Minimal change disease: a review

Evaluation of corneal and lens densitometry with Pentacam HR in children with Nephrotic Syndrome: A controlled, prospective study

BACKGROUND

This study aimed to compare the corneal and lens densitometry values between children with Nephrotic Syndrome (NS) and healthy individuals.

METHODS

This cross-sectional comparative study included 23 patients with NS and 26 healthy controls. Corneal topographic and corneal and lens densitometric values were measured using Pentacam HR. Densitometry measurements in different layers were analyzed and compared between groups. Correlations between steroid cumulative dose, age at diagnosis of the disease, duration of disease, number of relapses, and patients' densitometries values were evaluated.

RESULTS

The measurements of the keratometry, horizontal white-to-white, and iridocorneal angle values were significantly different between groups (p < 0.05). The 0-2 mm and 2-6 mm anterior corneal densitometry values were significantly higher in NS patients. (p = 0.009 and p = 0.033, respectively). The lens densitometry values of all zones were higher in the eyes with NS but there was no statistically significant difference from the healthy control eyes (p > 0.05). There was a positive strong correlation between the cumulative steroid dose and the posterior lens zone densitometry, a positive weak correlation between the number of attacks and anterior corneal densitometry, and between disease duration and central corneal densitometry and average lens density.

CONCLUSION

In eyes with NS, changes occur in corneal and lens densitometry in correlation with disease duration, number of attacks, and cumulative steroid dose. Significant density changes were detected especially in the anterior cornea and central 0-6 mm area.

Roles of microRNAs in renal disorders related to primary podocyte dysfunction

Through the regulation of gene expression, microRNAs (miRNAs) are capable of modulating vital biological processes, such as proliferation, differentiation, and apoptosis. Several mechanisms control the function of miRNAs, including translational inhibition and targeted miRNA degradation. Through utilizing high-throughput screening methods, such as small RNA sequencing and microarray, alterations in miRNA expression of kidneys have recently been observed both in rodent models and humans throughout the development of chronic kidney disease (CKD) and acute kidney injury (AKI). The levels of miRNAs in urine supernatant, sediment, and exosomal fraction could predict novel biomarker candidates in different diseases of kidneys, including IgA nephropathy, lupus nephritis, and diabetic nephropathy. The therapeutic potential of administrating anti-miRNAs and miRNAs has also been reported recently. The present study is aimed at reviewing the state-of-the-art research with regards to miRNAs involved in renal disorders related to primary podocyte dysfunction by laying particular emphasis on Focal Segmental Glomerulosclerosis (FSGS), Minimal Change Disease (MCD) and Membranous Nephropathy (MN).

Localization and Regulation of Polymeric Ig Receptor in Healthy and Diseased Human Kidney

The polymeric Ig receptor (PIgR) constitutes an important part of the immune system by mediating transcytosis of dimeric IgA into mucosal fluids. Although well studied in organs such as the intestine, the regulation and localization of PIgR in human kidney are incompletely characterized. Herein, using immunohistochemistry, we show that in healthy human kidneys, PIgR is expressed by the progenitor-like tubular scattered cells of the proximal tubules and by parietal epithelial cells of glomeruli. We further show that proximal tubular expression of PIgR becomes widespread during kidney disease, correlating to elevated levels of urinary secretory IgA. Urinary secretory IgA levels also correlated to the degree of tubular fibrosis, plasma creatinine, and urea levels. In addition, primary tubular cells were cultured to study the function and regulation of PIgR in vitro. Cellular PIgR expression was induced by conditioned medium from activated human leukocytes, as well as by inflammatory cytokines, whereas transforming growth factor-β1 caused decreased expression. Furthermore, interferon-γ increased the transcytosis of dimeric IgA in cultured tubular cells. Finally, a correlation study of mRNA data from the Genotype-Tissue Expression portal indicated that PIGR mRNA expression in kidney correlates to the expression of TNFSF13, a cytokine involved in plasma cell class switching to IgA. These results indicate that PIgR induction is an integral part of the injury phenotype of renal tubular cells.

