Serum CXC ligand 5 is a new marker of subclinical atherosclerosis in type 2 diabetes

Longitudinal Study Reveals Long-Term Proinflammatory Proteomic Signature After Ischemic Stroke Across Subtypes

Inflammation contributes both to the pathogenesis of stroke and the response to brain injury. We aimed to identify proteins reflecting the acute-phase response and proteins more likely to reflect proinflammatory processes present before stroke by broadly profiling inflammation-related plasma proteins in a longitudinal ischemic stroke study.

CXCL5 secreted from macrophages during cold exposure mediates white adipose tissue browning

Adipose tissue affects metabolic-related diseases because it consists of various cell types involved in fat metabolism and adipokine release. CXC ligand 5 (CXCL5) is a member of the CXC chemokine family and is highly expressed by macrophages in white adipose tissue (WAT). In this study, we generated and investigated the function of CXCL5 in knockout (KO) mice using CRISPR/Cas9. The male KO mice did not show significant phenotype differences in normal conditions. However, proteomic analysis revealed that many proteins involved in fatty acid beta-oxidation and mitochondrial localization were enriched in the inguinal WAT (iWAT) of Cxcl5 KO mice. Cxcl5 KO mice also showed decreased protein and transcript expression of genes associated with thermogenesis, including uncoupling protein 1 (UCP1), a well-known thermogenic gene, and increased expression of genes associated with inflammation. The increase in UCP1 expression in cold conditions was significantly retarded in Cxcl5 KO mice. Finally, we found that CXCL5 treatment increased the expression of transcription factors that mediate Ucp1 expression and Ucp1 itself. Collectively, our data show that Ucp1 expression is induced in adipocytes by CXCL5, which is secreted upon β-adrenergic stimulation by cold stimulation in M1 macrophages. Our data indicate that CXCL5 plays a crucial role in regulating energy metabolism, particularly upon cold exposure. These results strongly suggest that targeting CXCL5 could be a potential therapeutic strategy for people suffering from disorders affecting energy metabolism.

Association of metabolic syndrome with inflammatory markers in a sample of community-dwelling older adults

The study aimed to identify the cutoff points for inflammatory markers that best discriminate the occurrence of metabolic syndrome in community-dwelling older adults. Baseline data were used from the elderly cohort in the city of Bambuí, Minas Gerais State, Brazil. The target exposure was presence of metabolic syndrome, defined according to the Adult Treatment Panel III criterion, and the outcomes included the following inflammatory markers: cytokines (IL-1β, IL-6, IL-10, IL-12 e TNF), chemokines (CXCL8, CXCL9, CCL2, CXCL10, and CCL5), and C-reactive protein (CRP). Definition of the cutoff points for the inflammatory markers was based on the Classification and Regression Tree (CART) method. The associations between these markers and metabolic syndrome were estimated by logistic regression models, obtaining odds ratios and 95% confidence intervals, considering adjustment for confounding factors. Prevalence of metabolic syndrome was 49.1%, and IL-1β, IL-12, and TNF levels were not associated statistically with this exposure. After adjustment, presence of metabolic syndrome was associated with higher IL-6 and CRP levels and lower CXCL8 and CCL5. Significant associations were also observed with intermediate serum CXCL9 and CXCL10 levels. The combination of markers also showed a significant and consistent association with metabolic syndrome. In addition to demonstrating an association between metabolic syndrome and a wide range of biomarkers (some not previously described in the literature), the results highlight that this association occurs at much lower levels than previously demonstrated, suggesting that metabolic syndrome plays an important role in the inflammatory profile of the older adults.

ENA-78 Is a Novel Predictor of Wound Healing in Patients with Diabetic Foot Ulcers

OBJECTIVES

Chronic foot ulceration is a severe complication of diabetes, driving morbidity and mortality. The aim of our study was to identify novel biomarkers of impaired wound healing in diabetic foot ulcers.

