J Neurol Res

Journal of Neurology Research, ISSN 1923-2845 print, 1923-2853 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Neurol Res and Elmer Press Inc

Journal website https://jnr.elmerpub.com

Review

Volume 16, Number 3, September 2026, pages 150-157

Telmisartan for Apolipoprotein E ε4 Carriers as a Candidate Precision Medicine Strategy in Alzheimer’s Disease

↓ **Table 1.** Classification of Proposed Mechanisms According to Relevance to APOE ε4 Biology
Mechanism	Classification	Rationale
CypA–MMP9 BBB dysfunction	APOE ε4-specific/enriched	Direct mechanistic link to APOE ε4 BBB injury
BBB stabilization	APOE ε4-enriched	APOE ε4 carriers exhibit early BBB breakdown
Endothelial dysfunction	APOE ε4-enriched	Supported by human and animal vascular studies
Oxidative stress reduction	APOE ε4-enriched	Relevant to APOE ε4 vascular vulnerability
Neuroinflammation	Genotype-independent	Common mechanism across AD populations
Amyloid reduction	Genotype-independent	Observed in non-APOE-specific models
PPAR-γ activation	Genotype-independent	Broad anti-inflammatory and metabolic effects
Leptin transport/metabolic effects	Genotype-independent	Indirect relevance to APOE ε4 biology

↓ Table 1. Classification of Proposed Mechanisms According to Relevance to APOE ε4 Biology

Mechanism

Classification

Rationale

CypA–MMP9 BBB dysfunction

APOE ε4-specific/enriched

Direct mechanistic link to APOE ε4 BBB injury

BBB stabilization

APOE ε4-enriched

APOE ε4 carriers exhibit early BBB breakdown

Endothelial dysfunction

APOE ε4-enriched

Supported by human and animal vascular studies

Oxidative stress reduction

APOE ε4-enriched

Relevant to APOE ε4 vascular vulnerability

Neuroinflammation

Genotype-independent

Common mechanism across AD populations

Amyloid reduction

Genotype-independent

Observed in non-APOE-specific models

PPAR-γ activation

Genotype-independent

Broad anti-inflammatory and metabolic effects

Leptin transport/metabolic effects

Genotype-independent

Indirect relevance to APOE ε4 biology

↓ **Table 2.** Preclinical Study Comparison
Study	Model	Intervention/dose	Outcomes	Relevance to APOE ε4
Gohlke et al, 2001 [7]	Conscious normotensive rats; central Ang II response assays	Telmisartan IV and oral; CSF levels measured after repeated oral dosing	Dose/time-dependent inhibition of central Ang II responses; measurable CSF concentrations	Supports CNS exposure plausibility needed for BBB/neuroinflammatory effects in ε4 strategy
Tsukuda et al, 2009 [11]	Aβ1-40 ICV injection mouse model; cognition and CBF	Low-dose telmisartan (0.35 mg/kg/day) ± GW9662	Improved cognition, ↑ CBF, ↓ inflammatory transcripts, ↓ brain Aβ1-40; partial PPAR-γ dependence	Mechanistic fit to ε4’s inflammatory/vascular susceptibility; not genotype-specific
Torika et al, 2016 [13]	BV2 microglia + primary glia; 5XFAD mice	In vitro; intranasal telmisartan (1 mg/kg/day) up to 2 months	↓ LPS-induced NO/iNOS/TNF-α/IL-1β; ↓ amyloid burden and CD11b in cortex/hippocampus	Supports anti-inflammatory microglial modulation—relevant to ε4 pro-inflammatory bias
Torika et al, 2017 [14]	5XFAD mice	Intranasal telmisartan, long-term (5 months)	↓ amyloid, ↓ microglial accumulation, ↓ astrogliosis, ↓ neuronal loss	Strengthens disease-course relevance; still not APOE ε4 TR model
2023 JAD study (APP/PS1) [15]	APP/PS1 mice	Telmisartan daily (reported 5 mg/kg/day for 4 months)	Improved cognitive/executive measures; reduced neuropathology; links to microglial PPAR/NLRP3 pathways	Reinforces immunometabolic mechanism; genotype-specific relevance remains indirect
Schuster et al, 2018 [20]	High-fat diet mice; BBB leptin transport assays	Oral telmisartan; measures of leptin BBB transport/metabolic outcomes	Prevented diet-induced obesity; preserved leptin BBB transport; preserved glucose control	Indirectly supports metabolic/BBB transport axis relevant to ε4’s lipid/metabolic susceptibility

↓ Table 2. Preclinical Study Comparison

Study

Model

Intervention/dose

Outcomes

Relevance to APOE ε4

Gohlke et al, 2001 [7]

