Pentraxin 3 and complement cascade activation in the failure of arteriovenous fistula

Pentraxin-3-mediated complement activation in a swine model of renal ischemia/reperfusion injury

Pentraxins are a family of evolutionarily conserved pattern recognition molecules with pivotal roles in innate immunity and inflammation, such as opsonization of pathogens during bacterial and viral infections. In particular, the long Pentraxin 3 (PTX3) has been shown to regulate several aspects of vascular and tissue inflammation during solid organ transplantation.

Our study investigated the role of PTX3 as possible modulator of Complement activation in a swine model of renal ischemia/reperfusion (I/R) injury.

We demonstrated that I/R injury induced early PTX3 deposits at peritubular and glomerular capillary levels. Confocal laser scanning microscopy revealed PTX3 deposits co-localizing with CD31⁺ endothelial cells. In addition, PTX3 was associated with infiltrating macrophages (CD163), dendritic cells (SWC3a) and myofibroblasts (FSP1). In particular, we demonstrated a significant PTX3-mediated activation of classical (C1q-mediated) and lectin (MBL-mediated) pathways of Complement. Interestingly, PTX3 deposits co-localized with activation of the terminal Complement complex (C5b-9) on endothelial cells, indicating that PTX3-mediated Complement activation occurred mainly at the renal vascular level. In conclusion, these data indicate that PTX3 might be a potential therapeutic target to prevent Complement-induced I/R injury.

PMMA-Based Continuous Hemofiltration Modulated Complement Activation and Renal Dysfunction in LPS-Induced Acute Kidney Injury

Sepsis-induced acute kidney injury (AKI) is a frequent complication in critically ill patients, refractory to conventional treatments. Aberrant activation of innate immune system may affect organ damage with poor prognosis for septic patients. Here, we investigated the efficacy of polymethyl methacrylate membrane (PMMA)-based continuous hemofiltration (CVVH) in modulating systemic and tissue immune activation in a swine model of LPS-induced AKI. After 3 h from LPS infusion, animals underwent to PMMA-CVVH or polysulfone (PS)-CVVH. Renal deposition of terminal complement mediator C5b-9 and of Pentraxin-3 (PTX3) deposits were evaluated on biopsies whereas systemic Complement activation was assessed by ELISA assay. Gene expression profile was performed from isolated peripheral blood mononuclear cells (PBMC) by microarrays and the results validated by Real-time PCR. Endotoxemic pigs presented oliguric AKI with increased tubulo-interstitial infiltrate, extensive collagen deposition, and glomerular thrombi; local PTX-3 and C5b-9 renal deposits and increased serum activation of classical and alternative Complement pathways were found in endotoxemic animals. PMMA-CVVH treatment significantly reduced tissue and systemic Complement activation limiting renal damage and fibrosis. By microarray analysis, we identified 711 and 913 differentially expressed genes with a fold change >2 and a false discovery rate <0.05 in endotoxemic pigs and PMMA-CVVH treated-animals, respectively. The most modulated genes were Granzyme B, Complement Factor B, Complement Component 4 Binding Protein Alpha, IL-12, and SERPINB-1 that were closely related to sepsis-induced immunological process. Our data suggest that PMMA-based CVVH can efficiently modulate immunological dysfunction in LPS-induced AKI.

Complement C6 deficiency exacerbates pathophysiology after spinal cord injury

Historically, the membrane attack complex, composed of complement components C5b-9, has been connected to lytic cell death and implicated in secondary injury after a CNS insult. However, studies to date have utilized either non-littermate control rat models, or mouse models that lack significant C5b-9 activity. To investigate what role C5b-9 plays in spinal cord injury and recovery, we generated littermate PVG C6 wildtype and deficient rats and tested functional and histological recovery after moderate contusion injury using the Infinite Horizon Impactor. We compare the effect of C6 deficiency on recovery of locomotor function and histological injury parameters in PVG rats under two conditions: (1) animals maintained as separate C6 WT and C6-D homozygous colonies; and (2) establishment of a heterozygous colony to generate C6 WT and C6-D littermate controls. The results suggest that maintenance of separate homozygous colonies is inadequate for testing the effect of C6 deficiency on locomotor and histological recovery after SCI, and highlight the importance of using littermate controls in studies involving genetic manipulation of the complement cascade.