METHODS

109 patients with neuropathic diabetic foot ulcers and 30 burn victims otherwise healthy participated. Antibody-coated glass slide arrays were used to determine the levels of 80 human cytokines in pooled plasma or pooled wound exudate of diabetic foot ulcers with rapidly healing (RH, n = 12) and matched nonhealing (NH, n = 12) patients. Potential biomarkers were confirmed in an independent cohort by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Protein array profiling identified 27 proteins or 15 proteins significantly altered in protein profiling of pooled plasma or pooled wound exudate of 12 RH patients compared with 12 matched NH patients, respectively. In an independent cohort, quantitative ELISA validation confirmed a decrease in MCP-2 and ENA-78 levels in NH patients versus RH patients or burn victims. After adjusting for the traditional risk factors (sex, age, body mass index, fasting plasma glucose, ulcer area, HbA1C, diabetes duration, hyperlipidemia, and antibiotic therapy), only wound exudate level of ENA-78 remained having a significant association with an increased odds ratio (OR) for wound healing by binary logistic regression analysis (P < 0.05).

CONCLUSION

Decreased wound exudate ENA-78 was independently associated with wound healing of patients with diabetic foot. Exudate ENA-78 level is implicated as a novel predictor of wound healing in patients with diabetic foot ulcers.

Clinical Evidence Supports a Protective Role for CXCL5 in Coronary Artery Disease

Our goal was to measure the association of CXCL5 and molecular phenotypes associated with coronary atherosclerosis severity in patients at least 65 years old. CXCL5 is classically defined as a proinflammatory chemokine, but its role in chronic inflammatory diseases, such as coronary atherosclerosis, is not well defined. We enrolled individuals who were at least 65 years old and undergoing diagnostic cardiac catheterization. Coronary artery disease (CAD) severity was quantified in each subject via coronary angiography by calculating a CAD score. Circulating CXCL5 levels were measured from plasma, and both DNA genotyping and mRNA expression levels in peripheral blood mononuclear cells were quantified via microarray gene chips. We observed a negative association of CXCL5 levels with CAD at an odds ratio (OR) of 0.46 (95% CI, 0.27-0.75). Controlling for covariates, including sex, statin use, hypertension, hyperlipidemia, obesity, self-reported race, smoking, and diabetes, the OR was not significantly affected [OR, 0.54 (95% CI, 0.31-0.96)], consistent with a protective role for CXCL5 in coronary atherosclerosis. We also identified 18 genomic regions with expression quantitative trait loci of genes correlated with both CAD severity and circulating CXCL5 levels. Our clinical findings are consistent with the emerging link between chemokines and atherosclerosis and suggest new therapeutic targets for CAD.

Sex-specific regulation of chemokine Cxcl5/6 controls neutrophil recruitment and tissue injury in acute inflammatory states

BACKGROUND

Tissue infiltration by neutrophils during acute inflammatory states causes substantial tissue injury. While the magnitude of tissue neutrophil accumulation in innate immune responses is profoundly greater in males than females, fundamental aspects of the molecular mechanisms underlying these sex differences remain largely unknown.

METHODS

We investigated sex differences in neutrophil stimulation and recruitment in ischemia/reperfusion (I/R; mesenteric or renal) or carrageenan pleurisy in rats or mice, as well as skin injury in human volunteers. The induction of potent chemoattractive mediators (chemokines) and neutrophil adhesion molecules were measured by real-time PCR, flow cytometry, and protein assays.

RESULTS

Mesenteric I/R in age-matched Wistar rats resulted in substantially more neutrophil accumulation and tissue injury at 2 h reperfusion in males than females. Using intravital microscopy, we show that the immediate (<30 min) neutrophil response to I/R is similar in males and females but that prolonged neutrophil recruitment occurs in males at sites local and distal to inflammatory insult partly due to an increase in circulating neutrophil populations with elevated surface expression of adhesion molecules. Sex differences in neutrophil kinetics were correlated with sustained induction of chemokine Cxcl5 in the tissue, circulation, and bone marrow of males but not females. Furthermore, blockade of Cxcl5 in males prior to ischemia resulted in neutrophil responses that were similar in magnitude to those in females. Conversely, administration of Cxcl5 to males in the absence of I/R was sufficient to increase levels of systemic neutrophils. Cxcl5 treatment of bone marrow neutrophils in vitro caused substantial induction of neutrophil-mobilizing cytokine granulocyte colony-stimulating factor (GCSF) and expression of β2 integrin that accounts for sexual dimorphism in circulating neutrophil populations in I/R. Moreover, male Cxcl5-stimulated bone marrow neutrophils had an increased capacity to adhere to β2 integrin ligand ICAM-1, implicating a greater sensitivity of male leukocytes to Cxcl5-mediated activation. Differential induction of Cxcl5 (human CXCL6) between the sexes was also evident in murine renal I/R, rat pleurisy, and human skin blisters and correlated with the magnitude of neutrophil accumulation in tissues.

