Platelet-derived growth factor and platelet profiles in childhood nephrotic syndrome

Evaluation of immature granulocyte percentage and count in pediatric nephrotic syndrome

OBJECTIVE

The importance of immature granulocytes (IGs) in most infectious and inflammatory diseases has been highlighted. This study aimed to determine the clinical usability and importance of changes in the peripheral complete blood count profile, including IG percentage (IG%) and IG count (IG#), during the relapse and remission phases in pediatric nephrotic syndrome (NS) patients.

METHODS

This retrospective observational study was performed at a tertiary care hospital between February 2020 and August 2022. Demographic characteristics and laboratory parameters were recorded. The IG count and IG% were measured using an automated hematological analyzer.

RESULTS

IG% and IG# were both higher during the relapse phase of NS than during the remission phase (0.29% ± 0.14%, versus 0.23% ± 0.14%, p = 0.037 and 0.027 ± 0.015 × 103/µL, versus 0.018 ± 0.014 × 103/µL, p = 0.005, respectively). The neutrophil to lymphocyte ratio (NLR), platelet (PLT), white blood cell (WBC), and neutrophil counts had a strong positive correlation with IG# (r = 0.397, p < 0.001; r = 0.352, p < 0.001; r = 0.622, p < 0.001; r = 0.660, p < 0.001, respectively). The NLR, PLT, WBC, and neutrophil counts had a strong positive correlation with IG% (r = 0.348, p < 0.001; r = 0.187, p = 0.039; r = 0.303, p = 0.001; r = 0.426, p < 0.001, respectively). Receiver operating characteristic curve analysis showed that IG# had the best AUC value of 0.69 (95% CI: 0.58-0.77; p = 0.001) for the relapse phase of NS with a cutoff value of 0.025 × 103/µL (sensitivity: 81.0%, specificity: 78.1%).

CONCLUSIONS

It is probable that a high level of immature granulocyte count has a positive correlation for NS relapse in pediatric patients. The IG % and IG# can be used together as biomarkers of inflammation in pediatric NS relapse.

The Crosstalk between Nephropathy and Coagulation Disorder: Pathogenesis, Treatment, and Dilemmas

ABSTRACT

The interaction between the kidney and the coagulation system greatly affects each other because of the abundant vessel distribution and blood perfusion in the kidney. Clinically, the risks of complicated thrombosis and bleeding have become important concerns in the treatment of nephropathies, especially nephrotic syndrome, CKD, ESKD, and patients with nephropathy undergoing RRTs. Adverse effects of anticoagulant or procoagulant therapies in patients with nephropathy, especially anticoagulation-related nephropathy, heparin-induced thrombocytopenia, and bleeding, seriously worsen the prognosis of patients, which have become challenges for clinicians. Over the decades, the interaction between the kidney and the coagulation system has been widely studied. However, the effects of the kidney on the coagulation system have not been systematically investigated. Although some coagulation-related proteins and signaling pathways have been shown to improve coagulation abnormalities while avoiding additional kidney damage in certain kidney diseases, their potential as anticoagulation targets in nephropathy requires further investigation. Here, we review the progression of research on the crosstalk between the coagulation system and kidney diseases and systematically analyze the significance and shortcomings of previous studies to provide new sight into future research. In addition, we highlight the status of clinical treatment for coagulation disorder and nephropathy caused by each other, indicating guidance for the formulation of therapeutic strategies or drug development.

Nephrotic Syndrome – Different Risk of Venous Thromboembolism with Different Approaches to Justify Prophylactic Anticoagulation

All of the circumstances influencing any of the elements of Virchow’s Triad can increase the risk of venous thromboembolism. Assessing prothrombotic factors can sometimes be difficult. One of the examples of such a condition is nephrotic syndrome. In this condition at least two elements of Virchow’s triad are affected: physiological blood composition and the venous blood flow which is slowed down by the edema. Except for the cases mentioned in KDIGO (Kidney Disease: Improving Global Outcomes), the use of anticoagulant drugs in the prophylaxis of VTE (Venous Thromboembolism) in nephrotic syndrome seems unclear. Nevertheless, due to the increased risk of VTE, it is worth implementing mechanical anticoagulant prophylaxis, which can also improve the quality of life of patients by reducing swelling. The article analyzes the current knowledge on the field and gives some proposals with low bleeding risk.

Haemostatic profile of children with nephrotic syndrome attending University of Nigeria Teaching Hospital Ituku-Ozalla, Nigeria

Background

Haemostatic derangements are thought to be due to an imbalance between hepatic synthesis of pro-coagulants and urinary losses of anticoagulants.

Objectives

This study evaluated the coagulation profile of Nigerian children with nephrotic syndrome and examined the relationship between coagulation variables, disease state and steroid responsiveness.

Methods

A cross- sectional hospital based study on evaluation of coagulation profile of children with nephrotic syndrome compared with their age- and gender- matched controls.

