Pathobiochemistry of nephrotic syndrome

Nephrotic Syndrome: A Review

Nephrotic syndrome (NS) is characterized by hypoalbuminemia, severe proteinuria, and peripheral edema, frequently in conjunction with hyperlipidemia. Individuals usually show symptoms of weariness and swelling, but no signs of serious liver damage or cardiac failure. With characteristic medical symptoms and evidence of hypoalbuminemia and severe proteinuria, NS can be diagnosed. The majority of NS episodes are classified as unexplained or primary; the most prevalent histopathological subgroups of primary NS in people are focal segmental glomerulosclerosis and membraneous nephropathy. Thrombosis of the veins with high cholesterol levels is a significant NS risk. Acute renal damage and infection are further possible side effects. The pathobiochemistry of NS involves alterations in genes that affect the selectivity of the kidneys and abnormalities in proteins related to podocytes. Understanding the molecular mechanisms that influence these processes is crucial to developing specific and targeted therapeutic approaches. The need for invasive renal biopsies throughout the diagnosis process may be lessened by the development of non-invasive nephrotic syndrome biomarkers, such as microRNAs. Corticosteroids are frequently used as the initial line of defense in NS treatment. However, some individuals need other treatments since a resistant type of NS also exists. The use of calcineurin inhibitors, mycophenolate mofetil, and rituximab is mentioned in the text, along with current research to identify safer and more efficient therapeutic choices. The complicated kidney condition NS has several underlying causes and symptoms. For the diagnosis of this ailment as well as the creation of focused therapies, an understanding of the pathophysiology and the identification of possible biomarkers are essential.

[A patient with rheumatoid arthritis presenting a nephrotic syndrome: A case report]

A fifty-one years-old patient with a history of rheumatoid arthritis of recent diagnosis is hospitalized for exploration of a rapidly progressive anasarca state. First analysis discovered an impure nephrotic syndrome (acute renal failure, hematuria) and massive glomerular proteinuria. Auto-medication by nonsteroidal anti-inflammatory drug was revealed. Renal biopsy showed minimal glomerular disease and acute tubular necrosis. Corticosteroid use permitted a normalization of proteinuria and renal recovery was obtained. Literature review showed renal impairment occurring in rheumatoid polyarthritis. Minimal glomerular disease is rare but can be associated with rheumatoid arthritis. This disease, associated with the use of nonsteroidal anti-inflammatory drug, may be responsible of the patient condition.

Circulating follicular T helper cells are possibly associated with low levels of serum immunoglobulin G due to impaired immunoglobulin class-switch recombination of B cells in children with primary nephrotic syndrome

Clinically, most patients with primary nephrotic syndrome (PNS) have low serum IgG levels, which is an important factor in infection and in PNS relapse.To some extent, the mechanisms involved remain largely unknown. Here, we aimed to investigate the pathogenesis of the decreased IgG levels in PNS. Peripheral blood was collected from patients with PNS and closely age- and sex-matched healthy individuals. The frequency, phenotype and molecular function of different circulating B cell and T follicular helper cell (TFH) subsets were examined by flow cytometry. The function of the CD40/CD40 L interaction in immunoglobulin class-switch recombination (CSR) was evaluated by assessing the induction of activation-induced deaminase (AID) expression with CD40 L stimulation. We revealed an increase in the levels of circulating total plasmablasts, plasma cells and mature-naive B cells and a decrease in the levels of germinal centre-like B cells and CD19⁺IgG⁺ B cells in PNS. In addition, although the expression of CD86 on the surface of B cells and the expression of the inducible costimulator (ICOS) on the surface of TFH cells both were increased, the expression of CD40 L on the surface of TFH cells was decreased. Moreover, upon stimulation with CD40 L in vitro, the mRNA expression of AID in peripheral blood mononuclear cells (PBMCs) was decreased in patients with PNS compared with that in healthy controls. Our results indicate that the immunoglobulin CSR of B cells was partly dysfunctional and provide insights into the potential involvement of impaired TFH cell-dependent B cell responses in the pathogenesis of low IgG levels through downregulating CD40 L expression on TFH cells in PNS.