A systems pharmacology workflow with experimental validation to assess the potential of anakinra for treatment of focal and segmental glomerulosclerosis

Focal and Segmental Glomerulosclerosis (FSGS) is a severe glomerulopathy that frequently leads to end stage renal disease. Only a subset of patients responds to current therapies, making it important to identify alternative therapeutic options. The interleukin (IL)-1 receptor antagonist anakinra is beneficial in several diseases with renal involvement. Here, we evaluated the potential of anakinra for FSGS treatment. Molecular process models obtained from scientific literature data were used to build FSGS pathology and anakinra mechanism of action models by exploiting information on protein interactions. These molecular models were compared by statistical interference analysis and expert based molecular signature matching. Experimental validation was performed in Adriamycin- and lipopolysaccharide (LPS)-induced nephropathy mouse models. Interference analysis (containing 225 protein coding genes and 8 molecular process segments) of the FSGS molecular pathophysiology model with the drug mechanism of action of anakinra identified a statistically significant overlap with 43 shared molecular features that were enriched in pathways relevant in FSGS, such as plasminogen activating cascade, inflammation and apoptosis. Expert adjudication of molecular signature matching, focusing on molecular process segments did not suggest a high therapeutic potential of anakinra in FSGS. In line with this, experimental validation did not result in altered proteinuria or significant changes in expression of the FSGS-relevant genes COL1A1 and NPHS1. In summary, an integrated bioinformatic and experimental workflow showed that FSGS relevant molecular processes can be significantly affected by anakinra beyond the direct drug target IL-1 receptor type 1 (IL1R1) context but might not counteract central pathophysiology processes in FSGS. Anakinra is therefore not suggested for extended preclinical trials.

Study on Steroid Induced Ocular Findings in Children with Nephrotic Syndrome

INTRODUCTION

Long term use of corticosteroids in Nephrotic Syndrome (NS) is associated with ocular complications such as Posterior Subcapsular Cataract (PSC), glaucoma, increased intra-ocular pressure, ptosis, mydriasis, eyelid skin atrophy, keratisis, thinning of cornea and sclera, repeated hordeolum exacerbations.

AIM

To determine ocular abnormalities in children with NS and their association with steroid dosing and duration.

MATERIALS AND METHODS

Hundred patients with NS in the age group of 2-18 years, with no evidence of other systemic disease, were considered for the study. Group I included cases (66) who took standard steroid regimen for first episode of NS. Group II included cases (34) who took steroid irrationally (daily basis for long time) other than standard regimen. Steroid induced ocular complications were compared in both groups after detailed ophthalmological examination. Statistical analysis was done using Statistical Package for Social Science (SPSS-20.0).

RESULTS

Ocular abnormalities were found in 12 patients out of 66 in Group I (18%) and 16 patients out of 34 patients in Group II (47%). Out of 12 patients of Group I who had ocular problems, three had myopic astigmatism, eight patients had PSC and one had temporal disc pallor. While in Group II, out of 16 patients who had ocular complications, two patients had raised intra ocular pressure and two patients had myopic astigmatism and 12 patients had posterior sub capsular cataract. The difference in mean cumulative steroid doses in both groups was statistically significant but no such difference was there between duration of steroid intake in both group.

CONCLUSION

Our study concluded that ocular complications were more common in patients with irrationally steroid intake and cumulative steroid dose intake was also significantly higher in same patients.

