DNA damage and aging on hematopoietic stem cells: Impact of oxidative stress in ApoE-/- mice

The effects of aging on ROS production and DNA damage were assessed in hematopoietic stem cells (HSCs) from apolipoprotein E-deficient (ApoE^-/^-) mice (2-, 12- and 24-month-old), a traditional experimental model of atherogenic dyslipidemia. HSCs from aged ApoE^-/- mice were associated with increased ROS levels, leading to loss quiescence, DNA damage, apoptosis and telomere shortening. The concurrence of lack of ApoE and aging result in exhaustion and senescence of HSCs accompanied by increased oxidative stress and inflammation. Therefore, our data open avenues to a better understanding of age-related changes and genetic factors, which may synergistically compromise the efficacy of aged HSC recovery and/or transplantation.

Time course of changes in heart rate and blood pressure variability in rats with myocardial infarction

Our aim was to determine the time course of changes in autonomic balance in the acute (1 and 3 days), sub-acute (7 days) and chronic (28 days) phases of myocardial infarction (MI) in rats. Autonomic balance was assessed by temporal and spectral analyses of blood pressure variability (BPV) and heart rate variability (HRV). Pulsatile blood pressure (BP) recordings (30 min) were obtained in awake and unrestrained male Wistar rats (N = 77; 8-10 weeks old) with MI (coronary ligature) or sham operation (SO). Data are reported as means±SE. The high frequency (HF) component (n.u.) of HRV was significantly lower in MI-1- (P<0.01) and MI-3-day rats (P<0.05) than in their time-control groups (SO-1=68±4 vs MI-1=35.3±4.3; SO-3=71±5.8 vs MI-3=45.2±3.8), without differences thereafter (SO-7=69.2±4.8 vs MI-7=56±5.8; SO-28=73±4 vs MI-28=66±6.6). A sharp reduction (P<0.05) of BPV (mmHg²) was observed in the first week after MI (SO-1=8.55±0.80; SO-3=9.11±1.08; SO-7=7.92±1.10 vs MI-1=5.63±0.73; MI-3=5.93±0.30; MI-7=5.30±0.25). Normal BPV, however, was observed 4 weeks after MI (SO-28=8.60±0.66 vs MI-28=8.43±0.56 mmHg²; P>0.05). This reduction was mainly due to attenuation of the low frequency (LF) band of BPV in absolute and normalized units (SO-1=39.3±7%; SO-3=55±4.5%; SO-7=46.8±4.5%; SO-28=45.7±5%; MI-1=13±3.5%; MI-3=35±4.7%; MI-7=25±2.8%; MI-28=21.4±2.8%). The results suggest that the reduction in HRV was associated with decrease of the HF component of HRV suggesting recovery of the vagal control of heartbeats along the post-infarction healing period. The depression of BPV was more dependent on the attenuation of the LF component, which is linked to the baroreflex modulation of the autonomic balance.

A tool for selecting patients with a high probability of sustained virological response to peginterferon alfa-2a (40kD)/ribavirin

BACKGROUND & AIMS

Pretreatment identification of patients likely to achieve a sustained virological response (SVR) with peginterferon alfa-2a/ribavirin would be useful for individualizing treatment choices. The aim of this analysis was to devise a simple scoring system to identify patients with high probability of achieving an SVR with peginterferon alfa-2a/ribavirin.

METHODS

Using data from 2109 Caucasian treatment-naive hepatitis C virus (HCV) genotype 1 mono-infected patients from the PROPHESYS cohorts, the relationship between favourable baseline characteristics and SVR was explored using generalized additive model analysis, and a scoring system was devised to predict SVR.

RESULTS

Points were assigned for: age (years) (≤35: 2; >35, ≤45: 1; >45: 0); body mass index (kg/m(2)) (≤20: 2; >20, ≤22: 1; >22: 0); HCV RNA (IU/ml) (≤100,000: 3; >100,000-400,000: 2; >400,000-800,000: 1; >800,000: 0); platelets (>150 ×10(9)/l: 1; ≤150 ×10(9)/l: 0); alanine aminotransferase [×upper limit of normal (ULN)] (>3: 1; ≤3: 0); serum aspartate aminotransferase (×ULN) (≤1: 1; >1: 0). 1029, 698 and 382 patients had scores of 0-2, 3-4 and ≥5, respectively, among whom SVR rates were 35.0, 54.9 and 76.7%. SVR in patients with scores ≥5 and undetectable HCV RNA by week 4 was 86.7%. The score was tested against two databases of patients who received peginterferon alfa-2a/ribavirin in other clinical trials; similar high SVR rates in patients with scores ≥5 were reported.

CONCLUSIONS

The scoring system can reliably identify treatment-naive HCV genotype 1 mono-infected Caucasian patients who have a high probability of achieving an SVR with peginterferon alfa-2a/ribavirin and will be particularly useful where protease inhibitors are not readily available.