Albuminuria, serum antioxidant enzyme levels and markers of hemolysis and inflammation in steady state children with sickle cell anemia

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.

Frequency and factors associated with proteinuria in COVID-19 patients: a cross-sectional study

Proteinuria is a marker of severity and poor outcome of patients in intensive care unit (ICU). The objective of this study was to determine the frequency of proteinuria and the risk factors associated with proteinuria in Congolese COVID-19 patients. The present cross sectional study of proteinuria status is a post hoc analysis of data from 80 COVID-19 patients admitted at Kinshasa Medical Center (KMC) from March 10th to July 10th, 2020. The population under study came from all adult inpatients (≥18 years old) with a laboratory diagnosis by polymerase chain reaction (PCR) of COVID-19 were selected and divided into two groups (positive proteinuria and negative proteinuria group). Logistic regression models helped to identify the factors associated with proteinuria. The P value significance level was 0.05. Among 80 patients who tested positive for SARS-CoV-2 RT-PCR, 55% had proteinuria. The mean age was 55.2 ± 12.8 years. Fourty-seven patients (58.8%) had history of hypertension and 26 patients (32.5%) diabetes. Multivariable analysis showed age ≥ 65 years (aOR 5,04; 95% CI: 1.51-16.78), diabetes (aOR 3,15; 95% CI: 1.14-8.72), ASAT >40 UI/L (aOR 7,08; 95% CI: 2.40-20.87), ferritin >300 (aOR 13,47; 95% CI: 1.56-26.25) as factors independently associated with proteinuria in COVID-19 patients. Proteinuria is common in Congolese COVID-19 patients and is associated with age, diabetes, ferritin and aspartate aminotransferase (ASAT).

Relationship between lactate dehydrogenase and albuminuria in Chinese hypertensive patients

Lactate dehydrogenase (LDH) has been reported to be positively correlated with albuminuria assessed by urinary albumin‐to‐creatinine ratio (UACR) in patients with sickle cell disease; both LDH and albuminuria are positively associated with the severity of hypertension (HTN). Here, a cross‐sectional study was performed to investigate the association between LDH and albuminuria in Chinese hypertensives. A total of 1169 Chinese individuals (aged 58.0 ± 11.5 years, 60.4% male), who were admitted to our hospital, were included in this study. Based on the level of LDH, all hypertensives (n = 802) were divided into three groups: HTN1 (lowest tertile of LDH, n = 264), HTN2 (mediate tertile of LDH, n = 268), and HTN3 (highest tertile of LDH, n = 270). Hypertensives with hyperhomocysteinemia were defined as hypertensives with homocysteine ≥15μmol/L. Meanwhile, 367 normotensives served as controls. Compared with normotensives, the levels of LDH and UACR were significantly higher in hypertensives (p < .05). There was an increasing trend of albuminuria (UACR ≥30 mg/g) from control, HTN1, HTN2 to HTN3 group (4% vs. 12.1% vs. 14.9% vs. 19.6%, χ² = 38.886, p < .001). Stepwise multiple regression analysis showed an independent association between LDH and UACR in patients with HTN (β = 0.085, p < .05), but not in normotensives. After further stratification in hypertensive patients, this correlation remained in the male (β = 0.161, p < .001), elderly (age ≥65 years, β = 0.174, p < .001) and especially hypertensives with hyperhomocysteinemia (β = 0.402, p < .001). LDH combined with white blood cell (WBC) counts was observed to have better discrimination for albuminuria than creatinine united with cystatin C in hypertensives according to receiver operation characteristic curves (area under curve: 0.637 vs. 0.535, z = 2.563, p = .0104). In conclusion, the level of LDH was associated with albuminuria in Chinese patients with HTN, particularly in hypertensives with hyperhomocysteinemia. LDH combined with WBC provided better prediction of albuminuria than routine renal function assessment in hypertensives. Further studies are needed to confirm LDH as an early marker for the risk of kidney involvement among hypertensives.

Influence of Oxidative Stress Biomarkers and Genetic Polymorphisms on the Clinical Severity of Hydroxyurea-Free Senegalese Children with Sickle Cell Anemia

Oxidative stress would play a role in the pathophysiology of sickle cell anemia (SCA). We tested the impact of common SCA genetic modifiers (alpha-thalassemia, G6PD deficiency, HbF quantitative trait loci; QTL) and pro/antioxidant genes polymorphisms (SOD2 rs4880, XO rs207454, MPO rs233322) on oxidative stress biomarkers (AOPP, MDA, MPO, XO, MnSOD, CAT, GPx) and clinical severity in 301 Senegalese SCA hydroxyurea-free children at steady-state (median age 9.1 years, sex ratio H/F = 1.3). Plasma oxidative stress biomarkers were compared with those of a control group (AA). CAT activity, AOPP, and MDA levels were higher in SCA than in AA individuals while XO, GPX, and MnSOD activities were lower. The presence of alpha-thalassemia decreased MDA level and MPO activity but no effect of the HbF QTL or G6PD deficiency was observed. SCA children who experienced their first hospitalized complication before 3 years old had higher MnSOD and CAT activities than the other children while those with no hospitalized VOC in the previous 2 years presented higher GPX activity. Age of the first hospitalized complication and AOPP levels were affected by the MPO rs2333227 SNP. Our results suggest that alpha-thalassemia modulates oxidative stress in SCA, presumably because of a reduction in the MPO activity.

