Pancreatic Microcirculation Profiles in the Progression of Hypertension in Spontaneously Hypertensive Rats

Abstract

BACKGROUND Emerging evidence indicates that the pancreas serves as a major source of degrading protease activities and that uncontrolled proteolytic receptor cleavage occurs under hypertensive conditions, which leading to systemic dysfunction and end-organic damage. However, changes in pancreatic microcirculation profiles during the progression of hypertension remain unknown. METHODS Pancreatic microcirculatory blood distribution patterns and microvascular vasomotion of spontaneously hypertensive rats (SHRs) and normotensive control Wistar Kyoto rats (WKYs) at 5, 8, 13 and 18 weeks of age were determined. Wavelet transform analysis was performed to convert pancreatic micro-hemodynamic signals into time-frequency domains and construct three-dimensional spectral scalograms. The amplitudes of characteristic oscillators including endothelial, neurogenic, myogenic, respiratory and cardiac oscillators were compared among groups. Plasma nitrite/nitrate levels were measured using a Griess reaction. Additionally, endothelin-1, malondialdehyde, superoxide dismutase and interleukin-6 levels were determined by enzyme-linked immunosorbent assay. RESULTS SHRs exhibited a reduced blood distribution pattern with progressively decreased average blood perfusion, amplitude and frequency of microvascular vasomotion. Wavelet transform spectral analysis revealed significantly reduced amplitudes of endothelial oscillators from 8- to 18-week-old SHRs. Additionally, the blood microcirculatory chemistry complements explained the micro-hemodynamic profiles partially, as demonstrated by an increase in plasma nitrite/nitrate, endothelin-1, malondialdehyde, and interleukin-6 levels and a decreased superoxide dismutase level in SHRs. CONCLUSIONS Pancreatic microcirculation profiles are abnormal in the progression of hypertension in SHRs, including a disarranged blood distribution pattern, impaired microvascular vasomotion and reduced amplitudes of endothelial oscillators.

Lymphatic microcirculation profile in the progression of hypertension in spontaneously hypertensive rats

“…Microcirculation refers to the terminal vascular and lymphatic network of the systemic circulation, which consists of arterioles, capillaries, venules, and lymphatic vessels, and plays a vital role in maintaining the physiological function of tissues. Accumulating data, including ours, have demonstrated that decreased microvascular blood perfusion contributes to the development of essential hypertension through a loss of endothelial nitric oxide synthase (eNOS) activity or reduction in bioavailable NO 4,5 . In lymphatic endothelial cells, eNOS is required for robust lymphatic contractions under physiological conditions, 6 and eNOS can stimulate lymph‐angiogenesis and modulate the activity of afferent and efferent collecting lymphatics, which therefore enable blood pressure to be maintained within normal ranges.…”

“…Accumulating data, including ours, have demonstrated that decreased microvascular blood perfusion contributes to the development of essential hypertension through a loss of endothelial nitric oxide synthase (eNOS) activity or reduction in bioavailable NO. 4 , 5 In lymphatic endothelial cells, eNOS is required for robust lymphatic contractions under physiological conditions, 6 and eNOS can stimulate lymph‐angiogenesis and modulate the activity of afferent and efferent collecting lymphatics, which therefore enable blood pressure to be maintained within normal ranges. Nevertheless, even though it is a comprehensive aspect of integrated microcirculation profile, the relationship between lymphatic microcirculation and essential hypertension is not well studied.…”

Skin Microhemodynamics and Mechanisms of Its Regulation in Type 2 Diabetes Mellitus

“…The role of signal components mentioned above has been studied fragmentarily in microvasculature oscillatory processes. So, in spontaneously hypertensive rats at the age of 8 to 18 weeks, spectral analysis using wavelet transform revealed a significant decrease in the amplitudes of pancreatic microcirculation oscillations in the endothelial range, which can be partially explained by an increase in plasma levels of nitrite/nitrate, endothelin-1, malonic dialdehyde and interleukin-6 and a decrease in the level of superoxide dismutase in the blood [ 176 ]. A comprehensive study of the spectral characteristics of murine skin micro-hemodynamics oscillations and oscillations of Ca 2+ and NO concentrations in the cytoplasm of cultured murine microvascular endotheliocytes showed the presence of low-frequency oscillations of both Ca 2+ and NO concentrations in the frequency interval coinciding with the interval of NO-independent endothelial activity of skin microcirculation [ 177 ].…”