Pentraxin 3 as a novel bio-marker of inflammation and endothelial dysfunction in autosomal dominant polycystic kidney disease

Potential impact of epicardial fat thickness, pentraxin-3, and high-sensitive C-reactive protein on the risk of non-proliferative diabetic retinopathy

Purpose

We tried to clarify the potential association between systemic inflammatory markers like high-sensitive C-reactive protein (Hs-CRP), pentraxin-3 (PTX3), and epicardial fat thickness (EFT) with the non-proliferative diabetic retinopathy (NPDR) in patients with type 2 diabetes mellitus (T2D). Previous studies dealt with diabetic retinopathy as a whole entity rather than early stages of diabetic retinopathy. Early detection of various determinants of NPDR is prioritized in clinical practice.

Methods

A case-control study was conducted at Mansoura University Hospital, included 207 Egyptian subjects divided into 3 groups; 69 diabetic patients without retinopathy, 69 diabetic patients with NPDR, and 69 healthy control subjects. Participants were subjected to clinical history taking, physical examination, and laboratory assessment of Hs-CRP and plasma PTX3. Transthoracic echocardiography was applied to estimate EFT.

Results

Hs-CRP, PTX3, and EFT were significantly higher in patients with T2D without retinopathy than control cohort (p = 0.033, p < 0.00 and p < 0.00, respectively). Moreover, patients with NPDR showed significantly higher values of Hs-CRP, PTX3, and EFT than diabetic comparators without retinopathy (p = 0.002, p = 0.012, and p < 0.001, respectively). Although, NPDR was positively correlated with Hs-CRP, PTX3, and EFT (p < 0.001), Hs-CRP was not an independent determinant of NPDR meanwhile, EFT (OR = 1.094, 95%CI: 1.036-1.154, P = 0.001) and PTX3 (OR = 16.145, 95%CI: 1.676-155.551, P = 0.016) were.

Conclusion

Plasma pentraxin-3 and epicardial fat thickness showed more significant association with NPDR than high-sensitive C-reactive protein in patients with type 2 diabetes mellitus.

Epicardial fat thickness is associated with retinopathy in patients with newly diagnosed hypertension

OBJECTIVE

Hypertensive retinopathy develops based on endothelial dysfunction, inflammation, and atherosclerosis. Epicardial fat secretes various cytokines associated with endothelial dysfunction, oxidative stress, inflammation, and atherosclerosis. We aimed to evaluate whether epicardial adipose tissue (EAT) thickness is a marker for retinopathy in newly diagnosed hypertensive patients.

METHODS

A total of 73 newly diagnosed hypertension (HT) patients were included in the study. Transthoracic echocardiography (TTE) was used to measure EAT thickness. To evaluate the presence of retinopathy in HT patients, hypertensive retinopathy staging was performed by ophthalmologists, according to Scheie classification.

RESULTS

Retinopathy was detected in 27 (37.0%) of 73 patients. EAT thickness in HT patients with retinopathy was higher than the group without retinopathy (5.07±1.45 mm vs. 4.19±1.20 mm, p=0.007). Low-density lipoprotein cholesterol (LDL-C) levels in HT patients with retinopathy were higher than the group without retinopathy (162.4±41.2 mg/dl vs. 138.1±35.6 mg/dl, p=0.010). As a result of the regression analysis, LDL-C (OR=1.016, 95% CI 1.001-1.031, p=0.043) and EAT thickness (OR=1.674, 95% CI 1.069-2.626, p=0.043) were the independent predictors of retinopathy.

CONCLUSION

Increased EAT thickness is associated with the presence of retinopathy in hypertensive patients.

[Cardiovascular disorders in autosomal dominant polycystic kidney disease]

Autosomal dominant polycystic kidney disease is the most frequent genetic kidney disease. Cardiovascular disorders associated with autosomal dominant polycystic kidney disease are multiple and may occur early in life. In autosomal dominant polycystic kidney disease cardiovascular morbidity and mortality are related both to the nonspecific consequences of chronic kidney disease and to the particular phenotype of autosomal dominant polycystic kidney disease. Compared to the general population, patients with autosomal dominant polycystic kidney disease present an increased prevalence of hypertension, left ventricular hypertrophy, atrial fibrillation, valvular diseases, aneurisms and arterial dissections. This review article provides an update on cardiovascular disorders associated with autosomal dominant polycystic kidney disease and recent pathophysiological developments.

