Haematoloechus sp. attachment shifts endothelium in vivo from pro- to anti-inflammatory profile in Rana pipiens: evidence from systemic and capillary physiology

Am J Physiol Regul Integr Comp Physiol. 2023 Jun 5. doi: 10.1152/ajpregu.00041.2023. Online ahead of print.ABSTRACTThis prospective, descriptive study focused on lung flukes (Haematoloechus sp., H) and their impact on systemic and individual capillary variables measured in pithed Rana pipiens, a long-standing model for studies of capillary physiology. Three groups were identified based on H attachment: no Haematoloechus (No H), Haematoloechus not attached (H Not Att), and Haematoloechus attached (H Att). Among 38 descriptive, cardiovascular, and immunological variables, 18 changed significantly with H. Symptoms of H included weight loss, elevated immune cells, heart rate variability, faster coagulation, lower hematocrit, and fluid accumulation. Important capillary function discoveries included median baselines for hydraulic conductivity (Lp) of 7.0 (No H), 12.4 (H Not Att), and 4.2 (H Att) x 10-7 cm.s-1.cm H2O-1(P<0.0001) plus seasonal adaptation of sigma delta pi (s(pc - pi), P=0.03). Pro- and anti-inflammatory phases were revealed for Lp and plasma nitrite/nitrate concentration ([NOx]) in H Not Att and H Att and capillary wall tensile strength increased in H Att. H attachment was advantageous for the host due to lower edema and for the parasite via a sustained food source illustrating an excellent example of natural symbiosis. However, H attachment also resulted in host weight loss: in time, a conundrum for the highly dependent parasite. The study increases overall knowl...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Source Type: research