A Placebo-Controlled, Parallel-Group, Randomized Clinical Trial of AC-1204 in Mild-to-Moderate Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is characterized by amyloid-ß plaques, neurofibrillary tangles, and regional cerebral glucose hypometabolism. Providing an alternative metabolic substrate, such as ketone bodies, may be a viable therapeutic option. OBJECTIVE: The objective was to determine the efficacy and safety of the AC-1204 formulation of caprylic triglyceride administered daily for 26 weeks in APOE4 non-carrier participants with mild-to-moderate AD. METHODS: In a double-blind, placebo-controlled, randomized study (AC-12-010, NOURISH AD, NCT01741194), 413 patients with mild-to-moderate probable AD were stratified by APOE genotype and randomized (1 : 1) to receive either placebo or AC-1204 for 26 weeks. The primary outcome was the change from baseline to week 26 on the 11-item Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog11) among APOE4 non-carriers. The key secondary outcome was the change from baseline to week 26 in the Alzheimer's Disease Cooperative Study - Clinician's Global Impression of Change scale. RESULTS: Administration of AC-1204 was safe and well-tolerated. Mean changes from baseline in the primary outcome at 26 weeks in ADAS-Cog11 for placebo (n = 138) was 0.0 and for AC-1204 (n = 137) was 0.6 (LS differences of mean - 0.761, p = 0.2458) and secondary outcome measures failed to detect any drug effects. CONCLUSION: The AC-1204 formulation of caprylic triglyceride failed to improve cognition or functional ability in subjects with mild-to-moderate AD. The lack of efficacy observed in this study may have several contributing factors including a lower ketone body formation from AC-1204 than expected and a lack of decline in the patients receiving placebo.

Pharmacogenetic analysis of the effects of polymorphisms in APOE, IDE and IL1B on a ketone body based therapeutic on cognition in mild to moderate Alzheimer's disease; a randomized, double-blind, placebo-controlled study.

BACKGROUND: To examine the effect of genetic variation in APOE, IDE and IL1B on the response to induced ketosis in the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) in subjects with mild to moderate Alzheimer's disease (AD). METHODS: Genotype effects on ADAS-Cog scores from a randomized, double-blind, placebo-controlled study in mild to moderate AD were examined by an overall two way analysis of variance. In addition, interactions with the carriage status of the epsilon 4 allele of the APOE gene (APOE4) were examined. RESULTS: Significant differences in response to induced ketosis were found among non-carriers of putative gain-of-function polymorphisms in rs1143627 and rs16944 in the IL1B gene and among variants of the polymorphism rs2251101 in the IDE gene. Significant differences were found among non-carriers of the APOE4 gene, with notable improvement among the E3/E3 genotype group. CONCLUSIONS: Variants in APOE, IL1B and IDE may influence the cognitive response to induced ketosis in patients with mild to moderate AD. TRIAL REGISTRATION: This trial was registered with ClinicalTrials.gov, registry number NCT00142805.

Study of the ketogenic agent AC-1202 in mild to moderate Alzheimer's disease: a randomized, double-blind, placebo-controlled, multicenter trial.

BACKGROUND: Alzheimer's disease (AD) is characterized by early and region-specific declines in cerebral glucose metabolism. Ketone bodies are produced by the body during glucose deprivation and are metabolized by the brain. An oral ketogenic compound, AC-1202, was tested in subjects with probable AD to examine if ketosis could improve cognitive performance. METHODS: Daily administration of AC-1202 was evaluated in 152 subjects diagnosed with mild to moderate AD in a US-based, 90-day, randomized, double-blind, placebo-controlled, parallel-group study. Subjects were on a normal diet and continued taking approved AD medications. Primary cognitive end points were mean change from Baseline in the AD Assessment Scale-Cognitive subscale (ADAS-Cog), and global scores in the AD Cooperative Study - Clinical Global Impression of Change (ADCS-CGIC). AC-1202 was compared to Placebo in several population groups, including: intention-to-treat (ITT), per protocol, and dosage compliant groups. Results were also stratified by APOE4 carriage status (a predefined analysis based on the epsilon 4 (E4) variant of the apolipoprotein E gene). This trial was registered with ClinicalTrials.gov, registry number NCT00142805, information available at http://clinicaltrials.gov/ct2/show/NCT00142805 RESULTS: AC-1202 significantly elevated a serum ketone body (beta-hydroxybutyrate) 2 hours after administration when compared to Placebo. In each of the population groups, a significant difference was found between AC-1202 and Placebo in mean change from Baseline in ADAS-Cog score on Day 45: 1.9 point difference, p = 0.0235 in ITT; 2.53 point difference, p = 0.0324 in per protocol; 2.6 point difference, p = 0.0215 in dosage compliant. Among participants who did not carry the APOE4 allele (E4(-)), a significant difference was found between AC-1202 and Placebo in mean change from Baseline in ADAS-Cog score on Day 45 and Day 90. In the ITT population, E4(-) participants (N = 55) administered AC-1202 had a significant 4.77 point difference in mean change from Baseline in ADAS-Cog scores at Day 45 (p = 0.0005) and a 3.36 point difference at Day 90 (p = 0.0148) compared to Placebo. In the per protocol population, E4(-) participants receiving AC-1202 (N = 37) differed from placebo by 5.73 points at Day 45 (p = 0.0027) and by 4.39 points at Day 90 (p = 0.0143). In the dosage compliant population, E4(-) participants receiving AC-1202 differed from placebo by 6.26 points at Day 45 (p = 0.0011, N = 38) and 5.33 points at Day 90 (p = 0.0063, N = 35). Furthermore, a significant pharmacologic response was observed between serum beta-hydroxybutyrate levels and change in ADAS-Cog scores in E4(-) subjects at Day 90 (p = 0.008). Adverse events occurred more frequently in AC-1202 subjects, were primarily restricted to the gastrointestinal system, and were mainly mild to moderate in severity and transient in nature. CONCLUSION: AC-1202 rapidly elevated serum ketone bodies in AD patients and resulted in significant differences in ADAS-Cog scores compared to the Placebo. Effects were most notable in APOE4(-) subjects who were dosage compliant.

