Publications by authors named "Galina Nesterova"

12 Publications

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Nephropathic Cystinosis: A Distinct Form of CKD-Mineral and Bone Disorder that Provides Novel Insights into the Regulation of FGF23.

J Am Soc Nephrol 2020 09 6;31(9):2184-2192. Epub 2020 Jul 6.

Skeletal Disorders and Mineral Homeostasis Section, National Institutes of Dental and Craniofacial Research, Bethesda, Maryland.

Background: The rare lysosomal storage disease nephropathic cystinosis presents with renal Fanconi syndrome that evolves in time to CKD. Although biochemical abnormalities in common causes of CKD-mineral and bone disorder have been defined, it is unknown if persistent phosphate wasting in nephropathic cystinosis is associated with a biochemical mineral pattern distinct from that typically observed in CKD-mineral and bone disorder.

Methods: We assessed and compared determinants of mineral homeostasis in patients with nephropathic cystinosis across the predialysis CKD spectrum to these determinants in age- and CKD stage-matched patients, with causes of CKD other than nephropathic cystinosis.

Results: The study included 50 patients with nephropathic cystinosis-related CDK and 97 with CKD from other causes. All major aspects of mineral homeostasis were differentially effected in patients with CKD stemming from nephropathic cystinosis versus other causes. Patients with nephropathic cystinosis had significantly lower percent tubular reabsorption of phosphate and fibroblast growth factor-23 (FGF23) at all CKD stages, and lower blood phosphate in CKD stages 3-5. Linear regression analyses demonstrated lower FGF23 levels in nephropathic cystinosis participants at all CKD stages when corrected for eGFR and age, but not when adjusted for serum phosphate.

Conclusions: Nephropathic cystinosis CKD patients have mineral abnormalities that are distinct from those in CKD stemming from other causes. Persistently increased urinary phosphate excretion maintains serum phosphate levels within the normal range, thus protecting patients with nephropathic cystinosis from elevations of FGF23 during early CKD stages. These findings support the notion that phosphate is a significant driver of increased FGF23 levels in CKD and that mineral abnormalities associated with CKD are likely to vary depending on the underlying renal disease.
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http://dx.doi.org/10.1681/ASN.2019111172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7461669PMC
September 2020

Management of bone disease in cystinosis: Statement from an international conference.

J Inherit Metab Dis 2019 09 5;42(5):1019-1029. Epub 2019 Aug 5.

Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany.

Cystinosis is an autosomal recessive storage disease due to impaired transport of cystine out of lysosomes. Since the accumulation of intracellular cystine affects all organs and tissues, the management of cystinosis requires a specialized multidisciplinary team consisting of pediatricians, nephrologists, nutritionists, ophthalmologists, endocrinologists, neurologists' geneticists, and orthopedic surgeons. Treatment with cysteamine can delay or prevent most clinical manifestations of cystinosis, except the renal Fanconi syndrome. Virtually all individuals with classical, nephropathic cystinosis suffer from cystinosis metabolic bone disease (CMBD), related to the renal Fanconi syndrome in infancy and progressive chronic kidney disease (CKD) later in life. Manifestations of CMBD include hypophosphatemic rickets in infancy, and renal osteodystrophy associated with CKD resulting in bone deformities, osteomalacia, osteoporosis, fractures, and short stature. Assessment of CMBD involves monitoring growth, leg deformities, blood levels of phosphate, electrolytes, bicarbonate, calcium, and alkaline phosphatase, periodically obtaining bone radiographs, determining levels of critical hormones and vitamins, such as thyroid hormone, parathyroid hormone, 25(OH) vitamin D, and testosterone in males, and surveillance for nonrenal complications of cystinosis such as myopathy. Treatment includes replacement of urinary losses, cystine depletion with oral cysteamine, vitamin D, hormone replacement, physical therapy, and corrective orthopedic surgery. The recommendations in this article came from an expert meeting on CMBD that took place in Salzburg, Austria, in December 2016.
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http://dx.doi.org/10.1002/jimd.12134DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7379238PMC
September 2019

Skeletal Consequences of Nephropathic Cystinosis.

J Bone Miner Res 2018 10 20;33(10):1870-1880. Epub 2018 Jul 20.

Section on Skeletal Disorders and Mineral Homeostasis, National Institutes of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD, USA.

