Clinical Predictive Value of Cystatin C in Pediatric Sickle Cell Disease: A Marker of Disease Severity and Subclinical Cardiovascular Dysfunction

Homozygote drepanocytosis: Ferric status and inflammation in world and Africa: Review article and meta analysis

Background and Aims

Major sickle cell syndromes are subjected to a high frequency of hemolysis, infections, oxidative stress, and vasooclusive crises which promote inflammation and iron balance disorders. We aimed to systematically review and analyze the studies in this patients addressing in general, and Africa in particular.

Methods

The systematic review of published articles in the Pubmed and Google Scholar databases was carried out according to the recommendations of the PRISMA model. The case-control articles have been included. The data extracted from the articles were analyzed using statistical software R. The standardized mean difference (SMD) was used to assess the extent of the disease on the different variables studied.

Results

At the end, 128 articles were obtained; but only 33 were elligible for meta-analysis. A SMD of -1.79 was obtained for hemoglobin between the sickle cell patients and the controls due to the deviation from the overall mean hemoglobin in the cases (8 ± 2 g/dL) and in controls (13 ± 3 g/dL). Sickle cell disease showed a significant extent on ferritin [SMD = 2.61; (95% confidence interval, CI: 2.39-2.83); (p < 0.01)] compared to non-sickle cell patients thus describing a higher risk for sickle cell sufferer to have ferritin disorders. The included studies also described the influence of sickle cell anemia on serum iron [SMD = 1.52; (95% CI: 1.32-1.76); (p < 0.01)] compared to normal subjects. The high risk of inflammation has been described as higher in sickle cell patients [SMD = 0.38; (95% CI: 0.25-0.50)], reflecting the moderate extent of sickle cell disease on inflammation.

Conclusion

Patients with major sickle cell syndrome in inflammation have a higher risk of iron profile disorders compared to the normal population. Further studies are needed to explore mechanisms for preventing the deleterious effects of iron from this hemolysis, for example haptoglobin genotyping.

Effectiveness of Pharmacokinetic-Guided Hydroxyurea Dose Individualization in Patients with Sickle Cell Anemia: A Mini-Review

Inconsistent therapeutic responses have been observed among patients with sickle cell anemia (SCA) undergoing hydroxyurea (HU) following the adoption of the standardized protocol. Moreover, this treatment regimen necessitates a prolonged period to reach the maximum tolerated dose in which beneficial therapeutic effects are observed in most SCA patients. To overcome this limitation, several studies have performed HU dose adjustments in SCA patients based on individualized pharmacokinetic profiles. The present systematic mini-review aims to select and analyze published data to present an overview of HU pharmacokinetics studies performed in SCA patients, as well as evaluate the effectiveness of the dose adjustment strategy. A systematic search was performed in the Embase, Pubmed, Scopus, Web of Science, Scielo, Google Scholar, and the Virtual Library of Health databases from December 2020 to August 2022, with a total of five studies included. Inclusion criteria consisted of studies in which the dose adjustment was performed in SCA patients based on pharmacokinetic parameters. Quality analyzes were performed using QAT, while data synthesis was performed according to the Cochrane Manual of Systematic Reviews of Interventions. Analysis of the selected studies revealed improved HU treatment effectiveness using personalized dosages in SCA patients. Moreover, several laboratory parameters were utilized as biomarkers of the HU response, and methods designed to simplify the adoption of this practice were presented. Despite the scarcity of studies on this topic, HU-personalized treatment based on individualized pharmacokinetic profiles represents a viable alternative for SCA patients who are candidates for HU therapy, especially for pediatric patients. Registration number: PROSPERO CRD42022344512.

