Cystatin C is a disease-associated protein subject to multiple regulation

PM2.5 potentiates oxygen glucose deprivation-induced neurovascular unit damage via inhibition of the Akt/β-catenin pathway and autophagy dysregulation

Air pollution has recently emerged as a significant risk factor for ischemic stroke. Although there is a robust association between higher concentrations of ambient particulate matter (PM2.5) and increased incidence and mortality rates of ischemic stroke, the precise mechanisms underlying PM2.5-induced ischemic stroke remain to be fully elucidated. The purpose of this study was to examine the synergistic effect of PM2.5 and hypoxic stress using in vivo and in vitro ischemic stroke models. Intravenously administered PM2.5 exacerbated the ischemic brain damage induced by middle cerebral artery occlusion (MCAo) in Sprague Dawley rats. Alterations in autophagy flux and decreased levels of tight junction proteins were observed in the brain of PM2.5-administered rats after MCAo. The underlying mechanism of PM2.5-induced potentiation of ischemic brain damage was investigated in neurons, perivascular macrophages, and brain endothelial cells, which are the major components of the integrated neurovascular unit. Co-treatment with PM2.5 and oxygen-glucose deprivation (OGD) amplified the effects of OGD on the reduction of viability in primary neurons, immortalized murine hippocampal neuron (HT-22), and brain endothelial cells (bEND.3). After co-treatment with PM2.5 and OGD, the Akt/β-catenin and autophagy flux were significantly inhibited in HT-22 cells. Notably, the protein levels of metalloproteinase-9 and cystatin C were elevated in the conditioned media of murine macrophages (RAW264.7) exposed to PM2.5, and tight junction protein expression was significantly decreased after OGD exposure in bEND.3 cells pretreated with the conditioned media. Our findings suggest that perivascular macrophages may mediate PM2.5-induced brain endothelial dysfunction following ischemia and that PM2.5 can exacerbate ischemia-induced neurovascular damage.

Sex difference in the association between creatinine-to-cystatin C ratio and metabolic syndrome among Chinese adults

Background

Metabolic syndrome (MetS), characterized by central obesity, insulin resistance, dyslipidemia, and hypertension, affects 20-25% of the global population. The creatinine-to-cystatin C ratio (CCR) is an indicator of skeletal muscle mass. While CCR may play a role in MetS development, sex differences in these associations are not fully understood. Therefore, this study aimed to investigate how CCR levels are associated with MetS in a Chinese adult population, focusing on possible sex disparities.

Method

We conducted a retrospective cross-sectional analysis of 9,376 adults from Xiamen Chang Gung Hospital between 2014 to 2016. We examined the relationship between CCR and MetS, adjusting for cardiometabolic risk factors.

Results

The prevalence of MetS was 24.7% in males and 18.0% in females. Interestingly, we observed significant sex differences in the association between CCR quartiles and MetS. Females in the lowest CCR quartile had a significantly higher risk of MetS (odds ratio=1.84). Receiver operating characteristic curve analysis revealed acceptable diagnostic power of CCR for MetS in females (area under the curve=0.65) but not in males.

Conclusion

Our findings suggest that CCR is an independent risk factor for MetS in females, highlighting the importance of sex-specific assessments when evaluating MetS risk.

Copper interaction with cystatin C: effects on protein structure and oligomerization

Human cystatin C (hCC), a small secretory protein, has gained attention beyond its classical role as a cysteine protease inhibitor owing to its potential involvement in neurodegenerative disorders. This study investigates the interaction between copper(II) ions [Cu(II)] and hCC, specifically targeting histidine residues known to participate in metal binding. Through various analytical techniques, including mutagenesis, circular dichroism, fluorescence assays, gel filtration chromatography, and electron microscopy, we evaluated the impact of Cu(II) ions on the structure and oligomerization of hCC. The results show that Cu(II) does not influence the secondary and tertiary structure of the studied hCC variants but affects their stability. To explore the Cu(II)-binding site, nuclear magnetic resonance (NMR) and X-ray studies were conducted. NMR experiments revealed notable changes in signal intensities and linewidths within the region 86His-Asp-Gln-Pro-His90, suggesting its involvement in Cu(II) coordination. Both histidine residues from this fragment were found to serve as a primary anchor of Cu(II) in solution, depending on the structural context and the presence of other Cu(II)-binding agents. The presence of Cu(II) led to significant destabilization and altered thermal stability of the wild-type and H90A variant, confirming differentiation between His residues in Cu(II) binding. In conclusion, this study provides valuable insights into the interaction between Cu(II) and hCC, elucidating the impact of copper ions on protein stability and identifying potential Cu(II)-binding residues. Understanding these interactions enhances our knowledge of the role of copper in neurodegenerative disorders and may facilitate the development of therapeutic strategies targeting copper-mediated processes in protein aggregation and associated pathologies.

Associations of serum cystatin C concentrations with total mortality and mortality of 12 site-specific cancers

Purpose

Cystatin C (CysC), beyond its biomarker role of renal function, has been implicated in various physical and pathological activities. However, the impact of serum CysC on cancer mortality in a general population remains unknown. We aimed to examine the associations of serum CysC concentrations with total mortality and mortality of 12 site-specific cancers.

Methods

We included 241,008 participants of the UK Biobank cohort with CysC measurements who had normal creatinine-based estimated glomerular filtration rates and were free of cancer and renal diseases at baseline (2006-2010). Death information was obtained from the National Health Service death records through 28 February 2021. Multivariable Cox proportional hazards models were used to compute hazard ratios (HR) per one standard deviation increase in log-transformed CysC concentrations and 95% confidence intervals (95% CI) for mortality.

Results

Over a median follow-up of 12.1 (interquartile range, 11.3-12.8) years, 5,744 cancer deaths occurred. We observed a positive association between serum CysC concentrations and total cancer mortality (HR = 1.16, 95% CI: 1.12-1.20). Specifically, participants with higher serum CysC concentrations had increased mortality due to lung cancer (HR = 1.12, 95% CI: 1.05-1.20), blood cancer (HR = 1.29, 95% CI: 1.16-1.44), brain cancer (HR = 1.19, 95% CI: 1.04-1.36), esophageal cancer (HR = 1.20, 95% CI: 1.05-1.37), breast cancer (HR = 1.18, 95% CI: 1.03-1.36), and liver cancer (HR = 1.49, 95% CI: 1.31-1.69).

Conclusion

Our findings indicate that higher CysC concentrations are associated with increased mortality due to lung, blood, brain, esophageal, breast, and liver cancers. Future studies are necessary to clarify underlying mechanisms.

Human cystatin C induces the disaggregation process of selected amyloid beta peptides: a structural and kinetic view

Neurodegenerative diseases, such as Alzheimer's disease (AD) and various types of amyloidosis, are incurable; therefore, understanding the mechanisms of amyloid decomposition is crucial to develop an effective drug against them for future therapies. It has been reported that one out of three people over the age of 85 are suffering from dementia as a comorbidity to AD. Amyloid beta (Aβ), the hallmark of AD, transforms structurally from monomers into β-stranded aggregates (fibrils) via multiple oligomeric states. Astrocytes in the central nervous system secrete the human cystatin C protein (HCC) in response to various proteases and cytokines. The codeposition of Aβ and HCC in the brains of patients with AD led to the hypothesis that cystatin C is implicated in the disease process. In this study, we investigate the intermolecular interactions between different atomic structures of fibrils formed by Aβ peptides and HCC to understand the pathological aggregation of these polypeptides into neurotoxic oligomers and then amyloid plaques. To characterize the interactions between Aβ and HCC, we used a complementary approach based on the combination of small-angle neutron scattering analysis, atomic force microscopy and computational modelling, allowing the exploration of the structures of multicomponent protein complexes. We report here an optimized protocol to study that interaction. The results show a dependency of the sequence length of the Aβ peptide on the ability of the associated HCC to disaggregate it.

Mast cells in colorectal cancer tumour progression, angiogenesis, and lymphangiogenesis

The characteristics of the tumour cells, as well as how tumour cells interact with their surroundings, affect the prognosis of cancer patients. The resident cells in the tumour microenvironment are mast cells (MCs), which are known for their functions in allergic responses, but their functions in the cancer milieu have been hotly contested. Several studies have revealed a link between MCs and the development of tumours. Mast cell proliferation in colorectal cancer (CRC) is correlated with angiogenesis, the number of lymph nodes to which the malignancy has spread, and patient prognosis. By releasing angiogenic factors (VEGF-A, CXCL 8, MMP-9, etc.) and lymphangiogenic factors (VEGF-C, VEGF-D, etc.) stored in granules, mast cells play a significant role in the development of CRC. On the other hand, MCs can actively encourage tumour development via pathways including the c-kit/SCF-dependent signaling cascade and histamine production. The impact of MC-derived mediators on tumour growth, the prognostic importance of MCs in patients with various stages of colorectal cancer, and crosstalk between MCs and CRC cells in the tumour microenvironment are discussed in this article. We acknowledge the need for a deeper comprehension of the function of MCs in CRC and the possibility that targeting MCs might be a useful therapeutic approach in the future.