Nephropathic cystinosis is a rare lysosomal storage disorder. Patients present in the first year of life with renal Fanconi syndrome that evolves to progressive chronic kidney disease (CKD). Despite the multiple risk factors for bone disease, the frequency and severity of skeletal disorders in nephropathic cystinosis have not been described. We performed systematic bone and mineral evaluations of subjects with cystinosis seen at the NIH (n = 30), including history and physical examination, serum and urine biochemistries, DXA, vertebral fracture assessment, skeletal radiographs, and renal ultrasound. Additionally, histomorphometric analyses are reported on six subjects seen at the UCLA Bone and Mineral Metabolism Clinic. In NIH subjects, mean age was 20 years (range, 5 to 44 years), 60% were CKD stages G1 to G4, and 40% had a renal transplant. Mean bone mineral density (BMD) Z-scores were decreased in the femoral neck, total hip, and 1/3 radius (p < 0.05). Low bone mass at one or more sites was present in 46% of subjects. Twenty-seven percent of subjects reported one or more long bone fractures. Thirty-two percent of subjects had incidental vertebral fractures, which were unrelated to transplant status. Long-bone deformity/bowing was present in 64%; 50% had scoliosis. Diffuse osteosclerosis was present in 21% of evaluated subjects. Risk factors included CKD, phosphate wasting, hypercalciuria, secondary hyperparathyroidism, hypovitaminosis D, male hypogonadism, metabolic acidosis, and glucocorticoid/immunosuppressive therapy. Sixty-one percent of the non-transplanted subjects had ultrasonographic evidence of nephrocalcinosis or nephrolithiasis. Histomorphometric analyses showed impaired mineralization in four of six studied subjects. We conclude that skeletal deformities, decreased bone mass, and vertebral fractures are common and relevant complications of nephropathic cystinosis, even before renal transplantation. Efforts to minimize risk factors for skeletal disease include optimizing mineral metabolism and hormonal status, combined with monitoring for nephrocalcinosis/nephrolithiasis. © 2018 This article is a U.S. Government work and is in the public domain in the USA.
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http://dx.doi.org/10.1002/jbmr.3522DOI Listing
October 2018

Cystinosis: renal glomerular and renal tubular function in relation to compliance with cystine-depleting therapy.

Pediatr Nephrol 2015 Jun 20;30(6):945-51. Epub 2014 Dec 20.

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA,

Background And Objectives: Nephropathic cystinosis is a lysosomal storage disorder characterized by renal tubular Fanconi syndrome in infancy and glomerular damage leading to renal failure at ∼10 years of age. Therapy with the cystine-depleting agent cysteamine postpones renal failure, but the degree of compliance with this treatment has not been correlated with preservation of kidney function.

Methods: We assessed leucocyte cystine depletion by cysteamine and created the composite compliance score that incorporates the extent of leucocyte cystine depletion, as well as duration of cysteamine treatment, into a single integer. Age at renal failure was used to gauge preservation of renal function, and the Fanconi syndrome index (FSI), a measure of aminoaciduria, was used to assess renal tubular Fanconi syndrome.

Results: Age at renal failure varied directly and linearly with the composite compliance score (y = 0.3x +8.8; R(2) = 0.61). The slope indicated that for every year of excellent cystine depletion, nearly 1 year of renal function was preserved. Age at renal failure correlated roughly with mean leucocyte cystine level, but not with mean cysteamine dosage. There was no correlation between the FSI and the composite compliance score.

Conclusions: Greater compliance with oral cysteamine therapy yields greater preservation of renal glomerular, but not tubular, function. Oral cysteamine therapy should be given at the maximum tolerated dose, within the recommended limits.
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http://dx.doi.org/10.1007/s00467-014-3018-xDOI Listing
June 2015

Nephropathic cystinosis: an international consensus document.

Nephrol Dial Transplant 2014 Sep;29 Suppl 4:iv87-94

Department of Pediatric Nephrology and Growth and Regeneration, University Hospitals Leuven, Katholieke Universiteit Leuven, Leuven, Belgium.

