Urinary mRNA for the Diagnosis of Renal Allograft Rejection: The Issue of Normalization

Urinary messenger RNA (mRNA) quantification is a promising method for noninvasive diagnosis of renal allograft rejection (AR), but the quantification of mRNAs in urine remains challenging due to degradation. RNA normalization may be warranted to overcome these issues, but the strategies of gene normalization have been poorly evaluated. Herein, we address this issue in a case-control study of 108 urine samples collected at time of allograft biopsy in kidney recipients with (n = 52) or without (n = 56) AR by comparing the diagnostic value of IP-10 and CD3ε mRNAs-two biomarkers of AR-after normalization by the total amount of RNA, normalization by one of the three widely used reference RNAs-18S, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and Hypoxanthine-guanine phosphoribosyltransferase (HPRT)-or normalization using uroplakin 1A (UPK) mRNA as a possible urine-specific reference mRNA. Our results show that normalization based on the total quantity of RNA is not substantially improved by additional normalization and may even be worsened with some classical reference genes that are overexpressed during rejection. However, considering that normalization by a reference gene is necessary to ensure polymerase chain reaction (PCR) quality and reproducibility and to suppress the effect of RNA degradation, we suggest that GAPDH and UPK1A are preferable to 18S or HPRT RNA.

[Membranous nephropathy: Diagnosis, new insights in pathophysiology, and therapeutic approach]

Membranous nephropathy (MN) accounts for about 20% of cases of nephrotic syndrome in the adult. Thickening of glomerular capillary walls results from subepithelial formation of immune deposits containing IgG and the membrane attack complex of complement, which is the major mediator of proteinuria, and antigens. Idiopathic forms of MN (IMN) represent 70 to 80% of all cases. A major breakthrough was the identification of the podocyte antigen PLA2R as the target of circulating antibodies in about 70% of IMN, which confirmed that the disease was auto-immune in nature. The optimal treatment of patients with IMN is still a matter of debate. Thirty to 40% of affected patients will undergo spontaneous remission, usually within one year from disease onset, whereas about one third will progress to end-stage kidney disease. Both the evidence that B cells play a key role in the pathogenesis of IMN and drug toxicity led to target B-cells with rituximab. Rituximab induced remission of nephrotic syndrome in 60 to 80% of the patients with long-lasting proteinuria despite blockade of the renin-angiotensin system and in patients who had previously failed other treatments. Because of the lack of randomized controlled trial (RCT) using rituximab and of high rate of spontaneous remission, a French non-blinded, parallel group RCT was performed to compare rituximab added to supportive therapy, to supportive therapy alone, in patients with persistent nephrotic syndrome.

Influence of obesity-susceptibility loci (MC4R and INSIG2) on the outcome of weight loss and amelioration of co-morbidity in obese patients treated by a gastric-bypass

BACKGROUND

Genome-wide association and linkage studies have identified multiple susceptibility loci for obesity.

OBJECTIVE

We hypothesized that such loci may affect weight loss and comorbidity amelioration outcomes following a gastric-bypass.

DESIGN

A total of 200 obese patients who underwent a gastric bypass surgery were genotyped for single-nucleotide polymorphisms (SNPs) in insulin induced gene 2 (INSIG2) and melanocortin 4 receptor (MC4R) obesity genes.

RESULTS

After a follow-up of 18 month, the patients (192) data of weight excess loss (72%) and co-morbidities (Hypertension -62- and Diabetes -39-) were analyzed and compared. 26 Patients with SNP were found (9 MC4R and 17 INSIG2). No significant differences in weight excess loss and amelioration of comorbidities were revealed.

CONCLUSIONS

The data suggest no influence of weight excess loss and amelioration of co-morbidities after gastric-bypass by genetic susceptibility.

Evolution of communication abilities after cochlear implantation in prelingually deaf children

OBJECTIVE

This study tries to evaluate different factors on communication ability outcomes in cochlear implanted children.

METHODS

Communication abilities are studied using the validated APCEI-scale based on five components of the language: cochlear implant acceptance, perceptive language performance, comprehension of the oral orders, expressive language and speech intelligibility. APCEI-scores were calculated every 6 months for the first 2 years, then yearly. The studied variables were: gender, social origin, preoperative residual hearing, age, aetiology of hearing loss, and associated disabilities.

RESULTS

Communication ability scores increased with high socioeconomic level, presence of residual hearing, younger patients when no residual hearing, connexin mutation related deafness, and absence of associated disabilities. No significant difference has been noted between both sexes.

CONCLUSION

Many different factors influence the evolution of communication abilities of cochlear implanted children. Investigating the cause of hearing loss, presence of associated disabilities and residual hearing before surgery may help to predict outcome and plan appropriate care to those children with negative predictive factors.

