Platelet-Rich Plasma for Parosmia

Overseen By Homer Abaya, BS

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Stanford University

Must not be taking: Blood thinners

Disqualifiers: Pregnancy, Nasal abnormalities, Trauma, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 3 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 5

Duration: 6 weeks

40 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a treatment called platelet-rich plasma (PRP) to improve the sense of smell in individuals with parosmia, a distorted sense of smell often caused by an upper respiratory infection. PRP, derived from a person's own blood, may help heal and regenerate tissues. Participants will receive either PRP or a placebo through nasal injections. The trial seeks individuals who have experienced parosmia for at least six months but less than two years and have tried standard treatments like smelling strong odors. As an unphased trial, this study offers the chance to contribute to groundbreaking research that could lead to new treatment options for parosmia.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications. However, if you are on blood thinners like coumadin or plavix, you cannot participate in the trial.

What prior data suggests that platelet-rich plasma is safe for treating parosmia?

Research has shown that platelet-rich plasma (PRP) is generally safe for people. PRP, derived from a person's own blood, reduces the risk of rejection or serious side effects. Studies have found that PRP can reduce inflammation and aid in tissue repair and regeneration. It has been safely used in areas like bone and skin care to heal injuries and speed recovery.

In a past study on patients who lost their sense of smell after COVID-19, PRP proved both safe and effective. No major negative effects were reported, indicating patients did not experience serious problems from the treatment. Overall, PRP appears to be a safe choice for those considering participation in a clinical trial. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Unlike most treatments for parosmia, which often focus on masking the distorted smells or using medications like steroids, platelet-rich plasma (PRP) offers a novel approach by leveraging the body's own healing processes. PRP is derived from the patient's own blood, which is processed to concentrate the platelets—components rich in growth factors that promote tissue repair and regeneration. This method targets the olfactory system directly by injecting PRP into the nasal cavity, potentially accelerating recovery and restoring normal smell function more effectively. Researchers are excited about PRP because it represents a personalized treatment with the potential for fewer side effects compared to traditional pharmaceuticals.

What evidence suggests that platelet-rich plasma might be an effective treatment for parosmia?

Research has shown that platelet-rich plasma (PRP), which participants in this trial may receive, can greatly improve the sense of smell in individuals with smell problems, such as parosmia. In past studies, PRP injections boosted both smell test results and patients' perceptions of their sense of smell. For example, one study showed that PRP significantly improved smell scores. PRP likely helps by reducing inflammation and promoting healing, aiding the body's repair processes. It has successfully treated smell loss related to COVID-19, which affects smell similarly to parosmia. These findings suggest that PRP could be a promising treatment for improving smell issues. Participants in this trial will receive either PRP or saline injections, with saline serving as a comparator. ^{6 7 8 9 10}

Who Is on the Research Team?

Zara Patel, MD

Principal Investigator

Stanford Otolaryngology - Head and Neck Surgery

Are You a Good Fit for This Trial?

This trial is for individuals experiencing parosmia, a condition where the sense of smell is distorted. Participants should have this condition and be interested in trying an intranasal treatment derived from their own blood.

Inclusion Criteria

Patients must be able to read and understand English

Quantitative score under the 10th percentile on the SSParoT (HedRang and HedDir)

Patients must be able and willing to provide Informed Consent

Exclusion Criteria

I have a bleeding disorder or am taking blood thinners like coumadin or plavix.

I have lost my sense of smell due to injury, sinus issues, growths, or a brain condition for over 2 years.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive intranasal injections of either PRP or saline into the olfactory cleft three times, separated by two weeks each

6 weeks

3 visits (in-person)

Follow-up

Participants are monitored for changes in olfactory function using the Sniffin Sticks Parosmia Test and QOD scale score

3 months

2 visits (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Platelet-rich Plasma (PRP)

Trial Overview The study tests if injecting Platelet-rich Plasma (PRP), made from a patient's own blood, into the nasal cavity can help treat parosmia. PRP has shown promise in healing tissues. Patients will either receive PRP or saline (a placebo) to compare effects.

How Is the Trial Designed?

Group I: Saline Active Control 1 Intervention

Participants receive saline injections into the olfactory cleft three times, separated by two weeks each. (Sham/placebo injections).

Group II: Platelet Rich Plasma (PRP) Active Control 1 Intervention

Participants receive PRP intranasal injection into the olfactory cleft three times, separated by two weeks each. Blood is drawn from the patient. This is placed in a centrifuge and using a specialized PRP kit (Emcyte), the sequential spinning process isolates the platelet-rich plasma portion of the blood and we inject that back into the patient within the nasal cavity.

