Toward precision medicine : sex-specific effects of multi-drug therapies in mouse models of aging and Alzheimer's pathology

<p dir="ltr">As the population ages and comorbidities rise, concurrent use of multiple drugs (≥5, polypharmacy) has become a major challenge in geriatric medicine. While often necessary to manage chronic conditions, polypharmacy is also associated with increased risks, including functional decline and cognitive impairment. Yet, the biological mechanisms underlying these effects, and how they are shaped by age, sex, and pathological background, remain poorly understood. Notably, common age-related comorbidities such as cardiovascular conditions, and depression are also risk factors for Alzheimer's disease and related dementias (ADRD), and medications prescribed for their management, including some antihypertensives and antidepressants, are being investigated as repurposed therapies to prevent or slow AD progression.</p><p dir="ltr">This doctoral thesis aimed to investigate the impact of multi-drug therapies using mouse models of aging and AD-related pathology, focusing on sex-specific outcomes and mechanistic insights.</p><p dir="ltr">In <b>Papers I, II, and III</b>, we administered polypharmacy regimens comprising cardiovascular, analgesic, and antipsychotic agents to resemble common multi- drug therapies in older adults in Sweden. The tested regimens included: combination #1 (metoprolol, simvastatin, aspirin, paracetamol, and citalopram) and combination #2 (enalapril, atorvastatin, aspirin, paracetamol, and citalopram). In addition, selected monotherapies (metoprolol, simvastatin, and citalopram) were evaluated for comparison with the multi-drug treatments (in <b>Papers II </b>and<b> III</b>).</p><p dir="ltr">Papers <b>I and II</b> investigated the impact of these treatments in wild-type (WT) mice at different adult life stages. In young adult female WT mice (<b>Paper I</b>), long-term polypharmacy altered locomotion, and recognition memory, accompanied by downregulation of hippocampal synaptic proteins. In aged WT mice (<b>Paper II</b>), we identified pronounced sex-specific effects that varied depending on the drug combination. In males, both regimens induced negative outcomes on locomotor activity, stress-related responses, and cognitive functions, whereas females appeared more resilient. Serum metabolomic profiling, particularly in males exposed to combination #1, revealed a marked downregulation of metabolites including serotonin, lysophospholipids, ornithine, methionine, and other amino compounds linked to age-related pathways. In male mice, but not in females, these alterations were paralleled by a reduction in serotonergic receptor expression in the brain. Monotherapies recapitulated a small subset of outcomes induced by multi-drug regimens, highlighting the complexity of polypharmacy effects.</p><p dir="ltr"><b>Paper III</b> extended these investigations to App^NL-G-F knock-in (APP KI) mice, a model of AD-like amyloid pathology. In males, combination #1 improved cognitive performance and reduced amyloid plaque load, amyloidogenic enzyme levels, and microglial marker expression in the brain. However, substituting two drugs within the same regimen abolished these benefits in males and even impaired memory and learning in females. In females, polypharmacy did not markedly affect molecular readouts, whereas some monotherapies altered glial proteins such as Iba1 and GFAP. Notably, in males receiving combination #1, we detected upregulation of metabolomic pathways commonly dysregulated in AD, including kynurenine, carnitines, and fatty acids, which may underlie the cognitive benefits observed. Remarkably, the same metabolite classes were strongly reduced in females receiving this treatment.</p><p dir="ltr">In <b>Paper IV</b>, we compared the effects of a multimodal lifestyle intervention to a pharmacological intervention, in WT mice, as well as in CYP27A1 (CYP27Tg), and APP KI transgenic mice, models of cholesterol dysmetabolism and amyloid pathology. The lifestyle intervention improved memory in WT and APP KI mice, while proteomics revealed enhanced synaptic plasticity pathways in WTs and restoration of neuroinflammatory and immune processes in CYP27Tg mice despite limited cognitive effects. By contrast, the pharmacological intervention (atorvastatin and enalapril) did not influence behavior in WT mice but decreased memory performance in CYP27Tg and APP KI cohorts. Proteomic analysis showed a marked downregulation of proteins associated with synaptogenesis, synaptic plasticity, and glutamatergic signaling in CYP27Tg mice treated with pharmacological prevention, whereas the hippocampal proteome of WT and APP KI animals remained largely unaffected.</p><p dir="ltr">Collectively, this thesis demonstrates that polypharmacy outcomes are shaped by age, sex, and disease background. Depending on drug composition and biological context, multi-drug regimens impaired or had beneficial effects on functional and cognitive abilities, influencing domains linked to aging and disease.</p><p dir="ltr">These findings provide key insights into the molecular signatures of polypharmacy, informing precision medicine for aging and ADRD, and highlight the importance of sex and vulnerable groups when weighing harms and benefits.</p><h3>List of scientific papers</h3><p dir="ltr">I. <b>Francesca Eroli</b>, Kristina Johnell, Maria Latorre-Leal, Sarah N Hilmer, Jonas W Wastesson, Angel Cedazo-Minguez, Silvia Maioli. Long-term exposure to polypharmacy impairs cognitive functions in young adult female mice. Aging. 2021 Jun 2;13(11):14729-14744. <a href="https://doi.org/10.18632/aging.203132">https://doi.org/10.18632/aging.203132</a></p><p dir="ltr">II. <b>Francesca Eroli</b>, Kristina Johnell, Patricia Rodriguez-Rodriguez, Maria Latorre-Leal, Jonas W Wastesson, Sarah N Hilmer, Angel Cedazo- Minguez, Silvia Maioli. Sex differences in vulnerability to polypharmacy drive cognitive, functional, and metabolic alterations in aged mice. [Manuscript]</p><p dir="ltr">III. <b>Francesca Eroli</b>, Kristina Johnell, Zeynep Acararicin, Christina Tsagkogianni, Stefania Zerial, Saverio Lancia, Maria Latorre-Leal, Vilma Alanko, Sarah N Hilmer, Anna Matton, Jonas W Wastesson, Angel Cedazo-Minguez, Silvia Maioli. Commonly prescribed multi-medication therapies exert sex- specific effects on Alzheimer's disease pathology and metabolomic profiles in AppNL-G-F mice: Implications for personalized therapeutics in aging, Alzheimers Dement. 2025 Mar;21(3):e70081. <a href="https://doi.org/10.1002/alz.70081">https://doi.org/10.1002/alz.70081</a></p><p dir="ltr">IV. Vilma Alanko, <b>Francesca Eroli</b>, Ákos Végvári, Alina Solomon, Tobias Hartmann, Per Nilsson, Miia Kivipelto, Silvia Maioli, Anna Matton. Mouse PAW: reverse-translation of the FINGER multimodal lifestyle trial improves memory and dementia-related mechanisms in female mice [Manuscript]</p>