Modulation of complement activation by pentraxin-3 in prostate cancer

Pentraxin 3 (PTX3) is an essential component of the innate immune system and a recognized modulator of Complement cascade. The role of Complement system in the pathogenesis of prostate cancer has been largely underestimated. The aim of our study was to investigate the role of PTX3 as possible modulator of Complement activation in the development of this neoplasia. We performed a single center cohort study; from January 2017 through December 2018, serum and prostate tissue samples were obtained from 620 patients undergoing prostate biopsy. A group of patients with benign prostatic hyperplasia (BPH) underwent a second biopsy within 12–36 months demonstrating the presence of a prostate cancer (Group A, n = 40) or confirming the diagnosis of BPH (Group B, N = 40). We measured tissue PTX3 protein expression together with complement activation by confocal microscopy in the first and second biopsy in group A and B patients. We confirmed that that PTX3 tissue expression in the first biopsy was increased in group A compared to group B patients. C1q deposits were extensively present in group A patients co-localizing and significantly correlating with PTX3 deposits; on the contrary, C1q/PTX3 deposits were negative in group B. Moreover, we found a significantly increased expression of C3a and C5a receptors within resident cells in group A patient. Interestingly, C1q/PTX3 deposits were not associated with activation of the terminal Complement complex C5b-9; moreover, we found a significant increase of Complement inhibitor CD59 in cancer tissue. Our data indicate that PTX3 might play a significant pathogenic role in the development of this neoplasia through recruitment of the early components of Complement cascade with hampered activation of terminal Complement pathway associated with the upregulation of CD59. This alteration might lead to the PTX3-mediated promotion of cellular proliferation, angiogenesis and insensitivity to apoptosis possible leading to cancer cell invasion and migration.

Circadian Clock and Complement Immune System-Complementary Control of Physiology and Pathology?

Mammalian species contain an internal circadian (i.e., 24-h) clock that is synchronized to the day and night cycles. Large epidemiological studies, which are supported by carefully controlled studies in numerous species, support the idea that chronic disruption of our circadian cycles results in a number of health issues, including obesity and diabetes, defective immune response, and cancer. Here we focus specifically on the role of the complement immune system and its relationship to the internal circadian clock system. While still an incompletely understood area, there is evidence that dysregulated proinflammatory cytokines, complement factors, and oxidative stress can be induced by circadian disruption and that these may feed back into the oscillator at the level of circadian gene regulation. Such a feedback cycle may contribute to impaired host immune response against pathogenic insults. The complement immune system including its activated anaphylatoxins, C3a and C5a, not only facilitate innate and adaptive immune response in chemotaxis and phagocytosis, but they can also amplify chronic inflammation in the host organism. Consequent development of autoimmune disorders, and metabolic diseases associated with additional environmental insults that activate complement can in severe cases, lead to accelerated tissue dysfunction, fibrosis, and ultimately organ failure. Because several promising complement-targeted therapeutics to block uncontrolled complement activation and treat autoimmune diseases are in various phases of clinical trials, understanding fully the circadian properties of the complement system, and the reciprocal regulation by these two systems could greatly improve patient treatment in the long term.

PTX3 Predicts Myocardial Damage and Fibrosis in Duchenne Muscular Dystrophy

Pentraxin 3 (PTX3) is a main component of the innate immune system by inducing complement pathway activation, acting as an inflammatory mediator, coordinating the functions of macrophages/dendritic cells and promoting apoptosis/necrosis. Additionally, it has been found in fibrotic regions co-localizing with collagen. In this work, we wanted to investigate the predictive role of PTX3 in myocardial damage and fibrosis of Duchenne muscular dystrophy (DMD). DMD is an X-linked recessive disease caused by mutations of the dystrophin gene that affects muscular functions and strength and accompanying dilated cardiomyopathy. Here, we expound the correlation of PTX3 cardiac expression with age and Toll-like receptors (TLRs)/interleukin-1 receptor (IL-1R)-MyD88 inflammatory markers and its modulation by the so-called alarmins IL-33, high-mobility group box 1 (HMGB1), and S100β. These findings suggest that cardiac levels of PTX3 might have prognostic value and potential in guiding therapy for DMD cardiomyopathy.

