C-Reactive Protein: An In-Depth Look into Structure, Function, and Regulation

Systemic inflammation biomarkers during angioedema attacks in hereditary angioedema

Background

Hereditary angioedema (HAE) is a rare disease characterized by localized and self-limited angioedema (AE) attacks. A local increase of bradykinin (BK) mediates AE attacks in HAE, however the role of inflammation in HAE has been poorly explored We aim to analyze the role of inflammatory mediators in HAE patients during AE attacks.

Methods

Patients with a confirmed HAE diagnosis due to C1 inhibitor deficiency (HAE-C1INH) or patients F12 gene mutations (HAE-FXII) attending to our outpatient clinic between November-2019 and May-2022 were included. Demographic and clinical characteristics were analyzed. Blood samples were collected both during symptom-free periods (baseline) and during HAE attacks, and acute phase reactants (APR), such as serum amyloid A (SAA), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D-Dimer and white blood cells were measured.

Results

Seventy-eight patients were enrolled in the study, with a predominant representation of women (76%, n=59), and a mean age of 47.8 years (range 6-88). Among them, 67% (n=52) of patients had HAE-C1INH (46 classified as type 1 and 6 as type 2) while 33% (n=26) had HAE-FXII. During attack-free periods, the majority of patients exhibited normal levels of SAA, ESR, D-dimer, ACE and WCC. However, in a subset of patients (16% for SAA, 18% for ESR, and 14.5% for D-dimer), elevations were noted at baseline. Importantly, during HAE attacks, significant increases were observed in SAA in 88% of patients (p< 0.0001 vs. baseline), in ESR in 65% (p= 0.003 vs. baseline) and D-dimer in 71% (p=0.001 vs. baseline) of the patients. A comparison between baseline and acute attack levels in 17 patients revealed significant differences in SAA AA (p<0. 0001), ESR (p<0.0001) and D-dimer (p= 0.004). No significant differences were observed in CRP (p=0.7), ACE (p=0.67) and WCC (p=0.54). These findings remained consistent regardless of HAE type, disease activity or location of angioedema.

Conclusion

The systemic increase in APR observed during HAE attacks suggests that inflammation extends beyond the localized edematous area. This finding underscores the potential involvement of inflammatory pathways in HAE and highlights the need for further investigation into their role in the pathophysiology of HAE.

Green Tea Extract Reduced Lipopolysaccharide-Induced Inflammation in L2 Cells as Acute Respiratory Distress Syndrome Model Through Genes and Cytokine Pro-Inflammatory

Background

Acute Respiratory Distress Syndrome (ARDS) is a severe lung inflammatory condition that has the capacity to impair gas exchange and lead to hypoxemia. This condition is found to have been one of the most prevalent in patients of COVID-19 with a more serious condition. Green tea (Camellia sinensis L.) contains polyphenols that possess many health benefits. The purpose of this study was to assess the anti-inflammatory activities of green tea extract in Lipopolysaccharide (LPS)-induced lung cells as ARDS cells model.

Methods

In this study, rat lung cells (L2) were induced by LPS to mimic the inflammation observed in ARDS and later treated with green tea extract. Pro-inflammatory cytokines such as Interleukin (IL)-12, C-Reactive Protein (CRP) as well as Tumor Necrosis Factor-α (TNF-α) were investigated using the ELISA method. Gene expression of NOD-Like Receptor Protein 3 (NLRP-3), Receptor for Advanced Glycation End-product (RAGE), Toll-like Receptor-4 (TLR-4), and Nuclear Factor-kappa B (NF-κB) were evaluated by qRTPCR. Apoptotic cells were measured using flow cytometry.

Results

The results showed that green tea extract treatment can reduce inflammation by suppressing gene expressions of NF-κB, NLRP-3, TLR-4, and RAGE, as well as pro-inflammatory cytokines such as IL-12, TNF-α, and CRP, an acute phase protein. Apoptosis levels of inflamed cells also found to be lowered when green tea extract was administered; thus, also increasing live cells compared to non-treated cells.

Conclusion

These findings could lead to the future development of supplements from green tea to help alleviate ARDS symptoms, especially during critical moments such as the current pandemic.

Association of mTOR Pathway and Conformational Alterations in C-Reactive Protein in Neurodegenerative Diseases and Infections

Inflammatory biomarkers have been very useful in detecting and monitoring inflammatory processes along with providing helpful information to select appropriate therapeutic strategies. C-reactive protein (CRP) is a nonspecific, but quite useful medical acute inflammatory biomarker and is associated with persistent chronic inflammatory processes. Several studies suggest that different levels of CRP are correlated with neurological disorders such as Alzheimer's disease (AD). However, dynamics of CRP levels have also been observed in virus/bacterial-related infections leading to inflammatory responses and this triggers mTOR-mediated pathways for neurodegeneration diseases. The biophysical structural transition from CRP to monomeric CRP (mCRP) and the significance of the ratio of CRP levels on the onset of symptoms associated with inflammatory response have been discussed. In addition, mTOR inhibitors act as immunomodulators by downregulating the expression of viral infection and can be explored as a potential therapy for neurological diseases.

Biological significance of C-reactive protein, the ancient acute phase functionary

C-reactive protein (CRP) is one of the major members of the family of acute phase proteins (APP). Interest in this CRP was the result of a seminal discovery of its pattern of response to pneumococcal infection in humans. CRP has the unique property of reacting with phosphocholine-containing substances, such as pneumococcal C-polysaccharide, in the presence of Ca2+. The attention regarding the origin of CRP and its multifunctionality has gripped researchers for several decades. The reason can be traced to the integrated evolution of CRP in the animal kingdom. CRP has been unequivocally listed as a key indicator of infectious and inflammatory diseases including autoimmune diseases. The first occurrence of CRP in the evolutionary ladder appeared in arthropods followed by molluscs and much later in the chordates. The biological significance of CRP has been established in the animal kingdom starting from invertebrates. Interestingly, the site of synthesis of CRP is mainly the liver in vertebrates, while in invertebrates it is located in diverse tissues. CRP is a multifunctional player in the scenario of innate immunity. CRP acts as an opsonin in the area of complement activation and phagocytosis. Interestingly, CRP upregulates and downregulates both cytokine production and chemotaxis. Considering various studies of CRP in humans and non-human animals, it has been logically proposed that CRP plays a common role in animals. CRP also interacts with Fcγ receptors and triggers the inflammatory response of macrophages. CRP in other animals such as primates, fish, echinoderms, arthropods, and molluscs has also been studied in some detail which establishes the evolutionary significance of CRP. In mammals, the increase in CRP levels is an induced response to inflammation or trauma; interestingly, in arthropods and molluscs, CRP is constitutively expressed and represents a major component of their hemolymph. Investigations into the primary structure of CRP from various species revealed the overall relatedness between vertebrate and invertebrate CRP. Invertebrates lack an acquired immune response; they are therefore dependent on the multifunctional role of CRP leading to the evolutionary success of the invertebrate phyla.

