AAV-mediated gene therapy for cardiac tachyarrhythmia: A systematic review and meta-analysis
Authors, Journal, Affiliations, Type, DOI
- Juan Mundisugih, Saurabh Kumar, Eddy Kizana
- Heart Rhythm, Vol 21, No 6, June 2024, pp 939–949
- Centre for Heart Research, Westmead Institute for Medical Research; Department of Cardiology, Westmead Hospital; Sydney Medical School, University of Sydney, NSW, Australia
- Systematic review and meta-analysis; PROSPERO registered (CRD42023479448); PubMed + Embase search to January 2024
- DOI: https://doi.org/10.1016/j.hrthm.2024.02.001
Overview
This PROSPERO-registered systematic review and meta-analysis evaluates 26 preclinical in vivo studies of AAV-mediated gene therapy for cardiac tachyarrhythmia (7 AF, 4 acquired VA, 15 inherited VA), published up to January 2024. It identifies 22 novel molecular targets and quantifies treatment effect using odds ratios for arrhythmia inducibility. AAV9 was used in 92% of studies, and 88% employed small-animal models. Gene therapy reduced AF inducibility by 81% (OR 0.19) and VA inducibility by 94% overall (OR 0.06). As of the search date, only PKP2 had advanced to clinical trial for arrhythmia; SERCA2a entered clinical trial for heart failure, not arrhythmia. Significant methodological limitations — small animals, absence of blinding in ~50% of studies, and zero reported failures — constrain clinical interpretation.
Keywords
AAV; Gene therapy; Arrhythmia; Genetic heart disease; Biotechnology
Key Takeaways
Study Overview and Methods
- 26 studies included; 20 (77%) published in the last 5 years (2019–2024); 10 between 2022–2023 — field is accelerating rapidly
- Median journal impact factor 12.7 (IQR 6.1–23.2); 50% in journals with IF >10
- 22 novel molecular targets identified across AF, acquired VA, and inherited VA
- Gene therapy strategies: gene replacement 35%, pathway modulation 38%, genome editing 19%, allelic silencing 8%
- Vector: AAV9 in 92% of studies (n=21); systemic administration in 88% (n=23)
- Animal models: small animals (mice/rats) 88% (n=23)
- Only 7 studies reported transduction rates; all used qPCR or Western blot to confirm vector delivery
- Transduction data were mostly graphical — precise mRNA/protein quantification required for phenotypic correction not available in most studies
Quantitative Efficacy: Meta-Analysis Results
- Atrial fibrillation (n=5 studies in meta-analysis): AAV gene therapy reduced AF inducibility by 81% — odds ratio 0.19 (95% CI 0.08–0.45; I²=0%; p<0.01). Low heterogeneity suggests consistent effect across diverse AF targets
- Acquired ventricular arrhythmia: Reduction 89% in inducibility
- Inherited ventricular arrhythmia: Reduction 96% in inducibility
- Combined VA (all subtypes): OR 0.06 (95% CI 0.03–0.11; I²=27.3%; p<0.01) — a 94% reduction
- No study documented significant off-target effects or complications
Molecular Targets for Atrial Fibrillation (Table 1 — 7 targets)
| Target | Strategy | Model | Key finding |
|---|---|---|---|
| SERCA2a | Pathway modulation | Rabbit | SERCA2a overexpression reduced AF susceptibility and atrial remodelling (intrapericardial AAV9) |
| miR-27b | Pathway modulation | Mice | miR-27b reduced atrial fibrosis and AF via Smad-2/3 pathway inhibition (ALK5 targeting) |
| NLRP3 | Pathway modulation | Mice | Cardiomyocyte-specific NLRP3 knockdown (AAV9) suppressed AF development |
| TASK-1 | Allelic silencing | Pig | Anti-TASK-1 intervention reduced AF burden and corrected electrophysiological remodelling; pig model (translational strength) |
| IGF1 | Pathway modulation | Rats | IGF1 inhibition reduced AF inducibility and atrial fibrosis |