Molecular Mechanisms of Premature Aging in Hemodialysis: The Complex Interplay Between Innate and Adaptive Immune Dysfunction

Hemodialysis (HD) patient are known to be susceptible to a wide range of early and long-term complication such as chronic inflammation, infections, malnutrition, and cardiovascular disease that significantly affect the incidence of mortality. A large gap between the number of people with end-stage kidney disease (ESKD) and patients who received kidney transplantation has been identified. Therefore, there is a huge need to explore the underlying pathophysiology of HD complications in order to provide treatment guidelines. The immunological dysregulation, involving both the innate and adaptive response, plays a crucial role during the HD sessions and in chronic, maintenance treatments. Innate immune system mediators include the dysfunction of neutrophils, monocytes, and natural killer (NK) cells with signaling mediated by NOD-like receptor P3 (NLRP3) and Toll-like receptor 4 (TLR4); in addition, there is a significant activation of the complement system that is mediated by dialysis membrane-surfaces. These effectors induce a persistent, systemic, pro-inflammatory, and pro-coagulant milieu that has been described as inflammaging. The adaptive response, the imbalance in the CD4+/CD8+ T cell ratio, and the reduction of Th2 and regulatory T cells, together with an altered interaction with B lymphocyte by CD40/CD40L, have been mainly implicated in immune system dysfunction. Altogether, these observations suggest that intervention targeting the immune system in HD patients could improve morbidity and mortality. The purpose of this review is to expand our understanding on the role of immune dysfunction in both innate and adaptive response in patients undergoing hemodialysis treatment.

Inflammaging and Complement System: A Link Between Acute Kidney Injury and Chronic Graft Damage

The aberrant activation of complement system in several kidney diseases suggests that this pillar of innate immunity has a critical role in the pathophysiology of renal damage of different etiologies. A growing body of experimental evidence indicates that complement activation contributes to the pathogenesis of acute kidney injury (AKI) such as delayed graft function (DGF) in transplant patients. AKI is characterized by the rapid loss of the kidney's excretory function and is a complex syndrome currently lacking a specific medical treatment to arrest or attenuate progression in chronic kidney disease (CKD). Recent evidence suggests that independently from the initial trigger (i.e., sepsis or ischemia/reperfusions injury), an episode of AKI is strongly associated with an increased risk of subsequent CKD. The AKI-to-CKD transition may involve a wide range of mechanisms including scar-forming myofibroblasts generated from different sources, microvascular rarefaction, mitochondrial dysfunction, or cell cycle arrest by the involvement of epigenetic, gene, and protein alterations leading to common final signaling pathways [i.e., transforming growth factor beta (TGF-β), p16 ink4a , Wnt/β-catenin pathway] involved in renal aging. Research in recent years has revealed that several stressors or complications such as rejection after renal transplantation can lead to accelerated renal aging with detrimental effects with the establishment of chronic proinflammatory cellular phenotypes within the kidney. Despite a greater understanding of these mechanisms, the role of complement system in the context of the AKI-to-CKD transition and renal inflammaging is still poorly explored. The purpose of this review is to summarize recent findings describing the role of complement in AKI-to-CKD transition. We will also address how and when complement inhibitors might be used to prevent AKI and CKD progression, therefore improving graft function.

Circulating pentraxin-3 levels in patients with systemic lupus erythematosus: a meta-analysis

Aim: An existing meta-analysis have investigated the PTX3 levels in systemic lupus erythematosus (SLE) patients, but the number of studies has increased since 2015. We performed an updated meta-analysis to derive a more accurate estimation. Methods: The related literature was systematically searched in PubMed, Embase and The Cochrane Library database (up to 28 February, 2019). Results: SLE patients had significantly higher PTX3 levels than controls (pooled SMD = 0.48; 95% CI: 0.11-0.84). Subgroup analyses indicated SLE patients from non-Caucasian population, with age ≥45 years, SLE disease activity index (SLEDAI) ≥10 and plasma samples had higher PTX3 levels. Conclusion: Circulating PTX3 levels are increased in SLE patients, and affected by age, ethnicity, SLEDAI and sample type.

Inflammatory Biomarkers Predict Domain-Specific Cognitive Decline in Older Adults

BACKGROUND

Vascular risk factors, including inflammation, may contribute to dementia development. We investigated the associations between peripheral inflammatory biomarkers and cognitive decline in five domains (memory, construction, language, psychomotor speed, and executive function).

