From:  Therapeutic potential of microRNAs in neurological disorders: mechanisms, biomarkers, and emerging therapeutic strategies

 Limitations of conventional delivery methods for miRNA therapeutics in neurological disorders

LimitationDescriptionReference
BBB impedanceThe BBB restricts the passage of most therapeutic agents, including miRNAs, due to its selective nature and the hydrophilic, charged characteristics of miRNAs.[92]
Cellular uptakeEfficient cellular uptake of miRNAs into specific target cells in the brain is challenging due to the complex internalization mechanisms of neurons and glial cells.[93]
Rapid clearanceSystemically administered miRNAs may be rapidly cleared from the bloodstream and degraded by nucleases, reducing their bioavailability and therapeutic efficacy.[94]
Off-target effectsConventional delivery methods often lack specificity, leading to off-target effects on non-neural tissues and unwanted gene regulation.[92]
Stability and pharmacokineticsmiRNAs are susceptible to degradation in biological fluids, necessitating protection from enzymatic degradation to maintain therapeutic levels at the target site.[95]
ImmunogenicityRepeated administration of exogenous miRNAs may elicit immune responses, potentially limiting their long-term therapeutic application.[96]

miRNA: microRNA; BBB: blood-brain barrier