| Myl4 | Gene replacement | Mice | AAV9-Myl4 replacement alleviated familial AF phenotype in homozygous loss-of-function mice |
| SIRT3 | Pathway modulation | Mice | SIRT3 overexpression reduced alcohol-induced AF via SIRT3-AMPK signalling and improved mitochondrial dynamics |
- Limitation common to all AF targets: Gene transfer primarily addresses AF prevention, not established persistent/permanent AF — the clinically dominant phenotype requiring treatment
- Species relevance: TASK-1 tested in pig (most translatable); others in mice/rats
Molecular Targets for Acquired Ventricular Arrhythmia (Table 2 — 4 targets)
| Target | Strategy | Model | Key finding |
|---|---|---|---|
| SERCA2a | Pathway modulation | Pigs (AAV1) | Post-MI SERCA2a delivery improved electrophysiological properties by targeting rate-dependent action potential propagation |
| TBX5 | Gene replacement | Mice (AAV9) | TBX5 restoration normalised TBX5-dependent transcriptome, reduced arrhythmia propensity, and improved cardiac function in knockout mice |
| Dystrophin (CRISPR activation) | Genome editing | Mice (AAV9) | Forced dystrophin activation via CRISPR/dCas9 restored Nav1.5 membrane localisation and normalised cardiac conduction; reduced arrhythmia susceptibility |
| Adiponectin (LSG) | Gene replacement | Dogs (AAV2) | AAV-adiponectin overexpression in the left stellate ganglion chronically inhibited neural activity → improved ventricular electrophysiological stability. Potential non-surgical alternative to sympathectomy |
Molecular Targets for Inherited Ventricular Arrhythmia (Table 3 — 15 studies)
CPVT:
- CASQ2 replacement (4 studies): Single AAV9 injection cures CASQ2-deficient CPVT from birth to advanced age; curative effect sustained ≥1 year. Exogenous CASQ2 or triadin individually eliminates arrhythmia (triadin-CASQ2 interdependence confirmed)
- RYR2 — allelic silencing and CRISPR: Allele-specific silencing (Bongianino) and guide RNA-directed editing (Pan) effective in mice; translational barrier: >150 RYR2 variants linked to CPVT — variant-specific approach not scalable
- Engineered CaM protein: Interaction with RYR2 extended its refractoriness; reduced arrhythmia in CASQ2-mutant mice; mutation-agnostic approach but requires safety evaluation — CaM gene mutations cause VA; modified CaM proteins carry proarrhythmic risk
- CaMKII inhibitory peptide (cardiac-specific): Suppressed CPVT irrespective of mutation variant; notable: caused 10% QTc prolongation under β-agonist stimulation — proarrhythmic signal requiring careful evaluation
ACM:
- PKP2 (gene replacement, 4 studies): Only arrhythmia gene therapy target in clinical trial (as of January 2024). Bradford 2023: exogenous wild-type PKP2 restored all phenotypic manifestations including SCD prevention; effective even with late-stage administration
- PLN-R14del (CRISPR editing): AAV9-CRISPR improved cardiac function and reduced VA susceptibility in humanised PLN-R14del mice
- GJA1-20k (Connexin 43 trafficking): AAV-GJA1-20k replacement improved Cx43 trafficking and reduced arrhythmogenic phenotype independent of LV function
- BAG5: Novel gene target for inherited cardiomyopathy; exogenous BAG5 suppressed VA and improved LV function in homozygous knock-in mice
PRKAG2 syndrome:
- AAV9-CRISPR correction of H530R mutation at postnatal day 4 or 42 restored cardiac structure and function; two-fold reduction in ventricular preexcitation — demonstrates efficacy at both neonatal and post-neonatal timing
Brugada syndrome:
