Feng is integrating experiment data measured from spontaneously hypertensive rat (SHR) into a computational model to discover the potential mechanism of primary hypertension. By analyzing the dynamic baroreflex response to spontaneous fluctuations in arterial pressure, Feng find the existence of long intermittent periods (lasting up to several minutes) of engagement and disengagement of the baroreflex. And Feng is working with Ben Randall to develop an algorithm to calculate a new index called “on fraction” to describe how many percentage of time baroreflex engaging in the BP regulation.
Through a time series data analysis of many rats from many of different rat strains, there are many interesting findings:
- During normal dark‐cycle recording the fraction of time in the on state (the “on fraction”) ranges from 40‐85% for all rat strains observed
- The on fraction decreases with age only in the SHR and WKY strains
- The mean arterial pressure is tightly correlated with on fraction in only the SHR and WKY strains
- Mean pressures during off state are higher than during on state in the SHR and WKY strains for both sexes and at all ages studied.
On fraction results for WKY and SHR ratsThese observation yields the hypothesis that a lower proportion of engagement versus disengagement of the baroreflex in SHR rat compared to the WKY contributes to the hypertension (or increased blood pressure) in SHR compared to WKY. chronic increases in pressure following sino‐aortic denervation are higher in WKY compared to the SHR rats. These observations are consistent with the hypotheses that the differences in intermittent functioning of the baroreflex play a causal role in the development of hypertension in the SHR strain.
Mean arterial pressure (MAP) and change in MAP for denervated animals over time