CCL17 and CCL22 chemokines are upregulated in human obesity and play a role in vascular dysfunction

Omalizumab is ineffective in regulating proasthmatic serum cytokine and chemokine levels in nonresponders with high BMI

Background

Omalizumab provides clinical benefits to a fraction of patients with asthma. It remains unclear why some patients do not respond to omalizumab therapy.

Objective

We sought to investigate whether omalizumab could alter serum cytokine and chemokine levels that could be associated with asthma pathogenesis. We also investigated why omalizumab is ineffective in controlling proasthmatic serum cytokine and chemokine levels in nonresponders.

Methods

Serum cytokine and chemokine levels in patients with moderate to severe asthma (N = 45; 34 responders and 11 nonresponders) were assessed before and after 26 weeks of omalizumab therapy. Correlations between cytokine and chemokine levels and asthma symptoms as well as characteristics of responders and nonresponders were assessed. Nonasthmatic subjects (N = 22) served as controls for patients with asthma (N = 45).

Results

Omalizumab was more effective in patients with increased serum eotaxin-1 and IL-13 levels than in others at baseline. Omalizumab decreased eotaxin-1 and IL-13, along with levels of most of the cytokines and chemokines tested, including IL-7, CCL17, and CXCL10, in responders, except for CCL5 and CCL22, which can contribute to neutrophilic and type 2 airway inflammation, respectively. In contrast, omalizumab did not decrease such serum cytokine and chemokine levels in nonresponders. Of interest, serum CCL17, CCL22, CXCL10, and IL-7 levels in nonresponders were associated with their body mass index, which could explain why omalizumab was unable to reduce their concentrations in nonresponders.

Conclusions

Omalizumab can regulate most cytokine and chemokine levels in responders. However, in nonresponders, it is unable to modulate specific proasthmatic cytokines and chemokines due to their association with individual body mass index, which is not influenced by omalizumab.

Cytokine atlas of the population-based cohort SHIP-TREND-0 - Associations with age, sex, and BMI

BACKGROUND

The characterization of physiological immune signatures in a population-based cohort is a prerequisite for identifying pathological immune signatures associated with inflammatory or autoimmune diseases.

METHODS

Here, 47 plasma cytokines, chemokines, and growth factors were quantified with a bead-based multiplex-assay (Merck HCYTA-60 K) using a FLEXMAP 3D™ instrument in 1175 individuals of the Study of Health in Pomerania (SHIP; TREND cohort, 532 men and 643 women, age: 20 to 81, BMI: 17.7 to 53.6). Associations of cytokine concentrations with age, sex, BMI, season, and blood cell parameters (BCP) were examined by multivariate regression models.

RESULTS

The physiological cytokine concentrations differed strongly between analytes, with median concentrations ranging from 0.6 to 7820 pg/mL. Many cytokine levels showed a large dynamic range within the study population. Higher levels of the pro-inflammatory cytokines and chemokines IL-6, IL-8, CXCL9, CXCL10, IL-12p40, CCL2, CCL4, CCL11, IL-27, FLT3LG, and TNFα were significantly associated with increasing age. The strongest age-associated effects were seen for CXCL9 (βst = 0.4, p < 0.001) and CXLC10 (βst = 0.3, p < 0.001). Significant sex differences were detected for CCL2, CCL3, CCL4, CCL11, CCL22, IL-12p40, IL-1RA, IL-18, IL-27, and TNFα levels among which CCL11 showed the strongest effect (βst = -0.24, p < 0.001) with a lower level in women compared to men. Moreover, seven cytokines and chemokines, i.e. CCL4, CCL22, CXCL10, IL-1RA, IL-18, IL-6, and TNFα, displayed higher levels with increasing BMI. Among those, the strongest effect was seen for IL-1RA (βst = 0.19, p < 0.001), CCL4 (βst = 0.16, p < 0.001) and CXCL10 (βst = 0.14, p < 0.001). Only CCL11 (βst = -0.17, p < 0.001) decreased with increasing BMI. Subjects categorized as obese exhibited significantly elevated levels of CCL4, CCL22, CXCL10, and IL-1RA, while only CCL11 showed significantly reduced levels compared to normal weight. Certain cytokines such as IL-6, IL-18, or TNFα showed decreased significance levels after adjustment for blood cell components indicating blood cell components (BCPs) as potential confounders. We observed no significant non-linear seasonal effects for the investigated cytokines.

CONCLUSION

The generated cytokine atlas provides detailed information on cytokine variations in the general population and will provide a reference base for disease-related studies in the future. Furthermore, BCPs should be considered as potential confounders in association studies based on plasma cytokine levels.