Pathogenesis and Management of Acute Kidney Injury in Patients with Nephrotic Syndrome Due to Primary Glomerulopathies

Acute kidney injury in the context of nephrotic syndrome is a serious and alarming clinical problem. Largely, acute kidney injury is a relatively frequent complication among patients with comorbidities while it has been independently associated with an increased risk of adverse outcomes, including death and chronic kidney disease. Nephrotic syndrome, without hematuria or with minimal hematuria, includes a list of certain glomerulopathies; minimal change disease, focal segmental glomerulosclerosis and membranous nephropathy. In the light of primary nephrotic syndrome, pathophysiology of acute kidney injury is differentiated by the nature of the primary disease and the severity of the nephrotic state. This review aims to explore the clinical circumstances and pathogenetic mechanisms of acute kidney injury in patients with nephrotic syndrome due to primary glomerulopathies, focusing on newer perceptions regarding the pathogenesis and management of this complicated condition, for the prompt recognition and timely initiation of appropriate treatment in order to restore renal function to its baseline level. Prompt recognition of the precise cause of acute kidney injury is crucial for renal recovery. Clinical characteristics, laboratory and serological findings along with histopathological findings, if required, will reveal the implicated pathway leading to individualized approach and management.

Traditional Chinese Medicine for Refractory Nephrotic Syndrome: Strategies and Promising Treatments

Refractory nephrotic syndrome (RNS) is an immune-related kidney disease with poor clinical outcomes. Standard treatments include corticosteroids as the initial therapy and other immunosuppressants as second-line options. A substantial proportion of patients with RNS are resistant to or dependent on immunosuppressive drugs and often experience unremitting edema and proteinuria, cycles of remission and relapse, and/or serious adverse events due to long-term immunosuppression. Traditional Chinese medicine has a long history of treating complicated kidney diseases and holds great potential for providing effective treatments for RNS. This review describes the Chinese medical theories relating to the pathogenesis of RNS and discusses the strategies and treatment options using Chinese herbal medicine. Available preclinical and clinical evidence strongly supports the integration of traditional Chinese medicine and Western medicine for improving the outcome of RNS. Herbal medicine such as Astragalus membranaceus, Stephania tetrandra S. Moore, and Tripterygium wilfordii Hook F can serve as the alternative therapy when patients fail to respond to immunosuppression or as the complementary therapy to improve therapeutic efficacy and reduce side effects of immunosuppressive agents. Wuzhi capsules (Schisandra sphenanthera extract) with tacrolimus and tetrandrine with corticosteroids are two herb-drug combinations that have shown great promise and warrant further studies.

Immunoglobulin G and M levels in childhood nephrotic syndrome: two centers Egyptian study

INTRODUCTION

Idiopathic nephrotic syndrome (INS) is the most common glomerular disease in children. Immune cell subsets may play a role in pathogenesis of INS. We aimed to assess immunoglobulin G (IgG) and immunoglobulin M (IgM) levels in children with nephrotic syndrome (NS) to predict prognosis of the disease and response to treatment.

METHODS

This prospective case control study was done in Pediatric Nephrology Units at Minoufia and Benha University Hospitals, during the period from 1st March 2014 to 30th June 2015. Seventy-five children in the active stage of INS and 75 apparently healthy children of matched age and sex were included in this study. Statistical evaluation was performed by SPSS version 18.0 using independent-samples t-test, Chi-square, and Pearson's correlation coefficient (r).

RESULTS

Compared with healthy children, IgM level was high, IgG level and IgG/IgM ratio were low (p≤0.05). The IgG level and IgG/IgM ratio decreased more in FRNS than in IFRNS group, and was the lowest in SRNS group. The IgM level increased more in FRNS than in IFRNS group, and was the highest in SRNS group (p<0.05, respectively).

CONCLUSIONS

Our findings support the idea that IgG level has a prognostic value in NS in children.

Study of urinary proteomes in Anderson-Fabry disease

BACKGROUND

Anderson-Fabry disease (AFD) is an X-linked genetic disorder with deficient α-galactosidase A activity. The main aim of this work was to investigate possible differences in urine proteins between healthy controls and AFD patients and to identify abnormal proteins as potential biomarkers of disease.

MATERIAL AND METHODS

We studied 2D electrophoresis images of urine samples collected from AFD patients and healthy subjects. The proteins were separated using isoelectric focusing method followed by SDS-PAGE. The proteins were then visualized by silver staining and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

RESULTS

We found out that the urinary spectra of all the Fabry disease samples included identical proteins with molecular weight around 20-40 kDa. The concentration of some proteins was more than three times higher in the AFD samples, compared to the controls. The abundant proteins were identified by MALDI-TOF MS and included the following: alpha-1-antitrypsin, alpha-1-microglobulin, prostaglandin H2 d-isomerase, complement-c1q tumor necrosis factor-related protein, and Ig kappa chain V-III. Possible glycosylation at Asn51 and Asn78 sites of the prostaglandin H2 d-isomerase was detected.

