Design of the NL-ENIGMA study: Exploring the effect of Souvenaid on cerebral glucose metabolism in early Alzheimer's disease

The impact of a multi-domain intervention on cerebral glucose metabolism: analysis from the randomized ancillary FDG PET MAPT trial

Background

The Multidomain Alzheimer Preventive Trial (MAPT) was designed to assess the efficacy of omega-3 fatty acid supplementation, multidomain intervention (MI), or a combination of both on cognition. Although the MAPT study was negative, an effect of MI in maintaining cognitive functions compared to placebo group was showed in positive amyloid subjects. A FDG PET study (MAPT-NI) was implemented to test the impact of MI on brain glucose metabolism.

Methods

MAPT-NI was a randomized, controlled parallel-group single-center study, exploring the effect of MI on brain glucose metabolism. Participants were non-demented and had memory complaints, limitation in one instrumental activity of daily living, or slow gait. Participants were randomly assigned (1:1) to “MI group” or “No MI group.” The MI consisted of group sessions focusing on 3 domains: cognitive stimulation, physical activity, nutrition, and a preventive consultation. [¹⁸F]FDG PET scans were performed at baseline, 6 months, and 12 months, and cerebral magnetic resonance imaging scans at baseline. The primary objective was to evaluate the MI effect on brain glucose metabolism assessed by [¹⁸F]FDG PET imaging at 6 months. The primary outcome was the quantification of regional metabolism rate for glucose in cerebral regions involved early in Alzheimer disease by relative semi-quantitative SUVr (FDG-based AD biomarker). An exploratory voxel-wise analysis was performed to assess the effect of MI on brain glucose metabolism without anatomical hypothesis.

Results

The intention-to-treat population included 67 subjects (34 in the MI group and 33 in the No MI group. No significant MI effect was observed on primary outcome at 6 months. In the exploratory voxel-wise analysis, we observed a difference in favor of MI group on the change of cerebral glucose metabolism in limbic lobe (right hippocampus, right posterior cingulate, left posterior parahippocampal gyrus) at 6 months.

Conclusions

MI failed to show an effect on metabolism in FDG-based AD biomarker, but exploratory analysis suggested positive effect on limbic system metabolism. This finding could suggest a delay effect of MI on AD progression.

Trial registration

ClinicalTrials.gov Identifier, NCT01513252.

Exploring effects of Souvenaid on cerebral glucose metabolism in Alzheimer's disease

Introduction

Alzheimer's disease (AD) is associated with synapse loss. Souvenaid, containing the specific nutrient combination Fortasyn Connect, was designed to improve synapse formation and function. The NL-ENIGMA study explored the effect of Souvenaid on synapse function in early AD by assessing cerebral glucose metabolism (CMRglc) with ¹⁸F-fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography (PET).

Methods

We conducted an exploratory double-blind randomized controlled single-center trial. Fifty patients with mild cognitive impairment or mild dementia with evidence of amyloid pathology (cerebrospinal fluid or PET) were stratified for MMSE (20-24 and 25-30) and randomly 1:1 allocated to 24-week daily administration of 125 mL Souvenaid (n = 25) or placebo (n = 25). Dynamic 60-minute [¹⁸F]FDG-PET scans (21 frames) with arterial sampling were acquired at baseline and 24 weeks. CMRglc was estimated by quantitative (K_i) and semiquantitative (standardized uptake value ratio, reference cerebellar gray matter) measurements in five predefined regions of interest and a composite region of interest. Change from baseline in CMRglc was compared between treatment groups by analysis of variance, adjusted for baseline CMRglc and MMSE stratum. Additional exploratory outcome parameters included voxel-based analyses by Statistical Parametric Mapping.

Results

No baseline differences between treatment groups were found (placebo/intervention: n = 25/25; age 66 ± 8/65 ± 7 years; female 44%/48%; MMSE 25 ± 3/25 ± 3). [¹⁸F]FDG-PET data were available for quantitative (placebo n = 19, intervention n = 18) and semiquantitative (placebo n = 20, intervention n = 22) analyses. At follow-up, no change within treatment groups and no statistically significant difference in change between treatment groups in CMRglc in any regions of interest were found by both quantitative and semiquantitative analyses. No treatment effect was found in the cerebellar gray matter using quantitative measures. The additional Statistical Parametric Mapping analyses did not yield consistent differences between treatment groups.