Polychlorinated biphenyls induce immunometabolic switch of antiinflammatory macrophages toward an inflammatory phenotype

Polychlorinated biphenyls (PCBs) are a group of environmental toxicants associated with increased risk of diabetes, obesity, and metabolic syndrome. These metabolic disorders are characterized by systemic and local inflammation within adipose tissue, the primary site of PCB accumulation. These inflammatory changes arise when resident adipose tissue macrophages undergo phenotypic plasticity-switching from an antiinflammatory to an inflammatory phenotype. Thus, we sought to assess whether PCB exposure drives macrophage phenotypic switching. We investigated how human monocyte-derived macrophages polarized toward an M1, M2a, or M2c phenotype were impacted by exposure to Aroclor 1254, a PCB mixture found at high levels in school air. We showed that PCB exposure not only exacerbates the inflammatory phenotype of M1 macrophages but also shifts both M2a and M2c cells toward a more inflammatory phototype in both a dose- and time-dependent manner. Additionally, we show that PCB exposure leads to significant metabolic changes. M2 macrophages exposed to PCBs exhibit increased reliance on aerobic glycolysis and reduced capacity for fatty acid and amino acid oxidation-both indicators of an inflammatory macrophage phenotype. Collectively, these results demonstrate that PCBs promote immunometabolic macrophage plasticity toward a more M1-like phenotype, thereby suggesting that PCBs exacerbate metabolic diseases by altering the inflammatory environment in adipose tissue.

Therapeutic blockade of CCL17 in obesity-exacerbated osteoarthritic pain and disease

OBJECTIVES

We previously reported that CCL17 gene-deficient mice are protected from developing pain-like behaviour and exhibit less disease in destabilization of medial meniscus (DMM)-induced OA, as well as in high-fat diet (HFD)-exacerbated DMM-induced OA. Here, we explored if therapeutic neutralization of CCL17, using increasing doses of a neutralizing monoclonal antibody (mAb), would lead to a dose-dependent benefit in these two models.

DESIGN

DMM-induced OA was initiated in male mice either fed with a control diet (7% fat) or 8 weeks of a 60% HFD, followed by therapeutic intraperitoneal administration (i.e. when pain is evident) of an anti-CCL17 mAb (B293, 25mg/kg, 5mg/kg or 1mg/kg) or isotype control (BM4; 25mg/kg). Pain-like behaviour and arthritis were assessed by relative static weight distribution and histology, respectively. The effects of B293 (25mg/kg) on HFD-induced metabolic changes, namely oral glucose tolerance test, insulin tolerance test and liver triglyceride levels, were examined.

RESULTS

Therapeutic administration of B293 results in a dramatic amelioration of DMM-induced OA pain-like behaviour and the inhibition of disease progression, compared to BM4 (isotype control) treatment. A similar therapeutic effect was observed in HFD-exacerbated OA pain-like behaviour and disease. B293 treatment did not alter the measured HFD-induced metabolic changes.

CONCLUSIONS

Based on the data presented, CCL17 could be a therapeutic target in OA patients with joint injury alone or with obesity.

APOB and CCL17 as mediators in the protective effect of SGLT2 inhibition against myocardial infarction: Insights from proteome-wide mendelian randomization

AIMS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors offer a novel therapeutic avenue for myocardial infarction (MI). However, the exact nature of this relationship and the underlying mechanisms are not fully understood.

METHODS

Utilizing a two-sample Mendelian Randomization (MR) analysis, we elucidated the causal effects stemming from the inhibition of SGLT2 on MI. Then, The pool of 4907 circulating proteins within the plasma proteome were utilized to explore the mediators of SGLT2 inhibitors on MI. Protein-protein network and enrichment analysis were conducted to clarify the potential mechanism. Finally, employing MR analysis and meta-analysis techniques, we systematically assessed the causal associations between SGLT2 inhibition and coronary heart diseases (CHD).

RESULTS

SGLT2 inhibition (per 1 SD decrement in HbA1c) was associated with reduced risk of MI (odds ratio [OR] = 0.462, [95% CI 0.222, 0.958], P = 0.038). Among 4907 circulating proteins, we identified APOB and CCL17 which were related to both SGLT2 inhibition and MI. Mediation analysis showed evidence of the indirect effect of SGLT2 inhibition on MI through APOB (β = -0.557, 95%CI [-1.098, -0.155]) with a mediated proportion of 72%, and CCL17 (β = -0.176, 95%CI [-0.332, -0.056]) with a mediated proportion of 17%. The meta-analysis result showed that SGLT2 inhibition was associated with a lower risk of CHD.