Treatment of Experimental Nephrotic Syndrome with Artesunate

The present study was designed to test the therapeutic effect of a new antimalarial drug, artesunate in experimental model of nephrotic syndrome. To induce this experimental model, Adriamycin was given once by a single intravenous injection (7.5 mg/kg) through the tail vein. Six days after injection of Adriamycin, therapeutic protocol was developed by intraperitoneally (IP) administration of 5 mg/kg artesunate (ARS). Total of IP injections were 14, of which 5 injections were made every day and 9 injections were carried out at regular 48-h intervals. Therapeutic protocol was terminated on day 28 and animals were killed on day 49. The results showed that treatment with ARS caused a significant reduction in the level of proteinuria, urine urea and urine sodium compared with nontreated controls. In addition, decrease in serum triglyceride and increase in the level of serum albumin was significant in treated group with ARS compared with nontreated controls. Moreover, treatment with ARS significantly reduced glomerular polymorphonuclear (PMN) and mononuclear cells infiltration, hypercellularity, karyorrhexis, wire loops, and hydropic change in capillary network within the renal cortex, as well as decreased hyalin casts. On the other hand, healthy controls receiving ARS showed a significant decrease in amounts of serum triglyceride, urine urea, and urine sodium and potassium compared with normal group. These data suggest that artesunate therapy can ameliorate proteinuria, and suppress the progression of glomerular lesions in experimental model of nephrotic syndrome; it may also be recommended as a lipid-lowering drug.

A series of patients with minimal change nephropathy treated with rituximab during adolescence and adulthood

Background

The treatment of immune suppression dependent minimal change nephropathy (MCN) can be challenging and frequently leads to serious complications. In paediatric patients, successful treatment with rituximab is described in steroid-dependent MCN. There is limited information about the potential efficacy of rituximab for the treatment of MCN in adults and adolescence. We describe our experience with rituximab in adolescent and adult patients with immune suppression dependent MCN.

Results

Ten adolescents and adults with immune suppression dependent MCN and therapy related complications were treated with rituximab. At a mean age of 26 years, about 10.5 years after first presentation, they received two doses of rituximab (375 mg/m²). Maintenance immunosuppressive medication was stopped. After a mean follow-up of 43 months, three patients had four relapses. Three relapses were successfully retreated with rituximab again, after induction therapy with 60 mg prednisone per day. Rituximab was well tolerated and no infectious complications were recorded.

Conclusion

Treatment with rituximab induces a long-term remission of immune suppression dependent MCN in adolescents and adults. A timely treatment with rituximab could be considered to limit side effects of immunosuppressive medication.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1255-0) contains supplementary material, which is available to authorized users.

Proteomic analysis of whole glomeruli in patients with IgA nephropathy using microsieving

BACKGROUND

To promote understanding of immunoglobulin A nephropathy (IgAN) pathophysiology, we tried to elucidate glomerular protein profiles in IgAN, using microsieving that we established recently to isolate glomeruli from renal biopsy samples and proteomic approaches.

METHODS

Glomeruli were isolated from renal biopsy samples of patients with IgAN (n = 5) and with minimal change nephrotic syndrome (MCNS; n = 5) using microsieving. Proteins extracted from the isolated glomeruli were separated by 2-dimensional differential gel electrophoresis (2D-DIGE). Proteins with different amounts between the two groups were identified by mass spectrometry. One of the identified proteins, α-actinin-4 (ACTN4), was further analyzed by Western blotting, RT-polymerase chain reaction (PCR), and immunohistochemistry.

RESULTS

By 2D-DIGE, 72 out of the detected 1,170 protein spots showed significantly different intensity between the two groups (p < 0.05). Thirty-four out of the 72 protein spots showed more than 1.5-fold or less than 1/1.5-fold intensity, out of which 16 protein spots were successfully identified. No microbial protein was identified. ACTN4 molecules with a low molecular weight of approximately 77 kDa were found to increase in the IgAN group. Lack of an N-terminal part of ACTN4 was demonstrated by Western blotting. No defect of mRNA for ACTN4 was evidenced by RT-PCR. Predominant existence of ACTN4 in capillary walls of glomeruli of IgAN patients was demonstrated by immunohistochemistry in glomerular sections of patients with IgAN.