Results

The median fibrinogen level in subjects and controls was the same (2.9 g/L). Sixteen of 46 (35%) children with nephrotic syndrome had hyperfibrinogenaemia. The median fibrinogen level of children in remission was 2.3 g/L and differed significantly when compared with those of children in relapse (p = 0.001). The median APTT of children with nephrotic syndrome was 45.0 s and differed significantly compared with those of controls (42.0 s) (p value = 0.02). The median prothrombin time in children with and without nephrotic syndrome were 12.0 and 13.0 s respectively, (p = 0.004). About 90% of children with nephrotic syndrome had INR within reference range. Thrombocytosis was found in 15% of children with nephrotic syndrome. The median platelet count in children with new disease was 432 × 10³cells/mm³ and differed significantly when compared with those of controls (p = 0.01).

INR was significantly shorter in children with steroid resistant nephrotic syndrome (SRNS) (median 0.8 s; IQR 0.8 -0.9 s) compared with controls (median 1.0 s; IQR 1.0 -1.1 s) (p = 0.01). Steroid sensitivity was the strongest predictor of remission in children with nephrotic syndrome; steroid sensitive patients were 30 times more likely to be in remission than in relapse (OR 30.03; CI 2.01 – 448.04).

Conclusion

This study shows that the haemostatic derangements in childhood nephrotic involve mostly fibrinogen, APTT, PT, INR and platelet counts. Antithrombin levels are largely unaffected. Variations in fibrinogen, APTT, PT and INR values may be due to the heterogeneous nature of the disease.

Platelet abnormalities in nephrotic syndrome

Nephrotic syndrome (NS) is a common kidney disease associated with a significantly increased risk of thrombotic events. Alterations in plasma levels of pro- and anti-coagulant factors are involved in the pathophysiology of venous thrombosis in NS. However, the fact that the risk of both venous and arterial thrombosis is elevated in NS points to an additional role for blood platelets. Increased platelet counts and platelet hyperactivity have been observed in nephrotic children. Platelet hyperaggregability, increased release of active substances, and elevated surface expression of activation-dependent platelet markers have been documented. The mechanisms underlying those platelet alterations are multifactorial and are probably due to changes in plasma levels of platelet-interfering proteins and lipid changes, as a consequence of nephrosis. The causal relationship between platelet alterations seen in NS and the occurrence of thromboembolic phenomena remains unclear. Moreover, the efficiency of prophylactic treatment using antiplatelet agents for the prevention of thrombotic complications in nephrotic patients is also unknown. Thus, antiplatelet medication is currently not generally recommended for routine prophylactic therapy.

Pituitary adenylate cyclase-activating polypeptide deficiency associated with increased platelet count and aggregability in nephrotic syndrome

BACKGROUND

Pituitary adenylate cyclase-activating polypeptide (PACAP) was recently identified as an inhibitor of megakaryopoiesis and platelet aggregability.

OBJECTIVE

We studied PACAP levels in children with nephrotic syndrome (NS), which is associated with thrombocytosis, platelet hyperaggregability, and an increased risk of thrombosis.

PATIENTS/METHODS

In four children with congenital NS (CNS) and 24 children with idiopathic NS (INS), plasma and urine levels of PACAP and ceruloplasmin were measured, as were platelet counts and platelet aggregation responses to collagen. In CNS patients, in vitro megakaryopoiesis and nuclear factor-κB expression in platelet lysates were also measured. All tests were performed during the nephrotic state and the non-nephrotic state.

RESULTS

Urinary losses of PACAP and ceruloplasmin were observed during the nephrotic state, and disappeared during the non-nephrotic state. Plasma PACAP deficiency was more pronounced in CNS patients than in INS patients. Thrombocytosis was observed in all CNS patients and in 11 of 29 INS patients during the nephrotic state. During the PACAP-deficient state, in vitro megakaryopoiesis was increased for CNS patients, and this effect could be reversed by the addition of recombinant PACAP. Platelet hyperaggregability was observed during the nephrotic state in both CNS and INS patients. In INS patients, the addition of recombinant PACAP to patients' platelets was studied, and resulted in decreased aggregation during the nephrotic state. Platelet aggregation correlated inversely with plasma PACAP levels, but not with serum albumin levels.

CONCLUSIONS

We demonstrate urinary losses of PACAP and plasma PACAP deficiency in children with NS, associated with thrombocytosis and platelet hyperaggregability.

The role of platelet activation in determining response to therapy in patients with primary nephrotic syndrome

To test the role of platelet activation in the prognosis of nephrotic syndrome (NS), we evaluated the mean platelet volume (MPV) in patients with NS undergoing treatment. In this prospective, multicenter clinical study 156 patients with primary NS under treatment were assigned and followed for one year. Patients were divided into three groups for complete remission, partial remission, and resistance. Biochemical parameters, estimated glomerular filtration rate, proteinuria level, and MPV levels were compared at baseline and 12 months after treatment. MPV, proteinuria, total cholesterol, triglyceride, LDL cholesterol, HDL cholesterol, total protein, albumin, and hs-CRP levels significantly decreased in partial and complete remission group after 12 months compared to the baseline (p < 0.05). However, MPV levels significantly increased and only LDL cholesterol significantly decreased in the resistance group (p < 0.05). Univariate analyses demonstrated that ΔMPV was significantly associated with Δproteinuria (r = 0.41, p < 0.001), Δhs-CRP (r = 0.39, p < 0.001), and ΔAlbumin (r = -0.30, p < 0.001). We found that ΔAlbumin (β = -0.33, p < 0.001), ΔTotal cholesterol (β = -0.20, p = 0.011), and Δhs-CRP (β = 0.19, p = 0.018) were statistically significant predictors of the Δproteinuria in multiple regression analysis. In subjects with primary NS, MPV is associated with the prognosis or the disease. This study provides the background for longer trials and the role of platelet activation in NS.