Current applications for measuring pediatric intima-media thickness

Intima-media thickness is a known subclinical radiologic marker of the early manifestations of atherosclerotic disease. It is the thickness of the vessel wall, most often the carotid artery. Intima-media thickness is measured on conventional US manually or automatically. Other measurement techniques include radiofrequency US. Because there is variation in its measurement, especially in children, several recommendations have been set to increase the measurement's validity and comparability among studies. Despite these recommendations, several pitfalls should be avoided, and quality control should be performed to avoid erroneous interpretation. This article summarizes current literature in relation to the clinical applications for intima-media thickness measurement in children with known risk factors such as obesity, liver steatosis, hypercholesterolemia, diabetes, hypertension, systemic inflammatory diseases, cancer survival, kidney and liver transplant, and sickle cell disease or beta thalassemia major. Most potential indications for intima-media thickness measurement remain in the research domain and should be interpreted combined with other markers. The objective of diagnosing an increased intima-media thickness is to start a multidisciplinary treatment approach to prevent disease progression and its sequelae in adulthood.

Sickle cell nephropathy: A review of novel biomarkers and their potential roles in early detection of renal involvement

Whether the underlying mutations are homozygous, heterozygous, or co-inherited with other hemoglobinopathies, sickle cell disease is known to afflict the kidneys, leading to the clinical entity known as sickle cell nephropathy (SCN). Although common, SCN remains diagnostically elusive. Conventional studies performed in the context of renal disorders often fail to detect early stage SCN. This makes the quest for early diagnosis and treatment more challenging, and it increases the burden of chronic kidney disease-related morbidity among patients. Novel diagnostic tools have been employed to overcome this limitation. In this study, we discuss various biomarkers of SCN, including those employed in clinical practice and others recently identified in experimental settings, such as markers of vascular injury, endothelial dysfunction, tubulo-glomerular damage, and oxidative stress. These include kidney injury molecule-1, monocyte chemoattractant protein-1, N-acetyl-B-D-glucosaminidase, ceruloplasmin, orosomucoid, nephrin, and cation channels, among others. Furthermore, we explore the potential of novel biomarkers for refining diagnostic and therapeutic approaches and describe some obstacles that still need to be overcome. We highlight the importance of a collaborative approach to standardize the use of promising new biomarkers. Finally, we outline the limitations of conventional markers of renal damage as extensions of the pathogenic process occurring at the level of the organ and its functional subunits, with a discussion of the expected pattern of clinical and biochemical progression among patients with SCN.

Assessment of cystatin C in pediatric sickle cell disease and β-thalassemia as a marker of subclinical cardiovascular dysfunction: a case-control study

Cardiovascular complications represent the main determinant of survival in patients with hemoglobinopathies. Serum cystatin C is a well-known marker of nephropathy in sickle cell disease (SCD) and β-thalassemia patients that has recently emerged as a strong predictor of cardiovascular dysfunction in patients with and without kidney disease. We performed a case control study to determine the role of cystatin C as a predictor of subclinical cardiovascular dysfunction in SCD and β-thalassemia patients. We enrolled 40 SCD patients with a mean age of 12.4 years, 40 β-thalassemia patients with a mean age of 11.4 years and 40 age and sex-matched controls. We assessed hematological profile, serum ferritin, urinary albumin-creatinine ratio (UACR), serum cystatin C, echocardiography and carotid intima media thickness (CIMT). UACR, cystatin C and CIMT were higher in SCD and β-thalassemia patients compared to controls (p < .001). Significantly higher cystatin C levels were observed in SCD and β-thalassemia patients with nephropathy or left ventricular systolic dysfunction (shortening fraction <30%, or ejection fraction <55%; p < .001). Moreover, SCD patients with pulmonary hypertension had significantly higher cystatin C levels. Cystatin C levels were positively correlated with CIMT in SCD (p = .02) and β-thalassemia patients (p < .001) while negatively correlated with ejection fraction and shortening fraction (p < .001). The cutoff values of cystatin C ≥ 16.03 and ≥ 13.2 (ng/mL) could detect subclinical cardiac dysfunction risk among SCD and β-thalassemia patients respectively. Cystatin C appears to be a promising marker for subclinical cardiovascular dysfunction in SCD and β-thalassemia patients.

