Assessment of kidney involvement in systemic sclerosis: From scleroderma renal crisis to subclinical renal vasculopathy

Bibliometric insights into systemic sclerosis with renal involvement: trends, contributions, and future directions

BACKGROUND

Renal involvement is not uncommon in patients with systemic sclerosis (SSc) and presents in various forms, particularly progressing to scleroderma renal crisis (SRC), which is associated with poor prognosis. Therefore, understanding the research trends in this field is critical for advancing clinical management and therapeutic strategies.

METHODS

A bibliometric analysis was conducted using the Web of Science Core Collection, examining publications related to SSc and renal involvement from January 2000 to November 2024. We analyzed publication trends, key contributors, institutions, and countries.

RESULTS

A total of 1,339 publications were identified in the field of SSc and renal involvement, demonstrating an upward trend in publication volume from 2000 to 2024. These articles have been cited a total of 61,234 times, with the majority of contributions coming from the United States, Italy, and East Asian countries. The University of Michigan and University College London were particularly prominent in terms of both publication volume and collaboration networks. Keyword analysis revealed a shift in research focus, with increasing attention on clinical aspects, pathophysiological mechanisms, and vascular complications.

CONCLUSIONS

This study provides a comprehensive overview of the research landscape on SSc with renal involvement, highlighting the key contributors and emerging trends.

Metabolic syndrome and cardiovascular-kidney-metabolic health: Evaluation of predictive risk factor for mortality in systemic sclerosis

BACKGROUND AND AIMS

Few studies have addressed the MetS in systemic sclerosis (SSc) patients. Several classifications have been proposed to define metabolic syndrome (MetS). The aim of the study was to evaluate if MetS and cardiovascular-kidney-metabolic health assessment may predict mortality in SSc patients during a 10-year follow-up.

METHODS AND RESULTS

Ninety consecutive SSc patients were enrolled. The diagnosis of MetS was made according to the criteria of the National Cholesterol Education Program Adult Treatment Panel III (NCEP/ATP-III), NCEP-R, International Diabetes Federation (IDF) and cardiovascular-kidney-metabolic syndrome (CKM) classification. Mortality was observed in 21 (23.3 %) SSc patients. Kaplan-Meier curves showed that overall survival probability was shorter in patients with MetS according to NCEP-ATPIII (p < 0.001), NCEP-R (p < 0.05) and IDF (p < 0.05) compared to patients without MetS; while the overall survival was similar in patients with CKM 0-1 and patients with CKM 2-3-4. Cumulative incidence rate of SSc-related death was similar in patients with MetS according to NCEP-ATPIII, NCEP-R and IDF compared to patients without MetS and in patients with CKM 0-1 and patients with CKM 2-3-4. Cumulative incidence rate for all-cause mortality not-SSc related was higher in patients with MetS according to NCEP-ATPIII (p < 0.001), NCEP-R (p < 0.01) and IDF (p < 0.01) compared to patients without MetS; while the cumulative incidence rate all-cause mortality not-SSc related was similar in patients with CKM 0-1 and patients with CKM 2-3-4.

CONCLUSIONS

MetS is a risk factor for all-cause mortality in SSc patients but not related to underlying disease.

Precision Medicine in Rheumatology: The Role of Biomarkers in Diagnosis and Treatment Optimization

Rheumatic diseases encompass a wide range of autoimmune and inflammatory disorders, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriatic arthritis (PsA), and systemic sclerosis (SSc). These conditions often result in chronic pain, disability, and reduced quality of life, with unpredictable disease courses that may lead to joint destruction, organ damage, or systemic complications. Biomarkers, defined as measurable indicators of biological processes or conditions, have the potential to transform clinical practice by improving disease diagnosis, monitoring, prognosis, and treatment decisions. While significant strides have been made in identifying and validating biomarkers in rheumatic diseases, challenges remain in their standardization, clinical utility, and integration into routine practice. This review provides an overview of the current state of biomarkers in rheumatic diseases, their roles in clinical settings, and the emerging advancements in the field.

Acute Kidney Injury in Systemic Sclerosis Beyond Scleroderma Renal Crisis: A Case-Control Study

BACKGROUND AND OBJECTIVES

Renal involvement in systemic sclerosis remains a significant concern with the focus often centered on scleroderma renal crisis (SRC). However, the broader spectrum of renal manifestations, beyond SRC, remains underrecognized. In our case-control analysis, we describe other causes, risk factors, and renal outcomes of acute kidney injury (AKI) in systemic sclerosis other than SRC.

