The Behaviour of IL-6 and Its Soluble Receptor Complex during Different Waves of the COVID-19 Pandemic.

In late December 2019, SARS-CoV-2 was identified as the cause of a new pneumonia (COVID-19), leading to a global pandemic declared by the WHO on 11 March 2020, with significant human, economic, and social costs. Although most COVID-19 cases are asymptomatic or mild, 14% progress to severe disease, and 5% develop critical illness with complications such as interstitial pneumonia, acute respiratory distress syndrome (ARDS), and multiple organ dysfunction syndrome (MODS). SARS-CoV-2 primarily targets the respiratory system but can affect multiple organs due to the widespread presence of angiotensin-converting enzyme 2 (ACE2) receptors, which the virus uses to enter cells. This broad distribution of ACE2 receptors means that SARS-CoV-2 infection can lead to cardiovascular, gastrointestinal, renal, hepatic, central nervous system, and ocular damage. The virus triggers the innate and adaptive immune systems, resulting in a massive cytokine release, known as a "cytokine storm", which is linked to tissue damage and poor outcomes in severe lung disease. Interleukin-6 (IL-6) is particularly important in this cytokine release, with elevated levels serving as a marker of severe COVID-19. IL-6 is a multifunctional cytokine with both anti-inflammatory and pro-inflammatory properties, acting through two main pathways: classical signalling and trans-signalling. Classical signalling involves IL-6 binding to its membrane-bound receptor IL-6R and then to the gp130 protein, while trans-signalling occurs when IL-6 binds to the soluble form of IL-6R (sIL-6R) and then to membrane-bound gp130 on cells that do not express IL-6R. The soluble form of gp130 (sgp130) can inhibit IL-6 trans-signalling by binding to sIL-6R, thereby preventing it from interacting with membrane-bound gp130. Given the central role of IL-6 in COVID-19 inflammation and its association with severe disease, we aimed to analyse the behaviour of IL-6 and its soluble receptor complex during different waves of the pandemic. This analysis could help determine whether IL-6 levels can serve as prognostic markers of disease severity.

Interleukin-6 and Its Soluble Receptor Complex in Intensive Care Unit COVID-19 Patients: An Analysis of Second Wave Patients.

In December 2019, a SARS-CoV-2 virus, coined Coronavirus Disease 2019 (COVID-19), discovered in Wuhan, China, affected the global population, causing more than a million and a half deaths. Since then, many studies have shown that the hyperinflammatory response of the most severely affected patients was primarily related to a higher concentration of the pro-inflammatory cytokine interleukin-6, which directly correlated with disease severity and high mortality. Our study analyzes IL-6 and its soluble receptor complex (sIL-6R and sgp130) in critically ill COVID-19 patients who suffered severe respiratory failure from the perspective of the second COVID wave of 2020. A chemiluminescent immunoassay was performed for the determination of IL6 in serum together with an enzyme-linked immunosorbent assay to detect serum levels of sIL-6R and sgp130, which confirmed that the second wave's serum levels of IL-6 were significantly elevated in the more severe patients, as with the first 2019 COVID-19 wave, resulting in adverse clinical outcomes. At present, considering that no specific treatment for severe COVID-19 cases in its later stages exists, these molecules could be considered promising markers for disease progression, illness severity, and risk of mortality.

The potential role of serum polyclonal free light chains as markers of immune activation in psoriatic patients.

BACKGROUND: Polyclonal free light chains (FLCs) of immunoglobulins include κ and λ chains and represent a sensitive marker of activation and/or dysfunction of the immune system. OBJECTIVES: The aim of this study was to investigate the role of FLCs as markers of immune activation in the management of psoriatic patients treated with biologics. MATERIALS & METHODS: The overall study population included 45 patients affected by mild-to-severe psoriasis with either ongoing biological treatment or without any current systemic therapy. Peripheral blood samples were taken from all patients and 10 healthy subjects in order to determine immunoglobulins, light chains and FLCs by quantitative nephelometric assay. Moreover, antinuclear antibodies (ANA) were detected by immunofluorescence. RESULTS: Psoriatic patients showed significant increased levels of κ and λ FLCs compared to healthy controls. Interestingly, κ and λ FLCs values were significantly increased only in psoriatic patients with ongoing biological treatment and, in particular, in responder subjects. Furthermore, both κ and λ FLCs significantly correlated with duration of therapy. For patients with FLC levels above normal range and under biological treatment for more than 12 months, the odds of being ANA+ was greater relative to patients with FLC levels above normal range but under biological treatment for less than 12 months. CONCLUSIONS: Increased FLC levels may represent a marker of immune reactivation in psoriatic patients treated with biologic agents. We suggest that determining FLC levels has clinical relevance, with a cost/benefit ratio justifying such evaluation in the clinical management of psoriasis.