The association between cystatin C and COPD: a meta-analysis and systematic review

BACKGROUND

In recent years, many studies have discovered that cystatin C (Cys C) may play an important role in respiratory diseases, especially in chronic obstructive pulmonary disease (COPD). However, the findings of these studies were inconsistent. This systematic review and meta-analysis aimed to assess the relationship between serum Cys C and COPD.

METHODS

We conducted a systematic literature search in PubMed, Embase, Web of Science, Wanfang databases, and the China National Knowledge Infrastructure. The standardized mean difference (SMD), Fisher's Z-value and 95% confidence interval (CI) were calculated to investigate the effect sizes. Subgroup analyses were performed on disease status, ethnicity, assay method, and study design. Sensitivity was performed, and publication bias was assessed.

RESULTS

A total of 15 studies, including 4079 COPD patients and 5949 controls, were included in this meta-analysis. The results showed that serum Cys C levels in patients with COPD were significantly higher than those in controls (SMD = 0.99, 95% CI =0.62-1.37, P < 0.001), especially in AECOPD (SMD = 1.59, 95% CI =1.05-2.13, P < 0.001), and there were statistically different among AECOPD and SCOPD (SMD = 0.35, 95% CI =0.10-0.59, P = 0.005). The serum Cys C levels were negatively correlated with FEV1%pre (Z = - 0.45, 95%CI = -0.58--0.32, P = 0.011) and FEV1/FVC (Z = - 0.32, 95%CI = -0.50--0.14, P = 0.006). The serum Cys C levels were independent of ethnicity, assay method, and study design.

CONCLUSION

Serum Cys C levels were associated with COPD and COPD exacerbation, and they were inversely correlated with FEV1%pre and FEV1/FVC.

Persistent hematuria among children with sickle cell anemia in steady state

Introduction

Persistent hematuria is a chronic complication of sickle cell anemia (SCA) which can progress to chronic kidney disease. The practice of early detection of persistent hematuria in children with SCA in steady state is important for timely intervention.

Objective

To determine the prevalence of persistent hematuria among children with sickle cell anemia in steady state and compare the result with that of a group of HbAA controls. The outcome will possibly strengthen the health policy on the need for regular screening for persistent hematuria in children with SCA.

Methods

Children with sickle cell anemia, aged 2–18 years in steady state, were recruited consecutively from the sickle cell clinic at the University of Nigeria teaching Hospital Enugu. The controls were similarly recruited from the children’s outpatient clinic. To determine persistent hematuria, dipstick urinalysis and microscopy were performed for both subjects and controls at enrollment and repeated after four weeks.

Results

Out of the 122 children with SCA studied, 5 (4.1%) had persistent hematuria. None (0%) of the 122 age- and gender-matched HbAA controls had persistent hematuria. This difference in prevalence of persistence between HbSS patients and HbAA controls was statistically significant (p = 0.02).

Conclusion

Persistent hematuria still occurs significantly more among children with SCA, even among those in steady state. Routine urinalysis at follow-up visits in children with SCA is strongly recommended, as this will aid early detection and prompt management to prevent progression to chronic kidney disease.

Angiopoietin-2 as a Marker of Retinopathy in Children and Adolescents With Sickle Cell Disease: Relation to Subclinical Atherosclerosis

OBJECTIVES

Angiopoietin-2 (Ang-2) is a multifaceted cytokine that functions in both angiogenesis and inflammation. A proangiogenic state has been found in adults with sickle cell disease (SCD), mainly because of elevated Ang-2 levels. We determined Ang-2 level in 40 children and adolescents with SCD compared with 40 healthy controls and assessed its relation to retinopathy as well as carotid intimamedia thickness (CIMT).

METHODS

Hematologic profile, serum ferritin, and serum Ang-2 were measured. CIMT was assessed using high-resolution ultrasound. Fundus examination was performed followed by fundus fluorescein angiography. Optical coherence tomography angiography (OCTA) was used to find small vascular changes not clinically manifested.

