Autophagy-Enhancers to Reduce Sleep Disturbances

This clinical trial investigates the effects of spermidine supplementation on sleep quality and sleep-dependent memory consolidation in older adults with Subjective Cognitive Decline (SCD) or Mild Cognitive Impairment (MCI), two populations at increased risk of future cognitive decline and dementia. Impaired sleep has been identified as a modifiable factor contributing to cognitive decline, and interventions targeting sleep architecture could offer therapeutic potential to prevent or slow down this decline. Spermidine is a naturally occurring polyamine found in foods such as wheat germ and soybeans. It induces autophagy, a cellular degradation and recycling process essential for neuronal maintenance and function. In animal studies, spermidine has been shown to improve memory performance, reduce neuroinflammation, and support mitochondrial health. Preliminary findings from human trials in individuals with SCD or MCI suggest potential cognitive benefits of spermidine, but results are not unequivocal, and the impact on sleep has not been systematically evaluated. In this randomized, double-blind, placebo-controlled trial, 76 participants aged 55 to 70 years with SCD or MCI will receive either spermidine (6 mg/day) or a placebo for 12 weeks. Sleep will be evaluated using overnight EEG in a controlled laboratory setting, focusing on measures such as slow-wave sleep and sleep spindle activity. Memory performance will be assessed before and after the intervention using standardized neuropsychological testing. Numerical skills will be tested at baseline only to compare SCD and MCI participants with healthy controls. Blood samples will be collected to quantify metabolic indicators, neurodegeneration-related biomarkers, and autophagy-associated proteins. A control group of 38 cognitively healthy individuals will undergo comparable sleep and cognitive assessments without receiving any supplementation. The primary objective of the study is to characterize the impact of spermidine on sleep-dependent memory consolidation and to identify associated biological changes relevant to aging and neurodegeneration. The results may inform the development of non-pharmacological strategies aimed at preserving cognitive function in individuals at risk for dementia.

Inclusion Criteria (SCD participants): * Men and women * Written consent to participate in the study * German at native speaker level * Age between 55 and 70 years * Subjective Cognitive Decline operationalized as: 1. Subjectively reported decline in cognitive function (particularly memory) despite objectively normal cognitive performance (e.g., WMS-LM) 2. Preservation of functional independence 3. No dementia Inclusion Criteria (MCI patients): * Men and women * Written consent to participate in the study * German at native speaker level * Age between 55 and 70 years * Mild cognitive impairment (MCI) operationalized as: 1. A change in cognitive abilities reported by the patient, relatives or clinic staff (i.e. historical or observed evidence of deterioration over time) 2. Objective evidence of memory impairment (at least 1.0 Standard Deviation (SD) below the normal range on the Wechsler Logical Memory Scale (WMS-LM)); other cognitive domains may also be affected (i.e. amnestic MCI and amnestic + MCI) 3. Preservation of independence of functional abilities 4. No dementia Exclusion Criteria (SCD and MCI participants): * Patients who are unable to give informed consent * Polyamine intake via dietary supplements and/or participation in corresponding intervention studies * Dementia according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) * Any condition that impairs clinical or neuropsychological examination procedures * Diabetes mellitus * Polycystic ovary syndrome * Signs of epilepsy, focal brain lesion or head injury with loss of consciousness or immediate post-injury confusion * Previous stroke * Severe untreated medical problems or unstable medical condition * Current major depressive episode * Psychotic disorder * Bipolar disorder * Current or previous substance abuse * Other neurodegenerative disease, e.g. Parkinson's disease * Vascular dementia * Alcohol abuse * Participation in an interventional study in the last 3 months and during the entire study period * Sleep disorders * Taking medication that primarily affects the central nervous system (e.g. antipsychotics, antidepressants, benzodiazepines or any type of over-the-counter sleep-inducing medication such as valerian; anti-dementia medication) * Known intolerances or allergies to wheat germ, gluten or histamine Inclusion criteria (healthy controls): * Men and women * Written consent to participate in the study * German at native speaker level * Age between 55 and 70 years * Subjective cognitive disorders are denied Exclusion criteria (healthy controls): * Subjects who are not able to give informed consent * Polyamine intake via dietary supplements and/or participation in corresponding intervention studies * Dementia according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) * Mild cognitive impairment (MCI), defined as described above in the patient inclusion criteria * Any condition that interferes with clinical or neuropsychological examination procedures * Diabetes mellitus * Polycystic ovary syndrome * Signs of epilepsy, focal brain lesion or head injury with loss of consciousness or immediate post-injury confusion * Previous stroke * Severe untreated medical problems or unstable medical condition * Current major depressive episode * Psychotic disorder * Bipolar disorder * Current or past substance abuse * Other neurodegenerative disease, e.g. Parkinson's disease * Vascular dementia * Alcohol abuse * Participation in an interventional study in the last 3 months and during the entire study period * Sleep disorders * Taking medication that primarily affects the central nervous system (e.g. antipsychotics, antidepressants, benzodiazepines or any type of over-the-counter sleep-inducing medication such as valerian; anti-dementia medication)