CONCLUSIONS

AFD urinary proteomics revealed increased secretion of several proteins. We postulate that the observed difference in the amount of prostaglandin H2 d-isomerase and its position on two-dimensional gels might be related to different glycosylation in AFD subjects.

Coincident activation of Th2 T cells with onset of the disease and differential expression of GRO-gamma in peripheral blood leukocytes in minimal change disease

BACKGROUND

Involvement of Th2 T cells/NFkappaB in minimal change disease (MCD) has been postulated. A promising but unconfirmed glomerular permeability factor (GPF) from MCD T cells has been described. We explored whether GPF was the consequence of Th2 cell activation.

METHODS

Peripheral blood leukocytes (PBL) from 16 MCD patients and 7 normal controls were analyzed and the results were statistically compared.

RESULTS

Flow cytometry demonstrated a significant expansion of CD4+ T cell population and dramatically increased CD69+ cells among CD4+ T cells in MCD, suggesting coincident activation of T cells with onset of the disease. RT-PCR on RNA from either freshly isolated PBL or post in vitroactivation showed high-level expression of the Th2 cytokine interleukin-4 in all MCD patients. Importantly, both antibody microarray assay on sera and RT-PCR on mRNA of PBL revealed expression of a CXC chemokine GRO-gamma (growth-related oncogene) in all MCD patients as compared with one of 7 controls.

CONCLUSIONS

Our results reveal an association between onset of MCD and activation of Th2 cells. The GRO family has been implicated in the function of endothelial cells, and its expression is under NFkappaB regulation. Thus, GRO-gamma is a promising candidate for Th2-associated GPF in MCD.

Effect of low-density lipoprotein apheresis on urinary protein and podocyte excretion in patients with nephrotic syndrome due to diabetic nephropathy

BACKGROUND

The aim of the present study is to determine whether low-density lipoprotein (LDL) apheresis affects proteinuria and urinary podocyte excretion in patients with type 2 diabetes and nephrotic syndrome.

METHODS

LDL apheresis was performed on patients with diabetes with long-standing nephrotic syndrome, and urinary protein level and number of urinary podocytes were compared between these patients (5 men, 3 women; mean age, 54.6 years) and 10 nephrotic patients with diabetes not treated with LDL apheresis (6 men, 4 women; mean age, 56.5 years).

RESULTS

LDL apheresis reduced total cholesterol (P < 0.001), LDL cholesterol ( P < 0.001), lipoprotein(a) (P < 0.001), creatinine (P < 0.05), and blood urea nitrogen (P < 0.05) levels and increased creatinine clearance (P < 0.05). The LDL apheresis group showed a significant decrease in urinary protein excretion (from 10.8 +/- 3.2 to 1.8 +/- 1.1 g/d; P < 0.001) and number of urinary podocytes (from 4.8 +/- 2.2 to 0.9 +/- 0.4 cells/mL; P < 0.01).

CONCLUSION

These data suggest that LDL apheresis effectively reduces proteinuria and podocyte excretion, ameliorating renal dysfunction in patients with nephrotic syndrome caused by diabetic nephropathy.

Therapy with statins in patients with refractory rheumatic diseases: a preliminary study

We have explored the therapeutic potential of statins in patients with different inflammatory rheumatic diseases refractory to conventional therapy. We found that simvastatin (80mg o.d. for eight days) induced a rapid and significant reduction in proteinuria levels in three systemic lupus erythematosus (SLE) patients. A similar kind of therapy had a marked beneficial effect in a patient with Wegener's granulomatosis and a patient with erythema nodosum. On the other hand, five patients with rheumatoid arthritis (RA) who received atorvastatin for eight days (20mg/day) showed reduction in C-reactive protein levels and a clinical improvement that was classified as an ACR20 response. Prior to the administration of statins, all these patients had received aggressive conventional therapy with no satisfactory response. A significant reduction in spontaneous apoptosis of peripheral blood lymphocytes and expression of CD69 and HLA-DR was observed in SLE patients after simvastatin therapy. These results prompted us to perform a pilot short-time comparative (simvastatin versus chloroquine) open clinical trial in 15 patients with RA who were receiving methotrexate as a single disease modifying antirheumatic drug with no satisfactory response. Most patients (9/10) who received simvastatin (40mg/day) showed an ACR50 or better response after eight weeks, whereas such a response was not observed in any patient (0/5) treated with chloroquine. Our preliminary results indicate that statins may be an important therapeutic tool for the treatment of inflammatory rheumatic diseases.