Systemic Succinate, Hypoxia-Inducible Factor-1 Alpha, and IL-1β Gene Expression in Autosomal Dominant Polycystic Kidney Disease with and without Hypertension

BACKGROUND AND OBJECTIVES

Cyst pressure induces renin-angiotensin-aldosterone system activation and kidney hypoxia in autosomal dominant polycystic kidney disease (ADPKD). Lipopolysaccharide-induced Toll-like receptor activation causes metabolic disturbances that are triggered by increased succinate levels and hypoxia inducible factors, which results in inflammation via IL-1β activation. Since we aimed to investigate the role of both inflammation and hypoxia in the clinical course of ADPKD, via succinate levels from sera samples, HIF-1α gene expression from whole blood and urine samples and IL-1βgene expression from whole blood were measured.

METHODS

One hundred ADPKD patients and 100 matched healthy controls were enrolled to this cross-sectional study. Twenty-four-hour ambulatory blood pressure monitoring was conducted in all participants. Blood, serum, and urine samples were taken after 12-h fasting for the measurement of biochemical parameters and succinate levels. Whole blood and urine samples were used for HIF-1α and IL-1β geneexpression by using quantitative real-time PCR.

RESULTS

There were significant differences in whole blood HIF-1α, IL-1β geneexpression, and serumsuccinate levels between the ADPKD patients and the control subjects. Whole blood HIF-1αgene expression, IL-1β geneexpression, and serumsuccinate levels were also significantly different in ADPKD patients with hypertension in comparison with normotensive ones (p < 0.05). Serum succinate levels and blood IL-1β geneexpression were increased in ADPKD patients with high levels of HIF-1α geneexpression (p = 0.018 and p = 0.029, respectively).

CONCLUSIONS

Increased age,low eGFR, and HIF-1α and IL-1β geneexpressions were also independently associated with hypertension in ADPKD patients. Inflammation and hypoxia are both relevant factors that might be associated with hypertension in ADPKD.

Elevated Systemic Pentraxin-3 Is Associated With Complement Consumption in the Acute Phase of Thrombotic Microangiopathies

Pentraxin-3 (PTX3) and C-reactive protein (CRP) have been shown to regulate complement activation in vitro, but their role has not been investigated in complement consumption in vivo. Thrombotic microangiopathies (TMA) are often accompanied by complement overactivation and consumption, therefore we analyzed the relation of the systemic pentraxin levels to the complement profile, laboratory parameters and clinical outcome of TMA patients. We determined the PTX3 and CRP levels, complement factor and activation product concentrations in blood samples of 171 subjects with the diagnosis of typical hemolytic uremic syndrome (STEC-HUS) (N = 34), atypical HUS (aHUS) (N = 44), secondary TMA (N = 63), thrombotic thrombocytopenic purpura (TTP) (N = 30) and 69 age-matched healthy individuals. Clinical data, blood count and chemistry were collected from medical records. To determine the in vitro effect of PTX3 on alternative pathway (AP) activation, sheep red blood cell-based hemolytic assay and AP activity ELISA were used. We found that PTX3 levels were elevated in the acute phase of STEC-HUS, aHUS and secondary TMA, whereas PTX3 elevation was exceptional is TTP. Conversely, a significantly higher median CRP was present in all patient groups compared to controls. PTX3, but not CRP was associated with signs of complement consumption in vivo, and PTX3 significantly decreased the AP hemolytic activity in vitro. Our results provide a detailed description of acute phase-TMA patients' complement profile linked to changes in the systemic pentraxin levels that may support further molecular studies on the function of PTX3 in disease pathogenesis and add to the laboratory assessment of complement consumption in TMA.

Pentraxin 3 promotes cardiac differentiation of mouse embryonic stem cells through JNK signaling pathway

Cardiovascular disease is a leading cause of death worldwide, requiring the development of new therapeutic strategies including stem cell therapy. Pentraxins (PTXs) are a superfamily of proteins highly involved in different myocardial disorders, and thus this study aimed to identify the modulation of long pentraxin 3 (PTX3) in the differentiation of mouse embryonic stem cells (mESCs) toward cardiomyocytes. Cell toxicity of PTX3 was detected by MTT and LDH assays in mESCs. Embryoid bodies (EBs) were differentiated using hanging drop method, and the beating was observed under microscope. Expressional levels of early cardiac progenitor marker genes were assessed by qRT-PCR. Expression of marker proteins in early myocardial development and the activation of JNK signaling pathway was evaluated by Western blot. PTX3 treatment at 50 ng/mL significantly promoted the expression of cardiac-specific marker genes including Nkx2.5, Mef2c, Tbx5, dHand, and αMHC, and increased the expression of cardiac maturity indicative markers including connexin 43 and troponin C1. PTX3 enhanced the phosphorylation of JNK across the incubation duration, whereas the activation of p38 remained the same as control group. Co-treatment of JNK signaling pathway inhibitor SP600125 impaired the PTX3-promoted transcription of Nkx2.5, Mef2c, Tbx5, dHand, and αMHC. This study revealed the promotion of PTX3 in the differentiation of mESCs into cardiomyocytes and the underlying mechanism.