METHODS

Community-dwelling older adults from the Ginkgo Evaluation of Memory Study (n = 1,159, aged 75 or older) free of dementia at baseline were included and followed for up to 7 years. Ten biomarkers were measured at baseline representing different sources of inflammation: vascular inflammation (pentraxin 3 and serum amyloid P), endothelial function (endothelin-1), metabolic function (adiponectin, resistin, and plasminogen activating inhibitor-1), oxidative stress (receptor for advanced glycation end products), and general inflammation (interleukin-6, interleukin-2, and interleukin-10). A combined z-score was created from these biomarkers to represent total inflammation across these sources. We utilized generalized estimating equations that included an interaction term between z-scores and time to assess effect of inflammation on cognitive decline, adjusting for demographics (such as age, race/ethnicity, and sex), cardiovascular risk factors, and apolipoprotein E ε4 carrier status. A Bonferroni-adjusted significance level of .01 was used. We explored associations between individual biomarkers and cognitive decline without adjustment for multiplicity.

RESULTS

The combined inflammation z-score was significantly associated with memory and psychomotor speed (p < .01). Pentraxin 3, serum amyloid P, endothelin-1, and interleukin-2 were associated with change in at least one cognitive domain (p < .05).

CONCLUSION

Our results suggest that total inflammation is associated with memory and psychomotor speed. In particular, systemic inflammation, vascular inflammation, and altered endothelial function may play roles in domain-specific cognitive decline of nondemented individuals.

Increased Plasma Levels of Pentraxin 3 Are Associated with Poor Prognosis of Colorectal Carcinoma Patients

Colorectal carcinoma (CRC) is one of the most common cancers globally. It is essential to identify a prognostic predictor for CRC. Pentraxin 3 (PTX3) is a glycoprotein that is secreted by a variety of human cells. It plays an important role in inflammation and immune regulation. Increasing evidence reveals that elevated PTX3 expression is related to poor prognosis in various cancers. The aim of the study was to determine the usefulness of plasma PTX3 level as a prognostic predictor in CRC. Total 184 CRC patients and 216 controls were included. Plasma levels of PTX3 were determined using Enzyme-linked immunosorbent assays. On admission, plasma PTX3 levels in CRC patients were higher than those in controls (11.8 ± 2.5 ng/ml vs. 3.1 ± 0.9 ng/ml, P < 0.001). After resection, plasma PTX3 levels in patients were decreased (6.0 ± 1.4 ng/ml, P = 0.007), and were elevated at the time of relapse (10.8 ± 2.8 ng/ml, P < 0.001). During the 60-month follow-up period, 108 patients suffered from relapse. Plasma PTX3 levels of ≥ 12 ng/ml on admission were associated with relapse (OR: 3.11, 95% CI: 1.74 ~ 6.29), and tumor-free survival rate in those patients with plasma PTX3 levels of ≥ 12 ng/ml was lower than that in other patients (P = 0.001). Furthermore, plasma PTX3 levels on admission showed positive linear correlations with plasma complement 3, 4 and 5b9 levels (P < 0.001, P < 0.001, P < 0.001). Therefore, we propose that PTX3 is an independent prognostic indicator in CRC.

Association of the long pentraxin PTX3 gene polymorphism (rs3816527) with migraine in an Iranian population

BACKGROUND

Migraine is a common neurovascular disorder with multifactorial and polygenic inheritance. It has been shown that migraine may be a form of sterile neurogenic inflammation. Pentaxins 3 (PTX3) has been detected in brain during inflammatory responses. The aim of our study was to investigate the association of rs3816527 polymorphism of the PTX3 gene and migraine in an Iranian population.

METHOD

We included 103 newly diagnosed migraine patients and 148 healthy subjects as control group. Genomic DNA samples extracted from the peripheral blood and genotypes of PTX3 rs3816527 gene polymorphism were determined. The patients filled out HIT-6 questionnaire as a scale to evaluate the severity of headache.