Outcome of renal transplantation in eight patients with Candida sp. contamination of preservation fluid

The complications of kidney graft preservation fluid infected by Candida sp. may range in severity from trivial infections to life-threatening complications, including graft arteritis and anastomotic rupture. Mandatory nephrectomy has recently been proposed as a means of preventing arterial wall rupture in such cases. We describe the clinical features and outcome of renal transplantation from a cadaveric donor in eight recipients with preservation fluid testing positive for Candida sp. Six patients were treated with antifungal drugs. After 1-2 years of follow-up, including regular imaging, none of the patients had developed arterial aneurysm, and all had a functional allograft and were alive. The contamination of renal graft preservation fluid with Candida sp. may be uneventful and should not systematically lead to removal of the graft. Until other risk factors for vascular complications have been determined, early antifungal treatment and repeated radiological monitoring are advisable for the prevention and/or early detection of such complications.

Lycopene in the prevention of prostate cancer

Based on the evidence from epidemiologic, animal, and in vitro data and human clinical trials, it is evident that lycopene, a non-provitamin A carotenoid, is a promising agent for prostate cancer chemoprevention. It is also clear that the form of lycopene used (purified versus food sources), dose of lycopene and concomitant use with other carotenoids and antioxidants, duration of exposure, specific target populations, and stage of disease appear to play a major role in determining agonistic or antagonistic effects. Based on our review, there is enough evidence to warrant use of lycopene in phase I and II clinical trials to examine its safety and efficacy as a potential chemopreventive agent for prostate cancer. The objective of this article is to review this evidence from epidemiologic, animal, in vitro, and clinical trials and provide the need and rationale to examine further the role of lycopene for prostate cancer prevention.

Intracranial Nocardia recurrence during fluorinated quinolones therapy

Nocardia infection is a well-recognized complication in renal transplant recipients and other immunocompromised hosts. It is mostly a primary pulmonary infection, which can disseminate to other organs in half of the cases. Nocardiosis is a life-threatening infection. Therefore, an efficient long-lasting treatment must be rapidly administered. We report 1 case of disseminated nocardiosis with pulmonary involvement, brain lesions, and bone lesions in a renal transplant patient, who was treated with stereotactic aspiration in association with high dose of trimethoprim/sulfamethoxazole (TMP/SMX) and imipenem, changed, after 3 weeks to moxifloxacin. First, clinical manifestations decreased after surgical drainage and combination therapy with the 2 antimicrobial agents, but later the patient developed a recurrence of brain lesions during treatment with quinolones. Consequently, the patient was again treated with TMP/SMX and imipenem, after which the patient recovered. It is surprising that moxifloxacin was efficient in vitro and the antimicrobial concentration in the central nervous system was high, yet the nocardial abscess recurred under this therapy.

Renal allograft biopsies with borderline changes: predictive factors of clinical outcome

The clinical outcome and appropriate management for patients showing 'borderline changes' on allograft biopsy after renal transplantation is still controversial. In an attempt to identify predictive factors of clinical outcome of patients with such lesions, we reviewed the clinical course of 91 patients with borderline changes. Multivariate analysis revealed significant and independent effects of histological stage (i + t < or = or > 2) and time to borderline changes (< or = or > 3 months after transplant) on serum creatinine levels at 1 year from borderline changes episodes (respectively, p = 0.04 and p = 0.02) and only a significant effect of time to borderline changes on serum creatinine levels at 2 years (p = 0.005). Renal function at 1 year and 2 years as 5- and 8-year graft survival were not significantly different in the group of patients treated with antirejection therapy (T group, n = 49) compared with the untreated group (UT group, n = 42). This study strongly suggests that borderline changes with histological score (i + t) > 2 and late episodes of borderline changes should be considered to be of poor prognosis.

Clinical expression and insulin sensitivity in type 2 diabetic patients with heterozygous mutations for haemochromatosis

BACKGROUND

Elevated iron metabolism indices as well as liver enzymes abnormalities have been reported in type 2 diabetic patients. The aim of this study was to determine the clinical and biological characteristics of overweight or obese type 2 diabetic subjects, with and without heterozygosity for HFE gene mutation (C282Y or H63D). We also assessed their insulin sensitivity and B cell function.

METHODS

90 patients (age and diabetes duration: 61 +/- 11 and 12 +/- 8 years [mean +/- 1 SD]) were included. BMI was 32 +/- 6 kg/m(2). HbA(1c) was 8.9 +/- 1.8%. HFE genotyping was performed by PCR and restriction enzyme cleavage. Insulin sensitivity and B cell function were measured by the Homeostasis Model Assessment (HOMA).

