Redox Metabolism and Vascular Calcification in Chronic Kidney Disease

Vascular calcification (VC) is a common complication in patients with chronic kidney disease which increases their mortality. Although oxidative stress is involved in the onset and progression of this disorder, the specific role of some of the main redox regulators, such as catalase, the main scavenger of H2O2, remains unclear. In the present study, epigastric arteries of kidney transplant recipients, a rat model of VC, and an in vitro model of VC exhibiting catalase (Cts) overexpression were analysed. Pericalcified areas of human epigastric arteries had increased levels of catalase and cytoplasmic, rather than nuclear runt-related transcription factor 2 (RUNX2). In the rat model, advanced aortic VC concurred with lower levels of the H2O2-scavenger glutathione peroxidase 3 compared to controls. In an early model of calcification using vascular smooth muscle cells (VSMCs), Cts VSMCs showed the expected increase in total levels of RUNX2. However, Cts VMSCs also exhibited a lower percentage of the nucleus stained for RUNX2 in response to calcifying media. In this early model of VC, we did not observe a dysregulation of the mitochondrial redox state; instead, an increase in the general redox state was observed in the cytoplasm. These results highlight the complex role of antioxidant enzymes as catalase by regulation of RUNX2 subcellular location delaying the onset of VC.

Serum phosphate is associated with increased risk of bone fragility fractures in hemodialysis patients

BACKGROUND

Bone fragility fractures are associated with high morbidity and mortality. This study analysed the association between the current biochemical parameters of CKD-MBD and bone fragility fractures in the COSMOS project.

METHODS

COSMOS is a 3-year, multicentre, open cohort, prospective, observational study carried out in 6797 hemodialysis patients (227 centres from 20 European countries). The association of bone fragility fractures (outcome) with serum calcium, phosphate and PTH (exposure), was assessed using Standard Cox proportional hazards regression and Cox proportional hazards regression for recurrent events. Additional analyses were performed considering all-cause mortality as a competitive event for bone fragility fracture occurrence. Multivariable models were used in all strategies, with the fully adjusted model including a total of 24 variables.

RESULTS

During a median follow-up of 24 months 252 (4%) patients experienced at least one bone fragility fracture (incident bone fragility fracture rate 28.5 per 1000 patient-years). In the fractured and non-fractured patients, the percentage of men was 43.7% and 61.4%, mean age 68.1 and 63.8 years and a haemodialysis vintage of 55.9 and 38.3 months respectively. Baseline serum phosphate > 6.1 mg/dL (reference value 4.3-6.1 mg/dL) was significantly associated with a higher bone fragility fracture risk in both regression models (HR: 1.53[95%CI: 1.10-2.13] and HR: 1.44[95%CI: 1.02-2.05]. The significant association persisted after competitive risk analysis (subHR: 1.42[95%CI: 1.02-1.98]) but the finding was not confirmed when serum phosphate was considered as a continuous variable. Baseline serum calcium showed no association with bone fragility fracture risk in any regression model. Baseline serum PTH > 800 pg/mL was significantly associated with a higher bone fragility fracture risk in both regression models, but the association disappeared after a competitive risk analysis.

CONCLUSIONS

Hyperphosphatemia was independently and consistently associated with an increased bone fracture risk, suggesting serum phosphate could be a novel risk factor for bone fractures in hemodialysis patients.

Treatment trends for clinically localised prostate cancer. National population analysis: GESCAP group

OBJECTIVES

To describe the established therapies for localised prostate cancer (PC) in Spain and to assess compliance with the 2010 UAE guidelines.

PATIENTS AND METHODS

This was an epidemiological, observational, prospective and multicentre study. Of the 3,918 patients diagnosed with PC during 2010, only those patients with localised PC were included. Follow-up was ultimately conducted for a minimum of one year from the diagnosis for 3,713 patients (94.77%). The treatment groups assessed were as follows: radical prostatectomy, radiation therapy, hormone therapy, brachytherapy, active surveillance or observation and experimental local treatment (cryotherapy or other treatment). Compliance with the recommendations of the EAU guidelines was studied, describing the treatment groups according to D'Amico risk stratification criteria (localised [low, intermediate and high risk] and locally advanced), age, PSA and Gleason score.

RESULTS

By applying the D'Amico criteria, we included 3,641 (92.93%) patients. Based on the UAE recommendations: 1) 68.87% of the patients at low-intermediate risk aged≤65 years underwent radical prostatectomy; 2) 34.51% of the patients>65 years at high risk with locally advanced disease were administered radiation therapy and hormone therapy; 3) 30.36% of the patients at high risk with locally advanced disease were only treated with hormone therapy; 4) 15.20% of the patients at low risk were only treated with brachytherapy; 5) active surveillance or observation was selected for 2.44% of the patients aged≤65 years and for 10.63% of the patients at low-intermediate risk who were>65 years. Lastly, 86.5% of the patients at low risk underwent a single treatment, and 43.62% of the patients at high risk with locally advanced disease underwent combined treatments.

