Membrane cholesterol is essential for cell membrane properties, just as serum cholesterol is important for the transport of molecules between organs. This review focuses on cholesterol transport between lipoproteins and lipid rafts on the surface of macrophages. Recent studies exploring this mechanism and recognition of the central dogma—the key role of macrophages in cardiovascular disease—have led to the notion that this transport mechanism plays a major role in the pathogenesis of atherosclerosis. The exact molecular mechanism of this transport remains unclear. Future research will improve our understanding of the molecular and cellular bases of lipid raft-associated cholesterol transport.

Preclinical biomedical research is limited by the predictiveness of in vivo and in vitro models. While in vivo models offer the most complex system for experimentation, they are also limited by ethical, financial, and experimental constraints. In vitro models are simplified models that do not offer the same complexity as living animals but do offer financial affordability and more experimental freedom; therefore, they are commonly used. Traditional 2D cell lines cannot fully simulate the complexity of the epithelium of healthy organs and limit scientific progress. The One Health Initiative was established to consolidate human, animal, and environmental health while also tackling complex and multifactorial medical problems. Reverse translational research allows for the sharing of knowledge between clinical research in veterinary and human medicine. Recently, organoid technology has been developed to mimic the original organ’s epithelial microstructure and function more reliably. While human and murine organoids are available, numerous other organoids have been derived from traditional veterinary animals and exotic species in the last decade. With these additional organoid models, species previously excluded from in vitro research are becoming accessible, therefore unlocking potential translational and reverse translational applications of animals with unique adaptations that overcome common problems in veterinary and human medicine.

Background: Albuminuria, an important marker of decreased kidney function in chronic kidney disease (CKD), is not routinely used for CKD detection or proteinuria appearance. Its relationships with biochemical parameters and blood pressure in dogs are poorly understood.Objectives: This study aimed to evaluate the relationship of albuminuria with various CKD markers, its correlation with the urinary protein to creatinine ratio (UPC), and hypertension in dogs with early stages of CKD. It also sought to determine the usability of the urinary albumin to creatinine ratio (UAC) for CKD screening.Methods: The study reviewed records of 102 dogs, categorising them into four groups based on disease status. UAC and UPC ratio, biochemistry and haematology variables, age, and systolic blood pressure were determined.Results: The Pearson's correlation coefficient between log‐transformed values of UPC and UAC was r = 0.902 (95% CI: 0.87 to 0.93). Median UAC ratio values were 2.1 mg/g for the Healthy control group (n = 17), 54.2 mg/g for early stages CKD (n = 42), 5.8 mg/g for Acute sick control (n = 30), and 104 mg/g for Chronic sick control (n = 13). Thresholding UAC ratio as an indicator for impaired kidney function with the threshold of 10 mg/g (established based on the receiver operating characteristic curve) had a sensitivity 81.8%, specificity of 89.4%, positive predictive value (PPV) 90%, and negative predictive value (NPV) 80.1%. The correlation of UAC with biochemistry and haematology variables was statistically significant; for SDMA (μg/L), it was r = 0.566 and for other variables, it was weak to moderate. UAC was markedly elevated in cases of severe hypertension.Conclusions: UAC ratio was significantly different among dogs with impaired and not impaired kidney function. The correlation strength for the UAC and UPC ratios was high. UAC ratio may be a promising marker for proteinuria analysis in dogs with CKD or other kidney function alterations.

While two-dimensional (2D) cell cultures, such as Caco-2 and Madin–Darby canine kidney (MDCK) cells are widely used in a variety of biological models, these two-dimensional in vitro systems present inherent limitations in replicating the complexities of in vivo biology. Recent progress in three-dimensional organoid technology has the potential to address these limitations. In this study, the characteristics of conventional 2D cell culture systems were compared to those of canine intestinal organoids (enteroids, ENT, and colonoids, COL). Light microscopy and transmission electron microscopy were employed to evaluate the microanatomy of ENT, COL, Caco-2, and MDCK cell monolayers, while transepithelial electrical resistance (TEER) values were measured to assess monolayer integrity. The TEER values of canine ENT monolayers more closely approximated reported TEER values for human small intestines compared to Caco-2 and MDCK monolayers. Additionally, canine ENT demonstrated greater monolayer stability than Caco-2 and MDCK cells. Notably, while all systems displayed desmosomes, canine ENT and COL exclusively produced mucus. These findings highlight the potential of the canine organoid system as a more biologically relevant model for in vitro studies, addressing the limitations of conventional 2D cell culture systems.

Inflammatory changes in perivascular adipose tissue are associated with atherosclerotic lesions in the adjacent artery and can also be used as a marker in patient workup. While adipocyte size is known to be closely related to adipose tissue dysfunction and inflammation, it has not been widely studied in perivascular adipose tissue obtained from healthy human subjects without clinical atherosclerosis. In this cross-sectional study, we addressed this issue by measuring adipocyte size and defining its relationship to cardiovascular risk factors in a healthy cohort of living kidney donors. The presence of cardiovascular risk factors was established by a standardized questionnaire, clinical measurements and body composition analyses. Adipocyte size was measured in the perivascular depot. The proportions of various macrophage subtypes were determined by flow cytometry. To confirm the results, the proportion of CD68 + macrophages was additionally assessed by immunohistochemistry. A correlation and principal component analyses were performed to explore associations. Adipocyte size in perivascular adipose tissue correlated with markers of lipid metabolism, inflammation, and glucose metabolism. Further, the positive correlation with the pro-inflammatory subpopulation of macrophages suggests a strong local effect of perivascular adipose tissue. Perivascular adipocyte size was associated with cardiovascular risk factors and markers of inflammation in a healthy cohort of living kidney donors. This further supports the local role of adipose tissue dysfunction and inflammation in early atherosclerosis development and detection.

The importance of macrophage polarization through atherogenesis is established. However, most studies rely on immunohistological approaches, which have several limitations, such as precluding comprehensive phenotypic analysis. The aim of this study was to perform an alternative analysis of macrophage phenotypes in advanced human atherosclerotic plaques and compare them with their presence in non‐atherosclerotic arteries. Atherosclerotic plaques from 70 individuals indicated for carotid endarterectomy, and samples of non‐atherosclerotic arterial tissue (renal artery, control group) from 45 living kidney donors were processed to obtain immunocytes and incubated with antibodies (CD45, CD14, CD16, CD36, CD163, and CD206) to be analyzed by flow cytometry. Macrophages in the atherosclerotic plaques tend to express CD16 more intensively than in non‐atherosclerotic arterial tissue (transient, CD16^low p < 0.001, pro‐inflammatory, CD16^high p < 0.001), and the expression is more closely associated with CD36 expression. Both transient and pro‐inflammatory macrophages are linked with the CD206⁻CD163⁺ or CD206⁺CD163⁺ phenotype in atherosclerotic plaques, while CD206⁻CD163⁻ dominates within the anti‐inflammatory (CD16^neg) population in the control group. Interestingly, when evaluating all macrophages (regardless of CD16 expression), almost all are CD163⁺ in both groups, supporting the critical importance of using a combination of specific markers. Our results provide a deeper insight into macrophage subpopulations in advanced human atherosclerotic plaques compared with those in non‐atherosclerotic vessels. Additionally, our data highlight the critical importance of using appropriate techniques, such as flow cytometry, allowing for simultaneous analysis of multiple markers to accurately and comprehensively characterize macrophages within the atherosclerotic plaque.