No abstract

To study the selectivity of neurotrophic actions in the brain, we analyzed the actions of several known growth factors on septal cholinergic, pontine cholinergic, and mesencephalic dopaminergic neurons in culture. Similar to nerve growth factor (NGF), basic fibroblast growth factor (bFGF) stimulated choline acetyltransferase activity in septal cultures. In contrast to NGF, bFGF also enhanced dopamine uptake in mesencephalic cultures and stimulated cell proliferation in all 3 culture types. Insulin and the insulin-like growth factors I and II stimulated transmitter-specific differentiation and cell proliferation in all culture types. Epidermal growth factor (EGF) produced a small increase in dopamine uptake by mesencephalic cells and stimulated cell proliferation in all culture types. In septal cultures, bFGF was most effective when given at early culture times, NGF at later times. The stimulatory actions of bFGF and insulin did not require the presence of glial cells and were not mediated by NGF. In mesencephalic cultures, the stimulation of dopamine uptake by bFGF and EGF was dependent on glial proliferation. The results suggest different degrees of selectivity of the neurotrophic molecules. NGF and, very similarly, bFGF seem to influence septal cholinergic neurons directly and rather selectively, whereas the neurotrophic actions of insulin and the insulin-like growth factors appear to be more general.

Recombinant human brain-derived neurotrophic factor (rhBDNF) and neurotrophin 3 (rhNT-3), two recently cloned molecules closely related to nerve growth factor (NGF), were produced from human cDNA expressed in human embr~yonic kidney cells. The recombinant proteins were tested in cultures of dissociated fetal rat brain cells containing basal forebrain cholinergic neurons. rhBDNF stimulated the differentiation of the cholinergic neurons, similar to NGF, which is well established as a neurotrophic factor for these cells. However, rhBDNF was particularly effective during the first few days in vitro, whereas the stimulatory action of rhNGF was more pronounced later in the development of the cultures. This finding indicates the existence of different time periods of responsiveness of the cholinergic neurons to BDNF and NGF. To assess the selectivity of the effect of rhBDNF-on cholinergic neurons, its actions were, tested in cultures of ventral mesencephalon containing dopaminergic cells. In contrast to NGF, which does not affect central dopaminergic neurons, rhBDNF increased dopamine uptake activity. The findings suggest that BDNF stimulates survival or differentiation of other cells besides the cholinergic neurons.Developmental growth, maintenance of function, and plasticity of neuronal populations are influenced by soluble proteins including neurotrophic, growth, and neuronal differentiation factors. Nerve growth factor (NGF), the first and best characterized neurotrophic factor, promotes survival, growth, and biochemical differentiation of peripheral sympathetic and sensory neurons and basal forebrain cholinergic neurons (1-4). Survival and growth of these cholinergic cells are also affected by factors primarily known to target nonneuronal cells. These factors include fibroblast growth factor, epidermal growth factor, and the insulin-like growth factors (5-7). Based on work by Barde et al. (8) brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3), two neurotrophic factors closely related to NGF, were discovered and cloned (9-12). Both molecules share -5Wo of their amino acids with NGF. BDNF, NT-3, and NGF support survival of selected populations of chick sensory neurons, suggesting independent roles in the regulation of neuronal survival during development. BDNF was originally purified from adult pig brain, and -high levels of BDNF and NT-3 mRNA occur in adult rodent brain (9-12), suggesting an important role of BDNF and NT-3 in the central nervous system. Identification of neuronal populations responsive to BDNF and NT-3 is an important initial step in elucidating their brain function. We studied the response of the basal forebrain cholinergic neurons, a neuronal population important for cognitive brain functions, and ofother cells, including dopaminergic neurons of the mesencephalon.MATERIALS AND METHODS Production of Recombinant Human (rh) BDNF and NT-3. A BDNF cDNA clone (1280 base pairs) was isolated from a human fetal brain cDNA library. Large-scale expression of rhBDNF was achieved by t...

on behalf of the Study of Anemia in Heart Failure Trial (STAMINA-HeFT) GroupBackground-Substantial evidence suggests that anemia is an independent risk factor for worse outcomes in patients with heart failure (HF). The Study of Anemia in Heart Failure Trial (STAMINA-HeFT) is the largest multicenter, randomized, double-blind, placebo-controlled trial to date evaluating the effect of treating anemia in HF. Methods and Results-Patients (Nϭ319) with symptomatic HF, left ventricular ejection fraction Յ40%, and hemoglobin Ն9.0 g/dL and Յ12.5 g/dL were randomized (double-blind) to placebo (Nϭ157) or darbepoetin alfa (Nϭ162) subcutaneously every 2 weeks for 1 year (target hemoglobin, 14.0Ϯ1.0 g/dL). The primary end point was change from baseline to week 27 in treadmill exercise time. Secondary end points were change from baseline in New York Heart Association class and quality of life at week 27. An additional prespecified efficacy analysis included the time to death by any cause or first HF-related hospitalization by 1 year. At baseline, the median (interquartile range) hemoglobin was 11.4 (10.9, 12.0) g/dL. At week 27, darbepoetin alfa treatment increased median (interquartile range) hemoglobin by 1.8 (1.1, 2.5) g/dL (placebo, 0.3 [Ϫ0.2, 1.0] g/dL; PϽ0.001). Of the patients treated with darbepoetin alfa, 85% achieved 2 consecutive hemoglobin levels of 14.0Ϯ1.0 g/dL during the study and experienced a hemoglobin increase of Ն1.0 g/dL from baseline. By intent-to-treat analysis, darbepoetin alfa treatment did not significantly improve exercise duration, New York Heart Association class, or quality of life score compared with placebo. A nonsignificant trend was observed toward a lower risk of all-cause mortality or first HF hospitalization in darbepoetin alfa-treated patients compared with placebo (hazard ratio, 0.68; 95% CI, 0.43, 1.08; Pϭ0.10). Occurrences of adverse events were similar in both treatment groups. Conclusions-In this study of patients with symptomatic HF and anemia, treatment with darbepoetin alfa was not associated with significant clinical benefits. Darbepoetin alfa treatment was well tolerated and effectively raised hemoglobin. A trend of lower risk of morbidity and mortality was observed. (Circulation. 2008;117:526-535.)