CONCLUSION

Use of microsieving enabled us to biochemically analyze glomerular proteins in renal biopsy samples from patients with glomerular diseases. With this method, we demonstrated skewed glomerular protein profiles in IgAN.

LPS and PAN-induced podocyte injury in an in vitro model of minimal change disease: changes in TLR profile

Minimal change disease (MCD), the most common idiopathic nephrotic syndrome in children, is characterized by proteinuria and loss of glomerular visceral epithelial cell (podocyte) ultrastructure. Lipopolysaccharide (LPS) and puromycin aminonucleoside (PAN) are used to study podocyte injury in models of MCD in vivo and in vitro. We hypothesized that LPS and PAN influence components of the innate immune system in podocytes such as the Toll-Like Receptor (TLRs), TLR adapter molecules, and associated cytokines. Our results show that cultured human podocytes constitutively express TLRs 1-6 and TLR-10, but not TLRs 7-9. LPS (25 μg/ml) or PAN (60 μg/ml) caused comparable derangement of the actin cytoskeleton in podocytes. Quantitative RT-PCR analysis show that LPS differentially up-regulated the expression of genes for TLRs (1 > 4 ≥ 2 > 3 > 6 > 5), the adapter molecule, MyD88, and transcription factor NF-κB within one hour. LPS also caused increased levels of IL-6, IL-8 and MCP1 without exerting any effect on TNF-α, IFN-α or TGF-β1 at 24 h. Immunofluorescence intensity analysis of confocal microscopy images showed that LPS induced a significant increase in nuclear translocation of NF-κB by 6 h. In contrast, PAN-induced only small changes in the expression of TLRs 2-6 that included a persistent increase in TLRs 2 and 5, a transient increase in TLR-4, and a gradual increase in TLRs 3 and 6 between 1 and 6 h. Correspondingly, it did not alter pro-inflammatory cytokine levels in podocytes. However, PAN induced a low but significant increase in NF-κB nuclear translocation within one hour that remained unchanged up to 6 h. In summary, these novel findings show that LPS, a known TLR-4 ligand, induced the gene expression of multiple TLRs with maximum effect on the expression of TLR-1 suggesting a loss of receptor selectivity and induction of receptor interactions in podocytes. A comparable derangement of the podocyte cytoskeleton and significant increase in the nuclear translocation of NF-κB by PAN suggest that disparate but complementary mechanisms may contribute to the development of podocytopathy in MCD.

Medullary nephrocalcinosis, distal renal tubular acidosis and polycythaemia in a patient with nephrotic syndrome

Background

Medullary nephrocalcinosis and distal renal tubular acidosis are closely associated and each can lead to the other. These clinical entities are rare in patients with nephrotic syndrome and polycythaemia is an unusual finding in such patients. We describe the presence of medullary nephrocalcinosis, distal renal tubular acidosis and polycythaemia in a patient with nephrotic syndrome due to minimal change disease. Proposed mechanisms of polycythaemia in patients with nephrotic syndrome and distal renal tubular acidosis include, increased erythropoietin production and secretion of interleukin 8 which in turn stimulate erythropoiesis.

Case presentation

A 22 year old Sri Lankan Sinhala male with nephrotic syndrome due to minimal change disease was investigated for incidentally detected polycythaemia. Investigations revealed the presence of renal tubular acidosis type I and medullary nephrocalcinosis. Despite extensive investigation, a definite cause for polycythaemia was not found in this patient. Treatment with potassium and bicarbonate supplementation with potassium citrate led to correction of acidosis thereby avoiding the progression of nephrocalcinosis and harmful effects of chronic acidosis.

Conclusion

The constellation of clinical and biochemical findings in this patient is unique but the pathogenesis of erythrocytosis is not clearly explained. The proposed mechanisms for erythrocytosis in other patients with proteinuria include increased erythropoietin secretion due to renal hypoxia and increased secretion of interleukin 8 from the kidney. This case illustrates that there may exist hitherto unknown connections between tubular and glomerular dysfunction in patients with nephrotic syndrome.

