PRION-1 scales analysis supports use of functional outcome measures in prion disease.

OBJECTIVES: Human prion diseases are heterogeneous but invariably fatal neurodegenerative disorders with no known effective therapy. PRION-1, the largest clinical trial in prion disease to date, showed no effect of the potential therapeutic quinacrine on survival. Although there are several limitations to the usefulness of survival as an outcome measure, there have been no comprehensive studies of alternatives. METHODS: To address this we did comparative analyses of neurocognitive, psychiatric, global, clinician-rated, and functional scales, focusing on validity, variability, and impact on statistical power over 77 person-years follow-up in 101 symptomatic patients in PRION-1. RESULTS: Quinacrine had no demonstrable benefit on any of the 8 scales (p > 0.4). All scales had substantial numbers of patients with the worst possible score at enrollment (Glasgow Coma Scale score being least affected) and were impacted by missing data due to disease progression. These effects were more significant for cognitive/psychiatric scales than global, clinician-rated, or functional scales. The Barthel and Clinical Dementia Rating scales were the most valid and powerful in simulated clinical trials of an effective therapeutic. A combination of selected subcomponents from these 2 scales gave somewhat increased power, compared to use of survival, to detect clinically relevant effects in future clinical trials of feasible size. CONCLUSIONS: Our findings have implications for the choice of primary outcome measure in prion disease clinical trials. Prion disease presents the unusual opportunity to follow patients with a neurodegenerative disease through their entire clinical course, and this provides insights relevant to designing outcome measures in related conditions.

Maternal nutrient restriction in early pregnancy programs hepatic mRNA expression of growth-related genes and liver size in adult male sheep.

The liver is a major metabolic and endocrine organ of critical importance in the regulation of growth and metabolism. Its function is determined by a complex interaction of nutritionally regulated counter-regulatory hormones. The extent to which hepatic endocrine sensitivity can be programed in utero and whether the resultant adaptations persist into adulthood is unknown and was therefore the subject of this study. Young adult male sheep born to mothers that were fed either a control diet (i.e.100% of total live weight-maintenance requirements) throughout gestation or 50% of that intake (i.e. nutrient restricted (NR)) from 0 to 95 days gestation and thereafter 100% of requirements (taking into account increasing fetal mass) were entered into the study. All mothers gave birth normally at term, the singleton offspring were weaned at 16 weeks, and then reared at pasture until 3 years of age when their livers were sampled. NR offspring were of similar birth and body weights at 3 years of age when they had disproportionately smaller livers than controls. The abundance of mRNA for GH, prolactin, and IGF-II receptors, plus hepatocyte growth factor and suppressor of cytokine signaling-3 were all lower in livers of NR offspring. In contrast, the abundance of the mitochondrial protein voltage-dependent anion channel and the pro-apoptotic factor Bax were up regulated relative to controls. In conclusion, maternal nutrient restriction in early gestation results in adult offspring with smaller livers. This may be mediated by alterations in both hepatic mitogenic and apoptotic factors.

Influence of maternal pre-pregnancy body composition and diet during early-mid pregnancy on cardiovascular function and nephron number in juvenile sheep.

The prenatal diet can program an individual's cardiovascular system towards later higher resting blood pressure and kidney dysfunction, but the extent to which these programmed responses are directly determined by the timing of maternal nutritional manipulation is unknown. In the present study we examined whether maternal nutrient restriction targeted over the period of maximal placental growth, i.e. days 28-80 of gestation, resulted in altered blood pressure or kidney development in the juvenile offspring. This was undertaken in 6-month-old sheep born to mothers fed control (100-150 % of the recommended metabolisable energy (ME) intake for that stage of gestation) or nutrient-restricted (NR; 50 % ME; n 6) diets between days 28 and 80 of gestation. Controls were additionally grouped according to normal (>3, n 7) or low body condition score (LBCS; <2, n 6), thereby enabling us to examine the effect of maternal body composition on later cardiovascular function. From day 80 to term (approximately 147 d) all sheep were fed to 100 % ME. Offspring were weaned at 12 weeks and pasture-reared until 6 months of age when cardiovascular function was determined. Both LBCS and NR sheep tended to have lower resting systolic (control, 85 (se 2); LBCS, 77 (se 3); NR, 77 (se 3) mmHg) and diastolic blood pressure relative to controls. Total nephron count was markedly lower in both LBCS and NR relative to controls (LBCS, 59 (se 6); NR, 56 (se 12) %). Our data suggest that maternal body composition around conception is as important as the level of nutrient intake during early pregnancy in programming later cardiovascular health.

Impact of maternal undernutrition and fetal number on glucocorticoid, growth hormone and insulin-like growth factor receptor mRNA abundance in the ovine fetal kidney.