Valproate-Induced Metabolic Syndrome

Valproic acid (VPA) and its salts (sodium calcium magnesium and orotic) are psychotropic drugs that are widely used in neurology and psychiatry. The long-term use of VPA increases the risk of developing adverse drug reactions (ADRs), among which metabolic syndrome (MetS) plays a special role. MetS belongs to a cluster of metabolic conditions such as abdominal obesity, high blood pressure, high blood glucose, high serum triglycerides, and low serum high-density lipoprotein. Valproate-induced MetS (VPA-MetS) is a common ADR that needs an updated multidisciplinary approach to its prevention and diagnosis. In this review, we consider the results of studies of blood (serum and plasma) and the urinary biomarkers of VPA-MetS. These metabolic biomarkers may provide the key to the development of a new multidisciplinary personalized strategy for the prevention and diagnosis of VPA-MetS in patients with neurological diseases, psychiatric disorders, and addiction diseases.

Identification, expression profiling, and functional characterization of cystatin C from big-belly seahorse (Hippocampus abdominalis)

Cystatins are natural inhibitors of lysosomal cysteine proteases, including cathepsins B, L, H, and S. Cystatin C (CSTC) is a member of the type 2 cystatin family and is an essential biomarker in the prognosis of several diseases. Emerging evidence suggests the immune regulatory roles of CSTC in antigen presentation, the release of different inflammatory mediators, and apoptosis in various pathophysiologies. In this study, the 390-bp cystatin C (HaCSTC) cDNA from big-belly seahorse (Hippocampus abdominalis) was cloned and characterized by screening the pre-established cDNA library. Based on similarities in sequence, HaCSTC is a homolog of the teleost type 2 cystatin family with putative catalytic cystatin domains, signal peptides, and disulfide bonds. HaCSTC transcripts were ubiquitously expressed in all tested big-belly seahorse tissues, with the highest expression in ovaries. Immune challenge with lipopolysaccharides, polyinosinic:polycytidylic acid, Edwardsiella tarda, and Streptococcus iniae caused significant upregulation in HaCSTC transcript levels. Using a pMAL-c5X expression vector, the 14.29-kDa protein of recombinant HaCSTC (rHaCSTC) was expressed in Escherichia coli BL21 (DE3), and its protease inhibitory activity against papain cysteine protease was determined with the aid of a protease substrate. Papain was competitively blocked by rHaCSTC in a dose-dependent manner. In response to viral hemorrhagic septicemia virus (VHSV) infection, HaCSTC overexpression strongly decreased the expression of VHSV transcripts, pro-inflammatory cytokines, and pro-apoptotic genes; while increasing the expression of anti-apoptotic genes in fathead minnow (FHM) cells. Furthermore, HaCSTC overexpression protected VHSV-infected FHM cells against VHSV-induced apoptosis and increased cell viability. Our findings imply the profound role of HaCSTC against pathogen infections by modulating fish immune responses.

Novel Biomarkers of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a highly prevalent condition worldwide. It represents one of the most common complications arising from diabetes mellitus (DM) and is the leading cause of end-stage kidney disease (ESKD). Its development involves three fundamental components: the hemodynamic, metabolic, and inflammatory axes. Clinically, persistent albuminuria in association with a progressive decline in glomerular filtration rate (GFR) defines this disease. However, as these alterations are not specific to DKD, there is a need to discuss novel biomarkers arising from its pathogenesis which may aid in the diagnosis, follow-up, therapeutic response, and prognosis of the disease.

Cancer Cells Enter an Adaptive Persistence to Survive Radiotherapy and Repopulate Tumor

Repopulation of residual tumor cells impedes curative radiotherapy, yet the mechanism is not fully understood. It is recently appreciated that cancer cells adopt a transient persistence to survive the stress of chemo- or targeted therapy and facilitate eventual relapse. Here, it is shown that cancer cells likewise enter a "radiation-tolerant persister" (RTP) state to evade radiation pressure in vitro and in vivo. RTP cells are characterized by enlarged cell size with complex karyotype, activated type I interferon pathway and two gene patterns represented by CST3 and SNCG. RTP cells have the potential to regenerate progenies via viral budding-like division, and type I interferon-mediated antiviral signaling impaired progeny production. Depleting CST3 or SNCG does not attenuate the formation of RTP cells, but can suppress RTP cells budding with impaired tumor repopulation. Interestingly, progeny cells produced by RTP cells actively lose their aberrant chromosomal fragments and gradually recover back to a chromosomal constitution similar to their unirradiated parental cells. Collectively, this study reveals a novel mechanism of tumor repopulation, i.e., cancer cell populations employ a reversible radiation-persistence by poly- and de-polyploidization to survive radiotherapy and repopulate the tumor, providing a new therapeutic concept to improve outcome of patients receiving radiotherapy.

Serum creatinine/cystatin C ratio as a muscle mass evaluating tool and prognostic indicator for hospitalized patients: A meta-analysis

Objective

Sarcopenia is a syndrome of decreased muscle mass and deficits in muscle strength and physical function. We aimed to investigate the relationship between creatinine/cystatin C ratio (CCR) and sarcopenia and the prognostic value of CCR in hospitalized patients.

Materials and methods

We searched for relevant studies in PubMed, EMBASE, and the Cochrane Database up to August 25, 2022. Meta-analyses were performed to evaluate the relationship between CCR and skeletal muscle [computed tomography-assessed skeletal muscle (CTASM), muscle strength, and physical performance], prognosis and important clinical outcomes in hospitalized adults. The pooled correlation coefficient, the area under the receiver operating characteristic (ROC) curves, and hazard ratio (HR) together with their 95% confidence intervals (CIs) were calculated. We also conducted subgroup analyses to explore the sources of heterogeneity.

Results

A total of 38 studies with 20,362 patients were eligible. These studies were of moderate to high quality. Our results showed that CCR was significant correlations with all CTASM types (Fisher's Z ranged from 0.35 to 0.5; P values ranged from < 0.01 to 0.01), handgrip strength (Fisher's Z = 0.39; 95% CI, 0.32-0.45; P < 0.001) and gait speed (Fisher's Z = 0.25; 95% CI, 0.21-0.30; P < 0.001). The ROC curves suggested that CCR had good diagnostic efficacy (0.689; 95% CI, 0.632-0.746; P < 0.01) for sarcopenia. CCR can reliably predict mortality in hospitalized patients, which was confirmed by regression analysis of CCR as both continuous (HR 0.78; 95% CI, 0.72-0.84; P < 0.01) and categorical variables (HR 2.05; 95% CI, 1.58-2.66; P < 0.0001). In addition, less evidence showed that higher CCR was independently associated with a shorter duration of mechanical ventilation, reduced length of stay in the intensive care unit and hospital, less nutritional risk, and decreased complications in hospitalized patients.

Conclusion

CCR could be a simple, economical, and effective screening tool for sarcopenia in hospitalized patients, and it is a helpful prognostic factor for mortality and other important clinical outcomes.

Systematic review registration

https://inplasy.com/inplasy-2022-9-0097/, identifier INPLASY202290097.

Association between Serum Cys C and PTB Cavitation

Background

Cystatin C (Cys C) not only regulates the body's immune defenses but also contributes to tissue degradation and destruction by causing an imbalance between protease and antiprotease in infectious diseases. Is Cys C involved in pulmonary tuberculosis (PTB) infection and cavitation? We therefore conducted a retrospective study on this question to provide a basis for further studies.

Methods

Cavitary PTB patients, noncavitary PTB patients, and healthy controls were recruited in our study. Serum Cys C, CRP, BUN, UA, and CR were measured in all subjects, and the Kruskal-Wallis test was used to compare medians of these clinical parameters in different groups. The Spearman rank correlation test was used to determine correlations between variables. In addition, a multivariate analysis using binary logistic regression was used to identify factors associated with PTB cavitation.

Results

In our study, elevated serum Cys C levels were found in cavitary PTB patients compared to healthy controls and noncavitary patients (p = 0.022). Serum Cys C levels were statistically correlated with serum BUN and CR concentrations (r = 0.278, p = 0.005; r = 0.281, p = 0.004) in PTB patients. The binary logistic regression analysis showed that elevated serum Cys C levels were correlated with pulmonary cavitation in PTB patients (OR = 1.426, 95% CI: 1.071-1.898).

Conclusion

Elevated serum levels of Cys C are associated with pulmonary cavitation in PTB patients.