Gender dimorphism in IgA subclasses in T2-high asthma.

Immunoglobulin A (Chan in J Allergy Clin Immunol 134:1394-14014e4, 2014), the second most abundant immunoglobulin in serum, plays an important role in mucosal homeostasis. In human serum, there are two subclasses of IgA, IgA1 (≅ 90%) and IgA2 (≅ 10%), transcribed from two distinct heavy chain constant regions. This study evaluated the serum concentrations of total IgA, IgA1, and IgA2, and total IgG, IgG1, IgG2, IgG3, and IgG4 in T2-high asthmatics compared to healthy controls and the presence of gender-related variations of immunoglobulins. Total IgA levels were increased in asthmatics compared to controls. Even more marked was the increase in total IgA in male asthmatics compared to healthy male donors. IgA1 were increased only in male, but not in female asthmatics, compared to controls. Concentrations of IgG2, but not IgG1, IgG3, and IgG4, were reduced in asthmatics compared to controls. IgG4 levels were reduced in female compared to male asthmatics. In female asthmatics, IgA and IgA1 levels were increased in postmenopause compared to premenopause. IgA concentrations were augmented in mild, but not severe asthmatics. A positive correlation was found between IgA levels and the age of patients and an inverse correlation between serum concentrations of IgA2 and IgE in asthmatics. A positive correlation between total IgA or IgA2 and IgG2 was found in asthmatics. These results highlight a gender dimorphism in IgA subclasses in male and female T2-high asthmatics. More adequate consideration of immunological gender disparity in asthma may open new opportunities in personalized medicine by optimizing diagnosis and targeted therapy.

Soluble Urokinase Receptor as a Promising Marker for Early Prediction of Outcome in COVID-19 Hospitalized Patients.

The Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, has rapidly spread to become a global pandemic, putting a strain on health care systems. SARS-CoV-2 infection may be associated with mild symptoms or, in severe cases, lead patients to the intensive care unit (ICU) or death. The critically ill patients suffer from acute respiratory distress syndrome (ARDS), sepsis, thrombotic complications and multiple organ failure. For optimization of hospital resources, several molecular markers and algorithms have been evaluated in order to stratify COVID-19 patients, based on the risk of developing a mild, moderate, or severe disease. Here, we propose the soluble urokinase receptor (suPAR) as a serum biomarker of clinical severity and outcome in patients who are hospitalized with COVID-19. In patients with mild disease course, suPAR levels were increased as compared to healthy controls, but they were dramatically higher in severely ill patients. Since early identification of disease progression may facilitate the individual management of COVID-19 symptomatic patients and the time of admission to the ICU, we suggest paying more clinical attention on patients with high suPAR levels.

Detection of CAF-1/p60 in peripheral blood as a potential biomarker of HNSCC tumors.

To date, a very small number of serum biomarkers have been identified for clinical use in squamous carcinomas of the head and neck region. Chromatin Assembly Factor-1 (CAF-1) heterotrimeric complex subunit CAF1/p60 expression levels have been reported to be of prognostic value in Oral Squamous Cell Carcinoma (OSCC), as well as in other human solid tumors. Here our aim was to detect and quantify CAF1/p60 in the peripheral blood of Head and Neck Squamous Cell Carcinoma (HNSCC) patients, and to investigate the possible associations between serum concentration of CAF-1/p60 and HNSCC tumors. A total of 63 HNSCC patients (51 OSCC, 8 OPSCC, 3 laryngeal SCC, and 1 rhinopharynx SCC) and 30 healthy controls were enrolled. The serum levels of CAF-1/p60 were measured by ELISA assay before and after surgery. Serum CAF-1/p60 concentration resulted significantly higher in cancer patients, compared with healthy controls, in pre-surgery samples (P < 0.05). Serum levels of CAF-1/p60 significantly decreased in serum samples taken after surgery (P < 0.05). Our results demonstrated that CAF-1/p60 may be detected in serum, suggesting a role for CAF-1/p60 as potential soluble biomarkers in HNSCC tumors.

