Pretenders and Contenders: Inflammation, C-Reactive Protein, and Interleukin-6

The effect and potential mechanisms of per- and polyfluoroalkyl substances (PFAS) exposure on kidney stone risk

Exposure to per- and polyfluoroalkyl substances (PFAS) may be associated with an increased prevalence of some kidney diseases. Kidney stones are common and have a high prevalence of kidney diseases. However, there is no evidence for the effect and potential mechanisms of PFAS on kidney stone risk. In this study, we designed a cross-sectional study using the National Health and Nutrition Examination Surveys (NHANES) data from 2017 to 2020. Our results revealed that PFAS were positively associated with kidney stone risk, and PFDA was the main contributing compound among PFAS. The triglyceride-glucose (TyG) index and the systemic immune-inflammatory (SII) index had significant mediation effects. In addition, target proteins, such as IL-6, TNF, ALB, IL-1B, and AKT1, and signaling pathways, including TNF and IL-17 pathways, might be potential mechanisms of PFAS in promoting kidney stone risk. In conclusion, PFAS, especially PFDA, increases the risk of kidney stones by the mediation effects of the TyG index and SII index. TNF and IL-17 signaling pathways may be potential mechanisms. Our findings provide new evidence for the effects and potential mechanisms of PFAS exposure in increasing kidney stone risk. However, in the future, it is still imperative to further explore and validate the underlying mechanisms of PFAS-induced kidney stone formation through experimental studies.

Impaired Peripheral Microvascular Function and Risk of Major Adverse Cardiovascular Events in Patients With Coronary Artery Disease

[Figure: see text].

Exercise for slowing the progression of atherosclerotic process: effects on inflammatory markers

Atherosclerosis is a dynamic process driven by all cardiovascular risk factors that can be briefly divided into an early and a late phase. Inflammation is one of the fundamental substrates that initiates the atherosclerotic process in the early stages and promotes and maintains it in the final stages. In the last decades, clinical and experimental data have shown that inflammation is supported by mediators that respond to physical activity. The present review aimed at investigating the effect of physical exercise on inflammatory mediators, both the positive ones that have a proinflammatory effect (interleukin 6, c-reactive protein and tumor necrosis factor α, interferon γ, high-mobility group box-1), and the negative ones which have an anti-inflammatory effect (interleukin 10). Pooled data support the evidence that physical exercise can directly modulate the activity of inflammatory cytokines slowing down or preventing the formation of the atherosclerotic stage.

Sex differences in the inflammatory response to stress and risk of adverse cardiovascular outcomes among patients with coronary heart disease

Stress may contribute to progression of coronary heart disease (CHD) through inflammation, especially among women. Thus, we sought to examine whether increased inflammatory response to stress among patients with CHD is associated with a greater risk of cardiovascular events and whether this risk is higher in women. We examined inflammatory biomarkers known to increase with mental stress (speech task), including interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and matrix metallopeptidase-9 (MMP-9) among 562 patients with stable CHD. Inflammatory response, the difference between post-stress and resting values, was examined as a predictor of major adverse cardiovascular events (MACE) using subdistribution hazards models for competing risks adjusting for demographics, cardiovascular risk factors, and medications. MACE was defined as a composite endpoint of cardiovascular death, myocardial infarction, unstable angina with revascularization, and heart failure. All biomarkers were standardized. The mean age was 63 years (range 34-79) and 24% were women. During a median follow-up of 3 years, 71 patients experienced MACE. Overall, there was no significant association between inflammatory response to stress and risk of MACE, but there were sex-based interactions for IL-6 (p = 0.001) and MCP-1 (p = 0.01). The risk of MACE increased 56% (HR: 1.56; 95% CI: 1.21, 2.01; p = 0.001) and 30% (HR: 1.30; 95% 1.09, 1.55; p = 0.004) for each standard deviation increase in IL-6 and MCP-1 response to mental stress for women, respectively, while there was no association among men. Increased inflammation in response to stress is associated with future adverse cardiovascular outcomes among women with CHD.

The Combined Use of Tocilizumab and Hemoadsorption in a Patient with SARS-COV-2-19-Associated Pneumonia: A Case Report

The SARS-COV-2-19-associated respiratory involvement is caused by the massive release of inflammatory cytokines ultimately leading to interstitial pneumonia and acute respiratory distress syndrome (ARDS). In the absence of an effective antiviral treatment, a reasonable causal approach could be constituted by the neutralization of these substances. The authors describe the clinical course of a patient with SARS-COV-2-19 interstitial pneumonia treated with the combination of an anti-interleukin 6 (IL-6) agent (tocilizumab) and hemoadsorption (HA). This combination was used to abate the surge of inflammatory mediators leading to the lung damage. Blood levels of IL-6 and C-reactive protein (CRP) were measured before the initiation of the treatment and in the following 3 days. At the end of the treatment, the values of IL-6 and CRP decreased from 1,040 to 415 pg/mL and from 229 to 59 mg/L, respectively. The gas exchanges and the chest imaging rapidly improved, and the patient was extubated 10 days later. The combination of tocilizumab and HA could be valuable in the treatment of SARS-COV-2-19-associated pneumonia and ARDS that are caused by the release of inflammatory mediators.