Mast cells inhibit colorectal cancer development by inducing ER stress through secreting Cystatin C

Mast cells (MCs) are abundantly distributed in the human intestinal mucosa and submucosa. However, their roles and mechanisms in the development of colorectal cancer (CRC) are still unclear. In the present research, we found that the infiltration density of MCs in CRC tissues was positively correlated with improved patients' prognoses. Moreover, MCs suppressed the growth and induced the apoptosis of CRC cells in vitro and in vivo but had no effect on normal colonic epithelial cells. The present study revealed that MCs specifically induced endoplasmic reticulum stress (ERS) and activated the unfolded protein response (UPR) in CRC cells but not in normal cells, which led to the suppression of CRC development in vivo. Furthermore, we found that the secreted Cystatin C protein was the key factor for the MC-induced ERS in CRC cells. This work is of significance for uncovering the antitumor function of MCs in CRC progression and identifying the potential of CRC to respond to MC-targeted immunotherapy.

Serum Cystatin C is Associated with Depression After Intracerebral Hemorrhage

Purpose

Cystatins are associated with neuronal degeneration and nervous system healing. Cystatin C (Cys C) has recently been linked to brain injury and immunological inflammation. This study aimed to determine the relationship between serum Cys C levels and depression following intracranial hemorrhage (ICH).

Patients and Methods

Between September 2020 and December 2022, 337 patients with ICH were sequentially recruited and followed up for three months. The post-stroke depression (PSD) and non-PSD groups were separated based on the 17-item Hamilton Depression Rating Scale (HAMD). The PSD diagnosis was established based on the DSM-IV criteria. Cys-C levels were documented within twenty-four hours of admission.

Results

Three months after ICH, 93 (27.6%) of 337 enrolled patients were diagnosed with depression. The Cys C levels were significantly higher in depressed patients than in nondepressed patients after ICH (1.32 vs 1.01; p<0.001). After adjusting for potential confounding variables, depression after ICH was associated with the highest quartile of Cys C levels (odds ratio (OR) = 3.195, 95% CI: 1.562-6.536; p=0.001). The receiver operating characteristic curve (ROC) curve predicted that the ideal cut-off for CysC levels as a predictor of depression after ICH would be 0.730, resulting in 84.5% sensitivity and 88.4% specificity, with an area under curve (AUC) of 0.880 (95% CI: 0.843-0.917; p< 0.0001).

Conclusion

Increased CysC concentrations were independently related to depression three months after ICH, highlighting that CysC levels at admission may be a potential biomarker for predicting the onset of depression following ICH.

Association between serum cystatin C level and cognition in older adults: a cross-sectional analysis

Introduction

Serum Cystatin C level, an indication of kidney function, has been implicated in the pathogenesis of Alzheimer's disease and cognitive impairment. In this cross-sectional study, we looked into the relation between serum Cystatin C levels and cognition in a group of U.S. older adults.

Method

The data of this study were from the National Health and Nutrition Examination Survey (NHANES) 1999-2002. A total of 4,832 older adults aged ≥60 who met the inclusion criteria were included. The Dade Behring N Latex Cystatin C assay, which is a particle-enhanced nephelometric assay (PENIA), was utilized to assess Cystatin C levels in participants' blood samples. Participants' cognition was examined using the digit symbol substitution test (DSST). Z-scores of the DSST were calculated based on sample means and standard deviations (SD). To investigate the relationships between the quartiles of serum Cystatin C level and DSST z scores, multiple linear regression models were developed while controlling for age, sex, race/ethnicity, and education.

Results

The average age of the participants was 71.1 (SD 7.8). The participants were about half female (50.5%), non-Hispanic White (61.2%), and (36.1%) who had completed at least some college. They had an average serum Cystatin C level of 1.0 mg/dl (SD 0.44). After performing multiple linear regression with a reference group consisting of participants in quartile one of plasma Cystatin C levels, we found that serum Cystatin C levels in quartiles three and four were independently associated with lower DSST z scores (β = -0.059, 95% CI -0.200 to -0.074 and β = -0.108, 95% CI -0.319 to -0.184, respectively).

Conclusion

Higher serum Cystatin C level is associated with worse processing speed, sustained attention, and working memory in older adults. Cystatin C level may be a biomarker for cognitive decline in older adults.

Cystatin C predicts cognitive decline in multiple system atrophy: A 1-year prospective cohort study

BACKGROUND

Accumulating evidence has suggested that cystatin C is associated with cognitive impairment in patients with neurodegenerative diseases. However, the association between cystatin C and cognitive decline in patients with multiple system atrophy (MSA) remains largely unknown.

OBJECTIVES

The objective was to determine whether cystatin C was independently associated with cognitive decline in patients with early-stage MSA.

METHODS

Patients with MSA underwent evaluation at baseline and the 1-year follow-up. Cognitive function was evaluated with Montreal cognitive assessment (MoCA). Changes in the MoCA score and the absolute MoCA score at the 1-year assessment were considered the main cognitive outcome. The cystatin C concentrations in patients with MSA and age, sex, and body mass index matched-healthy controls (HCs) were measured. A multiple linear regression model was used to test the association between cystatin C and cognitive decline.

RESULTS

A total of 117 patients with MSA and 416 HCs were enrolled in the study. The cystatin C levels were significantly higher in patients with MSA than in HCs (p < 0.001). Cystatin C levels were negatively correlated with MoCA score at baseline and at 1-year follow-up. Multiple linear regression model adjusted for potential confounders showed that baseline cystatin C levels were significantly associated with the MoCA score (p = 0.004) or change in the MoCA score (p = 0.008) at 1-year follow-up.

CONCLUSION

Our results suggested that cystatin C may serve as a potential biomarker of cognitive decline in patients with early-stage MSA.

Functional analysis of the Cystatin F gene response to SGIV infection in orange-spotted grouper, Epinephelus coioides

Cystatin F (CyF), an inhibitor of cysteine protease, was widely studied in immune defense and cancer therapy. However, the function of CyF and its latent molecular mechanism during virus infection in fish remain vacant. In our research, we cloned the open reading frame (ORF) of CyF homology from orange-spotted grouper (Ec-CyF) consisting of 342 nucleotides and encoding a 114-amino acid protein. Ec-CyF included two cystatins family sequences containing one KXVXG sequence without the signal peptide, and a hairpin ring containing proline and tryptophan (PW). Tissue distribution analysis indicated that Ec-CyF was highly expressed in spleen and head kidney. Besides, further analysis showed that the expression of Ec-CyF increased during SGIV infection in grouper spleen (GS) cells. Subcellular localization assay demonstrated that Ec-CyF was mainly distributed in cytoplasm in GS cells. Overexpressed Ec-CyF demoted the mRNA level of viral genes MCP, VP19 and LITAF. Meanwhile, SGIV-induced apoptosis in fat head minnow (FHM) cells was impeded, as well as the restraint of caspase 3/7 and caspase 8. In addition, Ec-CyF overexpression up-regulated the expression of IFN related molecules including ISG15, IFN, IFP35, IRF3, IRF7, MYD88 and down-regulated proinflammatory factors such as IL-1β, IL-8 and TNF-α. At the same time, Ec-CyF-overexpressing increased the activity of IFN3 and ISRE promoter, but impeded NF-κB promoter activity by luciferase reporter gene assay. In summary, our findings suggested that Ec-CyF was involved in innate immunity response and played a key role in DNA virus infection.

High serum cystatin C levels in juvenile myelomonocytic leukemia patients without abnormal kidney function

BACKGROUND

In pediatric cancer patients, the estimated glomerular filtration rate based on serum cystatin C (CysC) was reported to be suitable for estimating kidney function because of low serum creatinine (Cr) and high serum β₂-microglobulin. Recently, however, serum CysC levels have been reported to be elevated in some cancer patients other than those with juvenile myelomonocytic leukemia (JMML), regardless of normal kidney function.

CASE REPORTS

We describe two pediatric cases of JMML with an elevated serum CysC level. Urinalysis tests showed no abnormalities and no evidence of nephritis or nephropathy, and there were no findings indicating abnormal kidney function, such as Cr clearance in one case or the estimated glomerular filtration rate based on serum Cr in both cases, except for the serum CysC levels. There were no other causes of a high serum CysC level, including hyperthyroidism and steroid administration. The patients were treated with a conventional dosage of drugs, and their serum CysC levels decreased to the normal range when they were in complete remission after treatment.

CONCLUSION

An elevated serum CysC level may reflect tumor burden independent of kidney function in JMML patients. Therefore, creatinine or inulin clearance should be determined to more accurately estimate kidney function for administering an optimal dose of anticancer drugs. In addition, a high serum CysC level may be a potential biomarker of cancer progression.