Pro-inflammatory adipokine profile in psoriatic arthritis: results from a cross-sectional study comparing PsA subset with evident cutaneous involvement and subset "sine psoriasis".

OBJECTIVE: Adipokines have been considered in the pathogenesis of the inflammatory processes of psoriatic arthritis (PsA). The main aim of the current study is to investigate possible differences and correlations between adipokines and clinical expression in PsA patients with and without clinical evident psoriasis. METHODS: Serum levels of TNF-α, IL-6, leptin, resistin, visfatin, and ghrelin were measured in 80 consecutive PsA patients, 42 PsA patients with clinically evident psoriasis (group 1) and 38 PsA patients sine psoriasis (group 2), fulfilling the CASPAR criteria. RESULTS: Patients of the two groups were not significantly different for levels of TNF-α, IL-6, leptin, resistin, visfatin, and ghrelin. In the entire cohort, a positive association has been shown between leptin levels and female gender (ß = 0.3, p = 0.001), BMI (ß = 0.8, p < 0.0001), tender joint count (ß = 0.23, p = 0.05), and patient pain-VAS score (ß = 0.4, p = 0.049). In group 1, serum concentration of leptin was associated with female gender (ß = 0.41, p < 0.0001) and BMI (ß = 0.6, p = 0.012), whereas in group 2, a positive association was shown between leptin levels and BMI (ß = 0.7, p = 0.003) and CRP (ß = 0.35, p = 0.012). With regard to resistin, in the multivariate model, only the association between resistin and IL-6 was found (ß = 0.33, p = 0.002). The association between resistin and IL-6 was confirmed in group 1 (ß = 0.46, p = 0.004) but not in group 2. CONCLUSIONS: Until today, the present study represents the first investigating difference in the adipokine pattern between PsA patients with psoriasis and sine psoriasis. We report a strict interplay between leptin, female gender, BMI, and inflammatory activity in overall PsA patients. In PsA patients with clinical evident psoriasis, leptin was associated with female gender and BMI, and a close association between resistin and IL-6 was found. Further, a positive association between leptin levels and BMI and CRP was found in PsA sine psoriasis patients. Further studies are also advocated for clarifying the possible role of these adipokines as laboratory findings or as disease mediators in addressing the different phenotypes of the disease. Key Points •Levels of TNF-α, IL-6, leptin, resistin, visfatin, and ghrelin did not differ between PsA patients with clinical evident psoriasis and PsA sine psoriasis. •There is a strict interplay between leptin, female gender, BMI, and inflammatory activity in PsA. •There is a close association between resistin and IL-6 in PsA patients with clinical evident psoriasis.

Interleukin-6 trans-signaling and pathological low back pain in patients with Paget disease of bone.

The interleukin (IL)-6 biological system plays a key role in the pathogenesis of Paget disease (PD) of bone and pathological bone pain. Bone pain, particularly in the lower back region, is the most frequent symptom in patients with PD. This case-control study aimed to evaluate the relationship between the IL-6 system and low back pain (LBP) in patients with PD. We evaluated 85 patients with PD, with the disease localized in the lumbar spine, pelvis, and/or sacrum, and classified them based on the presence or absence of LBP, before and after aminobisphosphonate treatment. We also examined 32 healthy controls without LBP. Before treatment, IL-6 levels in patients with PD were higher than those in the controls, without difference between patients with or without LBP. Patients with PD with LBP (35/85) showed higher IL-6-soluble receptor (sIL-6R) and lower soluble glycoprotein (sgp) 130 levels compared with both patients with PD without LBP and controls (sIL-6R: 46.9 ± 7.4 vs 35.4 ± 8.6 vs 29.9 ± 4.2 ng/mL; sgp130: 307.2 ± 35.4 vs 341.4 ± 41.4 vs 417.1 ± 58.5 ng/mL, respectively). Paget disease remission, 6 months after treatment, is associated with LBP improvement. This phenomenon is associated with reduced sIL-6R levels and increased sgp130 levels in patients with PD with LBP at the baseline. Considering the biological properties of IL-6, sIL-6R, and sgp130, the results of the study suggest that the perception of LBP in patients with PD could be linked to an enhanced transmission of IL-6 signal in the specialized neural system activated by nociceptors.

