Insights Into Microbiome and Environmental Contributions to Sickle Cell Disease and Leg Ulcers Study (INSIGHTS Study)

Study Description:

Leg ulcers are a serious and debilitating complication of sickle cell disease (SCD). This study will explore microbial, genomic, and environmental (social and physical) factors, that may influence the onset and progression of leg ulcer formation and delayed healing in individuals living with SCD. The etiology of SCD-associated leg ulcers is unclear, and we hypothesize that predisposition to developing leg ulcers is multifactorial. This multisite study is an exploratory study of the microbiome and environment of individuals living with sickle cell disease leg ulcers. The study s objective is to identify triggers that may be integral in leg ulcer onset and progression. The central goal of this study is to obtain an improved understanding of the participants clinical phenotype, leg ulcer microbiome and the psychosocial and environmental factors that may impact this complication.

Objectives:

Primary Objective:

Employ genomic approaches to characterize the skin microbiome in individuals living with SCD with and without leg ulcers.

Secondary Objective:

• Employ social science research measures to identify psychosocial and physical environmental factors that impact quality of life in individuals living with SCD with and without leg ulcers.
• Develop new measure of severity for SCD that integrates clinical outcomes and the quality of life of the participant.
• Develop guidelines for researchers to address the needs of diverse and under-resourced groups in genetic research.

Endpoints:

Primary Endpoint:

To characterize the microbiome of leg ulcers in SCD.

Secondary Endpoints:

• To characterize the phenotypic variation in SCD.
• To identify similarities and differences of the microbial signatures of chronic diabetic foot ulcers and SCD leg ulcers.
• To investigate physical and psychosocial environmental indicators that impact quality of life in individuals living with SCD with and without leg ulcers.
• To determine if an association exists between the microbiome (microbial diversity) of SCD leg ulcers and the quality of life (psychosocial and physical environment) indicators of individuals with SCD leg ulcers.
• To determine if an association exists between the microbiome (microbial diversity) of SCD leg ulcers and clinical phenotype of individuals with SCD leg ulcers.
• To determine how leg ulcers influence one s physical function and one s perceptions of stigma and self-esteem.
• To identify factors that are indicators of both quality of life and clinical severity of the participant.
• To identify specific psychosocial and environmental factors related to resilience in our study population.
• To investigate current practices and policies around the return of secondary findings in genome sequencing studies in under-resourced study participant populations, and to explore ethical and clinical policies for returning secondary findings by examining various practices within the research community.
• To investigate SCD variation in phenotype, microbiome, physical and psychosocial environments in a cohort in Sierra Leone.
• To compare similarities and differences in phenotype, microbiome, physical and psychosocial environments between U.S. and Sierra Leone cohorts.

• INCLUSION CRITERIA:

We will enroll up to four-hundred and fifty (N=450) participants in the microbiome sampling cohort. In addition to the 300 SCD leg ulcer microbiome participants, we will recruit up to an additional 200-250 SCD participants that will complete the clinical evaluation, (including blood sample) and survey instruments for a total of up to 550 participants at three sites, NIH (n=200) and MMC (n=100), and Sierra Leone (n=250).

Of the total participants, we will resample the microbiome of up to 75 individuals from each of the 3 initial sampling groups: SCD with, without and never had SCD leg ulcers. Of those 75 individuals who are sampled longitudinally, those with clinically interesting cases may be sampled at multiple intervals.

All sampling, surveys, and processing of samples will take place at the NIH Clinical Center the second site, MMC, or in Sierra Leone. All samples will be stored at NIH.

To be eligible to participate in this study, an individual must meet all of the following criteria:

• All subjects must have a diagnosis of sickle cell disease (HbSS, HgSC, HbSB 0 or HBSB+)
• Be at least 18 years old.
• Provide written informed consent.
• For the Qualitative phase: must have a recurrent, active, or single-occurrence presentation of a leg ulcer(s).
• For the resilience study analysis: cohort will be determined by the research team based on the results of part I of this analysis. For part I, the inclusion criteria are that the individual must have enrolled and completed the INSIGHTS study.

Exclusion criteria

Any individual that meets any of the following criteria during baseline evaluation will be excluded from the study:

• Pediatric population (<18 years old)
• Participants for microbiome study (only) who have received oral and/or topical antibiotics or antifungals < 2 weeks prior to enrolling in the study for leg ulcers (for those with leg ulcers only)
• Subjects presenting with clinically diagnosed bacterial infection (i.e. clinical appearance, clinical judgment, fever, redness around ulcer, purulent drainage etc.) at the site of ulceration. (This can only be diagnosed clinically by the research nurse during sampling

and is only applicable to those with leg ulcers only).