CONCLUSIONS

Our study reveals that sex-specific induction of chemokine Cxcl5/CXCL6 contributes to sexual dimorphism in neutrophil recruitment in diverse acute inflammatory responses partly due to increased stimulation and trafficking of bone marrow neutrophils in males.

Increased serum CXCL1 and CXCL5 are linked to obesity, hyperglycemia, and impaired islet function

Proinflammatory cytokines are thought to play a significant role in the pathogenesis of type 2 diabetes (T2D) and are elevated in the circulation even before the onset of the disease. However, the full complement of cytokines involved in the development of T2D is not known. In this study, 32 serum cytokines were measured from diabetes-prone BKS.Cg-m+/+Lepr(db)/J (db/db) mice and heterozygous age-matched control mice at 5 weeks (non-diabetic/non-obese), 6-7 weeks (transitional-to-diabetes), or 11 weeks (hyperglycemic/obese) and then correlated with body weight, blood glucose, and fat content. Among these 32 cytokines, C-X-C motif ligand 1 (CXCL1) showed the greatest increase (+78%) in serum levels between db/db mice that were hyperglycemic (blood glucose: 519±23 mg/dl, n=6) and those that were non-hyperglycemic (193±13 mg/dl, n=8). Similarly, increased CXCL1 (+68%) and CXCL5 (+40%) were associated with increased obesity in db/db mice; note that these effects could not be entirely separated from age. We then examined whether islets could be a source of these chemokines. Exposure to cytokines mimicking low-grade systemic inflammation (10 pg/ml IL1β+20 pg/ml IL6) for 48 h upregulated islet CXCL1 expression by 53±3-fold and CXCL5 expression by 83±10-fold (n=4, P<0.001). Finally, overnight treatment with the combination of CXCL1 and CXCL5 at serum levels was sufficient to produce a significant decrease in the peak calcium response to glucose stimulation, suggesting reduced islet function. Our findings demonstrated that CXCL1 and CXCL5 i) are increased in the circulation with the onset of T2D, ii) are produced by islets under stress, and iii) synergistically affect islet function, suggesting that these chemokines participate in the pathogenesis of T2D.

Platelets direct monocyte differentiation into epithelioid-like multinucleated giant foam cells with suppressive capacity upon mycobacterial stimulation

BACKGROUND

Epithelioid, foam, and multinucleated giant cells (MNGCs) are characteristics of tuberculosis granulomas, yet the precise genesis and functions of these transformed macrophages are unclear. We evaluated the role of platelets as drivers of macrophage transformation in mycobacterial infection.

METHODS

We employed flow cytometry and microscopy to assess cellular phenotype and phagocytosis. Immune assays allowed quantification of cytokines and chemokines, whereas gene microarray technology was applied to estimate global transcriptome alterations. Immunohistochemical investigations of tuberculosis granulomas substantiated our findings at the site of infection.

RESULTS

Monocytes differentiated in presence of platelets (MP-Macs) acquired a foamy, epithelioid appearance and gave rise to MNGCs (MP-MNGCs). MP-Macs up-regulated activation markers, phagocytosed mycobacteria, and released abundant interleukin 10. Upon extended culture, MP-Macs shared transcriptional features with epithelioid cells and M2 macrophages and up-regulated CXCL5 transcripts. In line with this, CXCL5 concentrations were significantly increased in airways of active tuberculosis patients. The platelet-specific CD42b antigen was detected in MP-Macs, likewise in macrophages, MNGCs, and epithelioid cells within tuberculosis granulomas, along with the platelet aggregation-inducing factor PDPN.

CONCLUSIONS

Platelets drive macrophage differentiation into MNGCs with characteristics of epithelioid, foam, and giant cells observed in tuberculosis granulomas. Our data define platelets as novel participants in tuberculosis pathogenesis.

Association between serum uric acid levels and cardiovascular disease in middle-aged and elderly Chinese individuals

BACKGROUND

A link between uric acid (UA) levels and cardiovascular diseases has been previously reported. However, its importance as a risk factor is still controversial. This study sought to determine whether elevated serum uric acid levels are associated with cardiovascular disease (CVD) in middle-aged and elderly Chinese individuals.

