The intestinal microbiota of broiler chickens and the microbiota in the litter have been well studied, but the interactions between these two microbiotas remain to be determined. Therefore, we examined their reciprocal effects by analyzing the intestinal microbiotas of broilers reared on fresh pine shavings versus reused litter, as well as the litter microbiota over a 6-week cycle. Composite ileal mucosal and cecal luminal samples from birds (n ؍ 10) reared with both litter conditions (fresh versus reused) were collected at 7, 14, 21, and 42 days of age. Litter samples were also collected at days 7, 14, 21, and 42. The microbiotas were profiled and compared within sample types based on litter condition using PCR and denaturing gradient gel electrophoresis (PCR-DGGE). The microbiotas were further analyzed using 16S rRNA gene clone libraries constructed from microbiota DNA extracted from both chick intestinal and litter samples collected at day 7. Results showed significant reciprocal effects between the microbiotas present in the litter and those in the intestines of broilers. Fresh litter had more environmental bacteria, while reused litter contained more bacteria of intestinal origin. Lactobacillus spp. dominated the ileal mucosal microbiota of fresh-litter chicks, while a group of bacteria yet to be classified within Clostridiales dominated in the ileal mucosal microbiota in the reused-litter chicks. The Litter condition (fresh versus reused) seemed to have a more profound impact on the ileal microbiota than on the cecal microbiota. The data suggest that the influence of fresh litter on ileal microbiota decreased as broilers grew, compared with temporal changes observed under reused-litter rearing conditions.
BACKGROUND
Although serum lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerosis in the general population and Lp(a) levels are increased in hemodialysis patients, an association of Lp(a) with the risk of clinical events attributed to atherosclerosis has not been established in the chronic hemodialysis patient population. We therefore determined the association between Lp(a) levels and the risk of clinical events of presumed atherosclerotic etiology in a prospective study of an outpatient hemodialysis population.
METHODS AND RESULTS
Lp(a) was measured by radioimmunoassay in a baseline cardiovascular disease risk assessment in a consecutive series of 129 hemodialysis patients. The relation between baseline Lp(a) and clinical events of presumed atherosclerotic etiology was determined during 48 months of follow-up. Hemodialysis patients had a median Lp(a) concentration that was approximately four times as high as the median Lp(a) concentration in normal controls and twice as high as the levels in controls with angiographic evidence of coronary artery disease [median Lp(a), 38.4 versus 16.9 mg/dl; p less than 0.001]. Baseline Lp(a) levels were no different in participants with or with no history of a previous clinical event at the time of the baseline examination. However, baseline Lp(a) concentration (p less than 0.001) and a history of atherosclerotic clinical events (p = 0.001) were associated with clinical events during the period of follow-up. In contrast, baseline serum total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol, age, gender, race, or duration of hemodialysis were unrelated to this risk in the prospective study. Stepwise multiple logistic regression analysis demonstrated that serum Lp(a) concentration (p = 0.001) and the presence of a previous clinical event (p = 0.004) were the only independent contributors to the risk of a clinical event during the period of follow-up.
CONCLUSIONS
Lp(a) is an independent risk factor for clinical events attributed to atherosclerotic cardiovascular disease in patients receiving chronic hemodialysis treatment of end-stage renal disease.
Preclinical and limited clinical data suggest that statins decrease the progressive decline in renal function that occurs in patients with renal disease. Pooled analysis of data obtained from a population of hyperlipidemic patients enrolled in the rosuvastatin (Crestor®) clinical development program permitted assessment of its effects on renal function both early and later in the course of treatment. Study participants were initially included in controlled clinical trials that evaluated the lipid-lowering efficacy and safety of rosuvastatin when compared with placebo or other lipid-lowering agents (i.e., atorvastatin, simvastatin, pravastatin, cholestyramine, fenofibrate or extended-release niacin). The median duration of treatment with the various doses of statins in these trials was approximately 8 weeks. Following completion of a controlled clinical trial, patients were permitted to enter an open-label extension trial and received rosuvastatin treatment. These data permitted assessment of renal function in a diverse group of over 10,000 patients who received rosuvastatin in its recommended dose range (5–40 mg) for up to 3.8 years. Mean serum creatinine concentrations were lower when compared with baseline both early and later in the course of rosuvastatin treatment. In contrast, no change in mean serum creatinine was observed with placebo. Mean glomerular filtration rates (GFR) predicted from the Modification of Diet in Renal Disease (MDRD) equation were higher when compared with baseline both early and later in the course of rosuvastatin treatment. No change in GFR was observed in the placebo group. Among patients who received long-term rosuvastatin treatment (≧96 weeks), GFR was unchanged or tended to increase, rather than decrease, when compared with baseline irrespective of age, gender, hypertensive or diabetic status, level of renal function (GFR ≧60 vs. <60 ml/min/1.73 m2) at entry or urine dipstick protein status prior to or during the period of treatment. These findings suggest that rosuvastatin may arrest the progression of renal disease.
Rosuvastatin reduces first cardiovascular events and all-cause mortality among men and women with LDL-C <130 mg/dl, elevated hsCRP, and concomitant evidence of moderate CKD. (JUPITER-Crestor 20 mg Versus Placebo in Prevention of Cardiovascular [CV] Events; NCT00239681).
Diabetic patients have greater risk for coronary heart disease (CHD) events after coronary artery bypass graft (CABG) surgery than nondiabetic patients. The Post CABG trial studied the effects of aggressive cholesterol lowering and low-dose anticoagulation in diabetic patients compared with nondiabetic patients. A double-blind, randomized clinical trial in 1,351 patients (1-11 years after CABG), the Post CABG trial consisted of two interventions (aggressive cholesterol-lowering versus moderate lowering and low-dose warfarin versus placebo) on angiographic end points. Angiographic changes in saphenous vein graft conduits 4.3 years after entry were compared in 116 diabetic and 1,235 nondiabetic patients. Seven clinical centers participated in the trial, as well as the National Institutes of Health project office (National Heart, Lung, and Blood Institute), the coordinating center (Maryland Medical Research Institute), and the Angiogram Reading Center (University of Minnesota). Baseline characteristics of the diabetic patients differed from the nondiabetic patients in the following ways: percentage of women participants, 15 vs. 7%, P = 0.002; mean baseline weight, 87.4 vs. 82.8 kg, P = 0.006; mean BMI, 29.5 vs. 27.6 kg/m2, P = 0.0002; mean systolic blood pressure, 141.7 vs. 133.6, P < 0.0001; mean triglyceride concentrations, 2.09 vs. 1.77 mmol/l, P < 0.0001; and mean HDL cholesterol concentrations, 0.93 vs. 1.02 mmol, P = 0.0001. The percentage of clinical events was higher in diabetic than nondiabetic patients (20.6 vs. 13.4, P = 0.033) and angiographic outcomes were not different. The benefits of aggressive cholesterol lowering were comparable in diabetic and nondiabetic patients for the angiographic end points. Warfarin use was not associated with clinical or angiographic benefit. Diabetic patients in the Post CABG trial had more CHD risk factors at study entry and higher clinical event rates during the study than nondiabetic patients. The benefits of aggressive cholesterol lowering in diabetic patients were comparable to those in nondiabetic patients for both angiographic and clinical end points. The small number of diabetic patients provided limited power to detect significant differences between diabetic and nondiabetic patients or between diabetic patients in the aggressive versus moderate cholesterol treatment strategies.
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