Aki Sinkkonen, an ecologist at the Natural Resources Institute Finland, studies the influence of urban ecosystems on immunoregulation.
Marja Roslund
A decade ago, Aki Sinkkonen, an ecologist at the Natural Resources Institute Finland, went on a wilderness hike with an immunologist colleague. Watching their children swim in a muddy lake, surrounded by nature’s microbial medley, they discussed the biodiversity hypothesis, which posits that rising rates of immune-mediated diseases may result from reduced contact with nature.1 With few studies to turn to, Sinkkonen shifted his research to explore the impact that urban biodiversity interventions in daycares and homes have on human immune regulation and skin microbiota.
How did daycare modifications impact children’s immune responses?
The immune system develops in childhood, so we studied environments that children are exposed to. Typical daycare playgrounds often lack natural elements like vegetation and dirt. We found that adding microbially-rich materials to playgrounds can impact immunoregulation.2 After 28 days, children in these enhanced playgrounds showed increased skin and gut microbiota diversity, circulating immune suppressive cytokine levels, and regulatory T cells.
What are some prophylactic practices that you’ve explored in offices and homes?
Growing evidence suggests that microbially-rich home environments can improve health, so we conducted a small, placebo-controlled, double-blinded indoor gardening intervention.3 City-dwelling adults who handled microbially-rich soil daily showed diversified skin microbiota and elevated anti-inflammatory cytokine IL-10 levels after two weeks. We also investigated if air-circulating green walls could increase exposure to environmental microbiota.4 We found that office greening may improve the skin microbiome diversity and reduce proinflammatory cytokine activities, though further research is needed.
What experiments are needed to collect more conclusive evidence?
Our intervention studies point to immune modulation from environmental microbiota exposure, but to study disease incidence, we need long-term human observations. We are currently conducting several longitudinal, double-blinded studies on disease incidence and changes in urban environments.