Hydrogel BDNF Depot for Stroke Motor Recovery
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Solution Overview
Problem
Current therapies for stroke do not effectively promote recovery and are limited by the need for immediate administration of tPA, which does not target tissue repair and can cause bleeding if given after 4.5 hours, with no therapies available for stroke recovery beyond vessel obstruction.
Innovation Solution
A method involving the administration of a therapeutically effective amount of brain-derived neurotrophic factor (BDNF) to the infarct cavity using a hydrogel depot delivery system that provides sustained release, bypassing the blood-brain barrier and minimizing inflammation, to facilitate motor recovery and tissue repair after stroke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tPA is administered to dissolve blood vessels obstructed in stroke, then the blood vessel obstruction is treated, but it does not target tissue repair and can cause bleeding into the brain if given after 4.5 hours
Solution Approach 1:
The patent applies preliminary action by delivering BDNF to the peri-infarct region before the stroke event occurs. The hydrogel is implanted prophylactically, and BDNF is released over time to promote neuronal survival and plasticity. If a stroke occurs, the pre-positioned BDNF provides immediate neuroprotective effects, eliminating the need for post-stroke administration within a narrow time window.
Solution Approach 2:
The patent employs dynamics through the use of a hydrogel delivery system that provides sustained, time-dependent release of BDNF. The hydrogel degrades over weeks to months, dynamically adjusting the amount of BDNF released at different time points. This dynamic release profile allows the therapy to remain effective regardless of when the stroke occurs, extending the treatment window far beyond the 4.5-hour limit of tPA.
2Reliability
If BDNF is delivered systemically to promote neuronal survival, then the blood-brain barrier must be crossed, but this approach may promote inflammation or tissue damage
Solution Approach 1:
The patent applies local quality by delivering BDNF directly to the peri-infarct region through a locally implanted hydrogel rather than systemic administration. This localized delivery ensures high concentrations of BDNF are present where they are most needed (in the region surrounding the infarct) while avoiding exposure of other brain regions to potentially harmful effects. The hydrogel is positioned in the peri-infarct white matter, providing targeted therapy that spares healthy tissue.
Solution Approach 2:
The patent uses the hydrogel as an intermediary carrier that mediates BDNF delivery to the brain tissue. The hydrogel serves as a biocompatible matrix that slowly degrades and releases BDNF over time, acting as a controlled intermediary between the BDNF molecule and the target neurons. This intermediary approach allows for sustained release at therapeutic concentrations without the need for repeated injections or systemic circulation, thereby minimizing inflammatory responses.
3Quantity of substance
If growth factor delivery is done systemically, then the growth factor must cross the blood-brain barrier, but delivery is not localized to the specific region needing repair
Solution Approach 1:
The patent applies local quality by delivering BDNF directly to the peri-infarct region through a locally implanted hydrogel rather than systemic administration. This localized delivery ensures high concentrations of BDNF are present where they are most needed (in the region surrounding the infarct) while avoiding exposure of other brain regions to potentially harmful effects.
4Duration of action of moving object
If BDNF is administered repeatedly to maintain therapeutic levels, then sustained neuroprotection is achieved, but multiple injections increase brain damage risk
Solution Approach 1:
The patent implements continuity of useful action through the hydrogel's sustained release of BDNF over weeks to months. The hydrogel provides continuous BDNF delivery without requiring repeated injections, maintaining therapeutic levels continuously as the hydrogel degrades. This single-implantation approach eliminates the need for multiple punctures into the brain, thereby preventing cumulative damage while ensuring prolonged neuroprotective effects.
Solution Approach 2:
The patent uses a disposable hydrogel implant that is designed to degrade and release its payload over a predetermined period. The hydrogel acts as a temporary, single-use delivery system that accomplishes sustained BDNF release without requiring retrieval or replacement. This disposable approach simplifies the treatment protocol compared to reusable systems that would require multiple interventions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method improves motor recovery and tissue repair by sustained release of BDNF directly to the brain injury site, enhancing functional recovery and reducing infarct size, with potential for administration up to a year post-stroke, addressing the limitations of existing therapies.
Implementation Method 1
provides a sustained release of BDNF
Implementation Method 2
hydrogel comprising cells that provide a sustained release of BDNF
Data Source
Figure 1A
Figure 1B
Figure 2A~2C
AI summary
Methods of improving recovery of a mammal after an ischemic event (e.g., stroke) are provided. In various embodiments the methods involve administering a neural growth factor (e.g., BDNF) into the infarct (e.g., stroke) cavity in a biocompatible hydrogel formulation. In certain embodiments the hydrogel comprises a thiolated hyaluronan and a thiolated gelatin with an optional thiolated heparin.