METHODS

Patients diagnosed with SSC, with and without AKI, between 2017 and 2023 at Albany Medical Center, were included in the case-control study using International Classification of Diseases , 10th Revision codes and electronic medical records. Patients with SRC were carefully excluded. Data were collected and compared between AKI and non-AKI groups for patients' demographics, clinical characteristics, and baseline treatment. Additionally, data were collected for baseline, peak, and follow-up creatinine, etiology of AKI, treatment, and outcomes. Statistical analysis was performed using R (version 4.3.0) and Minitab (V19). Categorical variables were presented as frequencies/percentages, and continuous variables as means/standard deviations. Associations between categorical variables were assessed by χ 2 test and Fisher exact test. Odds ratios and 95% confidence intervals were calculated using binary logistic regression to separately assess the effect of each independent variable on the odds of AKI. Statistical significance was set at p < 0.05.

RESULTS

A total of 74 cases were identified. Out of these 74 cases, 27 had AKI and 47 did not have AKI. Out of the 27 AKI cases, 4 with SRC were excluded. Advanced age, chronic kidney disease, and heart failure were identified as risk factors for AKI development. The predominant cause of AKI was prerenal etiology, accounting for 47.8% (n = 11) of cases. This was followed by cardiorenal syndrome and acute tubular necrosis, accounting for 21.7% and 17.3% of the cases, respectively. Most of the cases with AKI had complete renal recovery 78% (n = 18), whereas 17% (n = 4) had progression of the underlying chronic kidney disease. One patient progressed to end-stage renal disease requiring hemodialysis.

CONCLUSIONS

This analysis highlights the risk factors and variable clinicopathological courses of renal involvement in patients with scleroderma. This may range from mild AKI with good prognosis to life-threatening SRC.

Iloprost infusion reduces serological cytokines and hormones of hypoxia and inflammation in systemic sclerosis patients

INTRODUCTION

Systemic sclerosis (SSc) is characterized by microvascular damage of skin and internal organs with chronic hypoxia and release of cytokines and hormones such as neutrophil gelatinase-associated lipocalin (NGAL), fibroblast growth factor-23 (FGF-23) and Klotho. Aim of the study was to evaluate FGF-23, Klotho and NGAL serum levels in SSc patients and healthy controls (HC) and to evaluate serum levels changes of FGF-23, Klotho and NGAL after Iloprost.

METHODS

Twenty-one SSc patients and 20 HC were enrolled. In SSc patients, peripheral venous blood samples were collected at the first day before the autumn Iloprost infusion (t0), 60 min (t1) and 14 days after Iloprost infusion (t2).

RESULTS

SSc patients had higher serum level of FGF-23 [18.7 ± 6.4 pg/ml versus 3.6 ± 2.2 pg/ml, p < 0.001], Klotho [5.1 ± 0.8 pg/ml versus 2.3 ± 0.6 pg/ml, p < 0.001] and NGAL [20.9 ± 2.6 pg/ml versus 14.5 ± 1.7 pg/ml, p < 0.001] than HC. Iloprost infusion reduces serum level of FGF-23 (18.7 ± 6.4 pg/ml versus 10.4 ± 5.5 pg/ml, p < 0.001), Klotho (5.1 ± 0.8 pg/ml versus 2.5 ± 0.6 pg/ml, p < 0.001) and NGAL (20.9 ± 2.6 pg/ml versus 15.1 ± 2.3 pg/ml, p < 0.001) between t0 and t1. The Iloprost infusion reduces serum level of FGF-23 (18.7 ± 6.4 pg/ml versus 6.6 ± 5.1 pg/ml), Klotho (5.1 ± 0.8 pg/ml versus 2.3 ± 0.4 pg/ml) and NGAL (20.9 ± 2.6 pg/ml versus 15.5 ± 1.9 pg/ml) between t0 and t2.

CONCLUSIONS

SSc patients had higher FGF-23, Klotho and NGAL than HC. Iloprost reduces serum levels of FGF-23, Klotho and NGAL.