RESULTS

Ang-2 levels and CIMT were significantly higher in SCD patients compared with controls. The incidence of nonproliferative retinopathy was 45%. SCD patients with retinopathy were older in age with a history of sickling crisis of >3 attacks per year and had a higher incidence of sickle cell anemia than sickle β-thalassemia. Ang-2 cutoff value 9000 pg/mL could significantly detect the presence of retinopathy among SCD patients with 100% sensitivity and specificity. Serum Ang-2 levels were positively correlated with HbS and CIMT. Logistic regression analysis revealed that Ang-2 and HbS significantly contribute to retinopathy among patients with SCD.

CONCLUSIONS

Elevated Ang-2 highlights the role of angiogenesis in the pathophysiology of SCD and may be considered a promising marker for screening of patients at risk of sickle retinopathy and vascular dysfunction.

Left Ventricular Structural and Functional Changes in Children With β-Thalassemia and Sickle Cell Disease: Relationship to Sleep-disordered Breathing

Cardiovascular complications are well recognized in β-thalassemia and sickle cell disease (SCD). The objective of this study was to evaluate left ventricular (LV) structural and functional changes and their relationship to sleep-disordered breathing (SDB) in children with β-thalassemia and SCD. One hundred patients recruited from the hematology clinic were subjected to Pittsburgh Sleep Quality Index score; 26 patients had positive score (Pittsburgh Sleep Quality Index ≥5) (15 β-thalassemia major and 11 SCD) and were compared with 25 age-matched and sex-matched controls. All underwent polysomnography and tissue Doppler echocardiography. SDB was detected in 73% of thalassemia patients (all had increased LV mass index [LVMI], diastolic dysfunction [increased E/Em], and 53% had pulmonary hypertension [tricuspid valve resurgence (TR) velocity ≥2.5 m/s]) and in 46% of SCD patients ( all had increased LVMI, 81.8% had pulmonary hypertension, and 76% had diastolic dysfunction). Sleep O2 saturation of β-thalassemia patients negatively correlated with TR velocity and LVMI (P=0.027, 0.015), and lower asleep O2 saturation was associated with increased E/Em. In SCD patients, sleep and awake O2 saturation negatively correlated with TR velocity and E/Em (P=0.024 and 0.041), and lower sleep O2 saturation was associated with increased LV diameter (P=0.021). SDB is common and associated with LV structural and functional changes in β-thalassemia and SCD.

Plasma chitotriosidase and carotid intima-media thickness in children with sickle cell disease

The relationship between chronic hemolysis with subsequent iron overload, inflammation, and premature atherosclerosis has been documented in hemolytic anemias, particularly β-thalassemia. However, no such relationship has been established in sickle cell disease (SCD). We sought to evaluate SCD as a risk factor for early vascular insult by measuring carotid intima-media thickness (CIMT) and plasma chitotriosidase and to assess the role of the latter as a potential quantitative indicator of vascular inflammation and atherogenesis. Thirty SCD pediatric patients (3-18 years) and 30 matched controls were enrolled. Full clinical history, with hematological and biochemical parameters, was evaluated. CIMT and chitotriosidase activity were also assessed for all study participants. CIMT values were significantly higher in SCD patients (median 0.42; range 0.32-0.6 mm) compared to controls (0.36; 0.34-0.45 mm), P = 0.03. CIMT correlated positively with age (r = 0.460, P = 0.011), and total number of vascular incidents necessitating hospital admission (r = 0.439, P = 0.015). Similarly, chitotriosidase activity was significantly higher among SCD patients (median 59.6; range 7.3-512 nmol/ml plasma/h) compared to controls (32.7; 6.8-63.1 nmol/ml plasma/h), P < 0.001, and showed a positive correlation with serum ferritin (r = 0.517, P = 0.003) and CIMT (r = 0.535, P = 0.002). SCD children are at risk of developing premature atherogenic changes. Plasma chitotriosidase and CIMT may represent useful predictors of these changes.