Conscious normotensive rats; central Ang II response assays

Telmisartan IV and oral; CSF levels measured after repeated oral dosing

Dose/time-dependent inhibition of central Ang II responses; measurable CSF concentrations

Supports CNS exposure plausibility needed for BBB/neuroinflammatory effects in ε4 strategy

Tsukuda et al, 2009 [11]

Aβ1-40 ICV injection mouse model; cognition and CBF

Low-dose telmisartan (0.35 mg/kg/day) ± GW9662

Improved cognition, ↑ CBF, ↓ inflammatory transcripts, ↓ brain Aβ1-40; partial PPAR-γ dependence

Mechanistic fit to ε4’s inflammatory/vascular susceptibility; not genotype-specific

Torika et al, 2016 [13]

BV2 microglia + primary glia; 5XFAD mice

In vitro; intranasal telmisartan (1 mg/kg/day) up to 2 months

↓ LPS-induced NO/iNOS/TNF-α/IL-1β; ↓ amyloid burden and CD11b in cortex/hippocampus

Supports anti-inflammatory microglial modulation—relevant to ε4 pro-inflammatory bias

Torika et al, 2017 [14]

5XFAD mice

Intranasal telmisartan, long-term (5 months)

↓ amyloid, ↓ microglial accumulation, ↓ astrogliosis, ↓ neuronal loss

Strengthens disease-course relevance; still not APOE ε4 TR model

2023 JAD study (APP/PS1) [15]

APP/PS1 mice

Telmisartan daily (reported 5 mg/kg/day for 4 months)

Improved cognitive/executive measures; reduced neuropathology; links to microglial PPAR/NLRP3 pathways

Reinforces immunometabolic mechanism; genotype-specific relevance remains indirect

Schuster et al, 2018 [20]

High-fat diet mice; BBB leptin transport assays

Oral telmisartan; measures of leptin BBB transport/metabolic outcomes

Prevented diet-induced obesity; preserved leptin BBB transport; preserved glucose control

Indirectly supports metabolic/BBB transport axis relevant to ε4’s lipid/metabolic susceptibility

↓ **Table 3.** Clinical Evidence Relevant to APOE ε4 Stratification and Telmisartan
Study	Population	Intervention/dose	Outcomes	Relevance to APOE ε4
Hu et al, 2020 [16]	1,244 hypertensive adults ≥ 60 years, baseline cognitively normal; APOE genotyped; ∼7 years follow-up	Telmisartan 40→80 mg daily and/or rosuvastatin 10 mg daily vs. matched placebos (2 × 2 factorial); background HCTZ	Reduced cognitive impairment progression and incident “possible dementia;” interaction among telmisartan, rosuvastatin, and APOE ε4 status	APOE-genotyped population; supports feasibility of APOE-stratified investigation but does not establish APOE ε4-specific telmisartan efficacy.
PRoFESS framework (telmisartan arm) [23]	Large post-ischemic stroke population; secondary prevention context	Telmisartan 80 mg daily vs. placebo within factorial design	Disability/cognitive endpoints formally assessed in trial program (contextual constraint on “neuroprotectant” claims)	Not APOE-stratified; Provides important context regarding the limitations of neuroprotective claims in human vascular populations.
Large observational ARB/dementia studies (example) [22]	Hypertensive or vascular-risk cohorts	ARB exposure vs. other antihypertensives	Lower dementia/AD incidence in some analyses	Indirect; does not isolate telmisartan or APOE ε4 effects

↓ Table 3. Clinical Evidence Relevant to APOE ε4 Stratification and Telmisartan

Study

Population

Intervention/dose

Outcomes

Relevance to APOE ε4

Hu et al, 2020 [16]

1,244 hypertensive adults ≥ 60 years, baseline cognitively normal; APOE genotyped; ∼7 years follow-up

Telmisartan 40→80 mg daily and/or rosuvastatin 10 mg daily vs. matched placebos (2 × 2 factorial); background HCTZ

Reduced cognitive impairment progression and incident “possible dementia;” interaction among telmisartan, rosuvastatin, and APOE ε4 status

APOE-genotyped population; supports feasibility of APOE-stratified investigation but does not establish APOE ε4-specific telmisartan efficacy.

PRoFESS framework (telmisartan arm) [23]

Large post-ischemic stroke population; secondary prevention context

Telmisartan 80 mg daily vs. placebo within factorial design

Disability/cognitive endpoints formally assessed in trial program (contextual constraint on “neuroprotectant” claims)

Not APOE-stratified; Provides important context regarding the limitations of neuroprotective claims in human vascular populations.

Large observational ARB/dementia studies (example) [22]

Hypertensive or vascular-risk cohorts

ARB exposure vs. other antihypertensives

Lower dementia/AD incidence in some analyses

Indirect; does not isolate telmisartan or APOE ε4 effects