Congratulations to Sithandiwe Eunice Mazibuko who successfully completed her PhD at the University of Zululand. Sithandiwe joined the Diabetes Discovery Platform (DDP) of the SAMRC on a contract post in 2007 as a Research Technologist. During her tenure at DDP, she registered for part-time postgraduate studies at the University of Zululand. Under the supervision of Dr Muller of DDP, Sithandiwe completed her BSc (Hons) in 2008 followed by her MSc in 2010. Her PhD project extensively investigated the effects of polyphenolic compounds on fatty acid-induced insulin resistance. Increased levels of saturated fatty acids (SFAs), such as palmitate, are associated with insulin resistance of the muscle, liver and fat. Skeletal muscle, which accounts for ~80% of peripheral glucose disposal, is particularly susceptible to elevated SFA concentrations. The aim of Sithandiwe’s PhD study was to establish whether Rooibos (Aspalathus linearis) and its inherent major phenolic compounds had a role in preventing or ameliorating the development of insulin resistance.
Using palmitate-induced insulin resistant cell models, Sithandiwe’s research demonstrated that extracts produced from Rooibos and the compounds aspalathin, orientin, isoorientin and rutin enhanced glucose uptake, mitochondrial activity and ATP production in these
insulin-resistant cells. At a cellular level, both an aspalathin-enriched Rooibos extract and pure aspalathin suppressed the intracellular inflammation pathway, which is up-regulated during insulin resistance. They also increased the activation of key transcription proteins (AKT and AMPK) involved in insulin-dependent and non-insulin regulated signal transduction, and increased the protein expression of glucose transporters 2 and 4 in liver and muscle cells, thereby enhancing glucose uptake into the cell. Treating obese insulin resistant rats with an aspalathin-enriched Rooibos extract improved their insulin sensitivity. At a molecular level, the expression of key insulin signalling effector proteins, activated AMPK and glucose transporters were increased in the muscle and liver by the treatment. Her study presents substantial evidence that Rooibos and its phenolic constituents could potentially ameliorate insulin resistance, a major risk factor in the pathogenesis of obesity and type-2 diabetes.
Congratulations to Anesh Sukhai from the MRC-UNISA Safety
and Peace Promotion Research Unit who recently defended and
completed his PhD at the University of East Anglia, Norwich,
UK. His dissertation, registered at the School of Environmental
Sciences, focused on ‘Understanding the physical and social
environmental determinants of road traffic injury in South Africa’.
A large range of physical and social environmental effects, using
various spatial and spatial- temporal frameworks, and empirical
models, were considered for this research. The findings have also
been published in local and international peer-reviewed journals,
including the South African Geographical Journal (SAGJ) and
Accident Analysis and Prevention Journal (AAPJ).
‘Epidemiology and risk of road traffic mortality in South Africa’
was published in the SAGJ (2009). Subsequent work examined
predictors of temporal variations in road traffic mortality using
a hierarchical time series framework. This work informed the
development of a journal article entitled ‘Temporal variations in
road traffic fatalities in South Africa’, which was published in the AAPJ (2011). Using a geographical framework, multi-level models
were used to delineate the predictors of spatial variations in road
traffic mortality by police areas across the country, and a journal
article based on this work, ‘Understanding geographical variations
in road traffic fatalities in South Africa’ was published in the SAGJ
(2013). A journal article on ‘Urban density, deprivation and road
safety’, based on a small area study in the eThekwini metropolitan
area, is being finalised for publication.
The research provides novel insights into the role of contextual
influences and predictors of road traffic mortality in the country.
In addition to important and well-recognised effects relating
to alcohol and travel exposure, findings have shown most
environmental influences on RTIs in SA to be developmentrelated,
including effects relating to social and area deprivation,
violence and crime, and rurality. The findings have implications
for alignment and integration of road safety policies and practices
with other developmental policies in the country. The adoption of
more sustainable spatial forms such as ‘compact cities’ and ‘new
urbanism’ are also proposed for addressing spatial disparities
arising from historically skewed planning policies.
A range of recommendations for policy and practice have been
detailed, which are also informing the release of a policy brief on
the determinants and necessary actions required for addressing road safety in the country.