Clinical outcomes and predictors for ESRD and mortality in primary GN

BACKGROUND AND OBJECTIVES

Relatively little is known about the long-term outcomes of different histologic types of primary glomerulonephritis in Asian populations.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From 1993 to 2006, 987 patients undergoing renal biopsy were studied, and 580 patients (mean age=44.4 years, male=58.5%) with the four most common forms of glomerulonephritis (membranous nephropathy, focal and segmental glomerulosclerosis, IgA nephropathy, and minimal change disease) were selected for analysis. Median follow-up period was 5.9 (interquartile range=5.7) years.

RESULTS

The focal and segmental glomerulosclerosis group displayed the highest incidence of ESRD (25.8%) and the fastest decline of estimated GFR (4.6 ml/min per 1.73 m(2) per year). The IgA nephropathy group also had a higher rate of ESRD than the membranous nephropathy patients (19.2% versus 4.3%, P<0.001). In contrast, the membranous nephropathy group exhibited an overall death rate similar to the focal and segmental glomerulosclerosis group (17.2% versus 14.4%) but higher than the IgA nephropathy and minimal change disease patients (4.6% and 3.7%, respectively, P<0.001). The most powerful predictor for ESRD was focal and segmental glomerulosclerosis, whereas the strongest predictor for all-cause mortality was membranous nephropathy with higher proteinuria. Protectors against ESRD included male sex and higher hemoglobin.

CONCLUSIONS

Most predictors for ESRD and overall mortality found in this ethnic Chinese cohort were similar to other studies. However, some risk factors linked with distinct glomerular pathologies displayed differential clinical outcomes.

Immunohistochemical evaluation of podocalyxin expression in glomerulopathies associated with nephrotic syndrome

It is now well established that morphological change of podocytes is closely correlated to the development of proteinuria. The aim of this study was to investigate the role of podocalyxin, a major podocyte protein, in the pathogenesis of glomerulopathies primarily associated with the nephrotic syndrome. Immunohistochemical expression of podocalyxin has been evaluated in 51 renal samples, including healthy controls, patients with podocytopathies (minimal change disease [MCD], focal segmental glomerulosclerosis [FSGS]) and membranous glomerulopathy (MG). A computerized image analysis program has been used. Statistical analysis was performed using analysis of variance and Bonferroni tests. Immunohistochemical expression of podocalyxin has been observed within the podocytes of healthy controls. In MCD, podocalyxin expression was globally reduced despite the normal appearance of the glomeruli. In FSGS, podocalyxin loss was observed in both the segmental sclerotic and the nonsclerotic areas being significantly more prominent in the former. Reduction of podocalyxin in MG was demonstrated for the first time immunohistochemically. The percentage of the stained area was statistical significantly higher in the controls than in each pathologic group. However, among pathologic groups (FSGS, MCD, MG), there was no statistically significant difference. This is one of the few studies investigating podocalyxin immunohistochemical expression in glomerulopathies associated with nephrotic syndrome. The observed reduction in podocalyxin expression suggests that it constitutes a target molecule in nephrotic syndrome pathogenesis regardless of the underlying cause.

Genetic effect of the NPHS2 gene variants on proteinuria in minimal change disease and immunoglobulin A nephropathy

BACKGROUND

Proteinuria varies in different glomerular diseases and even the same one. Podocin, encoded by gene NPHS2, is important in maintaining the integrity of slit diaphragm structure and avoiding proteinuria. Presently, case-control association studies were performed to investigate the genetic effect of variants in NPHS2 in a mass proteinuric glomerulopathy, minimal change disease (MCD) at first, followed by further investigation in immunoglobulin A nephropathy (IgAN).