C-reactive protein impairs immune response of CD8+ T cells via FcγRIIb-p38MAPK-ROS axis in multiple myeloma

BACKGROUND

C-reactive protein (CRP) is a prototypical acute phase protein in humans with the function of regulating immune cells. Serum CRP levels are elevated in multiple myeloma (MM), associated with MM cell proliferation and bone destruction. However, its direct effects on T lymphocytes in MM have not been elucidated.

METHODS

Public data sets were used to explore the correlation of CRP levels with immune cell infiltration and cytotoxicity score of CD8+ T cells in MM. In vitro, repeated freeze-thaw myeloma cell lines were taken as tumor antigens to load dendritic cells (DCs) derived from HLA-A*0201-positive healthy donors. MM-specific cytotoxic T cells (MM-CTL) were obtained from T lymphocytes of the corresponding donors pulsed with these DCs. B-cell maturation antigen (BCMA)-targeted chimeric antigen receptor (CAR)-T cells were manipulated by transfecting with lentivirus encoding an anti-BCMA single-chain variable fragment. Then T cells from healthy controls, MM-CTLs and BCMA CAR-T cells were exposed to CRP and analyzed for cell proliferation, cytotoxicity, immunophenotypes. CRP binding capacity to T cells before and after Fc gamma receptors IIb (FcγRIIb) blockage, p38 mitogen-activated protein kinase (MAPK) pathway and the downstream molecules were also detected. In vivo, both normal C57BL/6J mice and the Vk*MYC myeloma mouse models were applied to confirm the impact of CRP on T cells.

RESULTS

CRP levels were negatively correlated with cell-infiltration and cytotoxicity score of CD8+ T cells in MM. In vitro experiments showed that CRP inhibited T-cell proliferation in a dose-dependent manner, impaired the cytotoxic activity and upregulated expression of senescent markers in CD8+ T cells. In vivo results validated the suppressive role of CRP in CD8+ T cells. CRP could bind to CD8+ T cells, mainly to the naïve T subset, while the binding was dramatically decreased by FcγRIIb blockage. Furthermore, CRP resulted in increased phosphorylation of p38 MAPK, elevated levels of reactive oxygen species and oxidized glutathione in CD8+ T cells.

CONCLUSIONS

We found that CRP impaired immune response of CD8+ T cells via FcγRIIb-p38MAPK-ROS signaling pathway. The study casted new insights into the role of CRP in anti-myeloma immunity, providing implications for future immunotherapy in MM.

Mutations on a conserved distal enhancer in the porcine C-reactive protein gene impair its expression in liver

C-reactive protein (CRP) is an evolutionary highly conserved protein. Like humans, CRP acts as a major acute phase protein in pigs. While CRP regulatory mechanisms have been extensively studied in humans, little is known about the molecular mechanisms that control pig CRP gene expression. The main goal of the present work was to study the regulatory mechanisms and identify functional genetic variants regulating CRP gene expression and CRP blood levels in pigs. The characterization of the porcine CRP proximal promoter region revealed a high level of conservation with both cow and human promoters, sharing binding sites for transcription factors required for CRP expression. Through genome-wide association studies and fine mapping, the most associated variants with both mRNA and protein CRP levels were localized in a genomic region 39.3 kb upstream of CRP. Further study of the region revealed a highly conserved putative enhancer that contains binding sites for several transcriptional regulators such as STAT3, NF-kB or C/EBP-β. Luciferase reporter assays showed the necessity of this enhancer-promoter interaction for the acute phase induction of CRP expression in liver, where differences in the enhancer sequences significantly modified CRP activity. The associated polymorphisms disrupted the putative binding sites for HNF4α and FOXA2 transcription factors. The high correlation between HNF4α and CRP expression levels suggest the participation of HNF4α in the regulatory mechanism of porcine CRP expression through the modification of its binding site in liver. Our findings determine, for the first time, the relevance of a distal regulatory element essential for the acute phase induction of porcine CRP in liver and identify functional polymorphisms that can be included in pig breeding programs to improve immunocompetence.

Fueling the flames of colon cancer – does CRP play a direct pro-inflammatory role?

Background

Systemic inflammation, diagnostically ascribed by measuring serum levels of the acute phase reactant C-reactive protein (CRP), has consistently been correlated with poor outcomes across cancer types. CRP exists in two structurally and functionally distinct isoforms, circulating pentameric CRP (pCRP) and the highly pro-inflammatory monomeric isoform (mCRP). The aim of this pilot study was to map the pattern of mCRP distribution in a previously immunologically well-defined colon cancer (CC) cohort and explore possible functional roles of mCRP within the tumor microenvironment (TME).

Methods

Formalin-fixed, paraffin-embedded (FFPE) tissue samples from 43 stage II and III CC patients, including 20 patients with serum CRP 0-1 mg/L and 23 patients with serum CRP &gt;30 mg/L were immunohistochemically (IHC) stained with a conformation-specific mCRP antibody and selected immune and stromal markers. A digital analysis algorithm was developed for evaluating mCRP distribution within the primary tumors and adjacent normal colon mucosa.

Results

mCRP was abundantly present within tumors from patients with high serum CRP (&gt;30 mg/L) diagnostically interpreted as being systemically inflamed, whereas patients with CRP 0-1 mg/L exhibited only modest mCRP positivity (median mCRP per area 5.07‰ (95%CI:1.32-6.85) vs. 0.02‰ (95%CI:0.01-0.04), p&lt;0.001). Similarly, tissue-expressed mCRP correlated strongly with circulating pCRP (Spearman correlation 0.81, p&lt;0.001). Importantly, mCRP was detected exclusively within tumors, whereas adjacent normal colon mucosa showed no mCRP expression. Double IHC staining revealed colocalization of mCRP with endothelial cells and neutrophils. Intriguingly, some tumor cells also colocalized with mCRP, suggesting a direct interaction or mCRP expression by the tumor itself.