Generation and analysis of spheroids from human primary skin myofibroblasts: an experimental system to study myofibroblasts deactivation.

Myofibroblasts are activated fibroblasts involved in tissue repair and cancer. They are characterized by de novo expression of α-smooth muscle actin (α-SMA), immunoregulatory phenotype and paracrine interaction with normal and tumorigenic cells leading to cell proliferation. At the end of wound-healing myofibroblasts undergo apoptotic cell death, whereas in vitro-activated fibroblasts are also subjected to a programmed necrosis-like cell death, termed nemosis, associated with cyclooxygenase-2 (COX-2) expression induction and inflammatory response. Furthermore, myofibroblasts form clusters during wound healing, fibrotic states and tumorigenesis. In this study, we generated and analysed clusters such as spheroids from human primary cutaneous myofibroblasts, which represent a part of stromal microenvironment better than established cell lines. Therefore, we evaluated apoptotic or necrotic cell death, inflammation and activation markers during myofibroblasts clustering. The spheroids formation did not trigger apoptosis, necrotic cell death and COX-2 protein induction. The significant decrease of α-SMA in protein extracts of spheroids, the cytostatic effect exerted by spheroids conditioned medium on both normal and cancer cell lines and the absence of proliferation marker Ki-67 after 72 h of three-dimensional culture indicated that myofibroblasts have undergone a deactivation process within spheroids. The cells of spheroids reverted to adhesion growth preserved their proliferation capability and can re-acquire a myofibroblastic phenotype. Moreover, the spontaneous formation of clusters on plastic and glass substrates suggests that aggregates formation could be a physiological feature of cutaneous myofibroblasts. This study represents an experimental model to analyse myofibroblasts deactivation and suggests that fibroblast clusters could be a cell reservoir regulating tissues turnover.

Differentiation, apoptosis, and GM-CSF receptor expression of human gingival fibroblasts on a titanium surface treated by a dual acid-etched procedure.

OBJECTIVES: Analysis of the effects of titanium surface properties on the biological behavior of human gingival fibroblasts (HGFs). MATERIALS AND METHODS: HGFs were in vitro cultured on a titanium surface modified by a dual acid-etched procedure and on a control machined surface. Cell adhesion, proliferation, apoptosis, production of certain extracellular matrix (ECM) proteins, and expression of granulocyte macrophage-colony stimulating factor receptor (GM-CSFR) were investigated using in each experiment a total of 18 samples for each titanium surface. RESULTS: Cell attachment at 3 h of culture was statistically significantly higher on the etched surface. HGF growth increased on both surfaces during the entire experimental period and at day 14 of culture cell proliferation was statistically significantly higher on the treated surface than on the control. No statistically significant differences in percentage of apoptosis events were observed between the surfaces. ECM protein production increased progressively over time on both surfaces. A statistically significant deposition was observed at day 7 and 14 for collagen I and only at day 14 for fibronectin and tenascin, when compared to the baseline. GM-CSFR registered a positive expression on both surfaces, statistically significant at day 14 on the etched surface in comparison with the machined one. CONCLUSIONS: Data showed that titanium surface microtopography modulates in vitro cell response and phenotypical expression of HGFs. The etched surface promoted a higher cell proliferation and differentiation improving the biological behavior of HGFs. CLINICAL RELEVANCE: Results suggest a possible beneficial effect of surface etching modification on peri-implant biological integration and soft tissue healing which is critical for the formation of a biological seal around the neck of dental implants.

Upregulation of the N-formyl Peptide receptors in scleroderma fibroblasts fosters the switch to myofibroblasts.