Platelet-rich Plasma (PRP) is already approved in United States, European Union, Canada for the following indications:

Approved in United States as Platelet-rich Plasma for:

• Orthopedic conditions (e.g., tendonitis, osteoarthritis)
• Dermatological conditions (e.g., androgenic alopecia, wound healing)
• Sports medicine injuries

Approved in European Union as Platelet-rich Plasma for:

• Orthopedic conditions (e.g., tendonitis, osteoarthritis)
• Dermatological conditions (e.g., androgenic alopecia, wound healing)
• Sports medicine injuries

Approved in Canada as Platelet-rich Plasma for:

• Orthopedic conditions (e.g., tendonitis, osteoarthritis)
• Dermatological conditions (e.g., androgenic alopecia, wound healing)
• Sports medicine injuries

Who Is Running the Clinical Trial?

Stanford University

Lead Sponsor

Trials

2,527

Recruited

17,430,000+

Published Research Related to This Trial

In a study involving 126 patients with knee joint cartilage injuries and degenerative meniscus lesions, platelet-rich plasma (PRP) treatment showed significant improvement in knee function and pain relief three months after administration, with effects remaining stable at six months.

PRP therapy is a promising method for short-term pain reduction in knee injuries, but further research is necessary to establish its long-term effectiveness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intra-articular Platelet-Rich Plasma Injections for Treating Knee Pain Associated with Articular Cartilage and Degenerative Meniscal Lesions. Mitev, K., Longurov, A.[2020]

In a study involving 16 male mice, platelet-rich plasma (PRP) significantly improved olfactory function in a model of anosmia, as shown by better food-finding test scores compared to a saline control over 21 days.

Histopathological analysis revealed that PRP treatment resulted in less epithelial damage and greater epithelial thickness in the olfactory neuroepithelium, indicating a potential curative effect on olfactory functions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effectiveness of platelet-rich plasma in an anosmia-induced mice model. Yasak, AG., Yigit, O., Araz Server, E., et al.[2018]

Platelet-rich plasma (PRP) obtained from healthy adult cats using the PRGF®-Endoret® technology showed a significant increase in platelet concentration (1.5 times higher) compared to whole blood, while reducing red and white blood cell counts by over 99%.

The study demonstrated that PRP contains higher levels of platelet-derived growth factor BB (PDGF-BB) compared to platelet-poor plasma (PPP), indicating its potential for promoting tissue repair, although further research is needed to assess its clinical efficacy in treating various conditions in cats.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evaluation of a Standardized Protocol for Plasma Rich in Growth Factors Obtention in Cats: A Prospective Study. Miguel-Pastor, L., Satué, K., Chicharro, D., et al.[2022]

Platelet-rich plasma (PRP) significantly enhances the proliferation of human adipose-derived stem cells (hASCs), primarily through the action of platelet-derived growth factor (PDGF)-BB.

The proliferation induced by PRP is mediated via specific signaling pathways, including ERK1/2, PI3K/Akt, and JNK, while inhibitors like imatinib and sorafenib can effectively block this process.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Platelet-rich plasma enhances the proliferation of human adipose stem cells through multiple signaling pathways. Lai, F., Kakudo, N., Morimoto, N., et al.[2022]

Platelet-rich plasma (PRP) contains a high concentration of platelets and growth factors, making it useful in oral and maxillofacial surgery as well as orthopedics for repairing bone, cartilage, and soft tissues.

Key growth factors in PRP, such as PDGF and TGF-beta, are crucial for promoting healing and tissue regeneration during various stages of recovery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Research progress of the mechanism of repairing bone defect with PRP]. Chen, S., Zhang, N., Chen, WS., et al.[2012]

Autologous plasma rich in platelets (PRP) has shown to improve gingival recession in chronic periodontitis, with a significant effect size (SMD of 0.54) based on data from four randomized controlled trials.

The efficacy of PRP in promoting complete healing of chronic skin ulcers remains inconclusive, and while adverse effects were reported, there were no significant differences between treatment groups, indicating a need for further research on its safety.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efficacy and safety of the use of autologous plasma rich in platelets for tissue regeneration: a systematic review. Martínez-Zapata, MJ., Martí-Carvajal, A., Solà, I., et al.[2018]

In a study of 140 high-risk women undergoing cesarean sections, the use of autologous platelet-rich plasma (PRP) significantly improved wound healing compared to standard care, with an 85.5% reduction in the REEDA score for the PRP group versus 72% for the control group.

Patients receiving PRP also reported greater pain relief, with a 93% reduction in the visual analog scale (VAS) score compared to 79% in the control group, indicating that PRP not only enhances healing but also improves patient comfort post-surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Application of Autologous Platelet-Rich Plasma (PRP) on Wound Healing After Caesarean Section in High-Risk Patients. Tehranian, A., Esfehani-Mehr, B., Pirjani, R., et al.[2022]

Platelet-rich plasma (PRP) preparations are rich in growth factors that play crucial roles in healing and tissue regeneration, making them valuable for clinical applications in various fields such as orthopedic surgery and wound treatment.