Conclusion

Our data show that the pro-inflammatory mCRP isoform is expressed in the TME of CC, primarily in patients with high systemic pCRP values. This strengthens the hypothesis that CRP might not only be an inflammatory marker but also an active mediator within tumors.

Role of High-Sensitivity C-reactive Protein (Hs-CRP) in Non-communicable Diseases: A Review

Non-communicable diseases like cardiovascular diseases, cerebrovascular diseases, diabetes mellitus, and cancer are very common causes of death worldwide. Therefore, the need to search for novel, affordable, and easily accessible biomarkers and risk factors for non-communicable diseases continues, which can predict the future risk of having these diseases with greater accuracy and precision. In this context, among available biomarkers, high-sensitivity C-reactive protein (Hs-CRP) is considered to be the best-suited marker. Various drug intervention trials demonstrated positive results in reducing Hs-CRP in individuals with raised levels. Numerous pharmacological and non-pharmacologic interventions in the form of lifestyle modifications, exercise, and cessation of smoking are being investigated to study their effect on reducing serum C-reactive protein (CRP) levels.

This review article discusses the role of Hs-CRP and its isoforms in the pathogenesis of various disease conditions, factors affecting its serum concentration, its prognostic value, and its comparison with other risk factors. Further, its clinical significance in chronic inflammatory and degenerative diseases of the nervous system and other common non-communicable diseases, including recent advances in the management of various diseases, has also been discussed.

Association between Endodontic Infection, Its Treatment and Systemic Health: A Narrative Review

The ‘Focal Infection Era in Dentistry’ in the late 19th and early 20th century resulted in widespread implementation of tooth extraction and limited the progress of endodontics. The theory proposed that bacteria and toxins entrapped in dentinal tubules could disseminate systemically to remote body parts, resulting in many types of degenerative systemic diseases. This theory was eventually refuted due to anecdotal evidence. However, lately there has been increased interest in investigating whether endodontic disease could have an impact on general health. There are reviews that have previously been carried out on this subject, but as new data have emerged since then, this review aims to appraise the available literature investigating the dynamic associations between apical periodontitis, endodontic treatment, and systemic health. The available evidence regarding focal infection theory, bacteraemia and inflammatory markers was appraised. The review also collated the available research arguing the associations of apical periodontitis with cardiovascular diseases, diabetes mellitus, adverse pregnancy outcome and autoimmune disorders, along with the effect of statins and immunomodulators on apical periodontitis prevalence and endodontic treatment prognosis. There is emerging evidence that bacteraemia and low-grade systemic inflammation associated with apical periodontitis may negatively impact systemic health, e.g., development of cardiovascular diseases, adverse pregnancy outcomes, and diabetic metabolic dyscontrol. However, there is limited information supporting the effect of diabetes mellitus or autoimmune disorders on the prevalence and prognosis post endodontic treatment. Furthermore, convincing evidence supports that successful root canal treatment has a beneficial impact on systemic health by reducing the inflammatory burden, thereby dismissing the misconceptions of focal infection theory. Although compelling evidence regarding the association between apical periodontitis and systemic health is present, further high-quality research is required to support and establish the benefits of endodontic treatment on systemic health.

The Isopropyl Gallate Counteracts Cyclophosphamide-Induced Hemorrhagic Cystitis in Mice

Simple Summary

Ifosfamide (IFOS) is an antineoplastic drug used to treat various cancers. Hemorrhagic cystitis (HC) is the main adverse effect related to the use of IFOS. Acrolein, a metabolite of IFOS, is the main molecule responsible for this side-effect, resulting in increased oxidative stress and production of inflammatory mediators, which culminate in the degradation of bladder tissue. In clinical practice, mesna is used to reduce the incidence of HC. However, this drug presents some dose-dependent side effects. Isopropyl gallate (IPG), a gallic acid-derived compound, is promising for the development of new anti-inflammatory agents. In the present study, the effects of oral administration of IPG against IFOS-induced hemorrhagic cystitis in mice were investigated. Interestingly pretreatment of IPG was able to reduce IFOS-induced bladder damage evidenced by a decrease of inflammatory parameters and improvement in histology and antioxidants of the urinary bladder. Furthermore, IPG significantly decreased the expression levels of inflammatory biomarkers in the bladder tissue. These preliminary findings suggest that IPG represents a promising adjuvant therapy for protecting against IFOS-induced urotoxicity.

Abstract

Hemorrhagic cystitis is the main adverse effect associated with the clinical use of oxazaphosphorine, resulting in increased oxidative stress and proinflammatory cytokines, which culminate in injury of the bladder tissue. The aim of this study was to evaluate the protective effect of isopropyl gallate (IPG) against ifosfamide (IFOS)-induced hemorrhagic cystitis in mice. The induction of the hemorrhagic cystitis model was carried out using a single dose of IFOS (400 mg/kg, i.p.) four hours after oral pretreatment with IPG (6.25, 12.5, 25, and 50 mg/kg) or saline (vehicle). Mesna (positive control; 80 mg/kg, i.p.) was administered four hours before and eight hours after induction of cystitis. In the present study, IPG 25 mg/kg significantly decreased edema and hemorrhage, with a reduction of the bladder wet weight (36.86%), hemoglobin content (54.55%), and peritoneal vascular permeability (42.94%) in urinary bladders of mice. Interestingly, IPG increased SOD activity (89.27%) and reduced MDA levels (35.53%), as well as displayed anti-inflammatory activity by decreasing TNF-α (88.77%), IL-1β (62.87%), and C-reactive protein (56.41%) levels. Our findings demonstrate that IPG has a substantial protective role against IFOS-induced hemorrhagic cystitis in mice by enhancing antioxidant activity and proinflammatory mechanisms. Thus, IPG represents a promising co-adjuvant agent in oxazaphosphorine-based chemotherapy treatments.

Association of vitamin D status with COVID‐19 disease severity in pediatric patients: A retrospective observational study

Background and Aims

Methods

Results

Conclusion

C-reactive protein as a potential biomarker in psychiatric practice: Are we there yet?