RESULTS

Heterozygosity for C282Y (wt/C282Y) or H63D (wt/H63D) allele was found in 11 and 12 subjects respectively. There were no major differences in clinical status and iron parameters according to the single allelic presence of C282Y or H63D. However, systolic blood pressure [BP] was lower when such mutation was present. Insulin sensitivity and B cell function (HOMA) were comparable. When the cohort was divided according to gender, we found higher serum iron in females with than in those without HFE mutation (91 +/- 27 vs 73 +/- 25 microgram/dl;P=0.049), while a transferrin saturation index above 45% was observed in 36% of females with a mutation (vs 7% in wt/wt;P=0.06). When analysis was performed according to the presence of each particular mutation, we observed a transferrin saturation index higher than 45% in 60% of wt/C282Y patients vs 21% in the wt/wt group (P=0.008). A significantly lower BP was also identified in wt/C282Y patients. Cholesterol-HDL was 38 +/- 11 vs 46 +/- 12 mg/dl in wt/C282Y and wt/wt subjects, respectively (P=0.045). There were no differences in iron status, BP or lipids between wt/wt and wt/H63D subjects.

CONCLUSION

Type 2 diabetic patients, in particular females, with mono-allelic C282Y mutation, had slightly increased iron parameters. Systolic BP and cholesterol-HDL were also lower in wt/C282Y subjects. No difference in insulin sensitivity or B cell function was observed in the presence of mono-allelic HFE mutations.

Late-onset renal failure in Senior-Loken syndrome

We report on four patients, from three different families, with Senior-Loken syndrome (SLS). They were unusual in that they reached end-stage renal failure (ESRF) only during the fifth or sixth decade. SLS is an autosomal-recessive disorder defined by the association of nephronophthisis and retinal dystrophy. Affected individuals invariably progress to ESRF, usually before the age of 20 years. The diagnosis was based on typical clinical presentation and characteristic renal histology, that is, a picture of chronic interstitial nephritis with pronounced thickening and multilayering of tubular basement membranes. Deterioration of renal function was slow, leading to ESRF between the ages of 42 and 56 years. Retinal dystrophy, already symptomatic during childhood in two patients, led to severe visual impairment in all. In contrast with four cases of SLS recently reported in very young patients, the NPH1 gene (the main gene responsible for nephronophthisis) was not deleted in our two tested patients. We conclude that SLS should be considered in adults who suffer from both chronic interstitial nephropathy and retinal degeneration. Whether the SLS is a variant of nephronophthisis and whether early- and late-onset renal failure in SLS is accounted for by genetic or allelic heterogeneity remain to be determined.

NPHS2, encoding the glomerular protein podocin, is mutated in autosomal recessive steroid-resistant nephrotic syndrome

Familial idiopathic nephrotic syndromes represent a heterogeneous group of kidney disorders, and include autosomal recessive steroid-resistant nephrotic syndrome, which is characterized by early childhood onset of proteinuria, rapid progression to end-stage renal disease and focal segmental glomerulosclerosis. A causative gene for this disease, NPHS2, was mapped to 1q25-31 and we report here its identification by positional cloning. NPHS2 is almost exclusively expressed in the podocytes of fetal and mature kidney glomeruli, and encodes a new integral membrane protein, podocin, belonging to the stomatin protein family. We found ten different NPHS2 mutations, comprising nonsense, frameshift and missense mutations, to segregate with the disease, demonstrating a crucial role for podocin in the function of the glomerular filtration barrier.

High prevalence of GB virus C/hepatitis G virus in Kinshasa, Democratic Republic of Congo: a phylogenetic analysis

A prevalence of 10.3% of GB virus C (GBV-C)/hepatitis G virus (HGV) carriers was found in 97 pregnant women from Kinshasa, Congo (formerly Zaire), while prevalences of 1%, 4.1%, and 0% were found for hepatitis C virus, human immunodeficiency virus, and human T-lymphotropic virus respectively. Phylogenetic analysis of the ten GBV-C/HGV positives based on the 5' non-coding region using three different methods identified consistently three GBV-C/HGV genotypes. Four main clades were found within the type 1 sequences. All the Congolese isolates are GBV-C/HGV type 1 in two different clades. The clustering of seven Congolese isolates was inconsistent in different methods. Further likelihood-mapping analysis showed a well-resolved phylogeny, confirming the clustering of the seven Congolese isolates with a Belgian strain representing a new clade in the GBV-C/HGV type 1 sequences.

[Is there a link between secondary hemochromatosis and genetics? Apropos of 2 cases]

The authors report the case of two patients with secondary hemochromatosis in whom a C282Y mutation in the heterozygotic form was observed. They discuss the potential relationship between secondary hemochromatosis and the presence of the genetic abnormality.

