R3 Stem Cell publishes systematic review on intranasal stem cell therapy

By AI, Created 9:42 AM UTC, May 20, 2026, /AGP/ – R3 Stem Cell announced a peer-reviewed systematic review in Frontiers in Aging Neuroscience examining intranasal stem cell and exosome delivery across neurological and respiratory disorders. The review found the approach appears safe and feasible in early human studies, while also highlighting major evidence gaps that still block clinical adoption.

Why it matters: - The review adds one of the broadest human evidence summaries yet for intranasal stem cell therapy, a delivery route researchers say could change treatment for brain and lung disease. - The findings suggest early safety and feasibility across several disorders, but the current evidence is still too limited to support routine clinical use. - The paper also underscores how much larger, better-controlled trials are still needed before the field can move from early signals to standard care.

What happened: - R3 Stem Cell announced the publication of a systematic review in Frontiers in Aging Neuroscience. - The paper is titled “Intranasal administration of stem cells and their derivatives for neurological and respiratory disorders: a systematic review of human clinical trials.” - The review covers 19 human clinical studies conducted between January 2011 and December 2025. - The article appears in the Alzheimer’s Disease and Related Dementias section of Frontiers in Aging Neuroscience, Volume 18 (2026), under DOI: 10.3389/fnagi.2026.1834543. - The paper is available open access online at the full paper.

The details: - The research team searched PubMed, Google Scholar, Web of Science, Scopus and ClinicalTrials.gov under PRISMA 2020 guidelines. - The team screened 972 records and identified 19 eligible human studies. - The final set included 7 published peer-reviewed articles and 12 registry-only or grey-literature records. - The patient populations included Parkinson’s disease, Alzheimer’s disease and related dementias, ischemic stroke, cerebral palsy, ALS, refractory focal epilepsy, asthma and acute respiratory distress syndrome. - The included therapies involved mesenchymal stem cells, neural stem cells and cell-derived products such as exosomes, extracellular vesicles and secretome. - Across the studies, intranasal delivery was consistently described as safe and well-tolerated in humans. - No serious adverse events attributable to the intranasal route were reported. - Early efficacy signals included motor and non-motor improvements in Parkinson’s disease. - Pediatric cerebral palsy studies reported gains on the GMFM-88 gross motor scale. - Mild-to-moderate Alzheimer’s disease trials reported improvements on ADAS-cog, MMSE and MoCA-B after medium-dose MSC-derived exosomes. - One asthma study reported better pulmonary function and quality of life. - The review says intranasal stem cell treatment for Parkinson’s and Alzheimer’s may become standard or first-line care in the future if larger studies confirm the early findings. - The authors found no published trial with a low overall risk of bias. - Sample sizes were small, with a median of 13 analyzable participants per published study. - Most trials lacked sham controls and independent blinded outcome assessors. - Dose selection was largely empirical. - 63% of identified trials remained registry-only or grey-literature records, above the 30% threshold the authors cite as indicative of structural publication bias. - Human pharmacokinetic and biodistribution data are still missing. - Longer-term safety surveillance is still needed. - The review says cells and nanoscale exosomes may travel through the olfactory and trigeminal pathways and reach deep brain regions in roughly 30 minutes, bypassing the blood-brain barrier. - The paper catalogs delivery tools including nasal drops, patch-assisted infusion, nebulizers, atomizers and bi-directional sprays. - It also reviews dosing strategies ranging from cell-based formulations to exosome preparations of up to several hundred billion particles. - R3 Stem Cell calls for adequately powered, quadruple-blinded, placebo-controlled randomized trials with sham intranasal controls and independent blinded assessors. - The authors also want pre-registered statistical analysis plans, pre-specified minimal clinically important differences, human biodistribution endpoints using radiolabelled tracking, and tumorigenicity and immune surveillance beyond the typical 3-to-12-month follow-up window. - The team urges sponsors to publish results from completed registry trials to reduce publication bias.

Between the lines: - The review is both a progress report and a warning sign: the field has early human safety data, but the evidence base remains too thin and too biased to settle efficacy questions. - The inclusion of many registry-only records suggests the published literature may overstate the maturity of the field unless more negative or neutral studies are disclosed. - The mechanistic case for nasal-to-brain delivery is strong enough to justify more trials, but the lack of biodistribution and long-term safety data remains a major gap.

What’s next: - R3 Stem Cell says more clinical trials are being planned. - The authors want future studies to prove whether intranasal delivery can reliably deliver meaningful benefits across neurological and respiratory conditions. - The field’s next step is larger randomized trials that can measure where the cells go, how long they persist and whether the early signals hold up over time. - The company operates regenerative medicine clinics at 80 locations in 8 countries and says it continues to publish research aimed at translating regenerative medicine into clinical care.

The bottom line: - Intranasal stem cell therapy is moving from theory to early human evidence, but the review makes clear that the jump to standard treatment will depend on much bigger, cleaner trials.