Dietary enrichment with medium chain triglycerides (AC-1203) elevates polyunsaturated fatty acids in the parietal cortex of aged dogs: implications for treating age-related cognitive decline.

Dogs demonstrate an age-related cognitive decline, which may be related to a decrease in the concentration of omega-3 polyunsaturated fatty acids (n-3 PUFA) in the brain. Medium chain triglycerides (MCT) increase fatty acid oxidation, and it has been suggested that this may raise brain n-3 PUFA levels by increasing mobilization of n-3 PUFA from adipose tissue to the brain. The goal of the present study was to determine whether dietary MCT would raise n-3 PUFA concentrations in the brains of aged dogs. Eight Beagle dogs were randomized to a control diet (n = 4) or an MCT (AC-1203) enriched diet (n = 4) for 2 months. The animals were then euthanized and the parietal cortex was removed for phospholipid, cholesterol and fatty acid determinations by gas-chromatography. Dietary enrichment with MCT (AC-1203) resulted in a significant increase in brain phospholipid and total lipid concentrations (P < 0.05). In particular, n-3 PUFA within the phospholipid, unesterified fatty acid, and total lipid fractions were elevated in AC-1203 treated subjects as compared to controls (P < 0.05). Brain cholesterol concentrations did not differ significantly between the groups (P > 0.05). These results indicate that dietary enrichment with MCT, raises n-3 PUFA concentrations in the parietal cortex of aged dogs.

Hypometabolism as a therapeutic target in Alzheimer's disease.

The pathology of Alzheimer's disease (AD) is characterized by cerebral atrophy in frontal, temporal, and parietal regions, with senile plaques, dystrophic neurites, and neurofibrillar tangles within defined areas of the brain. Another characteristic of AD is regional hypometabolism in the brain. This decline in cerebral glucose metabolism occurs before pathology and symptoms manifest, continues as symptoms progress, and is more severe than that of normal aging. Ketone bodies are an efficient alternative fuel for cells that are unable to metabolize glucose or are 'starved' of glucose. AC-1202 is designed to elevate serum ketone levels safely. We previously showed that treatment with AC-1202 in patients with mild-to-moderate AD improves memory and cognition. Treatment outcomes were influenced by apolipoprotein E genotype status. These data suggest that AC-1202 may be an effective treatment for cognitive dysfunction by providing an alternative substrate for use by glucose-compromised neurons.

Ketone bodies as a therapeutic for Alzheimer's disease.

An early feature of Alzheimer's disease (AD) is region-specific declines in brain glucose metabolism. Unlike other tissues in the body, the brain does not efficiently metabolize fats; hence the adult human brain relies almost exclusively on glucose as an energy substrate. Therefore, inhibition of glucose metabolism can have profound effects on brain function. The hypometabolism seen in AD has recently attracted attention as a possible target for intervention in the disease process. One promising approach is to supplement the normal glucose supply of the brain with ketone bodies (KB), which include acetoacetate, beta-hydroxybutyrate, and acetone. KB are normally produced from fat stores when glucose supplies are limited, such as during prolonged fasting. KB have been induced both by direct infusion and by the administration of a high-fat, low-carbohydrate, low-protein, ketogenic diets. Both approaches have demonstrated efficacy in animal models of neurodegenerative disorders and in human clinical trials, including AD trials. Much of the benefit of KB can be attributed to their ability to increase mitochondrial efficiency and supplement the brain's normal reliance on glucose. Research into the therapeutic potential of KB and ketosis represents a promising new area of AD research.