Systemic sclerosis (SSc) is characterized by chronic inflammation and fibrosis. N-Formyl peptide (fMLF) receptors (FPRs) are chemotactic receptors involved in inflammation. Three FPRs have been identified: FPR1, FPR2, and FPR3. We have examined, by RT-PCR, Western blot and immunohistochemistry, FPRs expression in skin fibroblasts from 10 normal subjects and 10 SSc patients, showing increased expression in SSc fibroblasts. Several functions of FPRs occur through the interaction with a region of the urokinase-type plasminogen activator receptor (uPAR88-92), able to interact with FPRs and to mediate urokinase (uPA) or fMLF-dependent cell migration. Soluble uPAR84-95 peptide can act as a direct ligand of FPRs. Furthermore, uPA or its aminoterminal fragment (ATF) can promote the exposure of the uPAR88-92 region. The WKYMVm peptide is a FPRs pan-agonist. We investigated the functional effects of these agonists on normal and SSc fibroblasts. ATF, uPAR84-95, and WKYMVm regulated adhesion, migration, and proliferation of normal fibroblasts. Despite FPR overexpression, the response of SSc fibroblasts to the same agonists was greatly reduced, except for the proliferative response to ATF. SSc fibroblasts showed increased α-smooth muscle actin expression and improved capability to induce wound closure. Indeed, they overexpressed a cleaved uPAR form, exposing the uPAR88-92 region, and vitronectin, both involved in fibrosis and in the fibroblast-to-myofibroblast transition. FPR stimulation promoted α-smooth muscle actin expression in normal fibroblasts as well as motility, matrix deposition, αvß5 integrin expression, and radical oxygen species generation in normal and SSc fibroblasts. This study provides evidence that FPRs may play a role in fibrosis and in the fibroblast-to-myofibroblast transition.

Sandblasted-acid-etched titanium surface influences in vitro the biological behavior of SaOS-2 human osteoblast-like cells.

Osseointegrated dental implants have been successfully used over the past several years, allowing functional replacement of missing teeth. Surface properties of titanium dental implants influence bone cell response. Implant topography appears to modulate cell growth and differentiation of osteoblasts thus affecting the bone healing process. Optimal roughness and superficial morphology are still controversial and need to be clearly defined. In the present study we evaluated in vitro the biological behavior of SaOS-2 cells, a human osteoblast-like cell line, cultured on two different titanium surfaces, smooth and sandblasted-acid-etched, by investigating cell morphology, adhesion, proliferation, expression of some bone differentiation markers and extracellular matrix components. Results showed that the surface topography may influence in vitro the phenotypical expression of human osteoblast-like cells. In particular the tested sandblasted-acid-etched titanium surface induced a significantly increased Co I deposition and α2-ß1 receptor expression as compared to the relatively smooth surface, promoting a probable tendency of SaOS-2 cells to shift toward a mature osteoblastic phenotype. It is therefore likely that specific surface properties of sandblasted-acid-etched titanium implants may modulate the biological behavior of osteoblasts during bone tissue healing.

Insulin stimulates fibroblast proliferation through calcium-calmodulin-dependent kinase II.

Insulin effects are mediated by multiple integrated signals generated by the insulin receptor. Fibroblasts, as most of mammalian cells, are a target of insulin action and are important actors in the vascular pathogenesis of hyperinsulinemia. A role for calcium-calmodulin-dependent kinases (CaMK) in insulin signaling has been proposed but has been under investigated. We investigated the role of the CaMK isoform II in insulin signaling in human fibroblasts. A rapid and transient increase of intracellular calcium concentration was induced by insulin stimulation, followed by increase of CaMKII activity, via L type calcium channels. Concomitantly, insulin stimulation induced Raf-1 and ERK activation, followed by thymidine uptake. Inhibition of CaMKII abrogated the insulin-induced Raf-1 and ERK activation, resulting also in the inhibition of thymidine incorporation. These results demonstrate that in fibroblasts, insulin-activated CaMKII is necessary, together with Raf-1, for ERK activation and cell proliferation. This represents a novel mechanism in the control of insulin signals leading to fibroblast proliferation, as well as a putative site for pharmacological intervention.