RESULTS

The genotype frequency of PTX3 was significantly different between the migraine patients and the control subjects. CC variant homozygote genotype was statistically more frequent in the patients than in the controls (P<0.05; OR=1.74, 95% CI=1.04-2.94). Also the C allele was not significantly more frequent in the patients (P=0.096; OR=1.27, 95% CI=0.88-1.85). A separate analysis in male and female subjects showed no significant differences between the different genotypes and phenotypes of PTX3 rs3816527 gene and susceptibility to migraine in female subjects. Total HIT-6 score was significantly different between three PTX3 genotypes (P=0.008).

CONCLUSION

In conclusion our results showed the association between the PTX3 rs3816527 gene polymorphism with susceptibility to migraine only in the male patients. Also total HIT-6 scores as a scale for assessment of the severity were related to the PTX3 rs3816527 gene polymorphism. But this relation was not established by headache frequency.

Neurokinin 3 receptor and phosphocholine transferase: missing factors for pathogenesis of C-reactive protein in preeclampsia

C-reactive protein (CRP), an innate immune mediator, is elevated in the circulation before symptoms in patients with preeclampsia, a severe hypertensive pregnancy disorder with high mortality and morbidity. However, the specific sources underlying increased CRP and the role of elevated CRP in preeclampsia are undefined. Here, we report that circulating CRP levels are significantly increased in a large cohort of normotensive pregnant individuals when compared with nulligravid women and is further increased in patients with preeclampsia. These findings led us to discover further that placental syncytiotrophoblasts are previously unrecognized cellular sources of CRP and underlie elevated CRP in normotensive pregnant women and the additional increase in patients with preeclampsia. Next, we demonstrated that injection of CRP induces preeclampsia features, including hypertension (157 mm Hg CRP treated versus 119 mm Hg control), proteinuria (35.0 mg/μg CRP treated versus 14.1 mg/μg control), kidney, and placental damage and increased levels of sFlt-1 in pregnant mice but not in nonpregnant mice. Our study implicates that phosphocholine transferase, a placental-specific enzyme post-translationally modifying neurokinin B, is essential for the pathogenic role of CRP in preeclampsia through activation of the neurokinin 3 receptor. Overall, our studies have provided significant new insight on the pathogenic role of CRP in preeclampsia and highlighted innovative therapeutic strategies.

Pentraxin 3 as a biomarker of local inflammatory response to vascular injury in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disorder with organ injury related to vasculitis. Inflammation of blood vessels results from auto-immunological activation of endothelial cells. The pentraxin 3 (PTX3), might act as an indicator of vasculitides in many diseases. The aim of this study was to determine whether PTX3 might be useful as a marker of vascular injury in SLE. This study was carried out in a group of 56 SLE women, and in the 28 female volunteers control group. All participants' plasma and serum samples were collected to estimate concentrations (ELISA) of PTX3, soluble thrombomodulin, soluble E-selectin (sE-selectin), soluble P-selectin (sP-selectin), soluble form of vascular cell adhesion molecule 1 (sVCAM-1), soluble inter-cellular adhesion molecule-1 (sICAM-1), soluble platelet endothelial cell adhesion molecule 1, monocyte chemotactic protein-1 (MCP-1) and von Willebrand factor (vWF) activity. Anthropometric, demographic and lifestyle characteristics of SLE patients were also performed. The SLE patients had higher PTX3, vWF, MCP-1, sE-selectin and sVCAM-1 levels than the controls (1.82 ± 1.56 ng/mL, 237 ± 101%, 70.05 ± 18.31 ng/mL, 111.16 ± 49.15 ng/mL and 978.78 ± 462.35 ng/mL vs. 0.86 ± 0.40 ng/mL, 138 ± 43%, 58.56 ± 13.91 ng/mL, 66.04 ± 27.18 ng/mL and 499.07 ± 125.67 ng/mL, respectively). The independent factors affecting PTX3 expression included Systemic Lupus Erythematosus Disease Activity Index, prednisone dose and anemia severity. Moreover, the PTX3 areas under the curve-receiver operating characteristics curves 0.717 ± 0.056 with cut-off level of 1.96 ng/mL was comparable to vWF, MCP-1, sE-selectin, sP-selectin and sICAM-1. PTX3 and sVCAM-1 were the only factors related to SLE activity. Other vascular injury indicators associated with PTX3 were vWF and sVCAM-1. In conclusion, PTX3 concentrations in SLE patients might serve as a indicator of the activation/dysfunction of vascular endothelium.