METHODS

We conducted a population-based cross-sectional study in Shanghai, with a total of 8510 participants aged ≥40 years. The CVD included diagnosed coronary heart disease (CHD) and stroke. MetS was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans.

RESULTS

Uric acid levels were positively associated with BMI, waist circumference, triglycerides, systolic blood pressure, diastolic blood pressure, glycohemoglobin, fasting plasma glucose, postprandial 2-hour plasma glucose (all P < 0.05), and negatively associated with HDL-cholesterol (P < 0.001). The prevalence of CVD significantly increased with increasing quartiles of UA in those without MetS group (p trend < 0.001), but not necessarily increased in those with MetS. After adjustment for metabolic syndrome and other cardiovascular risk factors, multivariate logistic regression analysis showed that odds ratios (OR) for CHD, stroke, and CVD in those in the fourth quartiles were 2.34 (95% confidence interval [CI] 1.73 to 3.45), 2.18 (95% CI 1.86 to 3.28), and 2.16 (95% CI 1.80 to 3.29), respectively, compared with those in the first quartile of UA.

CONCLUSIONS

Elevated serum uric acid level was associated with CVD, independent of conventional cardiovascular disease risk factors and metabolic syndrome.

Serum osteocalcin level and its association with carotid atherosclerosis in patients with type 2 diabetes

Objective

To investigate the association of serum osteocalcin with carotid atherosclerosis in patients with type 2 diabetes.

Methods

We performed a cross-sectional community-based study in metropolitan area. Serum total osteocalcin was measured by radioimmunoassay in 382 men and 435 postmenopausal women. The carotid artery intima-media thickness (IMT) and carotid plaques (PLQ) were measured by B-mode ultrasound.

Results

The crude mean of serum osteocalcin concentrations were 4.52±2.43 ng/ml for men and 5.75±2.92 ng/ml for postmenopausal women (P <0.001), respectively. Osteocalcin levels were associated inversely with age, fasting serum insulin, HOMA-IR, ALT, triglycerides, total cholesterol, LDL- cholesterol, CRP (all P<0.001) and positively with adiponectin and HOMA-B (all P<0.05). After multiple adjustment, the odds ratios (ORs) were substantially higher risk for carotid plaques (OR 1.77 for 1 SD decrease in osteocalcin, 95% CI 1.23-2.76, p=0.005). These associations remained significant after further adjustment for potential confounder.

Conclusions

Serum osteocalcin levels is an independent risk factor for carotid atherosclerosis in patients with type 2 diabetes.

CXCL5 polymorphisms are associated with variable blood pressure in cardiovascular disease-free adults

Objective

Leukocyte count has been associated with blood pressure, hypertension, and hypertensive complications. We hypothesized that polymorphisms in the CXCL5 gene, which encodes the neutrophilic chemokine ENA-78, are associated with blood pressure in cardiovascular disease (CVD)-free adults and that these polymorphisms are functional.

Methods and results

A total of 192 community-dwelling participants without CVD or risk equivalents were enrolled. Two CXCL5 polymorphisms (−156 G > C (rs352046) and 398 G > A (rs425535)) were tested for associations with blood pressure. Allele-specific mRNA expression in leukocytes was also measured to determine whether heterozygosity was associated with allelic expression imbalance. In −156 C variant carriers, systolic blood pressure (SBP) was 7 mmHg higher than in −156 G/G wild-type homozygotes (131 ± 17 vs. 124 ± 14 mmHg; P = 0.008). Similarly, diastolic blood pressure (DBP) was 4 mmHg higher in −156 C variant carriers (78 ± 11 vs. 74 ± 11 mmHg; P = 0.013). In multivariate analysis of SBP, age, sex, body mass index, and the −156 G > C polymorphism were identified as significant variables. Age, sex, and the −156 G > C SNP were further associated with DBP, along with white blood cells. Allelic expression imbalance and significantly higher circulating ENA-78 concentrations were noted for variant carriers.

Conclusion

CXCL5 gene polymorphisms are functional and associated with variable blood pressure in CVD-free individuals. The role of CXCL5 as a hypertension- and CVD-susceptibility gene should be further explored.