Cystinosis is caused by mutations in the CTNS gene (17p13.2), which encodes for a lysosomal cystine/proton symporter termed cystinosin. It is the most common cause of inherited renal Fanconi syndrome in young children. Because of its rarity, the diagnosis and specific treatment of cystinosis are frequently delayed, which has a significant impact on the overall prognosis. In this document, we have summarized expert opinions on several aspects of the disease to improve knowledge and provide guidance for diagnosis and treatment.
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http://dx.doi.org/10.1093/ndt/gfu090DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4158338PMC
September 2014

1,25-(OH)2D-24 Hydroxylase (CYP24A1) Deficiency as a Cause of Nephrolithiasis.

Clin J Am Soc Nephrol 2013 Apr 4;8(4):649-57. Epub 2013 Jan 4.

Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.

Background And Objectives: Elevated serum vitamin D with hypercalciuria can result in nephrocalcinosis and nephrolithiasis. This study evaluated the cause of excess 1,25-dihydroxycholecalciferol (1α,25(OH)2D3) in the development of those disorders in two individuals.

Design, Setting, Participants, & Measurements: Two patients with elevated vitamin D levels and nephrocalcinosis or nephrolithiasis were investigated at the National Institutes of Health (NIH) Clinical Center and the NIH Undiagnosed Diseases Program, by measuring calcium, phosphate, and vitamin D metabolites, and by performing CYP24A1 mutation analysis.

Results: Both patients exhibited hypercalciuria, hypercalcemia, low parathyroid hormone, elevated vitamin D (1α,25(OH)2D3), normal 25-OHD3, decreased 24,25(OH)2D, and undetectable activity of 1,25(OH)2D-24-hydroxylase (CYP24A1), the enzyme that inactivates 1α,25(OH)2D3. Both patients had bi-allelic mutations in CYP24A1 leading to loss of function of this enzyme. On the basis of dbSNP data, the frequency of predicted deleterious bi-allelic CYP24A1 variants in the general population is estimated to be as high as 4%-20%.

Conclusions: The results of this study show that 1,25(OH)2D-24-hydroxylase deficiency due to bi-allelic mutations in CYP24A1 causes elevated serum vitamin D, hypercalciuria, nephrocalcinosis, and renal stones.
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http://dx.doi.org/10.2215/CJN.05360512DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3613951PMC
April 2013

Cystinosis: the evolution of a treatable disease.

Pediatr Nephrol 2013 Jan 18;28(1):51-9. Epub 2012 Aug 18.

NHGRI, Medical Biochemical Genetic Section, National Institutes of Health, Bethesda, MD, USA.

Cystinosis is a rare autosomal recessive disorder involving lysosomal storage of the amino acid cystine due to a defect in the membrane transport protein, cystinosin. Since the introduction of kidney transplants and the availability of cystine-depleting medical therapy, this previously fatal disease was transformed into a treatable disorder. Renal allografts and medical therapy targeting the basic metabolic defect have altered the natural hisotry of cystinosis so drastically that patients have a life expectancy extending past 50 years. Consequently, early diagnosis and appropriate therapy are critically important. In this article, we offer a review of the manifestations of cystinosis, including the proximal tubular dysfunction of renal Fanconi syndrome, and discuss the prevention and treatment of the disorder's systemic complications. We focus on the nephropathic forms of cystinosis, aiming to assist nephrologists and other physicians to develop early recognition and appropriate management of cystinosis patients.
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http://dx.doi.org/10.1007/s00467-012-2242-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3505515PMC
January 2013

Discordance in interpretation of chest radiographs between pediatric intensivists and a radiologist: impact on patient management.

J Crit Care 2010 Jun 13;25(2):179-83. Epub 2009 Aug 13.

Division of Pediatric Critical Care and Pulmonary Medicine, Georgetown University Children's Medical Center, Washington, DC 20007, USA.

Purpose: When radiologists are not available, chest radiographs (CXRs) of pediatric intensive care unit (PICU) patients are commonly interpreted by pediatric intensivists. We prospectively investigated the frequency of errors in CXR interpretation by pediatric intensivists and their impact on patient management.

Materials And Methods: Chest radiographs of PICU patients were evaluated by 5 pediatric intensivists then by a pediatric radiologist (the "gold standard"). If the interpretation of the radiologist and intensivist differed, an independent intensivist determined whether a management change took place. A pediatric pulmonologist determined how many intensivist interpretations were different from the radiologist's interpretations.

Results: Seven hundred twenty-eight radiographic findings were identified by the radiologist in 460 CXRs. There were 33 interpretation errors by the intensivists (4.5% of the findings in 7.1% of the CXRs). Only 3/33 error corrections (0.45% of the findings in 0.7% of the CXRs) resulted in change in patient management.