OBJECTIVES

Serum or plasma levels of C-reactive protein (CRP) and high-sensitivity CRP (hsCRP) are widely used clinical markers of inflammation in other branches of medicine, whereas its clinical use in psychiatry has been limited to research studies. We aimed to assess the possibility of using CRP/hsCRP in psychiatric practice. This is a review and evaluation of various lines of evidence supporting the concept of CRP as a biomarker for psychiatric disorders in certain conditions.

METHODS

We searched the literature for studies which assessed CRP/hsCRP levels in various psychiatric disorders.

RESULTS

The accumulating evidence from large studies and meta-analyses allows us to understand the role of CRP in major psychiatric disorders and increase our understanding of specific symptoms and subtypes of disorders. CRP may be considered a 'psychiatric biomarker' which can alert clinicians about neuroinflammation, adverse effects of medications, cardiometabolic status, co-morbidities, and may also predict clinical outcomes and guide optimal treatment.selection.

CONCLUSION

Although the underlying pathophysiological role of CRP and hsCRP is still elusive and the association between CRP and psychiatric disorders is inconsistent, CRP holds promise to become a psychiatric biomarker.

Pattern Recognition Proteins: First Line of Defense Against Coronaviruses

The rapid outbreak of COVID-19 caused by the novel coronavirus SARS-CoV-2 in Wuhan, China, has become a worldwide pandemic affecting almost 204 million people and causing more than 4.3 million deaths as of August 11 2021. This pandemic has placed a substantial burden on the global healthcare system and the global economy. Availability of novel prophylactic and therapeutic approaches are crucially needed to prevent development of severe disease leading to major complications both acutely and chronically. The success in fighting this virus results from three main achievements: (a) Direct killing of the SARS-CoV-2 virus; (b) Development of a specific vaccine, and (c) Enhancement of the host's immune system. A fundamental necessity to win the battle against the virus involves a better understanding of the host's innate and adaptive immune response to the virus. Although the role of the adaptive immune response is directly involved in the generation of a vaccine, the role of innate immunity on RNA viruses in general, and coronaviruses in particular, is mostly unknown. In this review, we will consider the structure of RNA viruses, mainly coronaviruses, and their capacity to affect the lungs and the cardiovascular system. We will also consider the effects of the pattern recognition protein (PRP) trident composed by (a) Surfactant proteins A and D, mannose-binding lectin (MBL) and complement component 1q (C1q), (b) C-reactive protein, and (c) Innate and adaptive IgM antibodies, upon clearance of viral particles and apoptotic cells in lungs and atherosclerotic lesions. We emphasize on the role of pattern recognition protein immune therapies as a combination treatment to prevent development of severe respiratory syndrome and to reduce pulmonary and cardiovascular complications in patients with SARS-CoV-2 and summarize the need of a combined therapeutic approach that takes into account all aspects of immunity against SARS-CoV-2 virus and COVID-19 disease to allow mankind to beat this pandemic killer.

The influence of sugar-protein complexes on the thermostability of C-reactive protein (CRP)

The purpose of the present study was to evaluate de influence of protein–sugar complexation on the stability and functionality of C-reactive protein, after exposure to constant high temperatures, in order to develop highly stable positive controls for in-vitro diagnostic tests. C-reactive protein is a plasmatic protein used as a biomarker for the diagnosis of a series of health problems such as ulcerative colitis, cardiovascular diseases, metabolic syndrome, due to its essential role in the evolution of chronic inflammation. The sugar–protein interaction was investigated using steady state and time resolved fluorescence. The results revealed that there are more than two classes of tryptophan, with different degree of accessibility for the quencher molecule. Our study also revealed that sugar–protein complexes have superior thermostability, especially after gamma irradiation at 2 kGy, the protein being stable and functional even after 22 days exposure to 40 °C.

Mechanism of Physical Exercise on Lowering Levels of C-Reactive Protein (CRP) in Overweight and Obese

Cases of overweight and obesity in the world increased continuously. In 2016, obesity increased by 3% in men and 6% in women compared to 1975. Overweight cases also increased by 20% in men and 23% in women compared to 1975. Overweight and obesity have been linked to an increase in adipose tissue in the body. Increased adipose tissue associated with inflammation, which one of its characteristics is an increase levels of C - Reactive Protein (CRP). This article aim is to describe the mechanism of physical exercise to diminish CRP level in overweight and obesity. Adipose tissue produces and releases various pro-inflammatory and anti-inflammatory factors such as leptin, adiponectin, resistin, TNF-α, IL-6, MCP-1 and CRP. One of the prevention and treatment of inflammatory for overweight and obesity cases is to do physical exercise. In cases of overweight and obesity, the physical exercise aims to increase energy expenditure. Physical exercise decreases the volume and amount of adipose and pre-adipose tissue as well as the number of endothelial cells and macrophages in adipose that contain pro-inflammation such as IL-1, TNF-α, CRP, serum amyloid protein (SAA), and cytokines. Physical exercise rises anti-inflammatory properties such as IL-10, IL-1ra which play a role in inhibiting the transduction of IL-1β signals and inhibiting TNF-α synthesis. Physical exercise also amplifies antioxidant enzymes such as SOD and GPX. The antioxidants play a role in fighting free radicals to reduce inflammation.

Nanodiagnostic Attainments and Clinical Perspectives on C-Reactive Protein: Cardiovascular Disease Risks Assessment

Cardiovascular disease (CVD) has become one of the leading causes of morbidity and mortality in both men and women. According to the World Health Organization (WHO), ischemic heart disease is the major issue due to the narrowing of the coronary artery by plaque formation on the artery wall, which causes an inadequate flow of oxygen and blood to the heart and is called 'coronary artery disease'. The CVD death rate increased by up to 15% in 2016 (~17.6 million) compared to the past decade. This tremendous increment urges the development of a suitable biomarker for rapid and early diagnosis. Currently, C-reactive protein (CRP) is considered an outstanding biomarker for quick and accurate outcomes in clinical analyses. Various techniques have also been used to diagnose CVD, including surface plasmon resonance (SPR), colorimetric assay, enzyme-linked immunosorbent assay (ELISA), fluoro-immunoassays, chemiluminescent assays, and electrical measurements. This review discusses such diagnostic strategies and how current, cutting-edge technologies have enabled the development of high-performance detection methodologies. Concluding remarks have been made concerning the clinical significance and the use of nanomaterial in medical diagnostics towards nanotheranostics.

