Intravital two-photon microscopy enables deep-tissue imaging at high temporospatial resolution in live animals. However, the endosteal bone compartment and underlying bone marrow pose unique challenges to optical imaging as light is absorbed, scattered and dispersed by thick mineralized bone matrix and the adipose-rich bone marrow. Early bone intravital imaging methods exploited gaps in the cranial sutures to bypass the need to penetrate through cortical bone. More recently, investigators have developed invasive methods to thin the cortical bone or implant imaging windows to image cellular dynamics in weight-bearing long bones. Here, we provide a step-by-step procedure for the preparation of animals for minimally invasive, nondestructive, longitudinal intravital imaging of the murine tibia. This method involves the use of mixed bone marrow radiation chimeras to unambiguously double-label osteoclasts and osteomorphs. The tibia is exposed by a simple skin incision and an imaging chamber constructed using thermoconductive T-putty. Imaging sessions up to 12 h long can be repeated over multiple timepoints to provide a longitudinal time window into the endosteal and marrow niches. The approach can be used to investigate cellular dynamics in bone remodeling, cancer cell life cycle and hematopoiesis, as well as long-lived humoral and cellular immunity. The procedure requires an hour to complete and is suitable for users with minimal prior expertise in small animal surgery.
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http://dx.doi.org/10.1038/s41596-023-00894-9 | DOI Listing |
Diabetes
January 2025
Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM) and Département de médecine, Université de Montréal, 900 Saint Denis Street, Montréal, QC Canada H2X 0A9.
The role of the intrarenal renin-angiotensin system (iRAS) in diabetic kidney disease (DKD) progression remains unclear. In this study, we generated mice with renal tubule-specific deletion of angiotensinogen (Agt; RT-Agt-/-) in both Akita and streptozotocin (STZ)-induced mouse model of diabetes. Both Akita RT-Agt-/- and STZ-RT-Agt-/- mice exhibited significant attenuation of glomerular hyperfiltration, urinary albumin/creatinine ratio, glomerulomegaly and tubular injury.
View Article and Find Full Text PDFActa Derm Venereol
January 2025
Department of Dermatology, University Hospital of Basel, Basel, Switzerland; Department of Dermatology, University Hospital of Zurich, Zurich, Switzerland; Faculty of Medicine, University of Zurich, Zurich, Switzerland.
Pregnancy-associated changes in melanocytic nevi (MN), apart from size increase on the trunk, remain a topic of debate. We conducted the first prospective study to investigate dermoscopic changes in MN comparing pregnant with non-pregnant women on all body parts using a market-approved convolutional neural network (CNN). We included 25 pregnant and 25 non-pregnant women from Basel, Switzerland, who underwent standard skin cancer screenings and whose MN > 2 mm were digitally recorded and analysed by a CNN.
View Article and Find Full Text PDFTheranostics
January 2025
Department of neurology, Dongguk University Ilsan Hospital, Goyang 10326, Republic of Korea.
It remains unclear why unilateral proximal carotid artery occlusion (UCAO) causes benign oligemia in mice, yet leads to various outcomes (asymptomatic-to-death) in humans. We hypothesized that inhibition of nitric oxide synthase (NOS) both transforms UCAO-mediated oligemia into full infarction and expands pre-existing infarction. Using 900 mice, we i) investigated stroke-related effects of UCAO with/without intraperitoneal administration of the NOS inhibitor (NOSi) N-nitro-L-arginine methyl ester (L-NAME, 400 mg/kg); ii) examined the rescue effect of the NO-donor, molsidomine (200 mg/kg at 30 minutes); and iii) tested the impact of antiplatelet medications.
View Article and Find Full Text PDFNature
January 2025
Laboratory of Cellular Metabolism and Metabolic Regulation, VIB Center for Cancer Biology, VIB, Leuven, Belgium.
Lung metastases occur in up to 54% of patients with metastatic tumours. Contributing factors to this high frequency include the physical properties of the pulmonary system and a less oxidative environment that may favour the survival of cancer cells. Moreover, secreted factors from primary tumours alter immune cells and the extracellular matrix of the lung, creating a permissive pre-metastatic environment primed for the arriving cancer cells.
View Article and Find Full Text PDFSci Rep
December 2024
Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
Despite decades of improvements in cytotoxic therapy, the current standard of care for locally advanced pancreatic cancer (LAPC) provides, on average, only a few months of survival benefit. Stereotactic Body Radiation Therapy (SBRT), a technique that accurately delivers high doses of radiation to tumors in fewer fractions, has emerged as a promising therapy to improve local control of LAPC; however, its effects on the tumor microenvironment and hypoxia remain poorly understood. To explore how SBRT affects pancreatic tumors, we combined an orthotopic mouse model of pancreatic cancer with an intravital microscopy platform to visualize changes to the in vivo tumor microenvironment in real-time.
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