METHODS

At first, 214 northern Chinese patients with MCD and 493 geographically-matched healthy controls were enrolled. Variants of the NPHS2 were screened. SNP-2 (rs3829795:C>T, c.-670C>T) and SNP-5 (rs3738423:C>T, c.288C>T) were selected as tagging single nucleotide polymorphisms (SNP) and haplotypes were reconstructed. Association was analyzed in MCD patients. Then, the identified SNP site was analyzed in IgAN patients with mild histological changes (Haas subclass I and II).

RESULTS

The C allele and CC genotype frequencies at the SNP-2 site, as well as the frequency of haplotype CC, were significantly lower in MCD patients than in healthy controls. Furthermore, they were also associated with the degree of proteinuria in MCD patients. But in IgAN patients, no such association was identified.

CONCLUSION

The study suggested the polymorphism and haplotype of NPHS2 gene were associated with the genetic susceptibility and also the degree of proteinuria to MCD. Proteinuria in MCD and IgAN might occur through different mechanisms.

A case of minimal change disease in a Fabry patient

Fabry disease is an X-linked lysosomal storage disorder caused by mutations of the GLA gene and deficiency in alpha-galactosidase A activity. Glycosphingolipids accumulation causes renal injury that manifests early during childhood as tubular dysfunction and later in adulthood as proteinuria and renal insufficiency. Nephrotic syndrome as the first evidence of Fabry-related kidney damage is rare. We report the case of a teenager with known Fabry disease and normal renal function who developed acute nephrotic syndrome. He was found to have typical glycosphingolipids accumulation with no other findings suggestive of alternative causes of nephrotic syndrome on kidney biopsy. After treatment with enzyme replacement therapy and oral steroids, he went into complete remission from nephrotic syndrome, a response that is atypical for Fabry disease patients who develop heavy proteinuria as a result of longstanding disease and chronic renal injury. The nephrotic syndrome in this patient appears to have developed secondary to minimal change disease. We recommend considering immunotherapy in addition to enzyme replacement therapy in those patients with confirmed Fabry disease and acute nephrotic syndrome with clinical and microscopic findings suggestive of minimal change disease.

Genes unlinked to the leptin receptor influence urinary albumin excretion in obese Zucker rats

We have previously shown that 90% of outbred obese Zucker Lepr(fa/fa) rats die prematurely of renal disease. Thus, renal disease in obese Zucker Lepr(fa/fa) rats may be caused by the LEPR mutation on chromosome 5, by the obesity, or it may be influenced by Zucker susceptibility alleles of genes on other chromosomes. We have searched for susceptibility genes on other chromosomes using urinary albumin excretion (UAE) as an early indicator of altered renal function in a backcross of (Brown Norway × inbred Zucker) F1 × inbred Zucker, which we name the BZZ cross. We killed 237 BZZ backcross animals at 15 wk of age. All included animals were homozygous for the fatty mutation of LEPR and were obese. Urinary creatinine measurements were used to calculate the albumin-to-creatinine ratio (ACR). We identified direct effect quantitative trait loci (QTLs) for UAE and ACR on chromosome 1 (LOD scores = 3.6 and 2.86, respectively) in males, and chromosome 4 (LOD score = 2.9) in females. Significant QTLs were identified for left kidney weight for females on chromosomes 3 and 12. We also demonstrated that kidneys from 15 wk old obese inbred Zucker rats already show evidence of kidney pathology: tubular dilation, proteinaceous fluid accumulation, evidence for inflammation, and mild mesangial and tubular membrane basement membrane thickening. Both lean Zucker rats and the Brown Norway rats showed no evidence for these changes. Thus, by removing the influence of the Lepr(fa/fa) mutation from analysis we have identified UAE QTLs unlinked to LEPR.