Semaphorin 7A in circulating regulatory T cells is increased in autosomal-dominant polycystic kidney disease and decreases with tolvaptan treatment

BACKGROUND

Semaphorin 7A (SEMA7A) is an immunomodulating protein implicated in lung and liver fibrosis. In autosomal-dominant polycystic kidney disease (ADPKD), the progressive expansion of renal cysts, inflammation, and subsequent renal fibrosis leads to end-stage renal disease (ESRD). SEMA7A may play a role in renal fibrosis and in ADPKD.

METHODS

We evaluated Sema7a in a mouse model of renal fibrosis and determined the expression of SEMA7A in human ADPKD kidney. We analyzed SEMA7A expression on peripheral blood mononuclear cells (PBMCs), including CD45⁺ (leukocyte), CD14⁺(monocyte), CD4+ (T lymphocytes) and CD4⁺Foxp3⁺CD25⁺ [regulatory T lymphocytes (Tregs)] from 90 ADPKD patients (11 tolvaptan treated and 79 tolvaptan naïve), and 21 healthy volunteers, using a Fluorescence-Activated Cell Sorting (FACS).

RESULTS

Sema7a is required for renal fibrosis. SEMA7A shows robust expression in ADPKD kidneys, localizing to cysts derived from distal tubules. SEMA7A is higher in circulating monocytes, but unchanged in CD4⁺ lymphocytes in ADPKD patients. The SEMA7A increase was detected early (stage 1 CKD) and seemed more prominent in patients with smaller kidneys (p = 0.09). Compared to tolvaptan-naïve ADPKD patients, those treated with tolvaptan showed reduced SEMA7A expression on monocytes, T lymphocytes, and Tregs, although the number of PBMCs was unchanged. After 1 month of tolvaptan treatment, SEMA7A expression on Tregs decreased.

CONCLUSIONS

SEMA7A shows potential as both a therapeutic target in mammalian kidney fibrosis and as a marker of inflammation in ADPKD patients. SEMA7A expression was lower after tolvaptan treatment, which may reflect drug efficacy.

Urinary metal and metalloid biomarker study of Henoch-Schonlein purpura nephritis using inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry

To obtain a better understanding as to whether concentration alterations of metals and metalloids in urine were related to Henoch-Schonlein purpura nephritis (HSPN), the profiles of as many as 29 elements in urine were compared among three groups, the Henoch-Schonlein purpura (HSP), HSPN and a healthy control group. To this end, a reliable method has been developed for the simultaneous quantification of multiple elements including Li, Be, B, Al, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Ba, Tl, Pb and Bi in urine using inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS). The process of sample pre-treatment used a direct 20-fold dilution method with centrifuged urine. The internal standard element used for quantification was ¹⁰³Rh, and 1,4-butanediol was chosen as a matrix matching reagent. The method detection limits of these 29 elements were in the range of 0.04-12ngmL^-1. Results of statistical analysis revealed that the concentrations of 15 elements and the element homeostasis were significantly different among these three groups. Our study provides a potential method for HSPN metal and metalloid biomarker discovery.

Update on the role of Pentraxin 3 in atherosclerosis and cardiovascular diseases

Pentraxin 3 (PTX3) is an acute-phase protein that was recently demonstrated to play pleiotropic activities in cardiovascular (CV) diseases. Tumor necrosis factor and interleukins up-regulates PTX3 transcription in different cell types (i.e. endothelial cells, phagocytes, smooth muscle cells, fibroblasts and glial cells) involved in atherogenesis. By interacting with numerous ligands, PTX3 acts as a modulatory molecule of complement system, inflammatory response, angiogenesis, and vascular/tissue remodeling. Experimental data point to a beneficial role of PTX3 in atherosclerotic plaque development and vulnerability. Animal studies indicated a protective role of PTX3 signaling in ischemic/reperfusion injury and failing heart. Clinical studies have so far provided contrasting results, highlighting a debated role of PTX3 as an active mediator of endothelial dysfunction, atherosclerotic plaque vulnerability and worse outcome after ischemic events. Therefore, substantial evidence suggests a dual role of PTX3 as modulator or amplifiers of the innate immune response. The final result of PTX3 activation might be determined by a fine tuning of time, space and environmental signals. The aim of this review is to provide an overview of biological properties of PTX3 in CV diseases and to discuss the ability of PTX3 to act as a crossroad between pro- and anti-inflammatory pathways.

