PuraStat is an innovative medical product, a transparent and biocompatible hydrogel designed to control bleeding during various medical procedures. It is categorized as a self-assembling peptide (SAP) solution, meaning its active components organize themselves into a complex structure upon contact with the body's physiological fluids. This unique mechanism makes it a valuable tool in modern pharmacology, particularly in gastroenterology and surgery.
The Science Behind PuraStat: A Self-Assembling Hydrogel
PuraStat is made from a synthetic, water-based solution of four repeating amino acid sequences, known as RADA16. In its initial state, the solution is acidic and highly viscous. The magic happens upon application to a bleeding site:
- pH Shift Trigger: When the acidic PuraStat solution comes into contact with more alkaline bodily fluids like blood or tissue secretions, the change in pH and ionic concentration triggers a rapid process of self-assembly.
- Nanofiber Formation: This ionic change causes the peptides to transition into beta-sheets, which quickly organize into a complex network of nanofibers.
- Mechanical Barrier: This nanofiber mesh forms a transparent, extracellular matrix-mimicking scaffold that adheres to the bleeding tissue. This physical barrier seals the damaged vessels, creating an ideal environment for the body's natural hemostasis processes to occur.
- Resorption: The entire structure is biodegradable. The body's enzymes break down the peptide scaffold into its constituent amino acids over approximately 30 days, which are then metabolized or excreted.
Primary Medical Uses of PuraStat
PuraStat's ability to quickly form a clear, stable hemostatic barrier makes it useful across several medical fields.
Endoscopic and Gastrointestinal Applications
- Intraprocedural Hemostasis: During complex endoscopic procedures like endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD), bleeding can occur from capillaries and small vessels. PuraStat is applied directly to the site to control this oozing, providing rapid hemostasis.
- Prophylaxis for Delayed Bleeding: After endoscopic resections, covering the resection site with PuraStat can help prevent delayed post-procedure bleeding, a risk factor for patients on antiplatelet or anticoagulant therapy.
- Managing Acute GI Bleeding: It is used to manage acute, non-variceal gastrointestinal bleeding, particularly effective for oozing-type hemorrhages.
- Rescue and Bridge Therapy: In cases where standard endoscopic techniques fail to stop severe bleeding, PuraStat can be used as a rescue agent to achieve temporary hemostasis, acting as a bridge to more definitive treatments like surgery or radiological embolization.
- Walled-Off Pancreatic Necrosis (WON) Bleeding: PuraStat has been used in pilot studies to help manage bleeding during endoscopic necrosectomy for WON, both for intraprocedural bleeding and for preventing delayed bleeding.
Surgical Applications
- Oozing from Tissues: PuraStat is indicated for controlling bleeding from small vessels and capillaries in the parenchyma of solid organs during surgery.
- Vascular Anastomoses: It can be used to manage oozing from vascular anastomoses during vascular, cardiac, and sinus surgery.
Other Specialized Indications
- Radiation Proctitis: For patients experiencing rectal bleeding due to chemotherapy or radiotherapy-induced mucositis, PuraStat can be used for symptomatic management by providing a protective layer over the rectal mucosa.
- Radiation Cystitis: A pilot study described the technique for applying PuraStat in the bladder to stop persistent bleeding caused by radiation cystitis, with promising initial results.
PuraStat vs. Conventional Hemostatic Techniques
When controlling bleeding, clinicians can choose from a range of options, each with distinct advantages and disadvantages.
| Feature | PuraStat | Hemostatic Powder Spray (e.g., Hemospray) | Conventional Endoscopic Methods (Clips, Cautery) |
|---|---|---|---|
| Application | Direct, precise application via endoscopic catheter or syringe. | Delivered via spray mechanism; less precise. | Requires precise targeting of bleeding vessel. |
| Visualization | Transparent gel allows clear visibility of underlying tissue. | Opaque powder obscures the mucosa, limiting further assessment. | Varies, depends on the technique and associated bleeding. |
| Ease of Use | Ready-to-use gel in prefilled syringe, requiring no preparation. | Requires gas delivery system and can be blocked by moisture. | Technically demanding, especially for difficult-to-reach lesions. |
| Mechanism | Self-assembling peptide forms a physical nanofiber matrix. | Absorbs water, swells, and forms a mechanical barrier. | Mechanical occlusion or thermal coagulation. |
| Efficacy | Effective for mild/moderate bleeding and oozing. | Broadly effective for non-variceal GI bleeding. | High rates of success for identified bleeding points. |
| Limitations | Less effective for severe, high-pressure arterial bleeds. | Not suitable for variceal bleeding; catheter blockage risk. | Can be challenging for diffuse or poorly visualized bleeding. |
Application and Safety Profile
PuraStat is designed to be straightforward to use, minimizing procedural time. A prefilled syringe is connected to an endoscopic catheter or applicator, and the gel is delivered to the bleeding site. Key steps include removing as much blood as possible from the site, applying an adequate amount of gel as close as possible to the source, and allowing the gel to set without disturbance. The transparent nature of the gel is a significant advantage, as it does not obstruct the view during the procedure, facilitating observation and further intervention if needed. The product's safety profile is generally favorable, with no systemic adverse events reported during its approved uses. Because it is synthetic, there is no risk of contamination from animal or human-derived products. The peptides degrade into natural amino acids, which are then absorbed by the body. In some studies, PuraStat use has been associated with fewer adverse events compared to conventional hemostatic techniques.
Conclusion
PuraStat is a valuable hemostatic tool that effectively expands the therapeutic options available for managing bleeding in both surgical and endoscopic settings. Its innovative self-assembling peptide technology offers several benefits over traditional methods, including ease of use, transparency, and a high safety profile. By forming a rapid, transparent, and resorbable barrier, it provides a simple yet effective solution for controlling mild and moderate hemorrhages, preventing delayed bleeding, and managing specific conditions like radiation proctitis. While not suitable for all types of bleeding, particularly high-pressure arterial spurting, its versatility and unique properties have solidified its role as a useful addition to the modern hemostatic toolkit. Ongoing research continues to explore its efficacy in specific clinical scenarios.