Serum cholesterol in idiopathic and lupus-related protein-losing enteropathy

Abstract The characteristics of protein-losing enteropathy were evaluated in patients with systemic lupus erythematosus. Among the patients with systemic lupus erythematosus (n=380) in a tertiary hospital, we reviewed the records of seven patients with generalized edema, hypoalbuminemia without proteinuria and positive results on 99mTc-labelled human serum albumin scintigrams. Patient characteristics and laboratory findings were compared between these seven patients and patients with lupus enteritis (n=15) or idiopathic protein-losing enteropathy (n=11). Compared with the lupus enteritis patients, the erythrocyte sedimentation rate and serum total cholesterol levels were significantly increased in patients with systemic lupus erythematosus-related protein-losing enteropathy. Compared with idiopathic protein-losing enteropathy patients, the level of serum total cholesterol was significantly increased, but the level of serum albumin was decreased in patients with systemic lupus erythematosus-related protein-losing enteropathy. Among patients with systemic lupus erythematosus-related protein-losing enteropathy, four patients had high serum total cholesterol levels (>or=248 mg/dL) and achieved complete remission after receiving high doses of steroid treatment. However, three patients who had low serum total cholesterol levels (<or=219 mg/dL) responded poorly to the steroid-only treatment, and could achieve complete remission only after 3 months of cyclophosphamide pulse treatment with concurrent corticosteroid therapy. The levels of serum total cholesterol are intriguing feature in systemic lupus erythematosus-associated protein-losing enteropathy patients.

Mutation in the key enzyme of sialic acid biosynthesis causes severe glomerular proteinuria and is rescued by N-acetylmannosamine

Mutations in the key enzyme of sialic acid biosynthesis, uridine diphospho-N-acetylglucosamine 2-epimerase/N-acetylmannosamine (ManNAc) kinase (GNE/MNK), result in hereditary inclusion body myopathy (HIBM), an adult-onset, progressive neuromuscular disorder. We created knockin mice harboring the M712T Gne/Mnk mutation. Homozygous mutant (Gne(M712T/M712T)) mice did not survive beyond P3. At P2, significantly decreased Gne-epimerase activity was observed in Gne(M712T/M712T) muscle, but no myopathic features were apparent. Rather, homozygous mutant mice had glomerular hematuria, proteinuria, and podocytopathy. Renal findings included segmental splitting of the glomerular basement membrane, effacement of podocyte foot processes, and reduced sialylation of the major podocyte sialoprotein, podocalyxin. ManNAc administration yielded survival beyond P3 in 43% of the Gne(M712T/M712T) pups. Survivors exhibited improved renal histology, increased sialylation of podocalyxin, and increased Gne/Mnk protein expression and Gne-epimerase activities. These findings establish this Gne(M712T/M712T) knockin mouse as what we believe to be the first genetic model of podocyte injury and segmental glomerular basement membrane splitting due to hyposialylation. The results also support evaluation of ManNAc as a treatment not only for HIBM but also for renal disorders involving proteinuria and hematuria due to podocytopathy and/or segmental splitting of the glomerular basement membrane.

Semen Preservation in Male Adolescents and Young Adults With Cancer: One Institution's Experience

Semen preservation is a feasible procedure for male adolescents and young adults who may become infertile as a result of cancer therapy. Treatment for several pediatric malignancies puts adolescents and young adults at a significant risk for fertility dysfunction. Eligible male adolescents and young adults (N = 32) treated from January 2004 to June 2005 at Cook Children's Medical Center were offered semen preservation at the time of diagnosis or presentation to the center for treatment. Fifteen (47%) young men were successful in semen preservation. Two (6%) adolescents did not participate because of parental refusal. Seven (22%) were too ill, and eight (25%) failed to produce an adequate sample. Several patients were not successful because of time constraints, lack of counseling, and parental anxiety. Efforts for success in semen preservation should include private discussions between nurses and adolescents. In addition, information on infertility needs to be given to families early in the diagnostic phase to provide them with an opportunity to ask questions.