Biomarkers and surrogate endpoints in kidney disease

Kidney disease and its related comorbidities impose a large public health burden. Despite this, the number of clinical trials in nephrology lags behind many other fields. An important factor contributing to the relatively slow pace of nephrology trials is that existing clinical endpoints have significant limitations. "Hard" endpoints for chronic kidney disease, such as progression to end-stage renal disease, may not be reached for decades. Traditional biomarkers, such as serum creatinine in acute kidney injury, may lack sensitivity and predictive value. Finding new biomarkers to serve as surrogate endpoints is therefore an important priority in kidney disease research and may help to accelerate nephrology clinical trials. In this paper, I first review key concepts related to the selection of clinical trial endpoints and discuss statistical and regulatory considerations related to the evaluation of biomarkers as surrogate endpoints. This is followed by a discussion of the challenges and opportunities in developing novel biomarkers and surrogate endpoints in three major areas of nephrology research: acute kidney injury, chronic kidney disease, and autosomal dominant polycystic kidney disease.

Early atherosclerosis in normotensive patients with autosomal dominant polycystic kidney disease: the relation between epicardial adipose tissue thickness and carotid intima-media thickness

Epicardial adipose tissue thickness (EATT) is suggested as a novel marker of subclinical atherosclerosis. Despite increased carotid intima-media thickness (CIMT) in autosomal dominant polycystic kidney disease (ADPKD) patients, the extent of the relationship between CIMT and EATT is unknown. The main purpose of our study was to evaluate the relation between EATT and CIMT in normotensive ADPKD patients with well-preserved renal function. Fifty-five normotensive ADPKD patients with normal renal function and 50 healthy control subjects were included in the study. EATT and CIMT were measured by echocardiography in all subjects. Correlation between EATT and CIMT was evaluated in ADPKD patients, while multivariate linear regression analysis was performed to determine factors predicting EATT and CIMT. ADPKD patients had significantly higher levels CIMT [0.7 (0.4–1.2) vs. 0.5 (0.4–0.8) mm, p < 0.001] and EATT (6.8 ± 2.7 vs. 4.8 ± 1.2 mm, p < 0.001) as compared with control subjects. Significant positive correlation was found between EATT and CIMT (r = 0.58, p < 0.001). Higher CRP levels (OR 54.7, 95 % CI 37.44–72.01, p < 0.001) and having ADPKD (OR 10.2, 95 % CI 2.53–17.86, p = 0.01) were the only independent factors associated with a higher EATT. A higher age (OR 0.35, 95 % CI −0.02 to 0.71, p = 0.06) tended to be independently associated with a higher EATT. In conclusion, our findings suggest that EATT, being simply measured by echocardiography and correlated with CIMT, can be used to detect subclinical atherosclerosis in normotensive ADPKD patients.

Correlation between arterial stiffness and inflammatory markers in autosomal dominant polycystic kidney disease patients with preserved renal function

AIM

To evaluate the association between arterial stiffness and inflammatory markers including C-reactive protein (CRP), pentraxin 3 (PTX3) and neutrophil-to-lymphocyte ratio (NLR) in autosomal dominant polycystic kidney disease (ADPKD) patients with preserved renal function.

METHODS

A total of 52 ADPKD patients [mean (SD) age 38.2 (12.8) years, 69.2 % were females] with preserved renal function and 25 healthy volunteers [mean (SD) age 35.5 (6.5) years, 48.0 % were females] were included. Data on patient characteristics, blood biochemistry, inflammatory markers [PTX3 (pg/mL), CRP (mg/dL) and NLR] and arterial stiffness [large artery elasticity index (LAEI) (mL/mmHg × 10) and small artery elasticity index (SAEI) (mL/mmHg × 100)] were recorded in patient and control groups. Correlation between inflammatory markers and arterial stiffness parameters was analysed in patients.

RESULTS

Overall, 42.3 % of ADPKD patients were hypertensive and 44.4 % were receiving renin-angiotensin-aldosterone system (RAAS) blockade therapy. Median levels for PTX3 [442.0 (20.0-4140.0) pg/mL vs. 220.5 (14.7-393.0) pg/mL, p < 0.001] and SAEI [4.90 (1.60-11.80) mL/mmHg × 100 vs. 6.45 (2.80-15.70) mL/mmHg × 10, p = 0.013] were significantly higher in ADPKD patients than in controls. PTX3 and CRP were not correlated with arterial elasticity, while NLR was significantly correlated with LAEI negatively (Rho = -0.278, p = 0.042).

CONCLUSION

In conclusion, our findings revealed increased PTX3 levels and reduced SAEI in patients as compared with controls, while no correlation between inflammatory markers studied and the small artery elasticity.