C-Reactive Protein Enhances IgG-Mediated Cellular Destruction Through IgG-Fc Receptors in vitro

Antibody-mediated blood disorders ensue after auto- or alloimmunization against blood cell antigens, resulting in cytopenia. Although the mechanisms of cell destruction are the same as in immunotherapies targeting tumor cells, many factors are still unknown. Antibody titers, for example, often do not strictly correlate with clinical outcome. Previously, we found C-reactive protein (CRP) levels to be elevated in thrombocytopenic patients, correlating with thrombocyte counts, and bleeding severity. Functionally, CRP amplified antibody-mediated phagocytosis of thrombocytes by phagocytes. To investigate whether CRP is a general enhancer of IgG-mediated target cell destruction, we extensively studied the effect of CRP on in vitro IgG-Fc receptor (FcγR)-mediated cell destruction: through respiratory burst, phagocytosis, and cellular cytotoxicity by a variety of effector cells. We now demonstrate that CRP also enhances IgG-mediated effector functions toward opsonized erythrocytes, in particular by activated neutrophils. We performed a first-of-a-kind profiling of CRP binding to all human FcγRs and IgA-Fc receptor I (FcαRI) using a surface plasmon resonance array. CRP bound these receptors with relative affinities of FcγRIa = FcγRIIa/b = FcγRIIIa > FcγRIIIb = FcαRI. Furthermore, FcγR blocking (in particular FcγRIa) abrogated CRP's ability to amplify IgG-mediated neutrophil effector functions toward opsonized erythrocytes. Finally, we observed that CRP also amplified killing of breast-cancer tumor cell line SKBR3 by neutrophils through anti-Her2 (trastuzumab). Altogether, we provide for the first time evidence for the involvement of specific CRP-FcγR interactions in the exacerbation of in vitro IgG-mediated cellular destruction; a trait that should be further evaluated as potential therapeutic target e.g., for tumor eradication.

Common and Novel Markers for Measuring Inflammation and Oxidative Stress Ex Vivo in Research and Clinical Practice-Which to Use Regarding Disease Outcomes?

Many chronic conditions such as cancer, chronic obstructive pulmonary disease, type-2 diabetes, obesity, peripheral/coronary artery disease and auto-immune diseases are associated with low-grade inflammation. Closely related to inflammation is oxidative stress (OS), which can be either causal or secondary to inflammation. While a low level of OS is physiological, chronically increased OS is deleterious. Therefore, valid biomarkers of these signalling pathways may enable detection and following progression of OS/inflammation as well as to evaluate treatment efficacy. Such biomarkers should be stable and obtainable through non-invasive methods and their determination should be affordable and easy. The most frequently used inflammatory markers include acute-phase proteins, essentially CRP, serum amyloid A, fibrinogen and procalcitonin, and cytokines, predominantly TNFα, interleukins 1β, 6, 8, 10 and 12 and their receptors and IFNγ. Some cytokines appear to be disease-specific. Conversely, OS-being ubiquitous-and its biomarkers appear less disease or tissue-specific. These include lipid peroxidation products, e.g., F2-isoprostanes and malondialdehyde, DNA breakdown products (e.g., 8-OH-dG), protein adducts (e.g., carbonylated proteins), or antioxidant status. More novel markers include also -omics related ones, as well as non-invasive, questionnaire-based measures, such as the dietary inflammatory-index (DII), but their link to biological responses may be variable. Nevertheless, many of these markers have been clearly related to a number of diseases. However, their use in clinical practice is often limited, due to lacking analytical or clinical validation, or technical challenges. In this review, we strive to highlight frequently employed and useful markers of inflammation-related OS, including novel promising markers.

Recombinant C-Reactive Protein: A Potential Candidate for the Treatment of Cutaneous Leishmaniasis of BALB/c Mice Caused by Leishmania major

PURPOSE

Leishmaniasis, a widespread parasitic disease, is a public health concern that is endemic in more than 90 countries. Owing to the drug resistance and also undesirable complications, designing new therapeutic methods are essential. C-reactive protein (CRP) is an acute phase protein of plasma with several immune modulatory functions. This study aimed to evaluate the effect of human recombinant CRP (hrCRP) on treating cutaneous leishmaniasis in mice models.

METHODS

hrCRP was expressed in E. coli Rosetta-gami and extracted from the SDS-PAGE gel. Male BALB/c mice were inoculated subcutaneously at the base of their tails by 1 × 10⁵ stationary-phase of Leishmania major promastigotes (MHRO/IR/75/ER) suspended in sterile phosphate buffered saline (PBS). Nodules and subsequently, ulcers developed 14 days post-injection. 1.5 µg of the purified protein was administered on lesions of pre-infected mice by Leishmania major in the intervention group for five consecutive days.

RESULTS

The mean area of the lesions was decreased by about seven folds in the intervention group as compared to the control group after two weeks of the treatment (p = 0.024). The results were verified by the real-time polymerase chain reaction so that the parasite burden was determined 2⁷ times in the control group as compared to the intervention group (p = 0.02). Two weeks after treatment, the conversion of the lesions to scars in the intervention group was observed.

CONCLUSION

The results indicate a potential therapeutic role for hrCRP in improving cutaneous leishmaniasis due to Leishmania major in mice models. The healing was in a stage-dependent manner.

Revisiting the clinical usefulness of C-reactive protein in the set of cancer cachexia

Cancer cachexia is a highly complex multifactorial disorder that is often misdiagnosed, leading to suboptimal health outcomes. Indeed, cachexia is a concern in cancer, typifying lower response to treatment and risk of death. Thus, efforts have been made to better understand the molecular basis of this syndrome, envisioning to improve its diagnosis and management.

C-reactive protein (CRP) has been reported to be consistently increased in the circulation of patients with body wasting associated to chronic diseases. However, the role of CRP in the pathogenesis of cachexia remains elusive. Several hypotheses have been advanced but most of experimental findings support an indirect effect on the activation of muscle proteolysis, mostly through its interplay with pro-inflammatory cytokines. Herein, we overview the contribution of CRP to body wasting and its putative biomarker value for the diagnosis and follow-up of the therapeutic management of cachexia.