Relationships between cystatin C and creatinine‐based eGFR with low tongue pressure in Japanese rural community‐dwelling older adults

Background

Sarcopenia is prevalent in patients with chronic kidney disease (CKD), which is defined as a low estimated glomerular filtration rate (eGFR). It has been reported that oral hypofunction characterized by decreased tongue pressure is related to sarcopenia. Although there are several previous reports regarding the association of renal dysfunction with oral hypofunction characterized by low tongue pressure, the association between tongue pressure and renal function is not fully understood.

Methods

This cross‐sectional study included 68 men aged 79.0 ± 4.8 years and 145 women aged 77.3 ± 5.4 years from a rural area in Hyogo Prefecture, Japan. We examined the relationships between cystatin C‐based CKD (CKDcys), creatinine‐based CKD (CKDcre), ratio of cystatin C‐based GFR (eGFRcys) divided by creatinine‐based GFR (eGFRcre): eGFRcys/eGFRcre, and tongue pressure in community‐dwelling older adults.

Results

Tongue pressure was significantly lower in participants with CKDcys than in those without CKDcys in men and women. However, there were no significant differences in tongue pressure with or without CKDcre. Tongue pressure was significantly lower in participants with eGFRcys/eGFRcre <1.0, than in those with eGFRcys/eGFRcre ≧ 1.0 in men. According to the receiver operating characteristic analysis, the optimal cut‐off value of tongue pressure for the presence of CKDcys was 36.6kPa, area under the curve (AUC) 0.74 (specificity 54.8%, sensitivity 84.6%) in men and 31.8kPa, AUC 0.65 (specificity 67.3%, sensitivity 60.5%) in women.

Conclusions

CKDcys but not CKDcre is associated with low tongue pressure. In addition, a lower eGFRcys/eGFRcre ratio is a useful screening marker of low tongue pressure in community‐dwelling older adults.

The value of cystatin C in evaluating the severity and prognosis of patients with severe fever with thrombocytopenia syndrome

Background

Severe fever with thrombocytopenia syndrome (SFTS) is a novel emerging viral infectious disease. We explore the value of cystatin C (CysC) level in the evaluation of disease severity and prognosis in patients with SFTS.

Methods

254 patients with SFTS were enrolled in this study. According to the classification and the outcome of the disease, the patients were divided into the general group and the severe group, the severe patients were divided into the fatal group and the non-fatal group. We compared the laboratory indexes by univariate and multivariate logistic regression analysis to explore the severity and prognostic risk factors of SFTS disease, ROC curve and Kaplan–Meier survival analysis curve were drawn to analyze the independent risk factors and the predictive value of disease severity and prognosis.

Results

Univariate analysis showed that the CysC level in severe group and fatal group was significantly higher than general group and non-fatal group (P < 0.05), respectively. Multivariate logistic regression showed that the CysC level was an independent risk factor for severe and death in SFTS patients, and it can effectively predict the risk of severe (AUC = 0.711, 95% CI: 0.645–0.777) and death (AUC = 0.814, 95% CI: 0.737–0.89). The risk of death in patients with cystatin C ≥ 1.23 mg/L was 5.487 times higher than that in patients with cystatin C < 1.23 mg/L.

Conclusions

The CysC level have good predictive value for disease severity and prognosis in patients with SFTS.

Trial registration Not applicable

Increased serum cystatin C levels and responses of pancreatic α- and β-cells in type 2 diabetes

BACKGROUND

Increased serum cystatin C (CysC) can predict the onset of type 2 diabetes (T2D). Meanwhile, impaired pancreatic α- and β-cell functions get involved in the pathophysiological processes of T2D. So this study was to explore the relationships between serum CysC levels and pancreatic α- and β-cell functions in T2D.

METHODS

In this cross-sectional observational study, a total of 2634 patients with T2D were consecutively recruited. Each recruited patient received a serum CysC test and oral glucose tolerance test for synchronous detection of serum C-peptide and plasma glucagon. As components of pancreatic β-cell function, insulin secretion and sensitivity indices were evaluated by C-peptide area under the curve (AUC-CP) and C-peptide-substituted Matsuda's index (Matsuda-CP), respectively. Fasting glucagon (F-GLA) and post-challenge glucagon calculated by glucagon area under the curve (AUC-GLA) were used to assess pancreatic α-cell function. These skewed indices and were further natural log-transformed (ln).

RESULTS

With quartiles of serum CysC levels ascending, AUC-CP, F-GLA and AUC-GLA were increased, while Matsuda-CP was decreased (P for trend <0.001). Moreover, serum CysC levels were positively related to lnAUC-CP, lnF-GLA and lnAUC-GLA (r= 0.241, 0.131 and 0.208, respectively, P < 0.001), and inversely related to lnMatsuda-CP (r= -0.195, P < 0.001). Furthermore, after controlling for other relevant variables via multivariable linear regression analysis, serum CysC levels were identified to account for lnAUC-CP (β= 0.178, t= 10.518, P < 0.001), lnMatsuda-CP (β= -0.137, t= -7.118, P < 0.001), lnF-GLA (β= 0.049, t= 2.263, P = 0.024) and lnAUC-GLA (β= 0.121, t= 5.730, P < 0.001).

CONCLUSIONS

Increased serum CysC levels may be partly responsible for increased insulin secretion from β-cells, decreased systemic insulin sensitivity, and elevated fasting and postprandial glucagon secretion from α-cells in T2D.

Circulating Cystatin C Is an Independent Risk Marker for Cardiovascular Outcomes, Development of Renal Impairment, and Long-Term Mortality in Patients With Stable Coronary Heart Disease: The LIPID Study

Background

Elevated plasma cystatin C levels reflect reduced renal function and increased cardiovascular risk. Less is known about whether the increased risk persists long‐term or is independent of renal function and other important biomarkers.

Methods and Results

Cystatin C and other biomarkers were measured at baseline (in 7863 patients) and 1 year later (in 6106 patients) in participants in the LIPID (Long‐Term Intervention with Pravastatin in Ischemic Disease) study, who had a previous acute coronary syndrome. Outcomes were ascertained during the study (median follow‐up, 6 years) and long‐term (median follow‐up, 16 years). Glomerular filtration rate (GFR) was estimated using Chronic Kidney Disease Epidemiology Collaboration equations (first GFR‐creatinine, then GFR‐creatinine‐cystatin C). Over 6 years, in fully adjusted multivariable time‐to‐event models, with respect to the primary end point of coronary heart disease mortality or nonfatal myocardial infarction, for comparison of Quartile 4 versus 1 of baseline cystatin C, the hazard ratio was 1.37 (95% CI, 1.07–1.74; P=0.01), and for major cardiovascular events was 1.47 (95% CI, 1.19–1.82; P<0.001). Over 16 years, the association of baseline cystatin C with coronary heart disease, cardiovascular, and all‐cause mortality persisted (each P<0.001) and remained significant after adjustment for estimated GFR‐creatinine‐cystatin C. Cystatin C also predicted the development of chronic kidney disease for 6 years (odds ratio, 6.61; 95% CI, 4.28–10.20) independently of estimated GFR‐creatinine and other risk factors. However, this association was no longer significant after adjustment for estimated GFR‐creatinine‐cystatin C.

Conclusions

Cystatin C independently predicted major cardiovascular events, development of chronic kidney disease, and cardiovascular and all‐cause mortality. Prediction of long‐term mortality was independent of improved estimation of GFR.

Registration

URL: https://anzctr.org.au; Unique identifier: ACTRN12616000535471.

Role of cystatin C in urogenital malignancy

Urogenital malignancy accounts for one of the major causes of cancer-related deaths globally. Numerous studies have investigated novel molecular markers in the blood circulation, tumor tissue, or urine in order to assist in the clinical identification of tumors at early stages, predict the response of therapeutic strategies, and give accurate prognosis assessment. As an endogenous inhibitor of lysosomal cysteine proteinases, cystatin C plays an integral role in diverse processes. A substantial number of studies have indicated that it may be such a potential promising biomarker. Therefore, this review was intended to provide a detailed overview of the role of cystatin C in urogenital malignancy.

Persistent Depressive Symptoms and the Changes in Serum Cystatin C Levels in the Elderly: A Longitudinal Cohort Study

BACKGROUND

The burden of depression in the elderly is increasing worldwide with global aging. However, there is still a lack of research on the relationship between depressive symptoms and the progression of renal function. Our aim is to evaluate the longitudinal association between baseline depressive symptoms and the changes in serum cystatin C levels over 10 years' follow-up period.

METHODS

We used longitudinal data from the Health and Retirement Study (HRS), an existing community based nationally representative aging cohort study which enrolled individuals over age 50 in the USA. Depressive symptoms were determined using an eight-item version of the Center for Epidemiologic Studies Depression Scale (CESD) at wave 7 (2004) and wave 8 (2006). Persistent depressive symptoms were defined as both CESD scores measured at waves 7 and 8 were ≥3; episodic depressive symptoms were defined as CESD scores ≥3 at wave 7 or wave 8. A linear mixed model was used to evaluate the correlation between baseline depressive symptoms and future changes in cystatin C levels.