Epidemiology and pathophysiology of nephrotic syndrome-associated thromboembolic disease

After infections, thromboembolism is considered by many experts to be the most significant life-threatening complication of nephrotic syndrome. The purpose of this review is to summarize the epidemiology, clinical and molecular pathophysiology, and management of this complication. Children (2.8%) are less likely than adults (26.7%) with nephrotic syndrome to develop thromboembolism. However, infants and children aged >12 years are at much greater risk. Membranous histologic changes increase thromboembolic risk at all ages; in particular, adults with membranous nephropathy have the highest reported risk (37.0%) and children with membranous histology have a rate (25%) that approaches the overall adult rate. There are striking, but variable, pathologic alterations of molecular hemostasis associated with nephrotic syndrome. No clear molecular therapeutic targets have been identified, but most studies show that the major pathologic changes involve antithrombin, fibrinogen, and factors V and VIII. There is inadequate evidence to support routine prophylactic therapy. Therapy includes anticoagulation in all cases, with thrombolysis reserved for those with the most severe thromboembolic disease. Future hemostatic research in nephrotic syndrome should focus on identifying cohorts at highest risk for thrombosis through the use of clinical markers and biomarkers as well as searching for molecular targets to correct the prothrombotic pathophysiology of this disease.

Low protein Z levels in children with nephrotic syndrome

Acquired deficiency of anticoagulant proteins, due to loss in the urine, has been proposed as one of the major thrombogenic alterations in nephrotic syndrome (NS). Protein Z (PZ) is a single-chain vitamin K-dependent glycoprotein. Low PZ levels are reported to be a risk factor for thrombosis. The aim of this study was to investigate protein Z and other natural anticoagulant levels in children with NS. Thirty children aged between 1.5 and 12 years with NS (Groups I and II) and 19 age-and-sex-matched healthy controls (Group III) were enrolled into the study. Patients were divided into two groups: Group I (proteinuria >40 mg/m2/hr) and Group II (patients in remission). Plasma PZ levels in Group I were significantly lower than Group II (p=0.009) and group III (p=0.018). Plasma levels of AT III for Group I were significantly lower than for Groups II and III (p=0.009, p=0.005, respectively). Protein C levels in Group I were higher than in Group II and Group III (p=0.002, p=0.000, respectively). Protein Z levels positively correlated with serum total protein and albumin levels (p=0.003, p=0.003, respectively) and negatively with the degree of proteinuria (p=0.000). Protein Z levels were positively correlated with AT III (r=0.037, p=0.04). Along with the other coagulation abnormalities, decreased protein Z may contribute to increased risk of thromboembolic complications in children with NS. The negative correlation between proteinuria and PZ level suggests the possibility of renal PZ loss. Further studies are needed to investigate the mechanism and role of decreased PZ in NS.

Relationship of serum interleukin-7 concentration and the coagulation state in children with nephrotic syndrome

BACKGROUND

Enhanced platelet reactivity may play a significant role in the hypercoagulable state of nephrotic syndrome (NS). Thrombocytosis with platelet aggregation cause the release of some cytokines, among them interleukin-7 (IL-7). The aim of the study was to evaluate serum IL-7 levels in children with the symptoms of NS and to determine a correlation between its concentration and platelet count, other hemostatic factors, and NS intensity.

METHODS

The study was performed in two groups. I--the examined group of 26 children with NS (12 boys, 14 girls) aged 6.8 +/- 2.1 years, subjected to two examinations: A--before treatment, B--during treatment with prednisone (60 mg/kg 24 h after albuminuria regression); and II--the control group (C) of 20 healthy children. Serum IL-7 level was assayed by enzyme-linked immunosorbent assay method using a R & D Quantikine set.

RESULTS

In group I, IL-7 level in examination A (33.33 +/- 33.24 pg/mL) was higher than in the control subjects (P < 0.01). In examination B, IL-7 concentration was reduced to the level of 10.86 +/- 5.22 pg/mL and did not differ from the controls (P > 0.05). A positive correlation was observed between IL-7 and platelet count and serum fibrinogen level. A negative correlation was noted with antithrombin III concentration. No correlation was found with serum levels of albumin and cholesterol or urine protein.

CONCLUSION

In children with NS, serum IL-7 level increases proportionally to the elevated platelet count and other hemostatic components, but shows no correlation with serum albumin or urine protein.