Monday, 22 August 2016

Tissue "archeology": Dating collagen fibers

ISTM recently ran a blog writing competition that was open to PhD students and young researchers with a view to improving their lay-writing skills and helping ISTM to play a greater role in the public dissemination of its research. After concluding the competition we will be publishing each entry in turn over the coming months. The 2nd prize winner of our competition was Homayemem Weli, a PhD student in Cell and Tissue Engineering at ISTM. 


Walking through the streets of London in mid-summer, I couldn’t help but notice its beautiful 'ornaments' of modern architecture, such as the "Gherkin" or the "Walkie-Talkie". Imposing as these are, they attract less curiosity than Wiltshire’s Stonehenge.

A graceful and strong modern building speaks of a firm foundation and good design, but an ancient monument raises questions such as "when", "how" and "why". Some of us recall the creation of the London skyscrapers - having possibly witnessed it - but I dare say none of us witnessed the making of Stonehenge! Instead, we rely on archaeological research to answer questions about its origin, age and significance. This ‘discovery science’ compels us to find out why things are the way they are, and go from the known to the unknown.

Stonehenge by David Ball -

Keen to unravel the unknown, I set out to study an aspect of why people age. My focus was on women and what happens to their vaginal and skin tissues before and after pregnancy. Adorned with laboratory clothing and gloves, as though performing carbon dating on the standing stones of Stonehenge, I examined the structure of collagen fibres and cross-links within the tissues. Collagen is a protein that supports structures within the body. Cross-links are bonds formed between collagen groups (called fibres) or between chemical substances such as amino acids or reducing sugars. The larger the number of certain cross-links within the collagen fibres, the older the fibres. Collagen 'cross-link dating' can separate old fibres from young ones.

I tested two groups of tissues, pregnant and non-pregnant, of similar biological ages. I separated a particular cross-link, pentosidine, which is a known marker of tissue ageing, from the tissue solutions with liquid chromatography (a method for identifying and separating substances present within a solution). I noted the amount of pentosidine in each tissue, and compared the values.

This process of 'cross-link dating' separated the age-matched tissues into two groups – ‘old’ and ‘young’. Before pregnancy, tissues were ‘older’, but after pregnancy, they appeared ‘younger’. During pregnancy, the signs of ageing appeared to reverse! 

Studying further, I discovered this was linked with a rise of a potent antioxidant, glyoxalase I, in the tissues during pregnancy. Antioxidants such as glyoxalase I protect the body cells from molecules that could cause damage or promote ageing.

Antioxidant glyoxalase I enzyme expression in vaginal tissues during (left) and after (right) pregnancy. Green glow, clearly visible within the pregnant tissue, represents presence of the antioxidant enzyme. The pregnant tissues had more antioxidant. 

Oestrogen, a well-known pregnancy hormone, influenced the amount of the antioxidant in the tissues. I found higher oestrogen levels in pregnant tissues as shown in the images below. This implied pregnancy resulted in higher oestrogen and antioxidant levels.

Oestrogen receptor expression in vaginal tissues during (left) and after (right) pregnancy. Red dots signify oestrogen activity within the tissue and show raised level of oestrogen during pregnancy.

I concluded that oestrogen influences the ‘age’ of collagen fibres of the skin and vaginal wall by increasing the antioxidant glyoxalase I. Rise in oestrogen as seen in pregnancy leads to rise in the enzyme, subsequently retarding collagen fibre ageing within the tissues. In this way, pregnancy results in younger appearing tissues.

Oestrogen is a female reproductive hormone that changes throughout the life of a woman. It increases in quantity during pregnancy and reduces as women grow older, finally reaching its lowest levels in menopause. My finding shows that pregnancy may retard this ageing process in the vaginal and skin tissues of women. A previous study noted a reduction in similar ageing cross-links within blood vessels also in association with higher oestrogen levels, suggesting that this effect may exist in many body tissues.

By studying pregnancy, I discovered a relationship between oestrogen, an antioxidant, and the ‘age’ of collagen fibres (change of the structure) in skin and vaginal tissues.

New knowledge can be gained from investigating age-old body processes. It's always worth asking "when", "how" and "why”!

Written by Homayemem Weli, PhD Student, ISTM
(2nd Prize in the ISTM Blog Post Competition 2016)

Friday, 12 August 2016

ISTM at the International Shoulder Group meeting

A few weeks ago I went to Winterthur, Switzerland to meet a group of old friends. It wasn’t a holiday; I was there for the biennial meeting of the International Shoulder Group, a technical group of the International Society of Biomechanics.

This is a meeting for people who work in the area of shoulder biomechanics. We try to understand how the shoulder works, what goes wrong after injury or disease, how to improve its movement in sport, and how to protect it in well-designed work environments. For those of us doing shoulder research (and probably nobody other than us) it is a fascinating topic, and we look forward to getting together every couple of years and discussing it.