RESULTS

The mean age of the 7,642 participants was 63.8 ± 10.8 years, and 60.9% were women. Among the participants, 1,240 (16.2%) had episodic depressive symptoms and 778 (10.2%) had persistent depressive symptoms. Compared with participants with no depressive symptoms at both waves, a significant increase in serum cystatin C levels was found among those with persistent depressive symptoms.

CONCLUSIONS

Our results showed that baseline persistent depressive symptoms were significantly associated with an increased rate of serum cystatin C levels. The level of serum cystatin C should be monitored in the elderly with persistent depressive symptoms.

Cystatin C and cystatin SN as possible soluble tumor markers in malignant uveal melanoma

Background

The aim of the study was to determine the concentration of endogenous cystatin C and cystatin SN, as potential tumor biomarkers, in the serum and biological fluids of the eye in both healthy controls and patients with uveal melanoma.

Patients and methods

The concentration of both cystatins was determined in the intraocular fluid (IOF), tear fluid, and serum of patients with uveal melanoma and compared to baseline measurements in IOF, tears, serum, cerebral spinal fluid, saliva and urine of healthy controls.

Results

The concentration of cystatin C in all the biological matrices obtained from healthy controls significantly exceeded the concentration of cystatin SN and was independent of gender. Cystatin C concentrations in the tear fluid of patients with uveal melanoma (both the eye with the malignancy, as well as the contralateral, non-affected eye), were significantly greater than cystatin C concentrations in the tear fluid of healthy controls and was independent of tumor size. The concentration of cystatin SN in IOF of patients with uveal melanoma was significantly less than the corresponding concentration of cystatin SN in healthy controls.

Conclusions

The ratio of cystatins (CysC:CysSN) in both the serum and tear fluid, as well as the concentration of cystatin SN in IOF, would appear to strongly suggest the presence of uveal melanoma. It is further suggested that multiple diagnostic criteria be utilized if a patient is suspected of having uveal melanoma, such as determination of the cystatin C and cystatin SN concentrations in serum, tears, and IOF, ocular fundus and ultrasound imaging, and biopsy with histopathological evaluation.

Associations of serum cystatin C with depressive symptoms and suicidal ideation in major depressive disorder

BACKGROUND

Individuals with major depressive disorder (MDD) have high suicidal ideation. There is evidence that serum cystatin C (Cys C) may be involved in the pathophysiology of MDD. The present study aimed to investigate Cys C concentration in patients with MDD and clarify its possible association with depressive symptoms and suicidal ideation.

METHODS

An online cross-sectional survey of 159 patients diagnosed with MDD was conducted. Serum Cys C levels were measured using ADVIA 2400 biochemical analyzer. The 24-item Hamilton Depression Scale (HAMD-24) was administered to evaluate the depressive symptoms. Generalized linear regression, logistic regression and restricted cubic spline models were used to examine the association of serum Cys C levels with depressive symptoms and suicidal ideation.

RESULTS

Serum Cys C levels were higher in MDD patients than in controls (p = 0.001) and were positively associated with scores on HAMD-24 in unadjusted (gender distribution, age, smoking, alcohol consumption, family history of depression and traumatic life events; (p = 0.003) and fully adjusted linear regression model (p = 0.005). The fully adjusted regression coefficient with 95% confidence intervals for serum Cys C levels and HAMD-24 score was 30.339 (9.602 to 51.077). The level of Cys C in the suicidal ideation (SI) group was significantly higher than that in the non-suicide ideation (non-SI) group (p = 0.001). Serum Cys C levels were positively associated with suicidal ideation in each logistic regression model (all p <  0.05).

CONCLUSION

Serum Cys C levels were elevated in MDD patients and appeared to be positively correlated with depressive symptoms and suicidal ideation. These findings suggest that the dysfunction of Cys C may be involved in the severity of depression and in the pathophysiological process of MDD. Thus, regulation of serum Cys C could potentially be an effective predictor of the severity of depression and potentially, play a role in reducing the risk of suicide in MDD patients.

Association between cystatin C and diabetic retinopathy among type 2 diabetic patients in China: a Meta-analysis

AIM

To explore the correlation between cystatin C (Cys-C) and diabetic retinopathy (DR) in those patients with type 2 diabetes mellitus (DM) in China.

METHODS

Articles were collected from China National Knowledge Infrastructure (CNKI), Wanfang, VIP, PubMed, EMBASE, Cochrane Library, Clinical Trials.gov, and Google Scholar. Quality and risk of bias within included studies was assessed using the Newcastle-Ottawa scale (NOS). Heterogeneity was determined by using Cochran's Q-test and Higgins I ² statistics. Mean differences (MDs) and 95% confidence intervals (CIs) of Cys-C within the diabetes without retinopathy (DWR) and DR, DWR and non-proliferative diabetic retinopathy (NPDR), NPDR and proliferative diabetic retinopathy (PDR) were collected by using random-effects model because of high heterogeneity. Meta-analysis was conducted based on 23 articles of 2331 DR including NPDR and PDR patients and 2023 DWR patients through Review Manager 5.3. Subgroup analyses were also performed according to DM duration, body mass index (BMI), total cholesterol (TC), total triglycerides (TG), low-density lipoprotein C (LDL-C), and high-density lipoprotein C (HDL-C), sample origins and methods. Publication bias was assessed by the funnel plot.

RESULTS

Cys-C level in DR patients was increased compared with that of DWR (total MD: 0.69, 95%CI: 0.41 to 0.97, Z=4.79, P<0.01). Besides, the synthesized results of the studies showed the similar findings in the DWR vs NPDR group (total MD: 0.29, 95%CI 0.20 to 0.39, Z=6.02, P<0.01) and the NPDR vs PDR group (total MD: 0.63, 95%CI 0.43 to 0.82, Z=6.33, P<0.01). Heterogeneity of most of the subgroup analyses was still obvious (I ²≥50%, P<0.1). Forest plots of different subgroups indicated that there was a slight increase of Cys-C during the period between DWR and DR, DWR and NPDR, NPDR and PDR. Funnel plot showed that there was no significant publication bias.

CONCLUSION

The elevated Cys-C is closely related with DR and probably plays a critical role in its progression.

Novel methods to identify and measure catabolism

PURPOSE OF REVIEW

Assess current potential catabolism-biomarkers to characterize patients developing prolonged critical illness.

RECENT FINDINGS

A raised urea-to-creatinine ratio (UCR) during critical illness is negatively associated with muscle mass with greater increases in UCR seen patients developing persistent critical illness. Similarly, sarcopenia index (a ratio of creatinine to cystatin-c concentrations) correlates well to muscle mass in intensive care populations. Elevated growth/differentiation factor-15 (GDF-15) has been inconsistently associated with muscle loss. Although GDF-15 was a poor marker of feeding tolerance, it has been associated with worse prognosis in intensive care.

SUMMARY

UCR is an available and clinically applicable biomarker of catabolism. Similarly, sarcopenia index can be used to assess muscle mass and indirectly measure catabolism based on readily available biochemical measurements. The utility of novel biomarkers, such as GDF-15 is less established.

Identification and molecular profiling of a novel homolog of cystatin C from rock bream (Oplegnathus fasciatus) evidencing its transcriptional sensitivity to pathogen infections

Cystatins are reversible inhibitors of cysteine proteases which show an omnipresent distribution in the life on earth. Although, cystatins with mammalian origin were well characterized and their roles in physiology were reported in details, those from teleostean origin are still underrepresented in literature. However, role of cystatins in fish physiology and immune defense is highlighted in few recent reports. In this study, a cystatin C holmologue from rock bream (Oplegnathus fasciatus); termed RbCytC was identified and molecularly characterized. The complete coding sequence of RbCytC was 387 bp in length, which codes for a polypeptide with 129 amino acids, including a signal peptide of 19 amino acids. The consensus cystatin family signatures including a G residue, turning up towards the N-terminus region, QVVAG motif, locating at the middle of the sequence and the PW motif at the c terminal region was found to be well conserved in RbCytC. Phylogenetic analysis using different cystatin counterparts affirmed the close evolutionary relationship of RbCytC with its teleostan homologs which belong to family 2 cystatins. The predicted molecular model of RbCytC resembled most of the structural features of empirically elucidated tertiary structures for chicken egg white cystatin. According to the qPCR assays, RbCytC showed detectable expression in all fish tissues used in the experiment, with markedly pronounced expression level in liver. Moreover, its basal mRNA expression was up-regulated in liver and spleen tissues by experimental rock bream iridovirus infection, whereas down regulated in the same tissues, post live Edwardsiella tarda injection. Collectively, outcomes of our study validate the structural homology of RbCytC with known cystatin C similitudes, especially those of teleosts and suggest its potential roles in proteolytic processes of rock bream physiology as well as in host immune defense mechanisms.

