The complement system is part of the innate immune response and as such defends against invading pathogens, removes immune complexes and damaged self-cells, aids organ regeneration, confers neuroprotection, and engages with the adaptive immune response via T and B cells. Complement activation can either benefit or harm the host organism; thus, the complement system must maintain a balance between activation on foreign or modified self surfaces and inhibition on intact host cells. Complement regulators are essential for maintaining this balance and are classified as soluble regulators, such as factor H, and membrane-bound regulators. Defective complement regulators can damage the host cell and result in the accumulation of immunological debris. Moreover, defective regulators are associated with several autoimmune diseases such as atypical hemolytic uremic syndrome, dense deposit disease, age-related macular degeneration, and systemic lupus erythematosus. Therefore, understanding the molecular mechanisms by which the complement system is regulated is important for the development of novel therapies for complement-associated diseases.
Adaptive Immunity ; Antigen-Antibody Complex ; Autoimmune Diseases ; Autoimmunity ; B-Lymphocytes ; Complement Activation ; Complement Factor H ; Complement System Proteins* ; Glomerulonephritis, Membranoproliferative ; Hemolytic-Uremic Syndrome ; Immunity, Innate ; Lupus Erythematosus, Systemic ; Macular Degeneration ; Physiology* ; Regeneration

The incidence of acute kidney injury (AKI) in critically ill pediatric patients has been reported as increasing to 25 %, depending on population characteristics. The etiology of AKI has changed over the last 10-20 years from primary renal disease to the renal conditions associated with systemic illness. The AKI in pediatric population is associated with increased mortality and morbidity, and prevention is needed to reduce the consequence of AKI. It is known that the most important risk factors for AKI in critically ill pediatric patients are clinical conditions to be associated with decreased renal blood flow, direct renal injury, and illness severity. Renal hypoperfusion leads to neurohormonal activation including renin-angiotensinaldosterone system, sympathetic nervous system, antidiuretic hormone, and prostaglandins. Prolonged renal hypoperfusion can result in acute tubular necrosis. The direct renal injury can be predisposed under the condition of renal hypoperfusion, and appropriate treatment of volume depletion is important to prevent AKI. The preventable causes of AKI include contrast-induced nephropathy, hemodynamic instability, inappropriate mediation use, and multiple nephrotoxic insults. Given the evidence of preventable factors for AKI, several actions such as the use of protocol for prevention of contrast-induced nephropathy, appropriate treatment of volume depletion, vigorous treatment of sepsis, avoidance of combinations of nephrotoxic medications, and monitoring of levels of drugs should be recommended.
Acute Kidney Injury* ; Child ; Critical Illness ; Hemodynamics ; Humans ; Incidence ; Mortality ; Necrosis ; Negotiating ; Population Characteristics ; Prostaglandins ; Renal Circulation ; Risk Factors ; Sepsis ; Sympathetic Nervous System

Hyperammonemia can be caused by several genetic inborn errors of metabolism including urea cycle defects, organic acidemias, fatty acid oxidation defects, and certain disorders of amino acid metabolism. High levels of ammonia are extremely neurotoxic, leading to astrocyte swelling, brain edema, coma, severe disability, and even death. Thus, emergency treatment for hyperammonemia must be initiated before a precise diagnosis is established. In neonates with hyperammonemia caused by an inborn error of metabolism, a few studies have suggested that peritoneal dialysis, intermittent hemodialysis, and continuous renal replacement therapy (RRT) are effective modalities for decreasing the plasma level of ammonia. In this review, we discuss the current literature related to the use of RRT for treating neonates with hyperammonemia caused by an inborn error of metabolism, including optimal prescriptions, prognosis, and outcomes. We also review the literature on new technologies and instrumentation for RRT in neonates
Ammonia ; Astrocytes ; Brain Edema ; Coma ; Diagnosis ; Edema ; Emergency Treatment ; Humans ; Hyperammonemia ; Infant, Newborn ; Metabolism ; Metabolism, Inborn Errors ; Peritoneal Dialysis ; Plasma ; Prescriptions ; Prognosis ; Renal Dialysis ; Renal Replacement Therapy ; Urea

Remarkable advances in genetic diagnosis expanded our knowledge about inherited tubulopathies and other genetic kidney diseases. This review suggests a simple categorization of inherited tubular disease, clarifies the concept of autosomal dominant tubulointerstitial kidney disease (ADTKD), and introduces novel therapies developed for tubulopathies. Facing patients with suspicious tubular disorders, clinicians should first evaluate the status of volume and acid-base. This step helps the clinicians to localize the affected segment and to confirm genetic diagnosis. ADTKD is a recently characterized disease entity involving tubules. The known causative genes are UMOD, MUC1, REN, and HNF1β. Still, only half of ADTKD patients show mutations for these four identified genes. Whole exome sequencing is a suitable diagnostic tool for tubulopathies, especially for ADTKD. Genetic approaches to treat tubulopathies have progressed recently. Despite the practical obstacles, novel therapies targeting inherited tubulopathies are currently in development.

