Monitoring dynamic alterations in calcium homeostasis by T₁‐mapping manganese‐enhanced MRI (MEMRI) in the early stage of small intestinal ischemia–reperfusion injury

Abstract

Manganese-enhanced MRI studies have proven to be useful in monitoring physiological activities associated with calcium ions (Ca(2+)) due to the paramagnetic property of the manganese ion (Mn(2+)), which makes it an excellent probe of Ca(2+) . In this study, we developed a method in which a Mn(2+)-enhanced T1 -map MRI could enable the monitoring of Ca(2+) influx during the early stages of intestinal ischemia-reperfusion (I/R) injury. The Mn(2+) infusion protocol was optimized by obtaining dose-dependent and time-course wash-out curves using a Mn(2+)-enhanced T1-map MRI of rabbit abdomens following an intravenous infusion of 50 mmol/l MnCl2 (5-10 nmol/g body weight (BW)). In the rabbit model of intestinal I/R injury, T1 values were derived from the T1 maps in the intestinal wall region and revealed a relationship between the dose of the infused MnCl2 and the intestinal wall relaxation time. Significant Mn(2+) clearance was also observed over time in control animals after the infusion of Mn(2+) at a dose of 10 nmol/g BW. This technique was also shown to be sensitive enough to monitor variations in calcium ion homeostasis in vivo after small intestinal I/R injury. The T1 values of the intestinal I/R group were significantly lower (P < 0.05) than that of the control group at 5, 10, and 15 min after Mn(2+) infusion. Our data suggest that MnCl2 has the potential to be an MRI contrast agent that can be effectively used to monitor changes in intracellular Ca(2+) homeostasis during the early stages of intestinal I/R injury.

Eliminating Nox2 reactive oxygen species production protects dystrophic skeletal muscle from pathological calcium influx assessed in vivo by manganese‐enhanced magnetic resonance imaging

“…Mn 2+ is a divalent cation similar in ionic radius and chemical properties to Ca 2+ that can pass through various Ca 2+ channels, and its paramagnetic properties make it a potent MRI spin lattice relaxation time constant (T1) contrast agent (Naruse & Sokabe, 1993;Dryselius et al 1999;Takeda, 2003;Waghorn et al 2009). Manganese-enhanced MRI (MEMRI) has been used to assess various conditions associated with Ca 2+ ions, such as brain activity (Cha et al 2016;Schroeder et al 2016), neuronal tract tracing and axonal transport (Inoue et al 2011;Majid et al 2014), injury (Rodriguez et al 2016;Yang et al 2016), ischaemia-reperfusion (Zhao et al 2015) and cardiac function (Chen et al 2012;Andrews et al 2015). However, it has never been used to assess aberrant Ca 2+ handling in dystrophic skeletal muscle.…”

Evaluation of the NMR-MOUSE as a new method for continuous functional monitoring of the small intestine during different perfusion states in a porcine model

“…Yet, it is possible that the assessment of alterations in the diffusion of other ions is more sensitive to detect intestinal perfusion changes. For instance, it has been shown that changes in calcium (Ca 2+ ) homeostasis due to early I/R injury can be detected using manganese-enhanced magnetic resonance imaging (MRI) in a rat model [ 31 ]. The investigation of Ca 2+ however is not feasible using a low-field scanner such as the NMR-MOUSE.…”

Photoacoustic imaging in evaluating early intestinal ischemia injury and reperfusion injury in rat models

“…Also, while conventional computed tomography (CT) and magnetic resonance imaging (MRI) are used to diagnose intestinal ischemia injury, they cannot evaluate changes in hemoglobin concentration and blood oxygen saturation in tissue. Therefore, it is necessary to establish a morphological diagnosis by CT and MRI and further evaluate the status of intestinal blood flow (7,8) by other means. Several commonly used detection techniques, such as sidestream dark-field imaging (9), spectrophotometry, and laser Doppler blood flow measurement, have been used to study intestinal microcirculation (10).…”