Living kidney donor transplantation: an alternative with limitations

BACKGROUND

The major issues involved in the decision to donate are the perioperative risk and the risk of chronic kidney disease or even end-stage renal disease. The usual glomerular filtration rate (GFR) in kidney donors after transplantation is approximately 70% of the predonation rate; however, some have a GFR <60 mL/min/1.73 m(2). So after kidney donation, mild to moderate renal insufficiency may occur. Thus, it is important to identify predictor factors of postdonation kidney function.

OBJECTIVES

To evaluate the influence of predictor factors in the evolution of the remaining kidney function and to quantify nonpredictable and unexpected developments in GFR at 1 year post donation.

METHODS

We performed a study of the evolution of renal function pre- and postnephrectomy of 55 living donors without perioperative comorbidities and a mean follow-up of 6.03 ± 2.7 years.

RESULTS

One year after nephrectomy donor function was 32% lower than the prenephrectomy value and 21% of donors had an eGFR <60 mL/min/1.73 m(2). In multivariate logistic regression a living donor with a predonation eGFR <100 but >80 mL/min/1.73 m(2) had 5.24 times a chance of having an eGFR <60 mL/min/1.73 m(2) at 1 year post donation than if he had an eGFR ≥100 mL/min/1.73 m(2). Among 15 donors with prenephrectomy eGFR ≥80 and <100 mL/min/1.73m(2), 8 (53%), RR = 3.26 (1.517-7.012) had eGFR <60 mL/min/ 1.73 m(2).

CONCLUSIONS

The eGFR predonation and donor age influenced the first-year postnephrectomy eGFR. Some donors had a more accelerated eGFR fall, not always related to predonation eGFR and age.

Camphor-based CCR5 blocker lead compounds – a computational and experimental approach

This study identifies novel camphor-derived compounds that bind the CCR5 receptor and can be used as lead compounds for drug discovery.

Rare double sex and mab-3-related transcription factor 1 regulatory variants in severe spermatogenic failure

The double sex and mab-3-related transcription factor 1 (DMRT1) gene has long been linked to sex-determining pathways across vertebrates and is known to play an essential role in gonadal development and maintenance of spermatogenesis in mice. In humans, the genomic region harboring the DMRT gene cluster has been implicated in disorders of sex development and recently DMRT1 deletions were shown to be associated with non-obstructive azoospermia (NOA). In this work, we have employed different methods to screen a cohort of Portuguese NOA patients for DMRT1 exonic insertions and deletions [by multiplex ligation probe assay (MLPA); n = 68] and point mutations (by Sanger sequencing; n = 155). We have found three novel patient-specific non-coding variants in heterozygosity that were absent from 357 geographically matched controls. One of these is a complex variant with a putative regulatory role (c.-223_-219CGAAA>T), located in the promoter region within a conserved sequence involved in Dmrt1 repression. Moreover, while DMRT1 domains are highly conserved across vertebrates and show reduced levels of diversity in human populations, two rare synonymous substitutions (rs376518776 and rs34946058) and two rare non-coding variants that potentially affect DMRT1 expression and splicing (rs144122237 and rs200423545) were overrepresented in patients when compared with 376 Portuguese controls (301 fertile and 75 normozoospermic). Overall our previous and present results suggest a role of changes in DMRT1 dosage in NOA potentially also through a process of gene misregulation, even though DMRT1 deleterious variants seem to be rare.

Improved serological detection of rheumatoid arthritis: a highly antigenic mimotope of carbonic anhydrase III selected in a murine model by phage display

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects around 1% of the human population worldwide. RA diagnosis can be difficult as there is no definitive test for its detection. Therefore, the aim of this study was to identify biomarkers that could be used for RA diagnosis.

METHODS

Sera from a collagen-induced arthritis mouse model were used to select potential biomarkers for RA diagnosis by phage display technology. In silico and in vitro analyses were performed to characterize and validate the selected peptides. Samples were classified into three groups: RA; two other immune-mediated rheumatic diseases (systemic lupus erythematosus (SLE) and ankylosing spondylitis (AS)); and healthy controls (HC). Enzyme-linked immunosorbent assay (ELISA) was carried out to determine antibody levels, and diagnostic parameters were determined by constructing receiver operating characteristic curves. Mass spectrometry and Western blot were performed to identify the putative autoantigen that was mimicked by a highly reactive mimotope.

RESULTS

After three rounds of selection, 14 clones were obtained and tested for immunoreactivity analysis against sera from RA and HC groups. The phage-fused peptide with the highest immunoreactivity (M12) was synthesized, and was able to efficiently discriminate RA patients from SLE, AS and HCs (p < 0.0001) by ELISA. The specificity and sensitivity of anti-M12 antibodies for RA diagnosis were 91 % and 84.3 %, respectively. The M12 peptide was identified as one that mimics a predicted antigenic site of the carbonic anhydrase III (CAIII) protein, a ubiquitous biomarker that has been identified in patients with other diseases.