Interleukin-10 and interleukin-12 modulation in patients with relapsing-remitting multiple sclerosis on therapy with interferon-beta 1a: differences in responders and non responders.

We examined the effects of interferon (IFN)beta-1a on interleukin (IL)-12p70 and IL-10 secretion in 27 Relapsing Remitting Multiple Sclerosis (RRMS) patients, divided in responders and non-responders. In responders, IFNbeta-1a does not change the IL-12p70 concentrations, but it leads to a remarkable increase in the IL-10 production. Besides, a high IL-10/IL-12 ratio is demonstrated during the first six months of therapy. In non-responders, there were not significant alterations in the cytokine profile. We suggest that IFNbeta-1a effect in RRMS patients could be explained by its modifying effect on cytokine pattern. Moreover, we propose a possible role of IL-10/IL-12 ratio as a serum marker predictive of favorable clinical course.

Granulocyte Macrophage-Colony Stimulating Factor receptor expression on human cardiomyocytes from end-stage heart failure patients.

BACKGROUND: In remodelling ventricles, the progression of heart failure is associated with structural changes involving the extra-cellular matrix (ECM) and the cytoskeleton of cardiomyocytes, associated with fibrosis, cellular damage and death. The role of some cytokines and haematopoietic growth factors in the mechanism of both damage and regeneration of cardiac tissue during acute myocardial infarction has been demonstrated. Following heart damage, the development of scarred tissue was considered to be the only outcome, since myocytes were considered to be terminally differentiated cells. However, recent studies in animal models and adult human hearts have shown that myocytes can proliferate under the modulation of several factors. AIMS: To assess Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) receptor expression in healthy and diseased human hearts, and to evaluate the possible role of GM-CSF and its receptor in the regeneration of cardiac tissue in chronic cardiomyopathy. METHODS AND RESULTS: GM-CSFR expression in human cardiac tissue from explanted hearts of ten patients with end-stage heart failure and in cardiac biopsies from eight normal human hearts was studied by immunohistochemistry, and cellular and molecular biology assays. Our results demonstrated an increase in GM-CSFR in cardiomyocytes from end-stage heart failure tissues as compared to normal control tissues. CONCLUSIONS: We hypothesize that GM-CSF plays a role in apoptotic and/or ECM deposition processes as well as in cytoskeleton modification in the myocardium.

Effect of granulocyte macrophage-colony stimulating factor on extracellular matrix deposition by dermal fibroblasts from patients with scleroderma.

OBJECTIVE: . To investigate the in vitro effect of granulocyte macrophage-colony stimulating factor (GM-CSF) on the deposition of extracellular matrix (ECM) in fibroblasts obtained from the skin of patients with systemic sclerosis (Ssc), compared to healthy controls. METHODS: Dermal fibroblasts obtained from 14 patients with SSc (7 with the diffuse form and 7 with CREST syndrome) and from 7 controls were studied. Both SSc and normal skin fibroblast cultures were stimulated for 4 and 8 days with 100 ng/ml GM-CFS. GM-CSF receptor (GM-CSFR) expression was determined by Western blot of cell lysates. Immunofluorescence was used to determine GM-CSFR expression and to investigate the deposition of ECM (type I collagen, fibronectin, and tenascin). Quantitative analysis of ECM was performed by ELISA. Expression of type I collagen and metalloproteinase 1 (MMP-1) mRNA was determined by real-time quantitative PCR. RESULTS: Deposition of ECM by normal fibroblasts appeared not to be influenced by stimulation with GM-CSF; in contrast, after stimulation with GM-CSF SSc fibroblasts showed increased deposition of fibronectin and tenascin, while type I collagen production was decreased; these results were found with both immunofluorescence and ELISA. Quantitative PCR revealed that GM-CSF inhibited the expression of mRNA type I collagen in SSc fibroblasts but not in normal fibroblasts, whereas levels of the main collagenolytic enzyme, MMP-1, were not affected. CONCLUSION: These results suggest that in SSc fibroblasts GM-CSF exerts a blocking effect on the deposition of type I collagen, through an inhibitory action on mRNA, while the production of other components of ECM such as fibronectin and tenascin is increased by stimulation with this cytokine.