Data and results – nikita salker internship portfolio brain anoxia

Cardiac heart defects (CHD)

Impact approximately 1.3 million infants every year and often result in

Irregular blood flow. As a result, many

CHD patients experience cerebral hypoxia, or the reduction in oxygen flowing to

The brain. This insufficiency leaves the white matter region as one of the

Areas most at risk of injury. However, due to the ethical and technical

Limitations of CHD focused research in humans, approaches to understand the

Cellular level of CHD pathologies are severely limited. Thus, there is a

Growing need for research focused on developing animal models to emulate the

Conditions and development of the brain under cerebral hypoxia.


The purpose of

Our project was to determine the effects of cerebral hypoxia on white matter

brain anoxia

Development and vascularization in neonatal piglets.

In humans, white matter

Represents nearly 50% of the entire brain volume. White matter is axon-dense,

Rich with neuron projections that transmit signals. White matter acts as the

Signaling headquarters of the brain, allowing all four lobes, in addition to

Other areas, to communicate. During development, white matter plays a key role

In establishing facets of personality as well as mental operations. The corpus

Callosum is one of the main white matter structures in the brain and connects the

Left and right hemispheres together to enabling communication between both

Sides of the brain. For CHD patients, the corpus callosum is often

Underdeveloped, putting these key mental communications at risk.Brain anoxia

White matter contains

Oligodendrocytes (ols), specialized glial cells responsible for producing the

Myelin sheaths around axons which facilitates neuronal signaling. Mature ols

Are the end result of a complex lineage beginning with neuroepithelial stem

Cells; these cells divide and differentiate to form numerous progenitors,

Including oligodendrocyte progenitor cells (opcs) (shenoy and blelloch, 2014).

OPCs then undergo proliferation, migration and differentiation to form mature

OLs. Due to the extreme metabolic demands that oligodendrocyte progenitor cells

(opcs) undergo during development, they require an adequate blood supply in the

White matter regions where they reside (yuen et al, 2014). Further research

brain anoxia

Could establish the impact of hypoxic conditions on the exact timeline of brain

OL development.

We focused our research on

Modeling the effects of CHD on oligodendrocyte populations and cerebral

Vascularization. In order to model CHD we created a hypoxia model using neonatal

Piglets. Pigs at 3 days of age were placed in a hypoxia chamber alongside normoxic

Conrol pigs. Hypoxia chambers were used in order to control the amount of

Oxygen and create similar conditions of subnormal cerebral oxygenation in CHD.

All histological protocols were performed 11 days post hypoxia on post natal

Day 14. Numerous immunohistochemistry protocols were conducted on 60 ┬Ám

Thick, free-floating sections to visualize various cellular and structural characteristics

brain anoxia

In both conditions. Olig2 and laminin markers were primarily used, allowing us

To observe the number of ols and the development of blood vessels,

Respectively, in the corpus callosum. Our data set consisted of 5 total pairs

(n=5), 5 normoxic and 5 hypoxic brains. Further

Analysis involved stereoinvestigator software, utilizing the area fractionator,

Spaceballs and optical fractionator probe to ensure systematic random sampling

And unbiased estimates overall, we examined several differences in various

Categories between normoxic and hypoxic brains, with a general reduction of ols

And vessel density in hypoxic brains.

Olig2 is a transcription factor

Present in all stages of the OL lineage; we used an antibody to olig2 as a

brain anoxia

General marker for ols. Thus, immunostains for olig2 were performed in order to

Compare the number of ols in the corpus callosum in both hypoxic and normoxic

Conditions.

Olig2 counts: while there was no significant difference, we did

Observe a general reduction in the density and number of olig2 + cells

In hypoxic compared to normoxic brains. This suggests that in response to a

Lack of oxygen, the overall number of ols were reduced. This overall reduction may

Reflect impaired OL generation by a reduction in OPC. Recent studies have

Demonstrated that opcs migrate along the vasculature during the development of

The central nervous system (tsai et al, 2016). Thus, establishing comparative

Counts of opcs and their interactions with the vasculature will provide

brain anoxia

Insights into how cerebral hypoxia depletes OL numbers.

Because we are investigating

Cerebral hypoxia, examining the vasculature within the white matter region

Provided insights on impact of CHD within the brain. Using a laminin stain, we

Were able to observe various characteristics of the vasculature, including

Vessel branch points, length and volume. Overall, we observed a significant

Reduction in branch points (valence 3), volume and vessel length. However, we

Observed an increase in branch points (valence 4) in hypoxic brains- though the

Difference was not significant.