The administration of angiotensin type 2 receptor blockers (ARBs) during pregnancy is known to cause ARB fetopathy, including renal insufficiency. We aimed to analyze the outcomes of two patients who survived ARB fetopathy and perform an accompanying literature review. Case 1 was exposed antenatally from a gestational age of 30 weeks to valsartan because of maternal pregnancy-induced hypertension. The patient presented with oliguria immediately after birth, and renal replacement therapy was administered for 24 days. Seven years after birth, renal function was indicative of stage 2 chronic kidney disease (CKD) with impaired urinary concentration. Case 2 had a maternal history of hypertension and transient ischemic attack and was treated with olmesartan until 30 weeks of pregnancy. Renal replacement therapy was performed for 4 days since birth. After 8 years, the patient is with CKD stage 2, with intact tubular function. Recent reports suggest that ARB fetopathy might manifest as renal tubular dysgenesis and nephrogenic diabetes insipidus, in contrast to mild alterations of glomerular filtration. Tubular dysfunction may induce CKD progression and growth retardation. Patients with ARB fetopathy should be monitored until adulthood. The ARB exposure period might be a critical factor in determining the severity and manifestations of fetopathy.

Hemodialysis is rarely used in neonates and infants due to the risk of major complications in the very young. Nevertheless, there are clinical situations where hemodialysis is needed and may be helpful in small children. Recently, new developments in specialized hemodialysis equipment and specifically trained personnel have made it possible to implement hemodialysis in neonates and infants. In this review, we will discuss hemodialysis for the treatment of small children with renal replacement therapy-requiring conditions, and consider indications, prescriptions, complications, and ethical issues.

IgA nephropathy usually presents as asymptomatic microscopic hematuria or proteinuria or episodic gross hematuria after upper respiratory infection. It is an uncommon cause of end-stage renal failure in childhood. Pulmonary hemorrhage associated with IgA nephropathy is an unusual life-threatening manifestation in pediatric patients and is usually treated with aggressive immunosuppression. Pulmonary hemorrhage and renal failure usually occur concurrently, and the pulmonary manifestation is believed to be caused by the same immune process. We present the case of a 14-year-old patient with IgA nephropathy who had already progressed to end-stage renal failure in spite of immunosuppression and presented with pulmonary hemorrhage during oral prednisone treatment. His lung disease was comparable to diffuse alveolar hemorrhage and was successfully treated with plasmapheresis followed by oral prednisone. This case suggests that pulmonary hemorrhage may develop independently of renal manifestation, and that plasmapheresis should be considered as adjunctive therapy to immunosuppressive medication for treating IgA nephropathy with pulmonary hemorrhage.
Adolescent ; Glomerulonephritis, IGA* ; Hematuria ; Hemorrhage* ; Humans ; Immunoglobulin A* ; Immunosuppression ; Kidney Failure, Chronic ; Lung Diseases ; Plasmapheresis ; Prednisone ; Proteinuria ; Renal Insufficiency

PURPOSE: Nafamostat mesilate (NM), a synthetic serine protease inhibitor, has been investigated as an anticoagulant for adult patients with a high risk of bleeding, who need chronic renal replacement therapy (CRRT). However, little is known about the use of NM as an anticoagulant in pediatric CRRT. The aim of this study was to evaluate the ideal dosage, efficacy, and safety of NM in pediatric CRRT. METHODS: We conducted a retrospective study of 40 pediatric patients who had undergone at least 24 h of venovenous CRRTs between January 2011 and October 2013. We divided the patients according to risk of bleeding. Those at high risk received no anticoagulation (group 1) or NM as an anticoagulant (group 2), while those at low risk received heparin (group 3). RESULTS: Forty patients (25 male and 15 female; mean age, 8.2+/-6.6 years) were enrolled. The mean duration of CRRT was 13.0 days, and the survival rate was 57.5%. The mean hemofilter lifespan was 39.3 h in group 1 and 11.3 h in group 3. In group 2, hemofilter lifespan was extended from 7.5 h to 27.4 h after the use of NM (P=0.001). The mean hemofilter lifespan with NM was greater than with heparin (P=0.018). No patient experienced a major bleeding event during treatment with NM. CONCLUSION: NM may be a good alternative anticoagulant in pediatric patients with a high risk of bleeding requiring CRRT, and is not associated with bleeding complications.
Adult ; Child* ; Female ; Hemorrhage* ; Heparin ; Humans ; Male ; Mesylates* ; Renal Replacement Therapy* ; Retrospective Studies ; Serine Proteases ; Survival Rate