Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2405.18760

Local nature of 0.1 Hz oscillations in microcirculation is confirmed by imaging photoplethysmography

Irina A. Mizeva·Natalia P. Podolyan·Oleg V. Mamontov·Anastasiia V. Sakovskaia·Alexei A. Kamshilin
View original source ↗Read source document ↗Export metadata ↓

Abstract

Low-frequency oscillations in the human circulatory system is important for basic physiology and practical applications in clinical medicine. Our objective was to study which mechanism (central or local) is responsible for changes in blood flow fluctuations at around 0.1 Hz. We used the method of imaging photoplethysmography synchronized with electrocardiography to measure blood-flow response to local forearm heating of 18 healthy male volunteers. The dynamics of peripheral perfusion was revealed by a correlation processing of photoplethysmography data, and the central hemodynamics was assessed from the electrocardiogram. Wavelet analysis was used to estimate the dynamics of spectral components. Our results show that skin heating leads to multiple increase in local perfusion accompanied by drop in blood flow oscillations at 0.1 Hz, whereas no changes in heart rate variability was observed. After switching off the heating, perfusion remains at the high level, regardless decrease in skin temperature. The 0.1 Hz oscillations are smoothly recovered to the base level. In conclusion, we confirm the local nature of fluctuations in peripheral blood flow in the frequency band of about 0.1 Hz. A significant, but time-delayed, recovery of fluctuation energy in this frequency range after cessation of the skin warming was discovered. This study reveals a novel factor involved in the regulation microcirculatory vascular tone. A comprehensive study of hemodynamics using the new technique of imaging photoplethysmography synchronized with electrocardiography is a prerequisite for development of a valuable diagnostic tool.

Explore related subjects

q-bio.TO

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Irina A. Mizeva, Natalia P. Podolyan, Oleg V. Mamontov, Anastasiia V. Sakovskaia, Alexei A. Kamshilin. 2024-05-29. Local nature of 0.1 Hz oscillations in microcirculation is confirmed by imaging photoplethysmography. https://doi.org/10.1016/j.bspc.2024.107188

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Simulation and Analysis of Solute Transport in Multi-Lymphangion Lymphatic Vessels

The lymphatic system (LS), a body-wide network of vessels and lymphoid organs governing fluid homeostasis and immune surveillance, has so far not been investigated as a domain for diagnostic and therapeutic molecular communications (MC) applications, despite several properties that make it a promising, complementary alternative to the cardiovascular system. These favorable properties include slower flow, simpler and less dense molecular fluid composition, and direct anatomical access to lymph nodes. Realizing this potential, however, requires a quantitative understanding of how solutes propagate through the LS, a problem that, unlike lymph flow itself, remains largely unaddressed in the literature. As a first step towards narrowing this gap, we develop a particle-based simulation (PBS) framework of solute transport through a three-dimensional chain of valve-separated, concatenated vessel segments, called lymphangions. We simulate the spatiotemporal evolution of solute concentration and qualitatively validate the resulting transport dynamics against existing in vivo measurements of fluorescent tracer propagation in multi-lymphangion lymphatic vessels. Our simulations show that the valve-gated nature of solute transport in lymphatic vessels leads to bursty solute concentrations over time, a characteristic that can also be observed in vivo. Additionally, we find that, within one pumping period, peak timing is dictated by the valves' synchronizing effect rather than the particle release time, while diffusivity and receiver placement determine peak sharpness. Overall, the proposed PBS framework provides a first quantitative basis for solute transport modeling in the LS and several concrete application scenarios for MC in this underexplored domain. Supplementary video material illustrating the PBS is publicly available on Zenodo [DOI: 10.5281/zenodo.21888066].

q-bio.TO↗
arXiv2026

A Combined ODE Model of Carbohydrate Fermentation and Colorectal Cancer

We formulate and analyze a system of non-linear ordinary differential equations that describe key metabolic and immunological interactions between butyrate produced by fiber-fermenting gut microbiota, colorectal cancer cells and host cell populations. The model is studied both independently and in conjunction with a pre-existing carbohydrate fermentation model. The parameter space is explored through sensitivity analyses. Simulation experiments are conducted to illustrate the emergence of varying dynamical behaviour driven by butyrate availability. Our model predicts that butyrate production is driven by fiber consumption and further supported by probiotics in the case of microbial dysbiosis. It also suggests that butyrate may help in suppressing tumour growth. We also show that by adding noise with sufficiently high intensity, cancer elimination occurs almost surely in infinite time and that this threshold level of noise intensity decreases with increasing butyrate concentrations.

q-bio.TO↗
arXiv2026

Intestinal villi and crypt density robustly maximizes nutrient absorption

The villi and crypts of the gastrointestinal tract increase the effective surface area of the intestinal mucosa, potentially enhancing nutrient absorption. It is commonly assumed that this is their primary function, and that a higher villi density necessarily leads to improved absorption. However, when villi are packed too closely together, diffusion can be hindered, potentially offsetting this benefit. In this work, we investigate quantitatively the relationship between the density of these structures and the overall efficiency of absorption. In three different simplified geometries, approximating leaf-like villi, finger-like villi, and colonic crypts, we calculate analytically the concentration profile and the absorption flux, assuming that there is only diffusion between these structures while the lumen is well mixed. When plotting the absorption flux per unit of gut length as a function of the structures' density, we observe that there is a density maximizing absorption. We study numerically this optimum. We find that it is robust to the nutrient absorption properties: a geometry optimal for one nutrient is close to optimum for another nutrient. Physiological data from various animal species fall within this predicted optimal range, consistent with the hypothesis that structure density is shaped by selection for efficient nutrient uptake.

q-bio.TO↗