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Chronic kidney disease (CKD) affects the morphological structure and causes significant degradation in kidney function, leading to renal replacement treatment in affected individuals. Vascular rarefaction is thought to be an important factor in accelerating kidney damage in CKD patients, therefore, the assessment of renal morphology and vasculature is crucial in nephrology. The objective of this study was to evaluate the morphological and vascular changes caused by CKD in mice kidneys. In this study, dual photoacoustic microscopy (PAM) and optical coherence microscopy (OCM) oriented wide-field high-resolution imaging modalities were employed for diseased renal imaging. The unilateral ureteral obstruction (UUO) model was used to prepare renal samples with CKD, and the developed wide-field dual imaging system was used to image both control and CKD-affected kidneys for assessing vascular and morphological changes during CKD progression. The obtained results reveal a gradual alteration in vascular intensity and pelvis space with the progress of UUO disease. Furthermore, a quantitative micro-vessel analysis was performed based on the node, junction, and mesh of the vessel, which provides details on the increasing microvascular-related characteristics in the peripheral area as the disease progresses. Thus, by concurrently employing the advantages of each optical imaging technique, the proposed method of assessing the OCM-based morphological and PAM-based vascular properties of the renal sample using a wide-field multimodal imaging system can be an efficient technique for whole volume analysis without any exogenous contrast agents in kidney histopathology. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: Massive small bowel resection (SBR) results in an adaptive response within the remnant bowel. We have previously shown an immediate reduction in intestinal blood flow and oxygen saturation (sO2) after SBR. We therefore sought to determine the duration of resection-induced intestinal hypoxia and expression of hypoxia-inducible factors (HIFs) following SBR. Methods: C57B6 mice were subjected to 50% proximal SBR or a sham procedure. Photoacoustic microscopy (PAM) was used to measure blood flow and sO2 on postoperative days (PODs) 1, 3, and 7. Ileal tissue was harvested 6h postoperatively and on PODs 1 and 2, and HIF1α, HIF2α, and VEGF mRNA expression were assessed via RT-PCR. A p value of less than 0.05 was considered significant. Results: Following SBR, reduction in intestinal blood flow persists for 24h and is followed with hyperemia by POD 3. The immediate reduction in venous sO2 and increased tissue oxygen utilization continued through POD 7. Enhanced expression of HIF1α was demonstrated 6h following SBR. Conclusion: Massive SBR results in an immediate relative hypoxic state within the remnant bowel with early enhanced expression of HIF1α. On POD 7, increased tissue oxygen extraction and elevated blood flow persist in the adapting intestine. [Copyright &y& Elsevier]

Abstract: Purpose: Massive small bowel resection (SBR) results in villus angiogenesis and a critical adaptation response within the remnant bowel. Previous ex vivo studies of intestinal blood flow after SBR are conflicting. We sought to determine the effect of SBR on intestinal hemodynamics using photoacoustic microscopy, a noninvasive, label-free, high-resolution in vivo hybrid imaging modality. Methods: Photoacoustic microscopy was used to image the intestine microvascular system and measure blood flow and oxygen saturation (So 2) of the terminal mesenteric arteriole and accompanying vein in C57BL6 mice (n = 7) before and immediately after a 50% proximal SBR. A P value of less than .05 was considered significant. Results: Before SBR, arterial and venous So 2 were similar. Immediately after SBR, the venous So 2 decreased with an increase in the oxygen extraction fraction. In addition, the arterial and venous blood flow significantly decreased. Conclusion: Massive SBR results in an immediate reduction in intestinal blood flow and increase in tissue oxygen utilization. These physiologic changes are observed throughout the remnant small intestine. The contribution of these early hemodynamic alterations may contribute to the induction of villus angiogenesis and the pathogenesis of normal intestinal adaptation responses. [Copyright &y& Elsevier]