Vitamin D deficiency is associated with COVID-19 positivity and severity of the disease

The present study examined the relationship between polymerase chain reaction (PCR) test positivity and clinical outcomes of vitamin D levels measured within the 6 months before the PCR test in coronavirus disease 2019 (COVID‐19)‐positive patients. In this retrospective cohort study, COVID‐19 (227) and non‐COVID‐19 patients (260) were divided into four groups according to their vitamin D levels: Group I (0–10 ng/ml), Group II (10–20 ng/ml), Group III (20–30 ng/ml), and Group IV (vitamin D > 30 ng/ml). Laboratory test results and the radiological findings were evaluated. In addition, for comparative purposes, medical records of 1200 patients who had a hospital visit in the November 1, 2019–November 1, 2020 period for complaints due to reasons not related to COVID‐19 were investigated for the availability of vitamin D measurements. This search yielded 260 patients with tested vitamin D levels. Vitamin D levels were below 30 ng/ml in 94.27% of 227 COVID‐19‐positive patients (average age, 46.32 ± 1.24 years [range, 20–80 years] and 56.54% women) while 93.07% of 260 non‐COVID‐19 patients (average age, 44.63 ± 1.30 years [range, 18–75 years] and 59.50% women) had vitamin D levels below 30 ng/ml. Nevertheless, very severe vitamin D deficiency (<10 ng/ml) was considerably more common in COVID‐19 patients (44%) (average age, 44.15 ± 1.89 years [range, 23–80 years] and 57.57% women) than in non‐COVID‐19 ones (31%) (average age, 46.50 ± 2.21 years [range, 20–75 years] and 62.5% women). Among COVID‐19‐positive patients, the group with vitamin D levels of  >30 ng/ml had significantly lower D‐dimer and C‐reactive protein (CRP) levels, number levels, number of affected lung segments and shorter hospital stays. No difference was found among the groups in terms of age and gender distribution. Elevated vitamin D levels could decrease COVID‐19 PCR positivity, D‐dime and CRP levels and the number of affected lung segments in COVID‐19‐positive patients, thereby shortening the duration of hospital stays and alleviating the intensity of COVID‐19.

Upregulation of C-Reactive Protein by Placenta-Derived Mesenchymal Stem Cells Promotes Angiogenesis in A Rat Model with Cirrhotic Liver

Background and Objectives

Liver cirrhosis is accompanied by abnormal vascular shunts. The Wnt pathway is essential for endothelial cell survival and proliferation. C-reactive protein (CRP), which is produced by hepatocyte, activates angiogenesis in cardiovascular diseases.

Methods and Results

The expression of CRP in CCl₄-injured rat livers was detected using qRT-PCR and Western blotting after transplantation of placenta-derived mesenchymal stem cells (PD-MSCs) into rats. To determine whether CRP functions in hepatic regeneration by promoting angiogenesis through the Wnt pathway, we detected VEGF and β-catenin in liver tissues and BrdU and β-catenin in hepatocytes by immunofluorescence. The expression levels of CRP, Wnt pathway-related and angiogenic factors were increased in CCl₄-injured and PD-MSCs transplanted rat livers. In vitro, the expression levels of Wnt signaling and angiogenic factors were decreased in siRNA-CRP-transfected rat hepatocytes.

Conclusions

CRP upregulation by PD-MSCs participates in vascular remodeling to promote liver regeneration via the Wnt signaling pathway during hepatic failure.

iTRAQ-based proteomics reveals serum protein changes in hypertensive rats induced by a high-salt diet

High-salt diets may increase both hypertension and risk of cardiovascular diseases. Although high-salt diets can result in hypertension and impaired vascular function, the molecular mechanisms underlying these dysfunctions are not fully known. Thus, the aims of the present study were to identify key proteins and their signaling pathways and associated molecular mechanisms that may contribute to, as well as be potential biomarkers of, the pathogenesis of hypertension-related cardiovascular diseases. To that end, the present study identified and quantitated serum proteins that were differentially expressed in male rats fed regular chow (n = 4) and those fed a high-salt diet (n = 4) to induce hypertension. The serum was collected from both groups, and the proteins differentially expressed in the serum were identified and quantitated using isobaric tags for relative and absolute quantitation combined with liquid chromatography-tandem mass spectrometry. Of 396 identified proteins, 24 were differentially expressed between the groups: 19 proteins were significantly (P < 0.05) upregulated (> 1.2 fold change), and 5 were significantly downregulated (< 0.8 fold change). Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that these differentially expressed proteins may contribute to cardiovascular diseases via the roles they play in endothelial function, vascular remodeling, the coagulation cascade, and the complement system. In addition, phagosome processes and the integrin-associated focal adhesion signaling pathway were determined to be potential underlying molecular mechanisms. The key proteins identified in this study warrant further development as new therapeutic targets or biomarkers of cardiovascular diseases associated with high-salt diet-induced hypertension.

Soluble pattern recognition molecules: Guardians and regulators of homeostasis at airway mucosal surfaces

Maintenance of homeostasis at body barriers that are constantly challenged by microbes, toxins and potentially bioactive (macro)molecules requires complex, highly orchestrated mechanisms of protection. Recent discoveries in respiratory research have shed light on the unprecedented role of airway epithelial cells (AEC), which, besides immune cells homing to the lung, also significantly contribute to host defence by expressing membrane‐bound and soluble pattern recognition receptors (sPRR). Recent evidence suggests that distinct, evolutionary ancient, sPRR secreted by AEC might become activated by usually innocuous proteins, commonly referred to as allergens. We here provide a systematic overview on sPRR detectable in the mucus lining of AEC. Some of them become actively produced and secreted by AECs (like the pentraxins C‐reactive protein and pentraxin 3; the collectins mannose binding protein and surfactant proteins A and D; H‐ficolin; serum amyloid A; and the complement components C3 and C5). Others are elaborated by innate and adaptive immune cells such as monocytes/macrophages and T cells (like the pentraxins C‐reactive protein and pentraxin 3; L‐ficolin; serum amyloid A; and the complement components C3 and C5). Herein we discuss how sPRRs may contribute to homeostasis but sometimes also to overt disease (e.g. airway hyperreactivity and asthma) at the alveolar–air interface.

