × 106) cell-injected groups. Injection of 2.5 × 106 reporter MSCs increased local bone mineral density at 4 weeks post-implantation. Injection of 0.5 × 106 constitutive IL-4 or NFκB-sensing IL-4-secreting MSCs increased bone mineral density at 2 weeks post-implantation. In the femoral explant organ culture model, LPS treatment induced IL-4 secretion in the NFκB-sensing IL-4-secreting MSC group and IL-10 secretion in all the femur samples. No significant differences in tumor necrosis factor (TNF)α and IL-1ß secretion were observed between the MSC-transplanted and control groups in the explant culture. DISCUSSION: Transplanted GM MSCs demonstrated prolonged cell viability when transplanted to a compatible niche within the bone marrow cavity. GM IL-4-secreting MSCs may have great potential to enhance bone regeneration in disorders associated with chronic inflammation.

Long non-coding RNA expression profiles in different severity EV71-infected hand foot and mouth disease patients.

Enterovirus 71 (EV71) is associated with the severe hand foot and mouth disease (HFMD) outcomes, however the host-virus interaction mechanism and the pathogenesis remain poorly understood. Long non-coding RNAs (lncRNAs) are involved in variety physiological and pathological processes, but the functions of lncRNAs in EV71 infection remain elusive. Here we profiled the expression of lncRNAs in peripheral blood mononuclear cells (PBMCs) from EV71-infected mild patients, severe patients as well as the healthy controls, and identified 8541 lncRNAs were differentially expressed. Focused on the dynamic changed lncRNAs, we performed systematic bioinformatics analysis with Series Test of Cluster (STC) algorithm, Gene Ontology (GO) analysis, pathway analysis and lncRNA-mRNA co-expression network analysis, and revealed the potential functions and related pathways of these lncRNAs were associated with immunity and inflammation during the clinical process of EV71-infected HFMD. Among the significant dynamic changed lncRNAs, ten lncRNAs were screened whose expression were further validated in EV71-infected mild patients, severe patients and healthy control. These results shed light on the potential roles of lncRNAs in EV71-infected HFMD, especially in distinguishing the mild and severe cases for early diagnose and treatment, moreover, provide deeper insight into the mechanism of EV71-induced immune and inflammatory responses, as well as the pathogenesis of the imbalanced inflammation in severe EV71 infection.

Establishment of NF-κB sensing and interleukin-4 secreting mesenchymal stromal cells as an "on-demand" drug delivery system to modulate inflammation.

Chronic inflammation is associated with up-regulation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and excessive inflammatory cytokine secretion by M1 macrophages. The anti-inflammatory cytokine interleukin (IL)-4 converts pro-inflammatory M1 macrophages into an anti-inflammatory and tissue-regenerative M2 phenotype, thus reducing inflammation and enhancing tissue regeneration. We have generated NF-κB responsive, or constitutively active IL-4 expression lentiviral vectors transduced into murine bone marrow-derived mesenchymal stromal cells (MSCs). MSCs with a constitutively active IL-4 expression vector produced large quantities of IL-4 continuously, whereas IL-4 secretion was significantly induced by lipopolysaccharide (LPS) in the NF-κB sensing MSCs. In contrast, LPS had no effect on MSCs with IL-4 secretion driven by a constitutively active promoter. We also found that intermittent and continuous LPS treatment displayed distinct NF-κB activation profiles, and this regulation was independent of IL-4 signaling. The supernatant containing IL-4 from the LPS-treated MSCs suppressed M1 marker (inducible nitric oxide synthase [iNOS] and tumor necrosis factor alpha [TNFα]) expression and enhanced M2 marker (Arginase 1, CD206 and IL1 receptor antagonist [IL1Ra]) expression in primary murine macrophages. The IL-4 secretion at the basal, non-LPS induced level was sufficient to suppress TNFα and enhance Arginase 1 at a lower level, but had no significant effects on iNOS, CD206 and IL1Ra expression. Finally, IL-4 secretion at basal or LPS-induced levels significantly suppressed osteogenic differentiation of MSCs. Our findings suggest that the IL-4 secreting MSCs driven by NF-κB sensing or constitutive active promoter have great potential for mitigating the effects of chronic inflammation and promoting earlier tissue regeneration.