Correlation of serum cystatin C with inflammatory cytokines in patients with traumatic brain injury

Traumatic brain injury (TBI) is a world-wide leading health problem with high morbidity and mortality rates. Emerging studies have demonstrated that TBI is the consequence of a series of inflammatory responses in the body. The alteration of Cystatin C (Cys C) was reported in a variety of chronic inflammatory diseases and was also recommended as a biomarker for predicting renal diseases. In this study, we aimed to investigate the relationship between serum Cys C and TBI, and to evaluate the prognostic role of Cys C in TBI prediction. One hundred and seventy-six patients with TBI were recruited and 102 patients were finally analyzed, with 30 healthy control subjects. The concentrations of Cys C were significantly reduced in the healthy control group compared to the TBI group, and correlated with high GCS scores. The levels of hsCRP, counts of white blood cells, and levels of IL-6 and TNF-α were remarkably elevated in the TBI patients compared with the control group in a severity-dependent manner. Moreover, the concentration of Cys C was negatively correlated with TBI severity and positively correlated with inflammatory factors. In conclusion, serum Cys is an inflammatory cytokine-related factor and might indicate the severity of TBI thus serving as a prognostic biomarker.

Serum Creatinine-to-Cystatin C Ratio in the Progression Monitoring of Non-alcoholic Fatty Liver Disease

Background

The simultaneous assessment of visceral adiposity and muscle mass might be useful to monitor the risk of non-alcoholic fatty liver disease (NAFLD) progression in large population. We aimed to investigate the value of serum creatinine-to-cystatin C ratio (CCR) in evaluating these two parameters and predicting liver steatosis and fibrosis.

Methods

154 overweight/obese inpatients (49 males, 105 females) scheduled for bariatric surgery and 49 non-overweight/obese volunteers (18 males, 31 females) responded to the hospital advertisement were involved in the cross-sectional study. Liver steatosis and fibrosis were diagnosed with transient elastography (TE). The psoas muscle area (PMA) and visceral fat area (VFA) were measured using magnetic resonance imaging.

Results

The body mass index, insulin resistance, and lipid profiles showed significant differences between the CCR tertiles. Multiple regression analyses revealed that the CCR was significantly associated with the controlled attenuation parameter (β = −0.30, P = 0.006 in males; β = −0.19, P = 0.017 in females) and liver stiffness measurements in males (β = −0.246, P = 0.044). A low CCR was associated with moderate-to-severe steatosis (P < 0.001), significant liver fibrosis (P < 0.01), and excellent predictive power for these two conditions (P < 0.01). The CCR had a negative correlation with the VFA/PMA ratio (r = −0.584, P < 0.001 in males; r = −0.569, P < 0.001 in females).

Conclusions

The CCR is a serum marker for muscle-adjusted visceral fat mass, and a low CCR is associated with an increased risk of progressive NAFLD.

pH-dependent and dynamic interactions of cystatin C with heparan sulfate

Cystatin C (Cst-3) is a potent inhibitor of cysteine proteases with diverse biological functions. As a secreted protein, the potential interaction between Cst-3 and extracellular matrix components has not been well studied. Here we investigated the interaction between Cst-3 and heparan sulfate (HS), a major component of extracellular matrix. We discovered that Cst-3 is a HS-binding protein only at acidic pH. By NMR and site-directed mutagenesis, we identified two HS binding regions in Cst-3: the highly dynamic N-terminal segment and a flexible region located between residue 70-94. The composition of the HS-binding site by two highly dynamic halves is unique in known HS-binding proteins. We further discovered that HS-binding severely impairs the inhibitory activity of Cst-3 towards papain, suggesting the interaction could actively regulate Cst-3 activity. Using murine bone tissues, we showed that Cst-3 interacts with bone matrix HS at low pH, again highlighting the physiological relevance of our discovery.

Natural cystatin C fragments inhibit GPR15-mediated HIV and SIV infection without interfering with GPR15L signaling

GPR15 is a G protein-coupled receptor (GPCR) proposed to play a role in mucosal immunity that also serves as a major entry cofactor for HIV-2 and simian immunodeficiency virus (SIV). To discover novel endogenous GPR15 ligands, we screened a hemofiltrate (HF)-derived peptide library for inhibitors of GPR15-mediated SIV infection. Our approach identified a C-terminal fragment of cystatin C (CysC95-146) that specifically inhibits GPR15-dependent HIV-1, HIV-2, and SIV infection. In contrast, GPR15L, the chemokine ligand of GPR15, failed to inhibit virus infection. We found that cystatin C fragments preventing GPR15-mediated viral entry do not interfere with GPR15L signaling and are generated by proteases activated at sites of inflammation. The antiretroviral activity of CysC95-146 was confirmed in primary CD4+ T cells and is conserved in simian hosts of SIV infection. Thus, we identified a potent endogenous inhibitor of GPR15-mediated HIV and SIV infection that does not interfere with the physiological function of this GPCR.

Plasma cystatin C is a marker of renal glomerular injury in children treated with cisplatin or ifosfamide

BACKGROUND

Plasma cystatin C is a potential marker of the glomerular filtration rate (GFR), and urinary cystatin C has been proposed as a marker of tubular dysfunction.

PROCEDURE

A prospective study (NCT02822404) was conducted to assess the benefit of considering cystatin C plasma and urinary levels to better evaluate cisplatin and/or ifosfamide renal toxicity in children with cancer. Plasma ⁵¹ Cr-EDTA clearance as a marker of GFR and urinary markers of tubular toxicity were monitored in 40 children treated by cisplatin and/or ifosfamide. Several equations previously proposed to estimate GFR, with or without inclusion of plasma cystatin C level, were compared. A population pharmacokinetic approach was also used to analyze plasma ⁵¹ Cr-EDTA data, and evaluate the relationship between patient covariates (including plasma cystatin C level) and GFR during the course of chemotherapy treatment.

RESULTS

Equations including plasma cystatin C described GFR changes during chemotherapy better than those without this variable. An equation based on plasma cystatin C, serum creatinine, and body weight enabled us to accurately describe the evolution of GFR during chemotherapy. The urinary cystatin C/creatinine ratio was compared between children with or without tubular toxicity, according to a standard assessment of tubular dysfunction. However, although the urinary cystatin C/creatinine ratio was increased in children with tubular toxicity, this marker does not provide additional information to the well-known markers of tubulopathy.

CONCLUSIONS

Monitoring of plasma cystatin C may be substituted to radionucleide glomerular exploration in children treated by cisplatin and/or ifosfamide.

Cystatin C is a potential predictor of unfavorable outcomes for cerebral ischemia with intravenous tissue plasminogen activator treatment: A multicenter prospective nested case-control study

BACKGROUND AND PURPOSE

The aim of this study was to explore whether cystatin C (CysC) could be used as a potential predictor of clinical outcomes in acute ischemic stroke (AIS) patients treated with intravenous tissue plasminogen activator (IV-tPA).

METHODS

We performed an observational study including a retrospective analysis of data from 125 AIS patients with intravenous thrombolysis. General linear models were applied to compare CysC levels between groups with different outcomes; logistic regression analysis and receiver-operating characteristic curves were adopted to identify the association between CysC and the therapeutic effects.

RESULTS

Compared with the "good and sustained benefit" (GSB) outcome group (defined as ≥4-point reduction in National Institutes of Health Stroke Scale or a score of 0-1 at 24 h and 7 days) and the "good functional outcome" (GFO) group (modified Rankin Scale score 0-2 at 90 days), serum CysC baseline levels were increased in the non-GSB and non-GFO groups. Logistic regression analysis found that CysC was an independent negative prognostic factor for GSB (odds ratio [OR] 0.010; p = 0.005) and GFO (OR 0.011; p = 0.021) after adjustment for potential influencing factors. Receiver-operating characteristic curves showed the CysC-involved combined models provided credible efficacy for predicting post-90-day favorable clinical outcome (area under the curve 0.86; p < 0.001).

CONCLUSIONS

Elevated serum CysC is independently associated with unfavorable clinical outcomes after IV-tPA therapy in AIS. Our findings provide new insights into discovering potential mediators for neuropathological process or treatment in stroke.

The role of cystatin C as a proteasome inhibitor in multiple myeloma

Objectives: Bone destruction and renal impairment are two frequent complications of multiple myeloma (MM). Cystatin C, an extracellular cysteine proteinase inhibitor, is encoded by the housekeeping gene CST3 and associated with human tumors. The role of cystatin C in multiple myeloma has been revealed recently. The purpose of this study was to explore the role of cystatin C as a proteasome inhibitor in multiple myeloma. Methods : A comprehensive literature review was conducted through Pubmed to summarize the published evidence on cystatin C in multiple myeloma. English literature sources since 1999 were searched, using the terms cystatin C, multiple myeloma. Results: cystatin C is a sensitive indicator for the diagnosis of myeloma nephropathy and has a dual role in myeloma bone disease. Also, cystatin C reflects tumor burden and is strongly associated with prognosis in patients with multiple myeloma. Conclusion: Cystatin C have great diagnostic and prognostic value in multiple myeloma. It can provide a new treatment direction for MM by designing and searching for antagonists of cystatin C or cysteine protease agonists using cystatin C as a therapeutic target.