Modulation of the interleukin-6 signalling pathway and incidence rates of atherosclerotic events and all-cause mortality: analyses from the Canakinumab Anti-Inflammatory Thrombosis Outcomes Study (CANTOS)

Aims

Canakinumab, a monoclonal antibody targeting interleukin (IL)-1β, reduces rates of recurrent cardiovascular events without lowering lipids. It is uncertain, however, to what extent these beneficial cardiovascular outcomes are mediated through interleukin-6 (IL-6) signalling, an issue with substantial pathophysiologic consequences and therapeutic implications.

Methods and results

A total of 4833 stable atherosclerosis patients in the Canakinumab Anti-Inflammatory Thrombosis Outcomes Study (CANTOS) had IL-6 levels measured before randomization and after treatment with placebo or one of three doses of canakinumab (50 mg, 150 mg, or 300 mg) given subcutaneously once every 3 months. Participants were followed for up to 5 years (median follow-up 3.7 years). Compared with those allocated to placebo, CANTOS participants receiving canakinumab who achieved on-treatment IL-6 levels below the study median value of 1.65 ng/L experienced a 32% reduction in major adverse cardiovascular events [MACE, multivariable adjusted hazard ratio (HRadj) 0.68, 95% confidence interval (CI) 0.56-0.82; P < 0.0001], a 30% reduction in MACE plus the additional endpoint of hospitalization for unstable angina requiring urgent revascularization (MACE+, HRadj 0.70, 95% CI 0.59-0.84; P < 0.0001), a 52% reduction in cardiovascular mortality (HRadj 0.48, 95% CI 0.34-0.68; P < 0.0001), and a 48% reduction in all-cause mortality (HRadj 0.52, 95% CI 0.40-0.68; P < 0.0001) with prolonged treatment. In contrast, those with on-treatment IL-6 levels equal to or above 1.65 ng/L after taking the first dose of canakinumab had no significant benefit for any of these endpoints. These differential findings based on the magnitude of IL-6 response were seen in analyses alternatively based on tertiles of on-treatment IL-6 levels, and in analyses using a statistical inference approach to estimate the effect of treatment among individuals who would achieve a targeted IL-6 level.

Conclusion

CANTOS provides proof of concept evidence in humans that modulation of the IL-6 signalling pathway, at least with canakinumab, associates with reduced cardiovascular event rates, independent of lipid lowering.

Clinical trial registration

ClinicalTrials.gov NCT01327846.

Young Women With Coronary Artery Disease Exhibit Higher Concentrations of Interleukin-6 at Baseline and in Response to Mental Stress

Background

Young women with coronary artery disease (CAD), a group with high psychosocial burden, were previously shown to have higher levels of interleukin‐6 (IL‐6) compared with men of similar age. We sought to examine IL‐6 response to acute stress in CAD patients across sex and age, and contrast results to healthy controls and other biomarkers known to increase with mental stress (monocyte chemoattractant protein‐1 and matrix metallopeptidase‐9) and known limited stress‐reactivity (high‐sensitivity C‐reactive protein).

Methods and Results

Inflammatory biomarkers were measured at rest and 90 minutes after mental stress (speech task) among 819 patients with CAD and 89 healthy controls. Repeated‐measures models were used to investigate age (continuous) and sex differences across time, before and after adjusting for demographics, CAD risk factors, depressive symptoms, medication use, and CAD severity. Among patients with CAD, the mean age was 60 years (range, 25–79) and 31% were women. Younger women with CAD had significantly higher concentrations of IL‐6 at rest, 90 minutes after mental stress, as well as a higher response to stress, compared with similarly aged men (P<0.05 for sex by age interactions). In contrast, IL‐6 increased with age, and there were no sex differences in IL‐6 levels or response to stress among controls. Inflammatory responses to stress for high‐sensitivity C‐reactive protein, monocyte chemoattractant protein‐1, and matrix metallopeptidase‐9 among CAD patients were similar in women and men.

Conclusions

IL‐6 response to mental stress are higher in young women with CAD than men of similar age.

Inflammageing: chronic inflammation in ageing, cardiovascular disease, and frailty

Most older individuals develop inflammageing, a condition characterized by elevated levels of blood inflammatory markers that carries high susceptibility to chronic morbidity, disability, frailty, and premature death. Potential mechanisms of inflammageing include genetic susceptibility, central obesity, increased gut permeability, changes to microbiota composition, cellular senescence, NLRP3 inflammasome activation, oxidative stress caused by dysfunctional mitochondria, immune cell dysregulation, and chronic infections. Inflammageing is a risk factor for cardiovascular diseases (CVDs), and clinical trials suggest that this association is causal. Inflammageing is also a risk factor for chronic kidney disease, diabetes mellitus, cancer, depression, dementia, and sarcopenia, but whether modulating inflammation beneficially affects the clinical course of non-CVD health problems is controversial. This uncertainty is an important issue to address because older patients with CVD are often affected by multimorbidity and frailty - which affect clinical manifestations, prognosis, and response to treatment - and are associated with inflammation by mechanisms similar to those in CVD. The hypothesis that inflammation affects CVD, multimorbidity, and frailty by inhibiting growth factors, increasing catabolism, and interfering with homeostatic signalling is supported by mechanistic studies but requires confirmation in humans. Whether early modulation of inflammageing prevents or delays the onset of cardiovascular frailty should be tested in clinical trials.