Induction of ketosis may improve mitochondrial function and decrease steady-state amyloid-beta precursor protein (APP) levels in the aged dog.

Region specific declines in the cerebral glucose metabolism are an early and progressive feature of Alzheimer's disease (AD). Such declines occur pre-symptomatically and offer a potential point of intervention in developing AD therapeutics. Medium chain triglycerides (MCTs), which are rapidly converted to ketone bodies, were tested for their ability to provide an alternate energy source to neurons suffering from compromised glucose metabolism. The present study determined the short-term effects of ketosis in aged dogs, a natural model of amyloidosis. The animals were administered a 2 g/kg/day dose of MCTs for 2 months. Mitochondrial function and oxidative damage assays were then conducted on the frontal and parietal lobes. Amyloid-beta (Abeta), amyloid precursor protein (APP) processing and beta-site APP cleaving enzyme (BACE1) assays were conducted on the frontal, parietal and occipital lobes. Aged dogs receiving MCTs, as compared to age-matched controls, showed dramatically improved mitochondrial function, as evidenced by increased active respiration rates. This effect was most prominent in the parietal lobe. The improved mitochondrial function may have been due to a decrease in oxidative damage, which was limited to the mitochondrial fraction. Steady-state APP levels were also decreased in the parietal lobe after short-term MCT administration. Finally, there was a trend towards a decrease in total Abeta levels in the parietal lobe. BACE1 levels remained unchanged. Combined, these findings suggest that short-term MCT administration improves energy metabolism and decreases APP levels in the aged dog brain.

daf-16 protects the nematode Caenorhabditis elegans during food deprivation.

Inhibition of either the insulin-like or target of rapamycin (TOR) pathways in the nematode Caenorhabditis elegans extends life span. Here, we demonstrate that starvation and inhibition of the C. elegans insulin receptor homolog (daf-2) elicits a daf-16-dependent up-regulation of a mitochondrial superoxide dismutase (sod-3). We also find that although heat and oxidative stress result in nuclear localization of the DAF-16 protein, these stressors do not activate a SOD-3 reporter, suggesting that nuclear localization alone may not be sufficient for transcriptional activation of DAF-16. We show that inhibition of either TOR activity or key components of the cognate translational machinery (eIF-4G and EIF-2B homologs) increases life span by both daf-16-dependent and -independent mechanisms. Finally, we demonstrate that at least one nematode hexokinase is localized to the mitochondria. We propose that the increased life spans conferred by alterations in both the TOR and insulin-like pathways function by inappropriately activating food-deprivation pathways.

A ketogenic diet reduces amyloid beta 40 and 42 in a mouse model of Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disorder that primarily strikes the elderly. Studies in both humans and animal models have linked the consumption of cholesterol and saturated fats with amyloid-beta (Abeta) deposition and development of AD. Yet, these studies did not examine high fat diets in combination with reduced carbohydrate intake. Here we tested the effect of a high saturated fat/low carbohydrate diet on a transgenic mouse model of AD. RESULTS: Starting at three months of age, two groups of female transgenic mice carrying the "London" APP mutation (APP/V717I) were fed either, a standard diet (SD) composed of high carbohydrate/low fat chow, or a ketogenic diet (KD) composed of very low carbohydrate/high saturated fat chow for 43 days. Animals fed the KD exhibited greatly elevated serum ketone body levels, as measured by beta-hydroxybutyrate (3.85 +/- 2.6 mM), compared to SD fed animals (0.29 +/- 0.06 mM). In addition, animals fed the KD lost body weight (SD 22.2 +/- 0.6 g vs. KD 17.5 +/- 1.4 g, p = 0.0067). In contrast to earlier studies, the brief KD feeding regime significantly reduced total brain Abeta levels by approximately 25%. Despite changes in ketone levels, body weight, and Abeta levels, the KD diet did not alter behavioral measures. CONCLUSION: Previous studies have suggested that diets rich in cholesterol and saturated fats increased the deposition of Abeta and the risk of developing AD. Here we demonstrate that a diet rich in saturated fats and low in carbohydrates can actually reduce levels of Abeta. Therefore, dietary strategies aimed at reducing Abeta levels should take into account interactions of dietary components and the metabolic outcomes, in particular, levels of carbohydrates, total calories, and presence of ketone bodies should be considered.

Reduced expression of frataxin extends the lifespan of Caenorhabditis elegans.