Cystatin C and Seminal Parameter Evaluation in Patients with End-Stage Renal Disease

OBJECTIVE

We aimed to investigate the possible relationship between seminal parameters and cystatin C seminal levels in an infertility evaluation of chronic hemodialysis patients.

MATERIALS AND METHODS

This was a cross-sectional study, aged 18-60 years, in a group of 60 men undergoing hemodialysis (case) for more than 6 months, and a group of 15 healthy men (control) without clinical or laboratory signs of genitourinary tract infection. We performed a spermogram, hormonal profile, and assessment of leukocytes and cystatin levels in the semen.

RESULTS

The ages in the case and control were similar (p = 0.060). The seminal cystatin was significantly different between the case group and control group (41.16 ± 26.59 vs. 79.00 ± 05.68 mg/l, respectively, p < 0.001) and between normospermia and oligospermia (83.50 ± 02.40 vs. 30.34 ± 02.52 mg/l, respectively, p < 0.001). The mean seminal cystatin levels identified by the degrees of oligospermia (severe, moderate, and slim) were similar to each other (p > 0.05) and significantly different (p < 0.05) in relation to normospermia in the case group. The seminal cystatin levels positively correlated (p < 0.05) with sperm motility and sperm density.

CONCLUSION

Seminal cystatin levels are associated with the numerical and motility changes evidenced in the spermogram and may be of help in the initial evaluation of clinical suspicion of sub-fertility and infertility.

Relationships between cystatin C- and creatinine-based eGFR in Japanese rural community- dwelling older adults with sarcopenia

BACKGROUND

Sarcopenia is prevalent in patients with chronic kidney disease (CKD). The indices of physical function, such as grip power and gait speed, decreased according to the decline in the estimated glomerular filtration rate (eGFR).

METHODS

We examined the relationships between cystatin C-based GFR (eGFRcys), creatinine-based GFR (eGFRcre), their ratio (eGFRcys/eGFRcre) and sarcopenia in community-dwelling older adults in Japan. This cross-sectional study included 302 men aged 73.9 ± 6.2 years and 647 women aged 72.9 ± 5.8 years from a rural area in Hyogo Prefecture, Japan. eGFRcys and eGFRcre were simultaneously measured, and sarcopenia based on the Asia Working Group for Sarcopenia (AWGS) 2019 criteria was evaluated.

RESULTS

eGFRcys and the eGFRcys/eGFRcre ratio were significantly correlated with grip power and gait speed (p < 0.001). The eGFRcys/eGFRcre ratio was also correlated with skeletal muscle mass index (SMI) (p < 0.01). Univariate logistic regression analysis showed eGFRcys and eGFRcys/eGFRcre ratio but not eGFRcre were associated with sarcopenia (p < 0.01). The presence of low eGFRcys (CKDcys) and low eGFRcys/eGFRcre ratio (< 1.0) but not that of low eGFRcre (CKDcre) were associated with sarcopenia (p < 0.01). In the multivariate logistic regression analysis, when the eGFRcys/eGFRcre ratio was added as a covariate to the basic model, it was significantly associated with sarcopenia in women (p < 0.05). Moreover, low eGFRcys/eGFRcre ratio (< 1.0) was associated with a higher risk of sarcopenia in men (p < 0.01).

CONCLUSION

In conclusion, CKDcys but not CKDcre is associated with sarcopenia. A lower eGFRcys/eGFRcre ratio may be a practical screening marker of sarcopenia in community-dwelling older adults.

A New Perspective for Isolated Coronary Artery Ectasia: Cystatin C

Introduction

The pathophysiology of isolated coronary artery ectasia (iCAE) has not been clearly identified, although multiple abnormalities, including arteritis, endothelial dysfunction, and vascular destruction, have been reported. In this study, we aimed to analyze serum cystatin C concentrations in patients with iCAE and controls.

Methods

Forty-seven patients with iCAE (mean age: 55.9 ± 11.5) and 32 individuals with normal coronary angiography (mean age: 57.8.1 ± 9.6) were included in the study. Plasma cystatin C levels were measured by using the principle of particle-enhanced turbidimetric immunoassay (PETIA).

Results

Serum cystatin C concentrations were significantly lower in patients with iCAE compared with the control group (0.98 ± 0.17 mg/L versus 1.17 ± 2.6 mg/L, p-value = 0.001). A significantly positive relationship was found between serum cystatin C levels and creatinine and high-sensitivity C-reactive protein (hs-CRP) levels in both groups (r-value = 0.288, p-value = 0.005, r-value = 0.143, p-value = 0.007, respectively). In multivariate logistic regression analysis, serum cystatin C level found to be a significant predictor for the presence of iCAE (OR: 0.837, CI: 95% (0.341 - 1.637), p-value = 0.013). Receiver operating characteristic (ROC) analysis determined that a cystatin C value < 1.02 mg/L had a sensitivity of 56% and a specificity of 78% for the prediction of ectasia.

Conclusion

We conclude that cystatin C independently can be a useful predictor for the presence of iCAE.

The potential of cystatin C as a predictive biomarker in breast cancer

INTRODUCTION

Breast cancer (BCa) is the leading cause of cancer-related deaths among women. Numerous efforts are being directed toward identifying novel tissue and/or circulating molecular markers that may help clinicians in detecting early-stage BCa patients and in providing an accurate estimation of the prognosis and prediction of response to clinical treatments. In this setting, emerging evidence has indicated Cystatin C (Cyst C), as the most potent endogenous inhibitor of cysteine cathepsins, as a possible useful marker in the clinical management of BCa patients.

AREAS COVERED

This review analyzes the results of emerging studies underpinning a potential clinical role of Cyst C, as additional marker in BCa.

EXPERT OPINION

Cyst C expression levels have been reported to be altered in tumor tissues and/or in biological fluids of BCa patients. Furthermore, clinical evidence has highlighted a significant correlation between altered Cyst C levels in tumor tissues and/or biological fluids and some clinco-biological parameters of BCa progression. These findings provide evidence for a potential clinical use of Cyst C as a novel marker to improve the clinical and therapeutic management of BCa patients and as a gauge for better clarifying the role of cysteine proteinases in the various steps of BCa progression.

Assessment of muscle mass in critically ill patients: role of the sarcopenia index and images studies

PURPOSE OF REVIEW

Sarcopenia is a progressive generalized decline in skeletal muscle mass, strength, and function. This condition is highly prevalent in critically ill patients and is associated with poor outcomes in the ICU. In this review, we describe the use, evidence, and limitations of the most common validated imaging studies used to assess muscle mass in ICU, and we provide an overview of the benefits of using the sarcopenia index [(serum creatinine/serum cystatin C) × 100]) in the ICU.

RECENT FINDINGS

Currently, the determination of muscle mass using anthropometric measurements and serum biomarkers is unreliable. Several new techniques, including a dual-energy X-ray absorptiometry, computed tomography scan, ultrasonography, and bioimpedance analysis, have been studied and validated for the diagnosis and prognosis of sarcopenia in the ICU. However, these techniques are often not accessible for the majority of critically ill patients. The sarcopenia index constitutes an accurate method to diagnose sarcopenia, predict ICU outcomes, and nutritional status in critically ill patients.

SUMMARY

Diagnosis of sarcopenia has substantial implications in ICU patients. Choosing the correct test to identify patients who may need preventive or therapeutic support for this condition will favorably impact ICU outcomes.

Association between serum Cystatin C and renal injury in patients with chronic hepatitis B

To explore the association between serum cystatin C (Cys-C) and renal damage in patients with chronic hepatitis B.We retrospectively analyzed the clinical data of 425 patients with chronic hepatitis B virus (HBV) infection. Liver stiffness measured by FibroScan was used to diagnosis liver fibrosis. Cys-C levels were detected via latex-enhanced immunoturbidimetric assay.A total of 425 patients were enrolled. Among them, 217 were patients with CHB with an eGFR > 90 mL/min/1.73 m and 208 with an eGFR ≤90 mL/min/1.73 m. Cys-C levels significantly differed in patients with eGFR > 90 mL/min/1.73 m compared with patients with eGFR ≤90 mL/min/1.73 m (0.81 ± 0.05 vs 1.05 ± 0.06 mg/L, P < .001). Moreover, the Cys-C levels were 0.82 ± 0.04 mg/L in patients without liver fibrosis, 0.98 ± 0.05 mg/L in patients with mild liver fibrosis, 1.05 ± 0.08 mg/L in patients with advanced liver fibrosis, and 1.12 ± 0.07 mg/L in patients with liver cirrhosis (P < .001). Multivariate analyses were conducted to explore the independent factors associated with a decreased eGFR. Multivariate analysis suggested that T2DM (P = .032), liver fibrosis (P = .013), and Cys-C level (P = .035) were the independent factors associated with the decreased eGFR in patients with CHB. While age (P = .020) and Cys-C level (P = .001) were the independent factors associated with the decreased eGFR in patients with CHB-related fibrosis.The fibrosis group had significantly higher Cys-C levels than those without fibrosis. Routine monitoring of Cys-C levels is of positive significance in preventing the development of renal impairment of CHB patients.