Conclusions: Errors in interpretation of CXRs by pediatric intensivists were common but less than that in other series, probably because of education of the pediatric intensivists through daily rounds with the radiologist. Although interpretation errors that affected patient management were rare, their clinical importance supports the growing practice of 24/7 remote radiograph reading by radiologists.
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http://dx.doi.org/10.1016/j.jcrc.2009.05.016DOI Listing
June 2010

Hypocalcemia in a patient with osteosarcoma and 22q11.2 deletion syndrome.

J Pediatr Hematol Oncol 2008 Aug;30(8):612-7

Pediatric Oncology Branch, Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

Hypocalcemia is a rare complication of osteosarcoma, having been described in only 4 reports. We present the case of a 16-year-old male with metastatic osteosarcoma of the right humerus who was found to have severe asymptomatic hypocalcemia. Cytogenetic analysis of peripheral blood revealed a microdeletion in band 22q11.2. Following amputation of the tumor-bearing extremity, the patient's calcium levels increased, but did not normalize. These findings suggested that the etiology of his hypocalcemia was osteoblastic utilization of calcium by the tumor, exacerbated by 22q11.2 deletion syndrome.
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http://dx.doi.org/10.1097/MPH.0b013e318168f072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2748653PMC
August 2008

Nephropathic cystinosis: late complications of a multisystemic disease.

Pediatr Nephrol 2008 Jun;23(6):863-78

Section on Human Biochemical Genetics, Human Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-1851, USA.

Cystinosis is a rare autosomal recessive disorder due to impaired transport of cystine out of cellular lysosomes. Its estimated incidence is 1 in 100,000 live births. End-stage renal disease (ESRD) is the most prominent feature of cystinosis and, along with dehydration and electrolyte imbalance due to renal tubular Fanconi syndrome, has accounted for the bulk of deaths from this disorder. Prior to renal transplantation and cystine-depleting therapy with cysteamine for children with nephropathic cystinosis, their lifespan was approximately 10 years. Now, cystinotic patients have survived through their fifth decade, but the unremitting accumulation of cystine has created significant non-renal morbidity and mortality. In this article we review the classic presentation of nephropathic cystinosis and the natural history, diagnosis, and treatment of the disorder's systemic involvement. We also emphasize the role of oral cysteamine therapy in preventing the late complications of cystinosis.
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http://dx.doi.org/10.1007/s00467-007-0650-8DOI Listing
June 2008

Safety and immunogenicity of a prototype enterotoxigenic Escherichia coli vaccine administered transcutaneously.

Infect Immun 2002 Apr;70(4):1874-80

Department of Enteric Infections, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910-7500, USA.

Transcutaneous immunization (TCI) is a new method for vaccine delivery that has been shown to induce immunity relevant to enteric disease vaccines. We evaluated the clinical safety and immunogenicity of a recombinant subunit vaccine against enterotoxigenic Escherichia coli (ETEC) delivered by TCI. Adult volunteers received patches containing the recombinant ETEC colonization factor CS6, either with heat-labile enterotoxin (LT) or patches containing CS6 alone. The vaccine was administered at 0, 1, and 3 months, and serum antibodies and antibody-secreting cells (ASCs) were assessed. Among the 26 volunteers that completed the trial, there were no responses to CS6 in the absence of LT. In the groups receiving both CS6 and LT, 68 and 53% were found to have serum anti-CS6 immunoglobulin G (IgG) and IgA, respectively; 37 and 42% had IgG and IgA anti-CS6 ASCs. All of the volunteers receiving LT had anti-LT IgG, and 90% had serum anti-LT IgA; 79 and 37% had anti-LT IgG and IgA ASCs. Delayed-type hypersensitivity (DTH), suggesting T-cell responses, was seen in 14 of 19 volunteers receiving LT and CS6; no DTH was seen in subjects receiving CS6 alone. This study demonstrated that protein antigens delivered by a simple patch could induce significant systemic immune responses but only in the presence of an adjuvant such as LT. The data suggest that an ETEC vaccine for travelers delivered by a patch may be a viable approach worthy of further evaluation.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC127863PMC
http://dx.doi.org/10.1128/iai.70.4.1874-1880.2002DOI Listing
April 2002