Defects in the expression of the mitochondrial protein frataxin cause Friedreich's ataxia, an hereditary neurodegenerative syndrome characterized by progressive ataxia and associated with reduced life expectancy in humans. Homozygous inactivation of the frataxin gene results in embryonic lethality in mice, suggesting that frataxin is required for organismic survival. Intriguingly, the inactivation of many mitochondrial genes in the nematode Caenorhabditis elegans by RNAi extends lifespan. We therefore investigated whether inactivation of frataxin by RNAi-mediated suppression of the frataxin homolog gene (frh-1) would also prolong lifespan in the nematode. Frataxin-deficient animals have a small body size, reduced fertility and altered responses to oxidative stress. Importantly, frataxin suppression by RNAi significantly extends lifespan in C. elegans.

Effects of beta-hydroxybutyrate on cognition in memory-impaired adults.

Glucose is the brain's principal energy substrate. In Alzheimer's disease (AD), there appears to be a pathological decrease in the brain's ability to use glucose. Neurobiological evidence suggests that ketone bodies are an effective alternative energy substrate for the brain. Elevation of plasma ketone body levels through an oral dose of medium chain triglycerides (MCTs) may improve cognitive functioning in older adults with memory disorders. On separate days, 20 subjects with AD or mild cognitive impairment consumed a drink containing emulsified MCTs or placebo. Significant increases in levels of the ketone body beta-hydroxybutyrate (beta-OHB) were observed 90 min after treatment (P=0.007) when cognitive tests were administered. beta-OHB elevations were moderated by apolipoprotein E (APOE) genotype (P=0.036). For 4+ subjects, beta-OHB levels continued to rise between the 90 and 120 min blood draws in the treatment condition, while the beta-OHB levels of 4- subjects held constant (P<0.009). On cognitive testing, MCT treatment facilitated performance on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) for 4- subjects, but not for 4+ subjects (P=0.04). Higher ketone values were associated with greater improvement in paragraph recall with MCT treatment relative to placebo across all subjects (P=0.02). Additional research is warranted to determine the therapeutic benefits of MCTs for patients with AD and how APOE-4 status may mediate beta-OHB efficacy.

High carbohydrate diets and Alzheimer's disease.

Alzheimer's disease (AD) is a common, progressive, neurodegenerative disease that primarily afflicts the elderly. A well-defined risk factor for late onset AD is possession of one or more alleles of the epsilon-4 variant (E4) of the apolipoprotein E gene. Meta-analysis of allele frequencies has found that E4 is rare in populations with long historical exposure to agriculture, suggesting that consumption of a high carbohydrate (HC) diet may have selected against E4 carriers. The apoE4 protein alters lipid metabolism in a manner similar to a HC diet, suggesting a common mechanism for the etiology of AD. Evolutionarily discordant HC diets are proposed to be the primary cause of AD by two general mechanisms. (1) Disturbances in lipid metabolism within the central nervous system inhibits the function of membrane proteins such as glucose transporters and the amyloid precursor protein. (2) Prolonged excessive insulin/IGF signaling accelerates cellular damage in cerebral neurons. These two factors ultimately lead to the clinical and pathological course of AD. This hypothesis also suggests several preventative and treatment strategies. A change in diet emphasizing decreasing dietary carbohydrates and increasing essential fatty acids (EFA) may effectively prevent AD. Interventions that restore lipid homeostasis may treat the disease, including drugs that increase fatty acid metabolism, EFA repletion therapy, and ketone body treatment.

The C. elegans Hand gene controls embryogenesis and early gonadogenesis.

The C. elegans genome encodes a single Hand bHLH transcription factor. Either hnd-1(RNAi) or a hnd-1 deletion causes partially penetrant defects in viability and gonadogenesis. Dead embryos and young larvae are often misshapen at the posterior end. Our primary focus has been the role of hnd-1 in gonadogenesis. Wild-type C. elegans has two somatic gonadal precursors and two primordial germ cells in stereotyped positions within its four-celled gonadal primordium. The hnd-1 gene affects the presence and position of both the somatic gonadal precursors and primordial germ cells within the primordium, but does not appear to have any role in later gonadogenesis. hnd-1 probably acts within the somatic gonadal precursors or their mesodermal predecessors; defects in primordial germ cells and germ line appear to be secondary. In hnd-1 mutants, somatic gonadal precursors are generated normally, but are not maintained properly and sometimes die. A similar role in controlling the maintenance of precursor fates has been described for other genes governing early organogenesis, including the zebrafish Hand gene hands off. We also report the discovery of two genes, ehn-1 and ehn-3, that have overlapping functions with hnd-1 in embryogenesis and gonadogenesis.