NOX4 Deficiency Exacerbates the Impairment of Cystatin C-Dependent Hippocampal Neurogenesis by a Chronic High Fat Diet

Hippocampal neurogenesis is linked with a cognitive process under a normal physiological condition including learning, memory, pattern separation, and cognitive flexibility. Hippocampal neurogenesis is altered by multiple factors such as the systemic metabolic changes. NADPH oxidase 4 (NOX4) has been implicated in the regulation of brain function. While the role of NOX4 plays in the brain, the mechanism by which NOX4 regulates hippocampal neurogenesis under metabolic stress is unclear. In this case, we show that NOX4 deficiency exacerbates the impairment of hippocampal neurogenesis by inhibiting neuronal maturation by a chronic high fat diet (HFD). NOX4 deficiency resulted in less hippocampal neurogenesis by decreasing doublecortin (DCX)-positive neuroblasts, a neuronal differentiation marker, and their branched-dendrites. Notably, NOX4 deficiency exacerbates the impairment of hippocampal neurogenesis by chronic HFD. Moreover, NOX4 deficiency had a significant reduction of Cystatin C levels, which is critical for hippocampal neurogenesis, under chronic HFD as well as normal chow (NC) diet. Furthermore, the reduction of Cystatin C levels was correlated with the impairment of hippocampal neurogenesis in NOX4 deficient and wild-type (WT) mice under chronic HFD. Our results suggest that NOX4 regulates the impairment of Cystatin C-dependent hippocampal neurogenesis under chronic HFD.

NGAL, albumin and cystatin C during cisplatin therapy

Cisplatin is a commonly used chemotherapeutic drugs. It is known for its nephrotoxic side effects with an increased risk of acute kidney injury. Finding of clinically feasible cisplatin nephrotoxicity markers is of importance. In our study, we compared neutrophil gelatinase-associated lipocalin (NGAL) in serum and urine, the estimated glomerular filtration rate (based on serum cystatin C) and urine albumin as markers of nephrotoxicity. The study involved 11 men and 9 women (mean ± SD age 58.2±9.5 years) with different malignancies treated with cisplatin in four cycles of chemotherapy (I - IV). Samples 0-4 were taken before, immediately after, in 3, 6 and 24 hours after administering chemotherapy. We detected significant increase of ACR in Sample 2 (p=0.03) and decrease of eGFR in Sample 4 (p=0.03) up to 24 hours after cisplatin administration in the first chemotherapy cycle only. When cumulative effect of cisplatin was assessed, significantly increased values of urine albumin (vs cycle I) were found in Sample 0 (p=0.00058), 1 (p=0.00256), 2 (p=0.00456), 3 (p=0.00006) and 4 (p=0.00319) in cycles II to IV. We found a correlation between values of urine NGAL and urine albumin (r=0.68, p<0.0001). In conclusion, urine albumin was the only measured marker that consistently and statistically significantly increased after cisplatin containing chemotherapy cycles.

Relation of Whole Blood Amino Acid and Acylcarnitine Metabolome to Age, Sex, BMI, Puberty, and Metabolic Markers in Children and Adolescents

Background: Changes in the metabolic fingerprint of blood during child growth and development are a largely under-investigated area of research. The examination of such aspects requires a cohort of healthy children and adolescents who have been subjected to deep phenotyping, including collection of biospecimens for metabolomic analysis. The present study considered whether amino acid (AA) and acylcarnitine (AC) concentrations are associated with age, sex, body mass index (BMI), and puberty during childhood and adolescence. It also investigated whether there are associations between amino acids (AAs) and acylcarnitines (ACs) and laboratory parameters of glucose and lipid metabolism, as well as liver, kidney, and thyroid parameters. Methods: A total of 3989 dried whole blood samples collected from 2191 healthy participants, aged 3 months to 18 years, from the LIFE Child cohort (Leipzig, Germany) were analyzed using liquid chromatography tandem mass spectrometry to detect levels of 23 AAs, 6 ACs, and free carnitine (C0). Age- and sex-related percentiles were estimated for each metabolite. In addition, correlations between laboratory parameters and levels of the selected AAs and ACs were calculated using hierarchical models. Results: Four different age-dependent profile types were identified for AAs and ACs. Investigating the association with puberty, we mainly identified peak metabolite levels at Tanner stages 2 to 3 in girls and stages 3 to 5 in boys. Significant correlations were observed between BMI standard deviation score (BMI-SDS) and certain metabolites, among them, branched-chain (leucine/isoleucine, valine) and aromatic (phenylalanine, tyrosine) amino acids. Most of the metabolites correlated significantly with absolute concentrations of glucose, glycated hemoglobin (HbA1c), triglycerides, cystatin C (CysC), and creatinine. After age adjustment, significant correlations were observed between most metabolites and CysC, as well as HbA1c. Conclusions: During childhood, several AA and AC levels are related to age, sex, BMI, and puberty. Moreover, our data verified known associations but also revealed new correlations between AAs/ACs and specific key markers of metabolic function.

Suppressed dendritic cell functions by cystatin C lead to compromised immunity in vivo

Pathogenic microorganisms utilize multiple approaches to break down host immunity in favor of their invasion, of which, cystatin C is one of the soluble factors secreted by parasites reported to affect host immunity in vivo. The cellular targets and mechanisms of action in vivo of cystatin C, however, are far from clear. As professional antigen-presenting cells, dendritic cells (DCs) are first immune cells that contact foreign pathogenic agents or their products to initiate immune responses. We previously reported that cystatin C can regulate the functions of DCs in terms of suppressed CD4⁺ T cell activation but enhanced Th1/Th17 differentiation via different mechanisms. Here, we further verified these regulatory effects of cystatin C on DCs in vivo. We found that the suppressive role of DC-mediated CD4⁺ T cell proliferation by cystatin C was partly cell-contact independent and extended to CD8⁺ T cells in vivo. Although cystatin C-overexpressing DCs trafficked equally as their mock-transduced counterparts, their adoptive transfer suppressed CD8⁺ T cell immunity and resulted in compromised tumor rejection in both vaccination and treatment regimes. Compared with their role in promoting Th17 differentiation in vivo, cystatin C-transduced DCs had far greater ability to induce T regulatory cells (Tregs), leading to collectively a higher Treg/Th17 ratio in an adoptively transferred disease model, and thus relieved Th17-dependent autoimmunity. Collectively, these data demonstrated strong in vivo evidences for immune regulatory roles of cystatin C in DCs and provided theoretical basis for the application of cystatin C-transduced cell therapy in the treatment or remission of certain autoimmune diseases. (246).

Cystatin C regulates major histocompatibility complex-II-peptide presentation and extracellular signal-regulated kinase-dependent polarizing cytokine production by bone marrow-derived dendritic cells

Cystatin C is a ubiquitously expressed cysteine protease inhibitor that protects cells from either improper hydrolysis by endogenous proteases or pathogen growth/virulence by exogenous proteases. Although commonly used as a serum biomarker for evaluating renal function, cystatin C is associated with many immunological disorders under various pathophysiological conditions. How cystatin C affects immune cells, especially dendritic cells (DCs), however, is far from clear. In this study, we found that pharmacological treatment with or genetic overexpression of cystatin C in bone marrow-derived DCs (BMDCs) reduced their capacity to stimulate CD4⁺ T-cell proliferation, despite increased antigen uptake. This reduced capacity corresponded with reduced major histocompatibility complex-II presentation owing to diminished levels of the chaperon H2-DM in BMDCs. Instead of promoting proliferation, cystatin C promoted skewing of T cells toward proinflammatory T-helper (Th)1/Th17 differentiation. This was mediated by augmented extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase phosphorylation in BMDCs, leading to secretion of polarizing cytokines, which in turn led to the Th deviation. Collectively, our study explained the cellular and molecular basis of how this protease inhibitor can regulate immune responses, namely by affecting BMDCs and their cytokine pathway. Our results might open up an avenue for the development of therapeutic agents for the treatment of cystatin C-related immunological diseases.