Role of kinurenic acid in the systemic sclerosis renal involvement

Systemic sclerosis (SSc) subclinical renal vasculopathy is characterized by progressive increase of intrarenal stiffness and reduction of parenchymal thickness due to post ischemic fibrosis secondary to the renal Raynaud phenomenon. Aims of this study were to evaluate kinurenic acid (KYNA) serum level in SSc patients and healthy controls (HC) and to assess the role of KYNA in SSc subclinical nephropathy. Serum level of KYNA was evaluated in 52 SSc patients and 20 HC, matched for sex and age. Renal function was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation to estimate glomerular filtration rate (eGFR) and renal doppler ultrasound was performed to evaluate kidneys' morphology and indices of intrarenal stiffness. The parameters registered were renal longitudinal length, atrophy index (AI), renal sinus, parenchymal thickness, renal resistive index (RRI), pulsatile index (PI) and systolic/diastolic ratio (S/D). SSc patients had lower median value of KYNA than HC [54.43 ng/ml (IQR 44.44-63.64) vs 61.94 ng/ml (IQR 55.23-88.75), p < 0.001]. SSc patients with AI ≥ 0.70 had lower KYNA than SSc patients with AI < 0.70 [47.85 ng/ml (IQR 41.16-59.91) vs 55.5 ng/ml (IQR 49.99-67.33), p < 0.05] and a slightly significant negative linear correlation was found between KYNA and AI (r =  - 0.249, p < 0.05). SSc patient with RRI ≥ 0.70 had higher KYNA than SSc patients with RRI < 0.70 [58.25 ng/ml (IQR 50.49-69.68) vs 50.07 ng/ml (IQR 42.70-56.31), p < 0.05] and a significant positive correlation was found between KYNA and RRI (r = 0.318, p < 0.05). KYNA may be used as a marker to evaluate the renal involvement in SSc patients.

Current Trends in Vascular Biomarkers for Systemic Sclerosis: A Narrative Review

Systemic sclerosis (SSc, scleroderma) is a multifaceted rare connective tissue disease whose pathogenesis is dominated by immune dysregulation, small vessel vasculopathy, impaired angiogenesis, and both cutaneous and visceral fibrosis. Microvascular impairment represents the initial event of the disease, preceding fibrosis by months or years and accounting for the main disabling and/or life-threatening clinical manifestations, including telangiectasias, pitting scars, periungual microvascular abnormalities (e.g., giant capillaries, hemorrhages, avascular areas, ramified/bushy capillaries) clinically detectable by nailfold videocapillaroscopy, ischemic digital ulcers, pulmonary arterial hypertension, and scleroderma renal crisis. Despite a variety of available treatment options, treatment of SSc-related vascular disease remains problematic, even considering SSc etherogenity and the quite narrow therapeutic window. In this context, plenty of studies have highlighted the great usefulness in clinical practice of vascular biomarkers allowing clinicians to assess the evolution of the pathological process affecting the vessels, as well as to predict the prognosis and the response to therapy. The current narrative review provides an up-to-date overview of the main candidate vascular biomarkers that have been proposed for SSc, focusing on their main reported associations with characteristic clinical vascular features of the disease.

Peripheral Macrovascular Involvement in Systemic Sclerosis: A Cohort Study by Color and Spectral Doppler Ultrasonography

OBJECTIVES

Systemic sclerosis (SSc) is a disease characterized by diffuse sclerosis of skin and organs and small vessel vasculopathy. Despite it, large vessels can also be involved with ulnar artery vasculopathy, revealing as a more frequent feature of SSc. The aim of this paper is to assess the macrovascular involvement of SSc patients through an ultrasound (US) evaluation of radial and ulnar arteries.

METHODS

Radial and ulnar resistance indices (RIs) and peak systolic velocity (PV) (cm/s) together with clinical features of SSc patients were evaluated. Raynaud phenomenon (RP) and healthy control (HC) groups were used for comparison.