Association between C reactive protein and all-cause mortality in the ELSA-Brasil cohort

Background

High-sensitivity C reactive protein (hsCRP) has been proposed as a marker of incident cardiovascular disease and vascular mortality, and may also be a marker of non-vascular mortality. However, most evidence comes from either North American or European cohorts. The present proposal aims to investigate the association of hsCRP with the risk of all-cause mortality in a multiethnic Brazilian population.

Methods

Baseline data (2008–2010) of a cohort of 14 238 subjects participating in the Brazilian Longitudinal Study of Adult Health were used. hsCRP was assayed with immunochemistry. The association of baseline covariates with all-cause mortality was calculated by Cox regression for univariate model and adjusted for different confounders after a mean follow-up of 8.0±1.1 years. The final model was adjusted for age, sex, self-rated race/ethnicity, schooling, health behaviours and prevalent chronic disease.

Results

The risk of death increased steadily by quartiles of hsCRP, from 1.45 (95% CI 1.05 to 2.01) in quartile 2 to 1.95 (95% CI 1.42 to 2.69) in quartile 4, compared with quartile 1. Furthermore, the persistence of a significant graded association after the exclusion of deaths in the first year of follow-up suggests that these results are unlikely to be due to reverse causality. Finally, the HR was unaffected by the exclusion of participants who had self-reported medical history of diabetes, cancer and chronic obstructive pulmonary disease.

Conclusions

Our study shows that hsCRP level is associated with mortality in a highly admixed population, independent of a large set of lifestyle and clinical variables.

Functionality of C-Reactive Protein for Atheroprotection

C-reactive protein (CRP) is a pentameric molecule made up of identical monomers. CRP can be seen in three different forms: native pentameric CRP (native CRP), non-native pentameric CRP (non-native CRP), and monomeric CRP (mCRP). Both native and non-native CRP execute ligand-recognition functions for host defense. The fate of any pentameric CRP after binding to a ligand is dissociation into ligand-bound mCRP. If ligand-bound mCRP is proinflammatory, like free mCRP has been shown to be in vitro, then mCRP along with the bound ligand must be cleared from the site of inflammation. Once pentameric CRP is bound to atherogenic low-density lipoprotein (LDL), it reduces both formation of foam cells and proinflammatory effects of atherogenic LDL. A CRP mutant, that is non-native CRP, which readily binds to atherogenic LDL, has been found to be atheroprotective in a murine model of atherosclerosis. Thus, unlike statins, a drug that can lower only cholesterol levels but not CRP levels should be developed. Since non-native CRP has been shown to bind to all kinds of malformed proteins in general, it is possible that non-native CRP would be protective against all inflammatory states in which host proteins become pathogenic. If it is proven through experimentation employing transgenic mice that non-native CRP is beneficial for the host, then using a small-molecule compound to target CRP with the goal of changing the conformation of endogenous native CRP would be preferred over using recombinant non-native CRP as a biologic to treat diseases caused by pathogenic proteins such as oxidized LDL.

Structure-Function Relationships of C-Reactive Protein in Bacterial Infection

One host defense function of C-reactive protein (CRP) is to protect against Streptococcus pneumoniae infection as shown by experiments employing murine models of pneumococcal infection. The protective effect of CRP is due to reduction in bacteremia. There is a distinct relationship between the structure of CRP and its anti-pneumococcal function. CRP is functional in both native and non-native pentameric structural conformations. In the native conformation, CRP binds to pneumococci through the phosphocholine molecules present on the C-polysaccharide of the pneumococcus and the anti-pneumococcal function probably involves the known ability of ligand-complexed CRP to activate the complement system. In the native structure-function relationship, CRP is protective only when given to mice within a few hours of the administration of pneumococci. The non-native pentameric conformation of CRP is created when CRP is exposed to conditions mimicking inflammatory microenvironments, such as acidic pH and redox conditions. In the non-native conformation, CRP binds to immobilized complement inhibitor factor H in addition to being able to bind to phosphocholine. Recent data using CRP mutants suggest that the factor H-binding function of non-native CRP is beneficial: in the non-native structure-function relationship, CRP can be given to mice any time after the administration of pneumococci irrespective of whether the pneumococci became complement-resistant or not. In conclusion, while native CRP is protective only against early stage infection, non-native CRP is protective against both early stage and late stage infections. Because non-native CRP displays phosphocholine-independent anti-pneumococcal activity, it is quite possible that CRP functions as a general anti-bacterial molecule.

Characterization of a subgroup of non-type 2 asthma with cow's milk hypersensitivity in young subjects

Background

Asthma with atopy is often characterized by type 2 inflammation but less progress has been made in defining non-type 2 asthma. We have previously identified a subgroup of young non-atopic asthmatics with perceived food hypersensitivity and poor asthma control.

Objective

Our aim was to further characterize this subgroup of non-type 2 asthmatics, including the use of a broad panel of inflammation-related proteins.

Methods

Sex- and age-matched subjects (10–35 years old) were divided into three groups with regard to history of asthma and atopy: non-atopic asthmatics with perceived cow’s milk hypersensitivity but with IgE antibodies < 0.35 kU_A/L (NAA; n = 24), non-atopic controls with IgE < 0.35 kU_A/L (NAC; n = 24), and atopic asthmatics with IgE ≥ 0.35 kU_A/L (AA; n = 29). Serum or plasma were analysed using the multi-allergen tests Phadiatop and fx5 (ImmunoCAP), a multiplex immunoassay comprising 92 inflammation-related proteins (Proseek Inflammation), and an ELISA for human neutrophil lipocalin (S-HNL). Fraction of exhaled nitric oxide (FeNO), blood eosinophil (B-Eos) count, C-reactive protein (CRP), airway responsiveness to methacholine (PD₂₀), and asthma-related quality of life (mAQLQ) were also measured.

Results

NAA had lower FeNO (p < 0.001) and B-Eos count (p < 0.001), but scored worse on mAQLQ (p = 0.045) compared with AA. NAA displayed higher levels of matrix metalloproteinase-1 (MMP-1) compared with both NAC (p = 0.011) and AA (p = 0.001), and lower PD₂₀ compared with NAC (p < 0.001). In NAA, S-HNL correlated negatively with PD₂₀ (rho = − 0.048, p < 0.05) and CRP correlated negatively with mAQLQ (rho = − 0.439, p < 0.05).