CONCLUSIONS

This is the first national European study to evaluate the therapeutic management of localised PC based on the risk group to which the patient belonged. Most young patients (≤65 years) with low-intermediate risk localised PC were treated with surgery, which adheres to the recommendations of the 2010 UAE guidelines. Various therapeutic combinations have been employed for patients with high-risk, locally advanced localised tumours, revealing the need for a multidisciplinary approach (Controlled-trials.com number: ISRCTN19893319).

Matrix Metalloproteinases and Bladder Cancer: What is New?

Urothelial bladder cancer represents a heterogeneous disease with divergent pathways of tumorigenesis. Tumor invasion and progression are a multifactorial process promoted by microenvironmental changes that include overexpression of matrix metalloproteinases (MMPs). Recent data clearly challenge the classic dogma that MMPs promote metastasis only by modulating the remodeling of extracellular matrix. Indeed, MMPs have also been attributed as an impact on tumor cell behavior in vivo as a consequence of their ability to cleave growth factors, cell surface receptors, cell adhesion molecules, and chemokines/cytokines. Levels of the different MMPs can be measured in several sample types, including tissue, blood (serum and plasma), and urine, and using different methodologies, such as immunohistochemistry, real-time PCR, western and northern blot analyses, enzyme-linked immunosorbent assay, and zymography. Several MMPs have been identified as having potential diagnostic or prognostic utility, whether alone or in combination with cytology. Although MMP inhibitors have shown limited efficacy, advances in the understanding of the complex physiologic and pathologic roles of MMPs might permit the development of new MMP-specific and tumor-specific therapies. In this paper we update the understanding of MMPs based on a systematic PubMed search encompassing papers published up to December 2011.

[The physiopathology and management of sexual dysfunction in epileptic patients]

AIM

To review sexual dysfunction in epileptic patients, which is an aspect of the disease that is often deemed as being of little importance, but which exerts a decisive influence on the quality of life of these patients.

DEVELOPMENT

The alterations in sexual functioning in epilepsy have a complex physiopathology, can be of different types and occur during seizures, the aura or in the intercritical periods. Their clinical expression depends on the sex and age of the patient. The severity and incidence of sexual dysfunction are influenced by the treatment being used, the psychosocial adjustment of the individual, and certain aspects of epilepsy such as the age at onset, time to progression, location of the focus, the type of seizures and the degree of control the patient has over them. The therapeutic strategy is based on adjusting or modifying the antiepileptic therapy and then treating the sexual dysfunction and/or possible hormonal upsets.

CONCLUSIONS

Sexuality is a fundamental human right and as a health provider, the physician must take this aspect of the disease into account when dealing with epileptic patients by attempting to detect and characterise the disorder. The patient must be informed of the possible effects of epilepsy and its treatment on sexual functioning, and also the therapeutic options the physician considers to be best suited to the patient's particular case. He or she should also be encouraged to play an active role in making decisions on the matter and it is necessary to carry out developmental monitoring that takes into account the impact that improved sexual functioning is going to have on the patient's psychosocial and family adjustment.

Comparison of intravenous flecainide, propafenone, and amiodarone for conversion of acute atrial fibrillation to sinus rhythm

In a prospective, single-blind trial, we randomized 150 consecutive symptomatic patients with acute (< or = 48 hours' duration) atrial fibrillation to receive intravenous flecainide, propafenone, or amiodarone. Flecainide and propafenone were administered as a bolus dose of 2 mg/kg in 20 minutes. A second bolus dose of 1 mg/kg in 20 minutes was administered if conversion to sinus rhythm was not achieved after 8 hours. Amiodarone was administered as a bolus of 5 mg/kg in 20 minutes followed by a continuous infusion of 50 mg/hour. By the end of a 12-hour observation period, conversion to sinus rhythm was achieved in 45 patients (90%) in the flecainide group, 36 (72%) in the propafenone group, and 32 (64%) in the amiodarone group (p = 0.008 for the overall comparison, p = 0.002 for flecainide vs amiodarone, p = 0.022 for flecainide vs propafenone, and p = 0.39 for propafenone vs amiodarone). When compared with amiodarone, this higher reversion rate with flecainide was present from the first hour of the study period. However, only after administering the second bolus was there a significant difference between flecainide and propafenone. Median time to conversion to sinus rhythm was different among groups (p < 0.001), and it was lower in the flecainide (25 minutes; range 4 to 660) and propafenone (30 minutes; range 10 to 660) groups than in the amiodarone group (333 minutes; range 15 to 710; p < 0.001 for both comparisons). Flecainide, at the doses administered in this study, is more effective than propafenone and amiodarone for conversion of acute atrial fibrillation to sinus rhythm. Propafenone and amiodarone have similar conversion rates, although propafenone was faster in achieving the conversion to sinus rhythm.