The human biome is a contemporary frontier of medical science. Might machines be imagined that enter the gut non-invasively and monitor, diagnose, or treat human health in original breakthrough ways?
Teresa L. Johnson, NAKFI Science Writing Scholar
Johns Hopkins University
The group thinking about Machines and the Human Biome at the Frontier of Medicine Science took on the challenge of conceptualizing machines capable of non-invasively entering the gut to monitor, diagnose, or treat human health and disease.
The gut plays an integral role in human health. Elements of the gut interface with the body’s internal and external environments, and respond to a diverse array of challenges ranging from the food we eat to the microbes that live in our bodies. The gut’s multilayered structure, self-regenerating capacity, and diverse ecology provide an intricate and sophisticated system for policing the human body’s inner borders. A key element in this system is the vast population of microbes that inhabit specialized niches within the gut. Collectively referred to as the microbiota, these microbes outnumber their human host’s cells by a factor of 10.
Almost no two individuals share the same microbiota, but similarities exist across family members, generations, and cultural groups. The microbiota and the genes it harbors constitute the human microbiome.
Humans coexist with their microbial partners in a symbiotic relationship in which host and microbes benefit one another. The human host provides a nutrient-rich, oxygen-free environment conducive to microbial growth, and in turn the microbes participate in nutrient synthesis and absorption, modulate cell signaling, regulate neuroendocrine systems, and mediate host defense mechanisms. Comparable to large populations of humans, these microbes act in communities and display community dynamics to modulate human health in ways not fully recognized or understood.
Current research has focused on the microbial diversity in the gut, characterized by its richness (the total number of species) and evenness (the differences in the abundance of the various species). Early measurements of the microbiota’s diversity arose from laboratory culture-based studies of anaerobic microbes. More recent culture-independent methods rely on highly conserved microbe-specific molecular markers and environmental sequencing, providing insight into the functional potential of this highly sophisticated biological system.
Technologies for modeling interactions between disparate biological systems, such as humans and their microbial symbionts, do not exist currently. As such, a key dimension of health assessment is absent. Research suggests that an integrated model would provide insight into a variety of health concerns, including autism spectrum disorder, cognitive function, fertility, immune function, inflammation, mood, neurodegenerative disease, obesity, psychiatric disorders, and others.
The group hypothesized that the diverse, dynamic microbial community in the human gut produces measurable sound, and this sound can be interpreted as a reflection of either health or disease. Physicians and nurses have long relied on sound as a means to monitor health and diagnose disease. For example, the sound produced during percussion, or gentle tapping, of the abdomen, back, or chest wall aids a practitioner in determining the presence of anomalies such as fluid in the lungs, or a mass in the gut. Auscultation with a stethoscope of the neck or chest may identify cardiovascular or respiratory dysfunction such as dysrhythmias or constrictions, respectively. Similarly, listening to the abdomen provides information about blood flow to the gut, peristaltic movement, and bowel disease. New insights into molecular cell biology suggest that some elements of cell signaling can be described by sound.
The group proposed the development of a means to detect and integrate the myriad ways the human body and the microbiota communicate and deliver information—an InnerNet. Analogous to the Internet, the InnerNet will tap into the communication networks of the billions of microbes that reside in the gut and their vast collection of “voices.”
The adage, “Listen to your body,” will become a reality, providing humans the opportunity to communicate with their inner symbionts and make informed decisions about their health. An advantage to such monitoring is that it will give a voice to individuals who are unable to communicate subjective information regarding their gut function, especially the very young or the very old, and will tap into the “quantified self” movement in healthcare, thus empowering users to modulate their health through utilization of data.
Implementation of the InnerNet requires advances in computation and the accompanying algorithms that make sense of data; new detection tools; and new user interfaces for healthcare providers and individuals to intuitively manage this information. As a first step, the group suggested a multidisciplinary, three-tiered approach that emphasizes knowledge acquisition, crowdfunding, and business development.
Knowledge acquisition would occur in a workshop setting in which a small team of experts can enlighten, imagine, and collaborate. The team identified several areas of expertise required:
- complex systems modeling
- sonification/sonic analysis
- sensor design
- wearable technologies
- health sciences
- technology transfer/intellectual property
The group imagined several possible implementation schemes for their InnerNet, including utilization of external intimate contact sensors in clothing or temporary tattoos; internal devices such as BioSilk, a novel, patentable sensor/microphone array that can interface with an individual’s smart phone or smart home, and provide real-time analysis of anomalies within the gut; and others. Sensor output will emphasize causal triggers that stand out from ambient background noise. Some devices will be pas-
sive (monitoring/diagnostic), while others will be active (therapeutic); both will address acute and chronic health needs. These varied approaches will take into consideration the rapidly changing dynamic of the human gut and health.
The team anticipates rapid dissemination of the newly developed technology to developing nations, ensuring widespread access to the new medical devices, especially in low-resource settings, and providing a layer of healthcare not currently available.