Vascular endothelial growth factor A (VEGF-A) is a prominent growth factor for both angiogenesis and lymphangiogenesis. Recent studies have shown the importance of VEGF-A in enhancing the growth of lymphatic endothelial cells in lymph nodes (LNs) and the migration of dendritic cells into LNs. VEGF-A is produced in inflamed tissues and/or in draining LNs, where B cells are a possible source of this growth factor. To study the effect of B cell-derived VEGF-A, we created transgenic mice (CD19^Cre/hVEGF-A^fl) that express human VEGF-A specifically in B cells. We found that the human VEGF-A produced by B cells not only induced lymphangiogenesis in LNs, but also induced the expansion of LNs and the development of high endothelial venules. Contrary to our expectation, we observed a significant decrease in the Ag-specific Ab production postimmunization with OVA and in the proinflammatory cytokine production postinoculation with LPS in these mice. Our findings suggest immunomodulatory effects of VEGF-A: B cell-derived VEGF-A promotes both lymphangiogenesis and angiogenesis within LNs, but then suppresses certain aspects of the ensuing immune responses.

Endothelial cells (ECs) form monolayers and line the interior surfaces of blood vessels in the entire body. In most mammalian systems, the capacity of endothelial cells to divide is limited and endothelial cells are prone to be senescent. Aging of ECs and resultant endothelial dysfunction lead to a variety of vascular diseases such as atherosclerosis, diabetes mellites, hypertension, and ischemic injury. However, the mechanism by which ECs get old and become senescent and the impact of endothelial senescence on the vascular function are not fully understood. Recent research has unveiled the crucial roles of miRNAs, which are small non-coding RNAs, in regulating endothelial cellular functions, including nitric oxide production, vascular inflammation, and anti-thromboformation. In this review, how senescent-related miRNAs are involved in controlling the functions of ECs will be discussed.

Background: A major concern in both the laboratory-medicine and research communities is the quality of human specimens for analysis. However, there is insufficient scientific evidence regarding optimal conditions for handling and storing routine specimens, especially those in liquid form. Thus, we investigated the stability of clinically relevant samples stored under various conditions. Materials and Methods: Ten clinical laboratories in Japan conducted analyses of the stability of post-clinical (left over after analysis) test samples in relation to temperature and storage duration. We examined serum, whole blood, and urine samples submitted to each laboratory for routine testing. In this study, at least 5 samples for each of 35 tests were analyzed at each laboratory. After completion of routine testing, specimens with sufficient residual volume and values between LL−R/2 (lower limit of reference interval) and UL+R/2 (upper limit) were divided into 300 μL aliquots, where R=UL − LL. Aliquots of serum specimens were stored at either room temperature (23°C), 4°C, −20°C, or −80°C without light exposure. Aliquots of whole blood and urine specimens were stored at either 23°C or 4°C. The storage time was either 1, 3, or 7 days. Average differences between pre- and post-storage test results were evaluated for each laboratory test by two-way ANOVA. F-values for between-day variations were used for judging the statistical significance of storage-related changes in test values, whereas the ratio of between-day SD to between-individual SD (one-fourth of reference interval) was used to indicate the practical significance of the change. Results and Conclusion: Sample denaturation is clearly temperature- and storage-duration dependent for almost all analytes. In general, specimens were most susceptible to denaturation at 23°C, then 4°C, −20°C, and −80°C. This study confirmed the accumulated routine, practice-based, detailed knowledge regarding specimen stability and will help to ensure the reliability of laboratory test results.

Vascular endothelial growth factor A (VEGF-A) plays pivotal roles in regulating tumor angiogenesis as well as physiological vascular function. The major VEGF-A isoforms, VEGF-A121 and VEGF-A165, in serum, plasma, and platelets have not been exactly evaluated due to the lack of the appropriate assay system. Antibodies against human VEGF-A121 and VEGF-A165 (hVEGF-A121 and hVEGF-A165) were successfully produced and Enzyme-Linked ImmunoSorbent Assay (ELISA) for hVEGF-A121 and hVEGF-A165 were separately created by these monoclonal antibodies. The measurement of recombinant hVEGF-A121 and hVEGF-A165 by the created ELISA showed no cross-reaction between hVEGF-A121 and hVEGF-A165 in conditioned media from HEK293 cells transfected with either hVEGF-A121 or hVEGF-A165 expression vector. The levels of VEGF-A121 and VEGF-A165 in serum, plasma, and platelets from 59 healthy volunteers proved that VEGF-A121 level was higher than VEGF-A165 in both plasma and serum in all the cases. VEGF-A121 or VEGF-A165 in serum represented higher level than that in plasma. In contrast, the level of VEGF-A165 was higher than VEGF-A121 in platelets. The newly developed ELISAs for hVEGF-A121 and hVEGF-A165 revealed different ratios of VEGF isoforms in serum, plasma, and platelets. Measuring these isoforms in combination provides useful information as biomarkers for diseases involving VEGF-A121 and VEGF-A165.