The effectiveness of PRP is largely determined by the concentration of platelets and their growth factors, which enhance processes like tissue healing and regeneration through autocrine and paracrine signaling mechanisms.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Growth factor content in PRP and their applicability in medicine. Lubkowska, A., Dolegowska, B., Banfi, G.[2022]

In a pilot study involving 7 patients with long-term olfactory loss, a single intranasal injection of platelet-rich plasma (PRP) was found to be safe and resulted in subjective improvements in smell for all participants shortly after treatment.

At the 3-month follow-up, 60% of patients with moderate olfactory loss showed significant improvement, with some achieving normal olfactory function, indicating potential efficacy of PRP for treating hyposmia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The use of platelet-rich plasma in treatment of olfactory dysfunction: A pilot study. Yan, CH., Mundy, DC., Patel, ZM.[2022]

A systematic review of nine randomized controlled trials involving 325 participants found no significant difference in the healing of chronic wounds when comparing autologous platelet-rich plasma (PRP) to standard treatments or placebo.

While some results showed a higher percentage of wound area healed with PRP in mixed chronic wounds, overall evidence does not support the efficacy of PRP for chronic wound treatment, highlighting the need for more robust clinical trials.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Autologous platelet-rich plasma for treating chronic wounds. Martinez-Zapata, MJ., Martí-Carvajal, AJ., Solà, I., et al.[2022]

In a study of 54 patients with long-term anosmia, platelet-rich plasma (PRP) injections were found to be safe and led to subjective improvements in smell, with 16 patients showing significant improvement after a single injection and 19 after double injections.

The study suggests that PRP may have potential efficacy in treating olfactory loss, particularly for patients with persistent anosmia, although further research is needed to optimize treatment frequency and duration.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Platelet-rich Plasma in Management of Anosmia (Single Versus Double Injections). Shawky, MA., Hadeya, AM.[2023]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11048638/

Platelet-Rich Plasma (PRP) in the Treatment of Long COVID ... The current evidence demonstrates that PRP injections can significantly improve smell function based on objective testing and patient-reported measures. PRP ...

2. cureus.com cureus.com/articles/418746-platelet-rich-plasma-for-covid-19-related-olfactory-dysfunction-a-systematic-review-and-meta-analysis-of-randomized-controlled-trials

Platelet-Rich Plasma for COVID-19-Related Olfactory ... PRP significantly improved objective olfactory scores (SMD = 1.86, 95% CI (0.14, 3.57), p = 0.03) and subjective olfactory scores (SMD = 0.92, ...

3. journals.sagepub.com journals.sagepub.com/doi/10.1177/01455613241291710

The Effect of Platelet-Rich Plasma and Hyaluronic Acid ... These results indicate that the PRP and HA nasal injections seemed to have both a fast and stronger effect in treating traumatic olfactory loss.

4. clinicaltrials.gov clinicaltrials.gov/study/NCT06930248?term=AREA%5BBasicSearch%5D(AREA%5BBasicSearch%5D(anosmia))&rank=6

Efficacy of Platelet-rich Plasma in Management of Anosmia Best evidence studies recommend olfactory training and topical steroid nasal irrigations as potential therapeutics, yet both have limited efficacy . PRP is an ...

5. researchgate.net researchgate.net/publication/396494229_Platelet-Rich_Plasma_for_COVID-19-Related_Olfactory_Dysfunction_A_Systematic_Review_and_Meta-analysis_of_Randomized_Controlled_Trials

(PDF) Platelet-Rich Plasma for COVID-19-Related ... With uncertain evidence, PRP may improve both objective and subjective smell function and clinical outcomes in people with long COVID-related OD ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7589810/

Platelet-Rich Plasma: New Performance Understandings and ... PRP therapy is based on the fact that platelet growth factors (PGFs) support the three phases of wound healing and repair cascade (inflammation, proliferation, ...

7. sciencedirect.com sciencedirect.com/science/article/pii/S2589004224029328

The role of platelet-rich plasma in biomedicine This blood derivative, enriched with platelet components, has shown great potential for promoting tissue repair and regeneration.

8. mdpi.com mdpi.com/2227-9059/12/4/808

Platelet-Rich Plasma (PRP) in the Treatment of Long ... PRP is an autologous concentration of platelets in a small volume of plasma, boasting anti-inflammatory and pro-regenerative properties. It contains growth ...

9. stemcellres.biomedcentral.com stemcellres.biomedcentral.com/articles/10.1186/scrt218

Platelet-rich plasma preparation for regenerative medicine Our study resulted in a consistent PRP preparation method that yielded a cytokine and growth factor pool from different donors with high reproducibility.

10. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC3445108/

Platelet-Rich Plasma: Where Are We Now and Where Are We ... Platelet-rich plasma (PRP) is a simple, efficient, and minimally invasive method of obtaining a natural concentration of autologous GFs.