RESULTS

Forty-three SSc patients were evaluated. Twelve patients (28%) had ulnar artery occlusions (UAOs). In nine cases (75%), UAOs were bilateral. A high UAO prevalence (42%) was found in SSc patients with late nailfold-video-capillaroscopy (NVC) pattern (p = 0.0264). Patients with UAOs had digital ulcers (DUs) in 10 cases (83.3%). Radial and ulnar PVs were lower in SSc and RP patients than the HC group. Radial and ulnar RIs were higher in SSc and RP patients than the HC group. A decision tree analysis led to the classification of 70% of SSc patients with an ulnar RI > 0.82 and ulnar PV > 2.8 cm/s. The most influential variables on UAO development were interstitial lung disease (ILD) (p = 0.002) and NVC pattern (p = 0.002). A positive correlation was shown between modified Rodnan skin score (mRSS) and ILD (p = 0.283; r = 0.033), mRSS and DU (r = 0.344; p = 0.012) and DU and ILD (r = 0.303; p = 0.024). Male sex was associated with increased UAO frequency (p = 0.042).

CONCLUSIONS

UAO is a peculiar feature of severe SSc present in 28% of the cases, particularly associated with the presence of ILD and late NVC pattern. In 75% of the cases, UAOs are bilateral. DUs are very frequent in patients with UAOs (83%). The RI evaluated by US could be useful to distinguish SSc from HC patients. US could be a useful tool for assessing high-risk DU development in patients.

A smartphone-assisted down/up-conversion dual-mode ratiometric fluorescence sensor for visual detection of mercury ions and l-penicillamine

Establishment of a rapid, sensitive, visual, accurate and low-cost fluorescence detection system to detect multiple targets was of great significance in food safety evaluation, ecological environment monitoring and human health monitoring. In this work, a smartphone-assisted down/up-conversion dual-mode ratiometric fluorescence sensor was proposed based on metal-organic framework (NH₂-MIL-101(Fe)) and CdTe quantum dots (CdTe QDs) for visual detection of mercury ions (Hg²⁺) and L-penicillamine (L-PA), in which NH₂-MIL-101(Fe) was used as the reference signal and CdTe QDs was used as the response signal. The down-conversion fluorescence system at excitation wavelength of 300 nm (ex: 330 nm) was used to detect Hg²⁺ and L-PA, in which the detection limit of Hg²⁺ was 0.053 nM with the fluorescence color changed from green to blue, and the detection limit of L-PA was 1.10 nM with the fluorescence color changed from blue to green. Meanwhile, the up-conversion fluorescence system at excitation wavelength of 700 nm (ex: 700 nm) was used to detect Hg²⁺ and L-PA. The detection limits of Hg²⁺ and L-PA were 0.11 nM and 2.93 nM, respectively. The detection of Hg²⁺ and L-PA were also carried out based on the color extraction RGB values identified by the smartphone with a detection limit of 0.091 nM for Hg²⁺ and 8.97 nM for L-PA. In addition, the concentrations of Hg²⁺ and L-PA were evaluated by three-dimensional dynamic analysis in complex environments. The smartphone-assisted down/up-conversion dual-mode ratiometric fluorescence sensor system provides a new strategy for detection Hg²⁺ and L-PA in food safety evaluation, environmental monitoring and human health monitoring.

[Renal manifestations in connective tissue diseases]

Connective tissue diseases (CTD) comprise a group of inflammatory systemic diseases that can affect various organs. Kidney involvement is frequently associated with significant irreversible damage and often before patients become symptomatic. Screening tests of blood and urine as well as clinical vigilance are therefore essential for all CTDs with possible renal involvement. A kidney biopsy is the gold standard for the diagnosis, prognosis and treatment decisions. A common and severe organ involvement in systemic lupus erythematosus (SLE) is glomerulonephritis (GN), also collectively referred to as lupus nephritis (LN). If left untreated LN often leads to end-stage renal failure. The treatment depends on the clinical parameters and histopathology of the renal involvement. Mycophenolate mofetil and cyclophosphamide are potent but nonspecific immunosuppressants which have been available for many years. Recently, new substances specific for LN have also been approved for the first time. Kidney involvement in Sjogren's syndrome has been far less studied. In studies the frequency of renal involvement is still unclear and ranges from 5% to 33%. Tubulointerstitial nephritis (IN) is the typical form of renal involvement which clearly differs from GN in its clinical presentation. Recommendations for treatment are based exclusively on retrospective studies. A renal crisis in systemic scleroderma (SSc) is a rare but feared complication with a high mortality. An antiphospholipid syndrome (APS) nephropathy (APSN) can occur during CTD. These entities are vasculopathies and often thrombotic microangiopathies, which clearly differ from GN and IN in terms of pathophysiology, clinical features and treatment. This article provides an overview of the diversity of the most important renal manifestations of CTDs.