CONCLUSION

M12 is the first peptide associated with the CAIII protein that may be used as an antigen for antibody detection to aid in RA diagnosis with high sensitivity and specificity.

Revisiting the tubulin folding pathway: new roles in centrosomes and cilia

Centrosomes and cilia are critical eukaryotic organelles which have been in the spotlight in recent years given their implication in a myriad of cellular and developmental processes. Despite their recognized importance and intense study, there are still many open questions about their biogenesis and function. In the present article, we review the existing data concerning members of the tubulin folding pathway and related proteins, which have been identified at centrosomes and cilia and were shown to have unexpected roles in these structures.

X-linked adrenal hypoplasia congenita: clinical and follow-up findings of two kindreds, one with a novel NR0B1 mutation

X-linked adrenal hypoplasia congenita typically manifests as primary adrenal insufficiency in the newborn age and hypogonadotropic hypogonadism in males, being caused by mutations in NR0B1 gene. We present the clinical and follow-up findings of two kindreds with NR0B1 mutations. The proband of kindred A had a diagnosis of primary adrenal insufficiency when he was a newborn. Family history was relevant for a maternal uncle death at the newborn age. Beyond 2 year-old steroid measurements rendered undetectable and delayed bone age was noticed. Molecular analysis of NR0B1 gene revealed a previously unreported mutation (c.1084A>T), leading to a premature stop codon, p.Lys362*, in exon 1. His mother and sister were asymptomatic carriers. At 14 year-old he had 3 mL of testicular volume and biochemical surveys (LH < 0.1 UI/L, total testosterone < 10 ng/dL) concordant with hypogonadotrophic hypogonadism. Kindred B had two males diagnosed with adrenal insufficiency at the newborn age. By 3 year-old both siblings had undetectable androgen levels and delayed bone age. NR0B1 molecular analysis identified a nonsense mutation in both cases, c.243C>G; p.Tyr81*, in exon 1. Their mother and sister were asymptomatic carriers. At 14 year-old (Tanner stage 1) hypothalamic-pituitary-gonadal axis evaluation in both males (LH < 0.1UI/L, total testosterone < 10 ng/dL) confirmed hypogonadotropic hypogonadism. In conclusion, biochemical profiles, bone age and an X-linked inheritance led to suspicion of NR0B1 mutations. Two nonsense mutations were detected in both kindreds, one previously unreported (c.1084A>T; p.Lys362*). Mutation identification allowed the timely institution of testosterone in patients at puberty and an appropriate genetic counselling for relatives.

[Renal artery embolism: thromboaspiration and catheter directed thrombolysis - A successful case]

Renal artery embolism is a rare event and is associated with high risk of hypertension and functional renal loss. We report the clinical case of a renal artery embolism, which was treated using a combination of thromboaspiration and catheter directed thrombolysis, as well a short literature review on this subject. A 60-year-old male with previous medical history of atrial septal defect surgical repair and cardiac pacemaker was presented in the Emergency Department with complains of abdominal pain and vomiting. Patient had suspended oral anticoagulation to undergo a dental surgical procedure. The Angio-CT scan revealed a left renal artery occlusion, suggestive of embolism, with infarction of the ipsilateral kidney. We underwent, 36 hours after the beginning of complains, a left renal artery recanalization with recovery of renal perfusion, using percutaneous thromboaspiration and catheter directed thrombolysis. Renal scintigraphy, at the end of first month, showed left kidney differential function of 38.9%. In the follow-up period (32 months), serum creatinine levels stabilized at 1 mg/dL (1.59 at the admission). Percutaneous interventions, including thromboaspiration and catheter directed thrombolysis, can be used effectively to treat renal artery embolism. Clinical suspicion, lenght of evolution and previous development of a collateral circulation network are key factors to achieve a therapeutic success.

Anti-type II collagen antibodies detection and avidity in patients with oligoarticular and polyarticular forms of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) refers to a heterogeneous group of illnesses that have in common the occurrence of chronic joint inflammation in children younger than 16 years of age. The diagnosis is made only on clinical assessment. The identification of antibody markers could improve the early diagnosis, optimizing the clinical management of patients. Type II collagen is one potential autoantigen that has been implicated in the process of arthritis development. The aims of our study were to investigate the occurrence of anti-type II collagen antibodies and also to determine the avidity of the antibody-antigen binding. Ninety-six patients with oligoarticular or polyarticular JIA, 13 patients with ankylosing spondylitis (AS) and 61 healthy controls (HC) were tested for anti-type II collagen antibodies by ELISA and avidity ELISA. Sensitivity and specificity were determined by the receiver operating characteristic (ROC) curve analysis. Forty-two JIA patients (44%) were positive for antibodies against type II collagen. Its detection was significantly higher in JIA patients than in AS patients (p=0.006) and HCs (p<0.0001). Furthermore, anti-type II collagen antibody detection was significantly more frequent in patients with JIA of ≤6 months duration (p=0.0007). Antibodies displaying high avidity to type II collagen were associated with disease activity (p=0.004). This study demonstrates that antibodies against type II collagen are present in the serum of patients with oligoarticular and polyarticular JIA, being its presence more prevalent in patients with early disease. It also demonstrates that JIA patients with active disease present antibodies with high avidity against type II collagen.