Sickle cell disease nephropathy: an update on risk factors and potential biomarkers in pediatric patients

One of the major chronic complications of sickle cell disease (SCD) is sickle cell nephropathy. The aim of this review is to discuss the pathophysiology, natural history, clinical manifestations, risk factors, biomarkers and therapeutic approaches for sickle cell nephropathy, focusing on studies with pediatric patients. The earliest manifestation of renal disease is an increase in the glomerular filtration rate. A finding that may also be observed in early childhood is microalbuminuria. Nephrin, KIM-1, VGFs, chemokines and renin-angiotensin system molecules have emerged as potential early markers of renal dysfunction in SCD. In regards to a therapeutic approach, renin-angiotensin system inhibitors and angiotensin receptor blockers seem to be effective for the control of albuminuria in adults with SCD, although new studies in children are needed. The precise moment to begin renoprotection in SCD patients who should be treated remains to be determined.

Magnitude of elevated iron stores and risk associated in steady state sickle cell anemia Congolese children: a cross sectional study

Background

The serum ferritin assay is recommended in Sickle Cell Anemia (SCA) patients receiving regular transfusions. According to several authors, elevated iron stores indicating iron chelation corresponds to hyperferritinemia ≥500 ng/ml, and becomes detectable after twenty blood transfusions. The objectives of the study were to determine the prevalence of elevated iron stores and identify associated risk factors in a case series of Steady state SCA Congolese children.

Material and methods

Serum ferritin was assayed in Steady state SCA children followed in 2 specialized hospitals in Kinshasa. Elevated iron stores was defined as serum ferritin level ≥ 500 ng/ml, and the associated risk factors were identified using univariate analysis.

Results

Seventy patients (median age 9 years, 56% boys, 53% receiving hydroxyurea) were selected in the study. Serum ferritin levels ranged from 24 to 2584 ng / ml with 21.4% of children having elevated iron stores. Mean levels of LDH, indirect bilirubin, plasma free Hb and CRP were similar between the 2 groups whereas history of polytransfusions (> 3 during the last year) was more frequent among patients with elevated iron stores (73% vs. 44%, p = 0.078). Receiving > 3 transfusions in a year vs. 0 was the main risk factor associated with elevated iron stores [OR 6.17 (95% CI: 1.81–20.96)].

Conclusion

In SCA children, hyperferritinemia requiring iron chelation is most strongly related to blood transfusion. This situation concerned almost one in five children in present study; this shows the magnitude of the problem which is underestimated.

Immunoengineering of the Vascular Endothelium to Silence MHC Expression During Normothermic Ex Vivo Lung Perfusion

Disparities at the major histocompatibility complex (MHC) antigens and associated minor antigens trigger harmful immune responses, leading to graft rejection after transplantation. We showed that MHC-silenced cells and tissues are efficiently protected against rejection. In complex vascularized organs, the endothelium is the major interface between donor and recipient. This study therefore aimed to reduce the immunogenicity of the lung by silencing MHC expression on the endothelium. In porcine lungs, short-hairpin RNAs targeting beta-2-microglobulin and class II-transactivator transcripts were delivered by lentiviral vectors during normothermic ex vivo perfusion to silence swine leukocyte antigen (SLA) I and II expression permanently. The results demonstrated the feasibility of genetically engineering all lung regions, achieving a targeted silencing effect for SLA I and II of 67% and 52%, respectively, without affecting cell viability or tissue integrity. This decrease in immunogenicity carries the potential to generate immunologically invisible organs to counteract the burden of rejection and immunosuppression.

Inflammation in sickle cell disease

The primary β-globin gene mutation that causes sickle cell disease (SCD) has significant pathophysiological consequences that result in hemolytic events and the induction of the inflammatory processes that ultimately lead to vaso-occlusion. In addition to their role in the initiation of the acute painful vaso-occlusive episodes that are characteristic of SCD, inflammatory processes are also key components of many of the complications of the disease including autosplenectomy, acute chest syndrome, pulmonary hypertension, leg ulcers, nephropathy and stroke. We, herein, discuss the events that trigger inflammation in the disease, as well as the mechanisms, inflammatory molecules and cells that propagate these inflammatory processes. Given the central role that inflammation plays in SCD pathophysiology, many of the therapeutic approaches currently under pre-clinical and clinical development for the treatment of SCD endeavor to counter aspects or specific molecules of these inflammatory processes and it is possible that, in the future, we will see anti-inflammatory drugs being used either together with, or in place of, hydroxyurea in those SCD patients for whom hematopoietic stem cell transplants and evolving gene therapies are not a viable option.