- MOG1 (Nav1.5 trafficking chaperone): AAV9-MOG1 reversed sodium channel defects and corrected cardiac electrophysiological abnormalities in BrS mouse model. Safety concern: MOG1 is a chaperone with diverse binding partners — off-target effects possible. Strategy also relevant for any SCN5A LOF variant that exceeds AAV packaging capacity
LQT3:
- SCN5A p.T1307M — adenine base editing (ABE): Dual AAV9-CRISPR/ABE rectified the SCN5A mutation, mitigating QT prolongation and preventing severe arrhythmias. Key finding: ~20% editing efficiency was sufficient to prevent fatal arrhythmias — suggesting a lower correction threshold than the >70% mosaicism threshold proposed for structural cardiac conditions. Safety profile must be characterised before human application
In Vitro Mechanistic Investigations (Promising Conceptual Work)
- BacNav (prokaryotic sodium channel): In vitro and in silico expression of codon-optimised BacNav improved excitability, conduction, and overcame unidirectional conduction blocks. Potential application in fibrotic tissue reentry and BrS SCN5A LOF mutations
- Desmoglein 2 (iPSC-CM): AAV replacement rescued abnormal excitation, fragility, and contractile force in patient-derived iPSC-CMs from a homozygous DSG2 stop-gain variant
Clinical Translation Status (January 2024)
- Only PKP2 has reached clinical trial for arrhythmia (ACM — Rocket trial via LEXEO)
- SERCA2a entered clinical trial (AskBio Phase 1 for CHF), but heart failure — not arrhythmia — is the primary endpoint
- All other 20 targets remain preclinical
Novel Vector Technology
- AAV2i8: Chimeric vector combining AAV2 and AAV8 elements; broad muscle tropism including myocardium; reduced liver transduction compared to AAV8 — may improve cardiac specificity for systemic delivery
Limitations of the document
- 88% small-animal studies (mice/rats) — significant physiological and anatomical gap from humans
- Variable AAV tropism and gene expression threshold for phenotypic correction across species
- ~50% of studies without blinding — risk of investigator bias
- No study reported a failure of AAV gene therapy — strong publication bias likely; funnel plots trend symmetric but sample too small to conclude
- Only 7/26 studies reported transduction rates explicitly
- Risk of bias unclear for many studies re: allocation concealment, random housing, outcome assessment
- All AF and VA targets focused on prevention paradigm; treatment of established arrhythmia not tested
Key Concepts Mentioned
- concepts/AAV-Gene-Delivery — meta-analysis efficacy data; 22 targets; AAV9 dominance; novel vector AAV2i8; PKP2 clinical trial status
- concepts/CRISPR-Cas9-in-Channelopathies — genome editing strategies for CPVT (RYR2), ACM (PLN-R14del), LQT3 (SCN5A ABE), PRKAG2 syndrome
- concepts/Gene-Silencing-Therapy — allelic silencing of mutant RYR2 in CPVT; TASK-1 knockdown in AF
Key Entities Mentioned
- entities/CPVT — CASQ2 replacement (4 studies; single injection; ≥1-year durability); RYR2 editing; CaM protein; CaMKII inhibitor
- entities/ARVC — PKP2 gene replacement (only arrhythmia target in clinical trial); PLN-R14del CRISPR; GJA1-20k; BAG5
- entities/Brugada-Syndrome — MOG1 chaperone gene therapy
- entities/Long-QT-Syndrome — SCN5A p.T1307M ABE; 20% editing threshold sufficient
- entities/RYR2 — allelic silencing and CRISPR for CPVT; >150 variants limits scalability
Wiki Pages Updated
- wiki/sources/aav-gene-therapy-arrhythmia-hr-2024.md (created)
- wiki/concepts/AAV-Gene-Delivery.md (updated — meta-analysis efficacy data; AF targets; acquired VA targets; PKP2 clinical trial status; AAV2i8; publication bias note)
- wiki/sourceindex.md (updated)