Reconstructing early life history
Maternal milk is fundamental to the health of newborns. But how has this crucial feature of early childhood development evolved in primates? This question has perplexed researchers for decades – the problem lies in trying to estimate what long-extinct populations were doing thousands of years ago.
In a major breakthrough, the study published today in the prestigious scientific journal Nature, was part of a wide-ranging collaboration between Australian Institutions (Sydney University’s Institute of Dental Research and Universities of Technology Sydney, Melbourne and Southern Cross), and US institutions including Mount Sinai, Harvard and the University of California at Berkeley where researchers developed a method that can be applied to fossil samples, showing that consumption of maternal milk and then later transition to non-milk foods leaves an imprint in teeth, one that can be uncovered using sophisticated lasers and microscopes many years later.
Authors Dr. Manish Arora and Christine Austin tested the validity of the imprint in modern samples over several years. “We used teeth from monkeys with known nursing histories and then confirmed our findings in children who had been studied for about 8 years” said Dr. Arora. It was after this long road of scientific discovery that the researchers were convinced that their method worked, and to prove it, they applied their technique to a several thousand-year old Middle Paleolithic Neanderthal tooth that was unearthed in Belgium.
“It was the intersection of several disciplines, including analytical chemistry, dentistry and evolutionary biology that made this discovery possible. Our dietary sources leave an imprint that can be recovered after many years in tissues like tooth enamel that remain stable for long periods”, says Dr. Austin.
Dietary patterns in our early life have far reaching consequences for our health, and are also a major feature that distinguishes us from other primates. It appears that we are what we eat, even thousands of years after the fact.
The proposed cohort will be a long-term resource for multidisciplinary research on oral diseases and their interaction with systemic diseases including cardiovascular diseases, diabetes and obesity. It is aligned with both the Faculty’s and the University’s strategic health research themes of Chronic Diseases and Healthy Ageing.
It will build research capacity by involving clinicians, laboratory scientists and postgraduate trainees in well-organised established projects that have ongoing ethics approval and archived bio-specimens for rapid research translation. Clinicians interested in undertaking formal research training will be provided with structured supervision and the opportunity to harvest archived data, access study participants, and use samples stored in bio-specimen banks.
Furthermore, by linking with other health databases, oral and systemic disease trends, the use of services and the success of treatments will be monitored, leading to research that directly informs policies on prevention and healthy ageing.
New strategies in tissue engineering and 3D-printing
Organ transplantation is one of the most important problems affecting health care worldwide. The number of available donors is far lower than the number of patients in transplant units. Tissue engineering is an interdisciplinary field that combines knowledge of engineering, biology and life sciences to understand and synthesize organ substitutes or their damaged tissues to address this shortage. Here, at the biomaterials research unit at the faculty of dentistry, in adition to the traditional dental materials research and characterization, we are starting to use microfabrication techniques -commonly used in the semiconductor industry - to engineer a variety of tissues and organ substitutes, ranging from bone, blood vessels, teeth and others. Some of the techniques that are being developed in our laboratory include the development of smart hydrogels that mimic the extracellular matrix of living systems; the utilization of soft-lithography, a technique that is used to create micro-patterns to guide cell differentiation and behavior and bioprinting, which utilizes 3D printers to assemble cells and extracellular matrix with biomimetic precision. With the development of these techniques we are expecting to catalyze an important revolution in restorative dentistry, tooth regeneration and point-of care diagnostics. The implementation of these technologies in our department at Sydney University should put Australia in the forefront of regenerative dentistry and dental tissue engineering.
Ancient teeth provide the key to Europe’s genetic makeup
The current genetic makeup of Europeans is the product of prehistoric events, such as migrations. However, which past events and how they have shaped modern European mitochondrial DNA (mtDNA) variation remains intensely debated. Dr Christina Adler is part of a study, recently published in the journal Science, which aims to address this question by using ancient human DNA from teeth. Teeth provide an ideal source of preserved genetic material. The DNA within the tooth is protected, being trapped within a calcified matrix, and the reduced porosity of teeth compared to bone makes them more resistant to contamination. This study presented a large-scale chronological study including 364 individuals from the Early Neolithic to the Early Bronze Age (5,500-1,550 cal BC). From these individuals, their teeth and bones were used as to create a detailed temporal mtDNAprofile of prehistoric culturesin Europe. This genetic transect through time was used to identify four successive population eventsduring the Neolithic era that led tothe formation of modern European genetic diversity.In particular, the authors of this study were able to identify akey role of Late Neolithic cultures at the dawn of metallurgy and stratified societies in contributing to the current genetic makeup of Europeans.