A gene encoding a liver-specific ABC transporter is mutated in progressive familial intrahepatic cholestasis

The progressive familial intrahepatic cholestases (PFIC) are a group of inherited disorders with severe cholestatic liver disease from early infancy. A subgroup characterized by normal serum cholesterol and gamma-glutamyltranspeptidase (gammaGT) levels is genetically heterogeneous with loci on chromosomes 2q (PFIC2) and 18q. The phenotype of the PFIC2-linked group is consistent with defective bile acid transport at the hepatocyte canalicular membrane. The PFIC2 gene has now been identified by mutations in a positional candidate, BSEP, which encodes a liver-specific ATP-binding cassette (ABC) transporter, sister of p-glycoprotein (SPGP). The product of the orthologous rat gene has been shown to be an effective bile acid transporter in vitro. These data provide evidence that SPGP is the human bile salt export pump (BSEP).

Molecular analysis of GB virus C isolates in Belgian hemodialysis patients

GB virus C (GBV-C) has been detected in Belgian hemodialysis patients. To study their genomic diversity and phylogenetic relationship, a 592 nucleotide fragment extending from the 5' non-coding region to part of the E1 gene of the GBV-C genome was amplified and sequenced from 12 Belgian hemodialysis patients in two different centers. Together with strains from different geographical origins, these sequences were analyzed phylogenetically using three different methods. A consistent tree topology was obtained with all methods. Three GBV-C genotypes were observed with two subtypes in type 2 and a questionable subtyping in type 1. Except for one isolate falling into type 1 cluster which mainly consists of African strains, all the other Belgian strains clustered within the type 2a branch. Two GBV-C isolates in two patients from the same hemodialysis center clustered together closely, suggesting a nosocomial transmission. In view of their long branch length, it seems unlikely that the other Belgian strains evolved recently from a common ancestor. Our results indicate that the major type circulating among Belgian hemodialysis patients seems to be 2a, which is usual for Europe and North America, but that the African type 1 also exists to a minor extent. Although patient to patient transmission of GBV-C in Belgian hemodialysis centers did occur, it may not account for the majority of infections.

Smooth muscle tumors associated with X-linked Alport syndrome: carrier detection in females

X-linked Alport syndrome (AS) associated with diffuse esophageal leiomyomatosis (DL) has been reported to be due to deletions removing the 5' ends of both the COL4A5 and COL4A6 genes, encoding the alpha 5 and alpha 6 chains of type IV collagen, respectively, whereas a variety of mutations in COL4A5 has been identified in patients with AS alone. Here we report three additional DL-AS patients who also display deletions removing the 5' ends of both COL4A5 and COL4A6 genes. Furthermore, we tracked the mutation in 15 females belonging to six DL-AS families by gene copy number determination. We found that, like AS, DL is transmitted as an X-linked dominant trait but, contrary to AS, DL is fully penetrant and completely expressed in females. These results are in agreement with our previous work suggesting that DL could be due to a dominant effect of an abnormal alpha 6 (IV) collagen chain. Finally, we have detected a similar deletion of the COL4A5 and COl4A6 genes in a DL affected female who showed no sign of nephropathy, demonstrating the AS carrier status of this DL patient. These results emphasize the importance of molecular analysis of female DL patients for genetic counseling.

Deletions of both alpha 5(IV) and alpha 6(IV) collagen genes in Alport syndrome and in Alport syndrome associated with smooth muscle tumours

Diffuse oesophageal leiomyomatosis (DL), an inherited smooth muscle proliferation process, has been reported to be associated with Alport syndrome (AS), a familial nephropathy, mainly dominant X-linked inherited, and characterized by ultrastructural changes of the glomerular basement membrane. The COL4A5 gene, encoding the alpha 5 chain of type IV collagen, has been identified as the site of mutations in families with X-linked AS. Recently, a novel alpha 6(IV) collagen chain encoding gene has been mapped closely upstream of COL4A5, and disruption of the 5' end of both genes has been reported in four patients with DL and AS (DL-AS). Here, we report a long-range restriction map around the COL4A6 locus, and show that the COL4A5/COL4A6 deletion observed in seven patients with DL-AS encompasses only the two first exons of COL4A6, with a breakpoint located in the second intron of COL4A6, whose size exceeds 65 kb. Furthermore, we demonstrate that three patients with AS without DL, known to have a deletion of the 5' part of the COL4A5 gene, display a larger deletion in COL4A6. Moreover, a COL4A6 mRNA product was detected by reverse-transcription-polymerase chain reaction in an oesophageal tumour sample of a patient with DL-AS. These results suggest that DL-AS could be caused by an abnormal truncated alpha 6(IV) chain.