Background: The systemic inflammatory response to coronary artery bypass grafting (CABG) is highly variable and a key driver of complications. We hypothesised that a pre-existing pro-inflammatory immune state, characterised by a skewed monocyte profile, ‘primes’ patients for an exaggerated response. This pilot prospective study aimed to test this hypothesis and to evaluate the Neutrophil-to-Albumin Ratio (NAR) as an integrated biomarker of this response, comparing it against the established Neutrophil-to-Lymphocyte Ratio (NLR). Methods: In this pilot prospective, single-centre pilot study, we enrolled 34 patients with multivessel coronary artery disease (CAD) scheduled for off-pump CABG and 20 control subjects. Preoperatively, peripheral blood monocyte subsets were quantified by flow cytometry. Neutrophil, lymphocyte, and albumin levels were measured before and after surgery to calculate NAR and NLR. Multivariable linear regression was used to test for independent predictors of the inflammatory response. Results: Preoperatively, CAD patients exhibited a reduced percentage of the classical monocyte subpopulation (p < 0.001), with a skew toward intermediate and non-classical subpopulations. Postoperatively, both NAR and NLR increased significantly (p < 0.001) and performed comparably in discriminating the postoperative state (AUC: 0.89 vs. 0.86, p > 0.05). Critically, in multivariable linear regression analysis, the preoperative percentage of classical monocytes remained a significant and independent predictor of the magnitude of the postoperative NAR surge (β = −0.028, p = 0.007), after adjusting for clinical confounders including atherosclerotic burden. Conclusion: A patient’s preoperative immune profile, specifically the degree of monocyte skew, is an independent predictor of the acute inflammatory response to CABG. This finding supports a ‘priming’ mechanism in high-risk patients. While NAR and NLR perform similarly as monitoring tools, the independent link between the underlying immunology and the postoperative outcome suggests that combining preoperative immunophenotyping with simple biomarker monitoring could offer a powerful new strategy for personalised risk stratification in cardiac surgery.

Hair growth is a highly complex process regulated at multiple levels, including molecular pathways, stem cell behavior, metabolic processes, and immune responses. The hair follicle exhibits metabolic compartmentalization, with some cells relying on glycolysis and others on oxidative phosphorylation. Interestingly, in mice, the onset of the anagen phase can be stimulated by locally suppressing oxidative phosphorylation in the skin. This study showed that topical application of palmitate or oleate accelerated the onset of anagen in mice, while lactate, the end product of glycolysis, delayed it. We also investigated the effects of fatty acids on cytokine production in various human cell cultures. Fatty acids did not induce a cytokine response in fibroblasts or keratinocytes but significantly affected monocytes. Specifically, palmitic acid induced the production of TNF-α, IL-8, and CCL2. Oleic acid, however, elicited almost no response. By comparing the “metabolic” and “inflammatory” hypotheses of anagen stimulation, the results of our study suggest that metabolic regulation holds significant promise for influencing hair growth.

Endotoxin tolerance in monocytes is a mechanism that reduces the secretion of inflammatory cytokines upon repeated pathogen exposure, thereby protecting tissues from hyperinflammation. Previously, we demonstrated that monocytes from patients with asymptomatic carotid atherosclerosis exhibit impaired LPS tolerance. In this study, we aimed to investigate monocyte tolerance impairments in coronary atherosclerosis in greater detail. The study included 46 male patients with ischemic heart disease, divided into two groups based on coronary angiography results with and without coronary atherosclerosis. CD14 + monocytes were isolated from patients' blood and subjected to LPS stimulation on days 1 and 7 of culture. Transcriptomic analysis of monocytes was conducted. Monocyte subpopulations were assessed and sorted based on CD14 and CD16 expression. Patients with coronary atherosclerosis exhibited disrupted inflammatory responses in monocytes, characterized by elevated basal and LPS-induced IL-1β secretion. These patients demonstrated impaired LPS tolerance, as evidenced by increased CCL2 secretion upon repeated stimulation. Transcriptomic analysis revealed upregulation of inflammatory genes, particularly those associated with minor CD16 + monocyte subpopulations. The proportions of non-classical and intermediate monocytes were elevated in patients with atherosclerosis, with IL-1β and CCL2 secretion levels correlating predominantly with the intermediate monocyte subset. Functional analysis revealed that non-classical monocytes from healthy donors developed stable endotoxin tolerance. In contrast, intermediate and classical monocytes from some donors exhibited a non-tolerant response to LPS, as evidenced by secretion of IL-1β, IL-6, and CCL2. The differentiation of classical monocytes into intermediate monocytes may play a key role in the impaired endotoxin tolerance observed in atherosclerosis.