My particular focus is mathematical modelling of the shoulder. Using models allows us to investigate how muscles and joints work without invasive procedures on actual people. It is a very useful tool, and one of the ways we use it is to design technological systems that tackle paralysis.

Co-presenter Ricardo Matias (University of Lisbon) during the modelling workshop
As part of the International Shoulder Group meeting this year, I ran a modelling workshop that aimed to introduce modelling to people who have not used it before. The response was very positive, and everyone seemed keen to give it a go. With participants from 13 different countries, it is great to know that our models could be used all over the world!

Dimitra and her thank-you gift for helping to organise the conference
Shoulder biomechanists are such a lovely lot, and I can’t wait to see everyone again in 2018!

Tuesday, 2 August 2016

Predicting injury in football

ISTM recently ran a blog writing competition that was open to PhD students and young researchers with a view to improving their lay-writing skills and helping ISTM to play a greater role in the public dissemination of its research.   After concluding the competition we will be publishing each entry in turn over the coming months. The 1st prize winner of our competition was Fraser Philp a PhD student at ISTM.  Fraser's PhD focuses on identifying within current practice and research, methods used for predicting injury and performance within football and Fraser used this topic as the theme for his blog post.


Association football or soccer is one of the most popular international sports, with approximately 200,000 professionals and a further 240 million amateur male and female participants worldwide. Football is England’s largest national team sport, with men’s and women’s football being the first and third largest team sports respectively. Associated with the high levels of participation in football is a high level of injury risk. As many as 47% of footballers have been forced to retire from the game due to injury throughout the season, an average outfield player is expected to sustain at least 1-2 injuries resulting in them being unavailable for 1 competitive game. High rates of injury can negatively impact on the performance of an individual. Likewise an increased number of individuals sustaining injury within a team can negatively affect team performance, which, in a competitive league can have further consequences.
Given the problems associated with injury, the medical and sports science teams who work with professional football teams try to minimise injuries occurring. One of the ways they attempt to do this is through screening. Screening can involve exercise tests and measures of physical performance that are used in an attempt to identify injury risk factors. These tests are usually carried out before the competitive season starts, in a period known as pre-season, and during the competitive season itself. Despite the widespread use of these tests and measures, many of them have not been and compared against other methods of measurement for validation purposes. 

My research project is aimed at comparing and providing numerical values to one of the exercise screening tests that is commonly used. The screening test being evaluated is the Functional Movement Systems (FMS) screen, and I will be using a video motion capture system, Vicon (©Vicon Motion Systems Ltd) for my evaluation. The FMS is partly made up of 7 exercise tests, in which the participant is required to complete the movements, a maximum of 3 times. These tests include things such as a squat with their arms above their head, lunges and other physical tests. The quality of the movements is then scored by an assessor and the participant is given a score for each test. The final score is then used to identify injury risk, with a lower score indicating a higher risk of injury. I have chosen to evaluate the FMS against a motion capture system as this has not been done yet and there are some limitations experienced when using the FMS test. The movement test takes into consideration some patterns of movement but does not describe the angles that are achieved at the joints. It is also difficult for the person assessing to observe multiple joints, whilst at the same time, scoring the movement and identify variations in movement patterns. These problems arise because the assessor has essentially a limited 2 dimensional view and of a complex dimensional. The use of motion capture can help with some of these challenges.

Motion capture is more widely known for its use in the movie industry in virtual recreation. It is also used as the gold standard measurement in hospital settings for measuring walking patterns and human movement patterns in people with neurological disorders. In order to measure the movements of the FMS with motion capture cameras, some additional preparation is needed. This requires placing reflective markers on selected body parts of the person. This is because the motion capture camera’s only pick up reflections from the infrared light that they send out. These markers can then be virtually recreated providing an outline of the person’s body parts on which they were placed. Once this has been done we are able to see the angles achieved by the participant in all 3 dimensions i.e. how much they bent their knee or how much their hip was rotating. It also allows for a description of the movement patterns that are occurring across the joints when the participant completes the FMS. Furthermore we can also attribute numerical values to the rules and scoring criteria of the FMS exercise tests.

Figure above shows the process after placing the markers on and then virtualy recreating them.

Alongside this we have monitored a football team over one competitive season and will investigate whether there is a link between the measurements we took and the injuries they sustained. Within this analysis we will also be investigating things such as the amount they trained, the surface they trained on and what their match fixtures were like. Hopefully a better understanding of all these factors will allow for fewer injuries in footballers.

Written by Fraser Philp, PhD Student, ISTM
(1st Prize in the ISTM Blog Post Competition 2016)