High-efficiency, high-average-power, CW Yb:YAG zigzag slab master oscillator power amplifier at room temperature.

We demonstrate a high-efficiency, high-average-power, CW master oscillator power amplifier based on a conduction-cooled, end-pumped Yb:YAG slab architecture at room temperature (RT). Firstly, the CW amplification property is theoretically analyzed based on the kinetics model for Yb:YAG. To realize high-efficiency laser amplification extraction for RT Yb:YAG, not only intense pump but also a high-power seed laser is of great importance. Experimentally, a composite Yb:YAG crystal slab with three doped and two un-doped segments symmetrically is employed as the gain medium, which is end-pumped by two high-power, 940-nm diode lasers. A high-power, narrow-spectral-width, 1030-nm fiber seed laser then double passes the composite slab to realize efficient power amplification. For 0.8-kW seed input, maximum output power of 3.54 kW is obtained at 6.7 kW of pump power, with the optical conversion efficiency of 41% and the highest slope efficiency of 59%. To the best of our knowledge, this is the highest power and efficiency reported for Yb:YAG lasing at RT except thin-disk lasers.

Death domain-associated protein 6 (Daxx) selectively represses IL-6 transcription through histone deacetylase 1 (HDAC1)-mediated histone deacetylation in macrophages.

As a multifunctional nuclear protein, death domain-associated protein 6 (Daxx) regulates a wide range of biological processes, including cell apoptosis and gene transcription. However, the function of Daxx in innate immunity remains unclear. In our study, we show that Daxx is highly expressed in macrophages and localized in nucleus of macrophages. The expression of Daxx is significantly up-regulated by stimulation with TLR ligands LPS and poly(I:C). Silence of Daxx selectively represses IL-6 expression at transcription level in LPS-activated macrophages. Upon stimulation of LPS, Daxx specifically binds to the promoter of IL-6 and inhibits histone acetylation at IL-6 promoter region. Further mechanism analyses show that histone deacetylase 1 (HDAC1) interacts with Daxx and binds to the promoter of IL-6. Daxx silencing decreases the association of HDAC1 to IL-6 promoter. Therefore, our data reveal that Daxx selectively represses IL-6 transcription through HDAC1-mediated histone deacetylation in LPS-induced macrophages, acting as a negative regulator of IL-6 during innate immunity and potentially preventing inflammatory response because of overproduction of IL-6.

Zinc finger protein 64 promotes Toll-like receptor-triggered proinflammatory and type I interferon production in macrophages by enhancing p65 subunit activation.

The molecular mechanisms that fine-tune the Toll-like receptor (TLR)-triggered innate immune response need further investigation. As an important transcription factor, zinc finger proteins (ZFPs) play important roles in many cell functions, including development, differentiation, tumorigenesis, and functions of the immune system. However, the role of ZFP members in the innate immune responses remains unclear. Here we showed that the expression of C2H2-type ZFP, ZFP64, was significantly up-regulated in macrophages upon stimulation with TLR ligands, including LPS, CpG oligodeoxynucleotides, or poly(I:C). ZFP64 overexpression promoted TLR-triggered TNF-α, IL-6, and IFN-ß production in macrophages. Coincidently, knockdown of ZFP64 expression significantly inhibited the production of the above cytokines. However, activation of MAPK and IRF3 was not responsible for the ZFP64-mediated promotion of cytokine production. Interestingly, ZFP64 significantly up-regulated TLR-induced NF-κB activation. ZFP64 could bind to the promoter of the TNF-α, IL-6, and IFN-ß genes in macrophages only after TLR ligation. Furthermore, ZFP64 associated with the NF-κB p65 subunit upon LPS stimulation, and TLR-ligated macrophages showed a lower level of p65 recruitment to the TNF-α, IL-6, and IFN-ß gene promoter in the absence of ZFP64. The data identify ZFP64 as a downstream positive regulator of TLR-initiated innate immune responses by associating with the NF-κB p65 subunit, enhancing p65 recruitment to the target gene promoters and increasing p65 activation and, thus, leading to the promotion of TLR-triggered proinflammatory cytokine and type I interferon production. Our findings add mechanistic insight into the efficient activation of the TLR innate response against invading pathogens.