Conclusion

In a subgroup of non-atopic young asthmatics with perceived cow’s milk hypersensitivity we observed poor asthma-related quality of life, airway hyperresponsiveness, and clinically relevant non-type 2 inflammation. MMP-1 was elevated in this group, which deserves further studies.

Electronic supplementary material

The online version of this article (10.1186/s13601-019-0250-2) contains supplementary material, which is available to authorized users.

Sleep Quality in Ulcerative Colitis: Associations with Inflammation, Psychological Distress, and Quality of Life

PURPOSE

Treatment of ulcerative colitis (UC), given its chronicity and its associated disruptive and often distressing symptoms, is increasingly focusing on maximizing patient quality of life. Poorer quality of life has been found among patients with poor sleep quality, which is much more common in patients with UC than in the general population and may be associated with inflammation and psychological distress.

METHOD

Forty-seven patients with UC (n = 11 flaring) completed measures of sleep quality, depression, state anxiety, gastrointestinal-related anxiety, perceived stress, and quality of life. Measures of inflammation were also obtained.

RESULTS

Patients endorsed high rates of poor sleep quality, which was highly correlated with depression and poorer inflammatory bowel disease-related quality of life, but was generally not related to other areas of psychological functioning or inflammation. Sleep quality was significantly independently associated with depression and female gender.

CONCLUSION

Poor sleep quality is prevalent in patients with UC and is strongly related to depression, suggesting that sleep and mood are important areas to assess in patients with UC in order to inform tailored treatment to improve quality of life.

The Effect of Pycnogenol Supplementation on Plasma C-Reactive Protein Concentration: a Systematic Review and Meta-Analysis

Pycnogenol is a standardized extract from the bark of the French maritime pine. The aim of the present systematic review and meta-analysis was to clarify the effect of Pycnogenol supplementation on C-reactive protein (CRP) concentration. To identify eligible studies in order to find clinical trials which examined the effect of Pycnogenol supplementation on the level of CRP in adult participants, PubMed, Scopus, and Google Scholar were systematically searched until December 2017. Mean of CRP was collected to estimate the effect size of the supplementation. Potential sources of heterogeneity were explored by subgroup analysis. Five trials including 324 participants were included in this meta-analysis. Pooled effect size showed significant effect of Pycnogenol supplementation on CRP (−1.22 mg/dL, 95% confidence interval, −2.43, −0.003; I² = 99%, p_{heterogeneity} < 0.001). When the meta-analysis was subgrouped by dose of Pycnogenol, heterogeneity was attenuated in > 150 mg/d category (I² = 0.0%, p = 0.42). There was significant difference between-subgroup heterogeneity (p < 0.001). Furthermore, no evidence of publication bias for CRP (p = 0.27, Begg's test and p = 0.62, Egger's test) was seen. Present systematic review and meta-analysis suggested Pycnogenol consumption can decrease the level of CRP and have anti-inflammatory effect. So, Pycnogenol as an anti-inflammatory agent might be a priority in interventions. Further studies with large-scale and better design are needed to confirm this result.

Evaluation of Potential Disease-Mediated Drug-Drug Interaction in Patients With Moderate-to-Severe Atopic Dermatitis Receiving Dupilumab

This open‐label drug–drug interaction study assessed whether blockade by dupilumab of interleukin (IL)‐4 and IL‐13 signaling affects the pharmacokinetics of drugs metabolized by cytochrome P450 (CYP450) enzymes. The pharmacokinetics of five CYP450 substrates given orally (midazolam, omeprazole, S‐warfarin, caffeine, and metoprolol, metabolized by CYP3A, CYP2C19, CYP2C9, CYP1A2, and CYP2D6, respectively) were evaluated before and 28 days after initiation of dupilumab treatment (subcutaneous 300 mg weekly) in 14 patients with moderate‐to‐severe atopic dermatitis. Dupilumab had no clinically relevant effects on the pharmacokinetics of CYP450 substrates, provided substantial clinical benefit, and was generally well tolerated. Only one serious adverse event was reported, an episode of systemic inflammatory response syndrome that resolved after treatment was discontinued. In summary, blockade of IL‐4/IL‐13 signaling in patients with type 2 inflammation does not appear to significantly affect CYP450 enzyme activities; the use of dupilumab in atopic dermatitis patients is unlikely to influence the pharmacokinetics of CYP450 substrates.

Clinical and metabolic factors associated with chronic low-grade inflammation in type 2 diabetic patients

Aim. To identify the clinical and metabolic factors associated with serum concentration of high sensitivity C-reactive protein (hsCRP) and α1-acid glycoprotein (α1-AGP) in patients with type 2 diabetes.Material and methods. The study involved 210 patients with type 2 diabetes. Levels of hsCRP and α1-AGP were measured using ELISA and compared with those of the control (30 healthy normal individuals). Levels of acute-phase proteins, fat mass and glucose variability (GV) were compared among demographic, anthropometric, biochemical and haematological parameters. The fat mass was determined with Dual-energy X-ray absorptiometry (DEXA). GV parameters including mean amplitude of glycaemic excursions, continuous overlapping net glycaemic action (CONGA), J-index, M-value and mean absolute glucose change (MAG) were derived from continuous glucose monitoring.Results. Levels of hsCRP and α1-AGP significantly increased (p 0.0001) in patients with diabetes compared with controls. hsCRP level positively correlated with total, truncal and android fat (r = 0.34, r = 0.28 and r = 0.31; respectively, p 0.00004). α1-AGP level showed no relationship with fat mass but positively correlated with mean glucose, CONGA, M-value and MAG (r = 0.38, r = 0.36, r = 0.43 and r = 0.4; respectively, p 0.0001). Patients with the highest hsCRP levels (75 percentile) had a greater body mass index (p = 0.00009) as well as truncal and android fat mass (p = 0.04 and p = 0.03, respectively) than those with the lowest levels (25 percentile). High level of α1-AGP (75 percentile) was associated with urinary albumin/creatinine ratio (p = 0.01) and GV indices (M-value: p = 0.02, MAG: p = 0.04).Conclusions. Levels of acute-phase proteins (hsCRP and α1-AGP) increased in patients with type 2 diabetes. Levels of hsCRP were associated with fat mass; meanwhile, α1-AGP levels were associated with short-time GV in these patients. The results lend support to the notion that both obesity and enhanced GV are involved in the development of chronic low-grade inflammation associated with type 2 diabetes.