CONCLUSION

Based on proteome-wide mendelian randomization, APOB and CCL17 were seen as mediators in the protective effect of SGLT2 inhibition against myocardial infarction.

Dawn-to-dusk dry fasting decreases circulating inflammatory cytokines in subjects with increased body mass index

BACKGROUND

The circadian rhythm involves numerous metabolic processes, including sleep/awakening, body temperature regulation, hormone secretion, hepatic function, cellular plasticity, and cytokine release (inflammation), that appear to have a dynamic relationship with all the processes above. Studies have linked various cytokines to the chronic state of low-grade inflammation and oxidative stress in obesity. Dawn-to-dusk dry fasting (DDDF) could alleviate the adverse effects of obesity by decreasing inflammation. This study examined the effects of DDDF on circulating inflammatory cytokines in subjects with increased body mass index (BMI).

METHODS

The current observational prospective study included adult subjects with a BMI equal to or greater than 25 kg/m2 who practiced the annual religious 30-day DDDF. Individuals with significant underlying medical conditions were excluded to limit confounding factors. All subjects were evaluated within two weeks before 30-day DDDF, within the fourth week of 30-day DDDF, and within two weeks after 30-day DDDF. Multiple cytokines and clinical health indicators were measured at each evaluation.

RESULTS

Thirteen subjects (10 men and three women) with a mean age of 32.9 years (SD = 9.7 years) and a mean BMI of 32 kg/m2 (SD = 4.6 kg/m2) were included. An overall associated decrease in the levels of multiple cytokines with DDDF was observed. A significant decrease in the mean interleukin 1 beta level was observed within the fourth week of 30-day DDDF (P = 0.045), which persisted even after the fasting period (P = 0.024). There was also a significant decrease in the mean levels of interleukin 15 (IL-15) (P = 0.014), interleukin 1 receptor antagonist (P = 0.041), macrophage-derived chemokine (MDC) (P = 0.013), and monokine induced by interferon gamma/chemokine (C-X-C motif) ligand 9 (P = 0.027) within the fourth week of 30-day DDDF and in the mean levels of fibroblast growth factor 2 (P = 0.010), interleukin 12 p40 subunit (P = 0.038), interleukin 22 (P = 0.025) and tumor necrosis factor alpha (P = 0.046) within two weeks after 30-DDDF. In terms of anthropometric parameters, there was a decrease in mean body weight (P = 0.032), BMI (P = 0.028), and hip circumference (P = 0.007) within the fourth week of 30-day DDDF and a decrease in mean weight (P = 0.026), BMI (P = 0.033) and hip circumference (P = 0.016) within two weeks after 30-day DDDF compared with the levels measured within two weeks before 30-day DDDF. Although there was no significant correlation between changes in weight and changes in circulating inflammatory cytokines, there was a significant positive correlation between changes in waist circumference and changes in specific inflammatory cytokines (e.g., IL-15, MDC, platelet-derived growth factor, soluble CD40L, vascular endothelial growth factor A) within the fourth week of 30-day DDDF and/or two weeks after 30-day DDDF. A significant decrease in mean average resting heart rate within the fourth week of 30-day DDDF was also observed (P = 0.023), and changes between average resting heart rate and changes in interleukin-8 levels within the fourth week of 30-day DDDF compared with baseline levels were positively correlated (r = 0.57, P = 0.042).

CONCLUSION

DDDF appears to be a unique and potent treatment to reduce low-grade chronic inflammation caused by obesity and visceral adiposity. Further studies with more extended follow-up periods are warranted to investigate the long-term anti-inflammatory benefits of DDDF in individuals with increased BMI.

Targeting systemic inflammation in metabolic disorders. A therapeutic candidate for the prevention of cardiovascular diseases?

Cardiovascular disease (CVD) remains the leading cause of death and disability worldwide. While many factors can contribute to CVD, atherosclerosis is the cardinal underlying pathology, and its development is associated with several metabolic risk factors including dyslipidemia and obesity. Recent studies have definitively demonstrated a link between low-grade systemic inflammation and two relevant metabolic abnormalities: hypercholesterolemia and obesity. Interestingly, both metabolic disorders are also associated with endothelial dysfunction/activation, a proinflammatory and prothrombotic phenotype of the endothelium that involves leukocyte infiltration into the arterial wall, one of the earliest stages of atherogenesis. This article reviews the current literature on the intricate relationship between hypercholesterolemia and obesity and the associated systemic inflammation and endothelial dysfunction, and discusses the effectiveness of present, emerging and in-development pharmacological therapies used to treat these metabolic disorders with a focus on their effects on the associated systemic inflammatory state and cardiovascular risk.