Synthesis and biological evaluation of novel C6-amino substituted 4-azasteroidal purine nucleoside analogues.

Novel C6-amino substituted purine nucleoside analogues (2-12) bearing a modified pyranose-like D ring of the 4-azasteroid moiety were efficiently synthesized through nucleophilic substitution at C6 position of the steroidal nucleoside precursors (1a, b) with versatile amines. All the synthesized new compounds were evaluated for their anticancer activity in vitro against Hela, PC-3 and MCF-7 cell lines. Among them, compounds 4b, 7b and 9b exhibited significant cytotoxicity with the IC50 values of 2.99 µM (PC-3), 2.84 µM, (PC-3) and 2.69 µM (Hela), respectively.

Role of spinal GABAA receptor reduction induced by stress in rat thermal hyperalgesia.

The mechanisms underlying stress-induced hyperalgesia (SIH) remain poorly understood. Recent findings have provided strong evidence indicating that SIH could be related, at least in part, to alterations in spinal cord GABA activity. In the present study, we first investigated how acute restraint stress impacted pain responses as assessed using the tail flick immersion test. These results showed that rats developed hyperalgesia at 6 h after being subjected to 1-h acute restraint stress. Second, we measured the activation of spinal neurons and alterations in expression of GABAA receptor ß2 and ß3 subunits as related to stress-induced hyperalgesia. Results from Western blot and immunofluorescence assays showed that c-fos protein increased in the dorsal horn of the lumbar spinal cord and GABAA receptor ß2 and ß3 subunit proteins decreased significantly at 6 h after exposure to 1 h of acute restraint stress. Finally, the effects of spinal GABAA receptor alteration on SIH were evaluated. These results showed that intrathecal administration of muscimol inhibited hyperalgesia induced by stress while bicuculline enhanced hyperalgesia in the control groups. Taken together, the present data reveal that GABAA receptor ß2 and ß3 decrease following 1 h of acute restraint stress and may play a critical role in SIH.

Association of serum calcium and metabolically healthy obese in US adults: a cross-sectional study.

OBJECTIVES: The relationship between serum calcium and occurrence of MHO (metabolically healthy obesity) and MUNO (metabolically unhealthy non-obesity) remains unclear, and distinguishing these two phenotypes is difficult within primary healthcare units. This study explores that relationship. METHODS: This survey included 28590 adults from the National Health and Nutrition Examination Survey (NHANES) 2001-2018. Obesity phenotypes were categorized based on BMI and presence or absence of metabolic syndrome components. Weighted multivariate logistic regression analyses were used to assess the association between serum calcium levels and the obesity phenotype. Restricted cubic spline analysis characterized dose-response relationships, and stratified analyses explored these relationships across sociodemographic and lifestyle factors. RESULTS: The overall prevalence of MHO and MUNO were 2.6% and 46.6%, respectively. After adjusting for covariates, serum calcium exhibited a negative association with MHO [OR (95%): 0.49 (0.36,0.67), p < 0.001], while exhibiting a positive association with MUNO [OR (95%): 1.48 (1.26,1.84), p < 0.001]. Additionally, we found a non-linear association between serum calcium levels and the incidences of MHO and MUNO. Stratified analyses demonstrated a strong negative correlation between serum calcium levels and MHO occurrence across various subgroups. There was no significant interaction between calcium and stratified variables except sex; the association between calcium and the occurrence of MHO was remarkable in female patients. Meanwhile, the predictive ability of serum calcium level for the occurrence of MUNO among all patients was consistent across various subgroups. There was a significant interaction between calcium level and stratified variables based on age, sex, race, and smoking status; the association was remarkable in older (≥ 40 years old), white, none or less smoking, and female patients. CONCLUSIONS: A significant correlation was identified between serum calcium levels and MHO or MUNO. The findings suggest that serum calcium levels may serve as an indicator for more accurate assessment and diagnosis of MUNO and MHO, especially among individuals with abdominal obesity.

Serum calcium levels exhibited an inverse relationship with metabolically healthy obesity (MHO) and a positive relationship with metabolically unhealthy non-obese (MUNO).A nonlinear association exists between serum calcium levels and the incidence of both MHO and MUNO.Serum calcium has the potential to enhance evaluation and screening for MUNO or MHO in the general US adult population.