Discussion

In this exploratory trial, we found no robust effect of 24-week intervention with Souvenaid on synapse function measured by [¹⁸F]FDG-PET. Possible explanations include short duration of treatment.

Mild Cognitive Impairment with a High Risk of Progression to Alzheimer's Disease Dementia (MCI-HR-AD): Effect of Souvenaid® Treatment on Cognition and 18F-FDG PET Scans

Background:

Previous studies have shown that Souvenaid (medical food) can have benefits on memory, cognition, and function in early Alzheimer’s disease (AD) and mild cognitive impairment (MCI).

Objective:

Demonstrate that Souvenaid could improve or maintain cognition and has an effect on neurodegeneration biomarkers.

Methods:

This cohort study was carried out from June 2015 through December 2016 in the Neurology Department, Infanta Cristina Hospital, Madrid, Spain. MCI-HR-AD were recruited using Petersen criteria, neuropsychology (NPS), and ¹⁸F-FDG PET scans to confirm the high risk of progression to dementia with one year of follow-up. Age, sex, vascular risk factors (VRF), and NPS values (Barcelona brief version) were analyzed. ¹⁸F-FDG PET scans were analyzed as a visual procedure. The study was approved by the Research Committee of ICH. Statistical analysis was made with SPSS 22.0 version.

Results:

Subjects included 43 MCI patients (58.5% women; mean age 69.78±7.89): 17 receiving Souvenaid^® treatment (ST), 24 receiving no treatment (WT) and 2 who withdrew. No differences were seen in VRF, only hypercholesterolemia, and were less prevalent in the ST group (p = 0.002). The rate of progression to dementia was 48.8% (no differences between groups, p = 0.654). A second round of ¹⁸F-FDG PET scans showed a significance worsening of glucose metabolism in WT (p = 0.001) versus ST, in which it was low (p = 0.050). For NPS testing, there was a significant worsening in memory performance in the WT group (p = 0.011) and a stabilization in ST (p = 0.083), as well as in executive functions and attention (worsening in WT, p = 0.014). For the Subjective Changing Scale (SCS), caregivers indicated a stabilization/improvement in ST (p = 0.017).

Conclusion:

Souvenaid had a significant effect on several cognitive domains, and on SCS in patients with MCI-HR-AD. Its intervention had an impact on preservation on ¹⁸F-FDG PET scans.

The medical food Souvenaid affects brain phospholipid metabolism in mild Alzheimer's disease: results from a randomized controlled trial

Background

Synaptic dysfunction contributes to cognitive impairment in Alzheimer’s disease and may be countered by increased intake of nutrients that target brain phospholipid metabolism. In this study, we explored whether the medical food Souvenaid affects brain phospholipid metabolism in patients with Alzheimer’s disease.

Methods

Thirty-four drug-naive patients with mild Alzheimer’s disease (Mini Mental State Examination score ≥20) were enrolled in this exploratory, double-blind, randomized controlled study. Before and after 4-week intervention with Souvenaid or an isocaloric control product, phosphorus and proton magnetic resonance spectroscopy (MRS) was performed to assess surrogate measures of phospholipid synthesis and breakdown (phosphomonoesters [PME] and phosphodiesters [PDEs]), neural integrity (N-acetyl aspartate), gliosis (myo-inositol), and choline metabolism (choline-containing compounds [tCho]). The main outcome parameters were PME and PDE signal intensities and the PME/PDE ratio.

Results

MRS data from 33 patients (60–86 years old; 42% males; Souvenaid arm n = 16; control arm n = 17) were analyzed. PME/PDE and tCho were higher after 4 weeks of Souvenaid compared with control (PME/PDE least squares [LS] mean difference [95% CI] 0.18 [0.06–0.30], p = 0.005; tCho LS mean difference [95% CI] 0.01 [0.00–0.02], p = 0.019). No significant differences were observed in the other MRS outcome parameters.

Conclusions

MRS reveals that Souvenaid affects brain phospholipid metabolism in mild Alzheimer’s disease, in line with findings in preclinical studies.

Trial registration

Netherlands Trial Register, NTR3346. Registered on 13 March 2012.

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-017-0286-2) contains supplementary material, which is available to authorized users.