PROJECT SUMMARY
Chronic wounds are an epidemic afflicting several million people in the United States, and many million more
worldwide. The elderly, the obese and those with diabetes have much higher incidence of chronic wounds,
and the proportion of the population that fall into these categories is rising. Chronic wounds are associated
with considerable reductions in quality of life, including increased rates of depression and mortality, among
others. The expansion of the chronic wound epidemic is also reflected in rapidly rising medical costs. The non-
healing nature of these wounds is heavily influenced by microbial infection, and multiple bacterial species are
commonly found to simultaneously occur in wounds as microbial communities. A recent study provided
evidence that one's genetics shape the bacterial species that inhabit their chronic wounds and these species
were consequential to healing rates. Recognizing the biomedical importance of understanding this
relationship, the specific aims of the project are to: 1) Identify patient genomic loci associated with chronic
wound microbiome characteristics; 2) Establish the feasibility of predictive modeling for chronic wound
infections; and, 3) Functionally validate associated loci. The study design consists of comparing patients'
chronic wound microbiomes to their genomes through a microbiome-genome wide association study. The
design includes a discovery cohort of greater than 1,000 samples, regional imputation around lead SNPs and
Bayesian fine-mapping to identify credible sets including likely causal variants. Based on results of association
studies, specific genomic regions will be used to build the first predictive models for bacterial species
occurrence in chronic wounds; it is anticipated that such models will eventually find application in predictive
and therapeutic medicine. Model development will be accomplished by using the Bayesian credible sets of
SNPs from associated regions to inform latent variables in a structural equation modeling framework. An
independent validation cohort of greater than 250 samples will be used to assess the predictive power of these
models. Also, wet lab functional validation experiments of SNPs most likely to be causal are expected to yield
new mechanistic insights about host-microbe interactions consequential to chronic wounds. The long-term
goal of this work is to leverage individual genetics to combat chronic wounds and improve public health
outcomes.