The hepcidin gene promoter nc.-1010C > T; -582A > G haplotype modulates serum ferritin in individuals carrying the common H63D mutation in HFE gene

Hereditary hemochromatosis is an autosomal recessive disorder characterized by severe iron overload. It is usually associated with homozygosity for the HFE gene mutation c.845G > A; p.C282Y. However, in some cases, another HFE mutation (c.187C > G; p.H63D) seems to be associated with the disease. Its penetrance is very low, suggesting the possibility of other iron genetic modulators being involved. In this work, we have screened for HAMP promoter polymorphisms in 409 individuals presenting normal or increased serum ferritin levels together with normal or H63D-mutated HFE genotypes. Our results show that the hepcidin gene promoter TG haplotype, originated by linkage of the nc.-1010C > T and nc.-582A > G polymorphisms, is more frequent in the HFE_H63D individuals presenting serum ferritin levels higher than 300 μg/L than in those presenting the HFE_H63D mutation but with normal serum ferritin levels or in the normal control group.Moreover, it was observed that the TG haplotype was associated to increased serum ferritin levels in the overall pool of HFE_H63D individuals. Thus, our data suggest that screening for these polymorphisms could be of interest in order to explain the phenotype. However, this genetic condition seems to have no clinical significance.

Mitochondrial thioredoxin reductase inhibition, selenium status, and Nrf-2 activation are determinant factors modulating the toxicity of mercury compounds

The thioredoxin system has essential functions in the maintenance of cellular redox homeostasis in the cytosol, nucleus, and mitochondria. Thioredoxin (Trx) and thioredoxin reductase (TrxR) are targets for mercury compounds in vitro and in vivo. This study aimed at understanding mechanistically how the mitochondrial and cytosolic thioredoxin systems were affected by mercurials, including the regulation of TrxR transcription. The effects of coexposure to selenite and mercurials on the thioredoxin system were also addressed. Results in HepG2 cells showed that TrxR1 expression was enhanced by Hg(2+), whereas exposure to MeHg decreased expression. Selenite exposure also increased the expression of TrxR1 and resulted in higher specific activity. Coexposure to 2 µM selenite and up to 5 µM Hg(2+) increased even further TrxR1 expression. This synergistic effect was not verified for MeHg, because TrxR1 expression and activity were reduced. Analysis of Nrf-2 translocation to the nucleus and TrxR mRNA suggests that induction of TrxR1 transcription was slower upon exposure to MeHg in comparison to Hg(2+). Subcellular fractions showed that MeHg affected the activity of the thioredoxin system equally in the mitochondria and cytosol, whereas Hg(2+) inhibited primarily the activity of TrxR2. The expression of TrxR2 was not upregulated by any treatment. These results show important differences between the mechanisms of toxicity of Hg(2+) and MeHg and stress the narrow range of selenite concentrations capable of antagonizing mercury toxicity. The results also highlight the relevance of the mitochondrial thioredoxin system (TrxR2 and Trx2) in the development of mercury toxicity.

A novel Alu-mediated microdeletion at 11p13 removes WT1 in a patient with cryptorchidism and azoospermia

This article describes a patient with cryptorchidism and nonobstructive azoospermia presenting a novel microdeletion of approximately 1 Mb at 11p13. It was confirmed by multiplex ligation-dependent probe amplification that this heterozygous deletion spanned nine genes (WT1, EIF3M, CCDC73, PRRG4, QSER1, DEPDC7, TCP11L1, CSTF3 and HIPK3) and positioned the breakpoints within highly homologous repetitive elements. As far as is known, this is the smallest deletion as-yet described encompassing the WT1 gene and was detected only once in a total of 32 Portuguese patients with isolated uni- or bilateral cryptorchidism. These findings suggest that molecular analysis in patients with genitourinary features suggestive of WT1 impairment, namely cryptorchidism and renal abnormalities, may reveal cryptic genetic defects.

[Subclavian Steal Syndrome and Cerebral Hypoperfusion during Hemodialysis: A case report]

Subclavian steal syndrome is caused by retrograde vertebral artery flow "stealing" vertebrobasilar perfusion. We report the clinical case of a 53 year-old dialysis dependent woman with several cardiovascular risk factors, who had episodes of vertebrobasilar insufficiency and resting pain of the left upper extremity, during hemodialysis sessions, through a left arm brachiobasilic arteriovenous fistula. Noninvasive studies demonstrated a preoclusive stenosis at the origin of left subclavian artery, together with a stenosis on the left internal carotid artery superior to 70% and reversion of flow in the left vertebral artery. The patient underwent endarterectomy and Dacron patch angioplasty of the left internal carotid artery and carotid-subclavian ePTFE bypass, with total resolution of the previously described clinical presentation.