Epidemiological and animal studies strongly indicate that the environment experienced in utero determines, in part, an individual's likelihood of developing cardiovascular disease in later life. This risk has been further linked to impaired kidney function, as a result of compromised development during fetal life. The present study therefore examined the influence of maternal nutrient restriction (NR), targeted at specific periods of kidney development during early to mid gestation, on the mRNA abundance of receptors for glucocorticoid (GCR), growth hormone (GHR) and insulin-like growth factors-I (IGF-IR) and -II (IGF-IIR), and the IGF-I and -II ligands. This was undertaken in both singleton and twin fetuses. At conception ewes were randomly allocated to either an adequately fed control group or one of four nutrient-restricted groups that were fed half the control amount from 0 to 30, 31 to 65, 66 to 110 or 0 to 110 days gestation. At 110 days gestation all ewes were humanely euthanased and fetal kidneys and surrounding adipose tissue sampled. There was no effect of NR or fetal number on kidney weight, shape or nephron number, but the surrounding fat mass was increased in singleton fetuses exposed to NR for 110 days. An increase in kidney mRNA abundance with NR only occurred in singleton fetuses where IGF-IR mRNA was enhanced with NR from 66-110 days gestation. In twin fetuses, NR had no effect on mRNA abundance. However, for all genes examined mRNA expression was lower in the kidneys of twin compared with singleton fetuses following NR, and the magnitude of the effect was dependent on the timing of NR. In conclusion, the abundance of mRNA for receptors which regulate fetal kidney development are lower in twin animals compared with singletons following periods of nutrient deficiency. This may impact on later kidney development and function.

Programming of adult cardiovascular function after early maternal undernutrition in sheep.

The prenatal nutritional environment influences the subsequent risk of hypertension in adulthood. Animal studies have used, generally, the rat as a model species to illustrate the association between maternal nutrient intake and blood pressure in the resulting adult offspring. No study to date has shown programming of adult cardiovascular function in the sheep through maternal dietary intervention. We therefore fed pregnant sheep to either 100% recommended intake from day 0 of gestation to term [ approximately 147 days gestational age (dGA); controls n = 8] or to 50% recommended intake from day 0 to 95 dGA and thereafter to 100% intake (NR; n = 9). Sheep lambed naturally, offspring were weaned at 16 wk, and the male offspring were reared on pasture until 3 yr of age. At this time, cardiovascular catheters were inserted under halothane anesthesia and sheep were allowed 2-4 days recovery. Basal cardiovascular status and pressor responses to infusion of norepinephrine, angiotensin II, and captopril were then assessed alongside basal plasma concentrations of glucose, cortisol, and leptin. NR sheep were of similar birth weight to controls but at 3 yr of age had higher blood pressure before, but not after, feeding. Peripheral sensitivity to vasoconstrictor infusion was similar between dietary groups, although a reflex bradycardia was not apparent in NR sheep during norepinephrine infusion. Circulating leptin correlated well with fat mass and increased more after vasoconstrictor infusion in NR sheep. In conclusion, early NR has been shown to program aspects of cardiovascular control and adipocyte function in adult sheep.

Maternal endocrine adaptation throughout pregnancy to nutritional manipulation: consequences for maternal plasma leptin and cortisol and the programming of fetal adipose tissue development.

Maternal nutrient restriction at specific stages of gestation has differential effects on fetal development such that the offspring are programmed to be at increased risk of adult disease. We investigated the effect of gestational age and maternal nutrition on the maternal plasma concentration of leptin and cortisol together with effects on fetal adipose tissue deposition plus leptin, IGF-I, IGF-II ligand, and receptor mRNA abundance near to term. Singleton bearing ewes were either nutrient restricted (NR; consuming 3.2-3.8 MJ/d of metabolizable energy) or fed to appetite (consuming 8.7-9.9 MJ/d) over the period of maximal placental growth, i.e. between 28 and 80 d gestation. After 80 d gestation, ewes were either fed to calculated requirements, consuming 6.7-7.5 MJ/d, or were fed to appetite and consumed 8.0-10.9 MJ/d. Pregnancy resulted in a rise in plasma leptin concentration by 28 d gestation, which continued up to 80 d gestation when fed to appetite but not with nutrient restriction. Plasma cortisol was also lower in NR ewes up to 80 d gestation, a difference no longer apparent when food intake was increased. At term, irrespective of maternal nutrition in late gestation, fetuses sampled from ewes NR in early gestation possessed more adipose tissue, whereas when ewes were fed to appetite throughout gestation, fetal adipose tissue deposition and leptin mRNA abundance were both reduced. These changes may result in the offspring of NR mothers being at increased risk of obesity in later life.