Background: Mitochondria play a key role in the regulation of inflammatory processes. It is well established that mitochondria contain their own mitochondrial DNA (mtDNA), which displays a substantially higher frequency of polymorphisms compared to the nuclear genome. To maintain mitochondrial functionality, cells employ a quality control mechanism known as mitophagy, which ensures the selective removal of dysfunctional mitochondria. The aim of this study was to investigate the relationship between mitochondrial polymorphisms, the efficiency of dysfunctional mitochondria clearance, and proinflammatory activation of inflammatory cells. Methods: In this study, we used cybrids derived from the THP-1 (human monocytic leukemia cell line) that differed in their mitochondrial genome. Results: Based on the levels of secreted proinflammatory cytokines (tumor necrosis factor (TNF), interleukin-1β (IL-1β), IL-6, IL-8, and C-C motif chemokine ligand 2 (CCL2)), cybrids were divided into two groups: one exhibiting a low and the other a high proinflammatory response. mtDNA sequencing revealed a higher number of polymorphisms in the high proinflammatory response group. Transcriptome analysis showed that signaling pathways associated with mitophagy were downregulated in cells with a high proinflammatory response. Functional assays confirmed that mitophagy was impaired in this group. Conclusions: Increased proinflammatory activity in cybrids correlated with a greater number of mtDNA polymorphisms and with impaired mitophagy. These observations point to an association between mitochondrial genomic variation, reduced mitochondrial quality control, and heightened proinflammatory activation of inflammatory cells. However, the data are associative and do not establish causality. Further mechanistic studies are required to determine whether and how mtDNA polymorphisms and defective mitophagy directly contribute to proinflammatory activation.

Macrophage tolerance to lipopolysaccharide (LPS) is characterized by reduced production of pro-inflammatory cytokines upon repeated stimulation. Impaired tolerance of circulating monocytes has been described in chronic inflammatory diseases, including atherosclerosis, systemic sclerosis and type 2 diabetes mellitus, which are associated with elevated levels of macrophage growth factors, cytokines and chemokines. This suggests that the inflammatory microenvironment may modulate macrophage tolerization. The aim of this study was to evaluate the effects of GM-CSF, M-CSF and selected cytokines and chemokines on the development of macrophage tolerance to LPS. CD14 + monocytes were isolated from peripheral blood of healthy donors and cultured with growth factors and cytokines, and exposed to one or two consecutive LPS stimulations at different rest intervals. Cytokine secretion, surface marker expression and cellular morphology were analyzed. GM-CSF–differentiated macrophages showed higher TNF secretion in response to LPS and a tendency toward higher IL-6 secretion, while retaining the ability to develop long-lasting tolerance. In contrast, M-CSF-derived macrophages exhibited only short-term tolerance and progressively regained responsiveness with longer rest intervals, accompanied by renewed cytokine and CCL2 production and cluster formation. Among mediators tested between LPS stimulations, IL-1β emerged as a potent tolerance-breaking self-amplified factor, while other factors promoted tolerization to varying degrees. In conclusion, GM-CSF and M-CSF are associated with distinct temporal patterns of long-interval LPS tolerance in human macrophages. Under the tested in vitro conditions, GM-CSF was associated with maintenance of long-interval LPS tolerance, whereas M-CSF-differentiated macrophages progressively regained responsiveness as the interval between stimulations increased. Collectively, macrophage tolerization is a highly plastic process regulated by multiple soluble mediators present in the inflammatory microenvironment.

Mesenchymal stem cells (MSC) are considered a promising tool for cell therapy due to their regenerative and immunomodulatory properties. However, results from clinical trials remain inconclusive: clinical improvements have been shown in some studies, while other trials did not reveal statistically significant differences from placebo-treated patients. Moreover, some participants experienced adverse effects. Targeted preconditioning of the cells aimed for modifying of their secretome seems to be a strategy to improve the safety and efficacy of MSC-based therapies. Another promising approach is modulation of mitophagy, a key mitochondrial quality-control mechanism that determines stress resilience and immunoregulatory capacity of MSCs. Active mitophagy reduces senescence and preserves immunomodulatory functions of MSCs, thus promoting resolution of inflammation. When mitophagy is impaired, the mitochondrial components and reactive oxygen species may accumulate, thus exacerbating local inflammation. As a result, the therapeutic potential of mesenchymal stem cells may be diminished. Thus, the aim of this study was to compare mitophagy and inflammatory tolerance of MSCs under different stimulation regimens. In the present study, we compared both strategies by examining the mitophagic response of mesenchymal stem cells to mitochondrial stress and the development of LPS-induced tolerance. We used the hTERT-immortalized adipose-derived line ASC52telo in two complementary experimental schedules. To probe mitophagy process, the cells were exposed to FCCP to depolarize mitochondria and then subjected to confocal microscopy after dual staining of mitochondria and lysosomes. To assess their tolerance, the cells were stimulated twice with LPS, and cytokine secretion was measured. We found that FCCP induced pronounced mitochondrial fragmentation and activation of mitophagy. In a separate set of experiments, repeated LPS stimulation led to a marked reduction in TNF and CCL2 secretion. Thus, activation of mitophagy in response to acute mitochondrial stress and establishment of endotoxin (LPS) tolerance in mesenchymal stem cells may be regarded as complementary adaptive mechanisms. These processes may be exploited as targets to increase the predictability and clinical efficacy of MSC-based therapies.