annual report - O'Brien Institute

Macrophages and Inflammation
Senior Scientist: Peter Vadiveloo
Members of the Laboratory: Matias Abregu, Angela
Arvanitis, Bruce Dowsing, Tanya Harkom, Effie
Keramidaris, Wayne Morrison, Rosalind Romeo.
...and Major Collaborators: Fiona Clay c , Matthias
Ernst c , Paul Hertzog b , John Hamilton d , Alastair Stewart a ,
and Gino Vairo e .
aDepartment of Pharmacology, University of Melbourne
bMonash Medical Centre, Clayton, Vic.
cLudwig Institute for Cancer Research, Parkville Vic.
dUniversity Department of Medicine, Royal Melbourne
Hospital, Parkville.
eWalter and Eliza Hall Institute, University of Melbourne,
Parkville.
Mechanisms of macrophage activation
Macrophages are derived from white blood cells called
monocytes. Macrophages are dynamic cells involved in
many important processes in the body, making them an
exciting cell type to study. Following surgery a variety of
processes may occur at the repaired site, including wound
healing, inflammation, fighting infection, new blood
vessel formation (angiogenesis) and blood vessel
thickening (atherosclerosis). Macrophages are known to
play central roles in all of these processes. Our studies aim
to discover the molecular mechanisms underlying
macrophage functions since knowledge of fundamental
biological processes will ultimately result in better
treatment of patients following trauma and surgery.
We have made the unique discovery that activated
macrophages make a protein called cyclin D2. We believe
this protein regulates macrophage functions. We are trying
to better understand the role of cyclin D2 in activated
macrophages. An exciting advance in these studies over
the past year has been the beginning of experiments using
cyclin D2 ‘knockout’ mice. These mice (which come from
our colleagues at the Dana Farber Cancer Institute in
Boston) have been genetically engineered with the cyclin
D2 gene knocked out. Our preliminary data indicate cyclin
D2 may regulate production of inflammatory cytokines by
macrophages. Confirmation of this finding will provide a
significant advance in our understanding of how
macrophages work. In other work on this project, Honors
student Matias Abregu is identifying cytokines that
stimulate cyclin D2 synthesis in macrophages.
In other studies that link in with work on nitric oxide
(NO), we have shown that NO production by
macrophages is mediated by type I IFNs, and that NO
does not play a role in preventing proliferation during
macrophage activation.
Macrophages and new blood vessel formation
(angiogenesis)
Macrophages are known to secrete a number of proteins
which regulate new blood vessel formation (angiogenesis).
We have shown that angiogenesis is altered in mice
lacking iNOS (inducible nitric oxide synthase). Given that
macrophages make iNOS protein, we propose that
synthesis of pro-angiogenic molecules such as vascular
endothelial growth factor (VEGF) is altered in
macrophages lacking iNOS. To explore this we are
measuring the release of angiogenic molecules from
macrophages derived from iNOS ‘knockout’ mice.
Wound Healing in Tendons
Senior Scientists: David McCombe, Tony Penington,
Wayne Morrison.
Members of the Laboratory: Rosalind Romeo, John
Hurley.
...and Major Collaborators:
Tracey Brown m , V Gunzler k , Erik W Thompson j and JF
Williams k
jVictorian Breast Cancer Research Consortium, St
Vincent’s Hospital Melbourne.
kDepartment of Engineering, University of Melbourne.
mDepartment of Biochemistry and Cell Biology, Monash
University
Tendon adhesions are a significant complication of tendon
injury or infection. After surgical repair of a tendon, scar
tissue often forms around the tendon, binding it to the
sheath (tunnel) in which it slides. In these experiment we
have been attempting to mimic these tendon adhesions in
the human using an animal model. We isolated a healthy
tendon and injected an irritant substance (eg. carrageenan,
iodine, oxytetracyclin, endotoxin or other abrasive agents)
into the sheath to create adhesions. The animal was
euthanised 1-3 weeks later and the limb isolated. A force
transducer was used to pull the digit into full flexion so
that the claw touches the sole of the foot, a measure of the
strength of the adhesions.
We also studied the effects of inhibitors of prolyl-4hydroxylase
and collagen synthesis on flexor tendon
adhesion formation and skin wound healing. Rats were
divided equally into three groups to receive post-operative
oral doses of two test drugs or no drug (control). Animals
were sacrificed fourteen days after a zone II tendon crush
injury with suture immobilization, and a dorsal skin patch
excision. Tendon adhesion formation was estimated
biomechanically using work of flexion (WOF) of the digit.
Skin healing was measured using wound area and histology.
Compared to the control group, WOF against adhesions was
reduced by approximately 70% in both drug groups. All
skin wounds healed equally well, but in both drug groups
there was minimal deposition of scar collagen. These drugs
may become useful clinically to reduce adhesions following
flexor tendon surgery and in hand and foot surgery where
modulating collagen scar formation is important.
stabilised our position financially both among the
business community and with government. We
will greatly miss Alan’s calm and charm and
sincerely thank him for his outstanding
contributions. We wish him well for the future.
This year through a generous donation of our
Chairman we have been able to employ a
Developmental Manager, Mr Sam Broughton.
Sam has an excellent track record both in
Victoria and South Australia where he has
worked with several bodies, most recently the
Red Cross. We are hopeful that this will lead to
new avenues of fundraising and increase our
professionalism in the marketplace.
This year we have instituted a younger group
under the auspices of the Microsurgery
Foundation. We are especially indebted to them
for their generosity for coming on board and
believe this will be an exciting development for
us in the future.
We are indebted to many large donors and
funding bodies, many of whom have repeatedly
supported us in a major way. These include the
Victorian State Government, National Health &
Medical Research Council, Transport Accident
Commission, The Jack Brockhoff Foundation,
National Australia Bank, Evelyn M. Coy Estate,
The Wellcome Trust, BHP Community Trust,
Tattersall’s, L.E.W. Carty Charitable Fund, HIH
Insurance Ltd.
We are grateful to Ms Sue McKay and Ms
Liliana Pepe and their staff in the Experimental
and Medical Surgical Unit. For many years they
have provided an outstanding level of
cooperation and support to the staff of the
Bernard O’Brien Institute of Microsurgery.
We also thank Dr Jim Shaw, Chairman of St.
Vincent’s Hospital Animal Ethics Committee and
his board members who oversee all our projects
and ensure the highest standards of animal care
are maintained.
We are also grateful to the ward staff and
operating theatre staff of both St. Vincent’s
Public and Private Hospitals.
Wayne A Morrison MD, BS, FRACS
Director
MICROSURGERY
FOUNDATION
24 17