# The effect of early-life nasal colonization with Lactobacillus on the development of the local immune response and the later onset of recurrent wheeze, childhood asthma, and allergic rhinitis

> **NIH NIH K23** · VANDERBILT UNIVERSITY MEDICAL CENTER · 2020 · $185,303

## Abstract

PROJECT SUMMARY
The aggregated evidence suggests that certain taxa of the early-life upper airway microbiome act as
gatekeepers to prevent the onset of childhood respiratory diseases, which are a leading cause of morbidity and
mortality in the pediatric population. In this context, the results from our prior studies in children and those from
multiple animal studies allude to a potential protective effect of nasal colonization with Lactobacillus in infancy
on the development of childhood asthma and other atopic diseases. However, this has not been adequately
studied in humans. The mechanisms through which nasal colonization with Lactobacillus in infancy could be
protective are also largely unknown. Furthermore, there are currently no available interventions to modify the
nasal microbiome in infants at risk of upper airway dysbiosis, such as those born by cesarean section. To
address these gaps in knowledge, we propose the following specific aims: Aim 1: To examine whether early-
life nasal colonization with Lactobacillus is associated with the establishment of a distinct local immune
response and the later development of recurrent wheeze, allergic rhinitis, and childhood asthma. Aim 2: To
determine the feasibility of a randomized controlled trial (RCT) assessing the utility of vaginal seeding in
modifying the early-life nasal microbiome of infants born by cesarean section. To achieve Aim 1, we will
conduct a nested cohort study among a group of healthy infants enrolled in an ongoing large, population-
based, birth cohort (n=749). To achieve Aim 2, we will conduct a single-center, parallel-arm, blinded, sham-
controlled, feasibility RCT in healthy cesarean-born infants (n=40).
The purpose of this NIH K23 – Independent Clinical Trial Required (PA-18-374) proposal is for the candidate to
develop expertise in how to study the impact of the early-life upper airway microbiome on childhood respiratory
diseases and how to translate findings to the implementation of clinical trials, so he can ultimately emerge as
an independent patient-oriented investigator in the primary prevention of childhood asthma. To accomplish
this, he will augment his research skills by achieving the proposed specific aims and through a combination of
expert mentorship, advanced didactic coursework, hands-on experience in clinical and microbiome research,
and other focused career development activities. He will work closely with a multidisciplinary team of mentors
with collective expertise in pediatric asthma epidemiology, microbiome research, microbiology and
immunology, and the design and conduct of clinical trials. This team also has extensive experience in fostering
the development of early-stage investigators, which —in addition to a strong institutional commitment to the
candidate’s research career and an exceptional academic environment— will undoubtedly ensure his
continued success.

## Key facts

- **NIH application ID:** 9995571
- **Project number:** 5K23HL148638-02
- **Recipient organization:** VANDERBILT UNIVERSITY MEDICAL CENTER
- **Principal Investigator:** Christian Rosas-Salazar
- **Activity code:** K23 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $185,303
- **Award type:** 5
- **Project period:** 2019-08-15 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9995571

## Citation

> US National Institutes of Health, RePORTER application 9995571, The effect of early-life nasal colonization with Lactobacillus on the development of the local immune response and the later onset of recurrent wheeze, childhood asthma, and allergic rhinitis (5K23HL148638-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9995571. Licensed CC0.

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