Blood-borne origin of neointimal smooth muscle cells in transplant arteriosclerosis

Transplant arteriosclerosis (TA) is a major complication after solid organ transplantation. TA is characterized by persistent perivascular inflammation and concentric intimal thickening consisting of α-actin-positive vascular smooth muscle (VSM) cells. The current view on TA is that donor-derived medial VSM cells of affected arteries migrate and proliferate into the subendothelial space, resulting in luminal narrowing. Following this concept, the VSM cells present in the arteriosclerotic lesions are of donor origin. In this study, the authors analyzed the origin (donor vs recipient) of endothelium (EC) and neointimal α-actin-positive VSM cells in 2 different experimental transplant models. Aortic and cardiac allografting was performed in the PVG (RT-1c) to AO (RT-1u) rat strain combination. Aorta recipients were not immunosuppressed, whereas cardiac allograft recipients were intrathymically immune modulated to prevent acute rejection. Transplants were performed from female donor to male recipient rats. The α-actin-positive VSM cells present in arteriosclerotic lesions, in aortic as well as cardiac allografts, were of recipient, rather than donor, origin. Following aortic allografts, the ECs are completely replaced by host-derived ECs, whereas in cardiac allografts the ECs are still of donor origin.</p

Understanding (and tackling) need satisfier escalation

Contemporary consumption patterns, embedded in profit-maximizing economic systems, are driving a worsening socio-ecological crisis, in particular through the escalating production and consumption of goods with high material and/or energy intensity. Establishing minimum and maximum standards of consumption (or “consumption corridors”) has been suggested as a way to address this crisis. Consumption corridors provide the normative basis for sustainable consumption, that is, enough consumption for individuals to satisfy needs, but not too much to collectively surpass environmental limits. Current consumption patterns (especially in the global North) do not yet fall within consumption corridors, and standards are not fixed over time. Consumption is socially constructed and can escalate due to socio-economic, technological, or infrastructural influences. In this article, we propose a framework to understand such escalating trends. This approach can be used as a tool for comprehending how consumption evolves over time, as well as for identifying the most effective leverage points to intervene and prevent escalation from happening in the first place. We build on theories of human-need satisfaction and combine these conceptual understandings with insights from research on socio-technical provisioning systems, sociological approaches to consumption, and perspectives on infrastructure lock-in. We illustrate our framework by systemically considering escalation for a specific technological product – the private car

Teasing out the role of aromatase in the healthy and diseased testis

Scientific discoveries over the past decade have shifted the stereotypical view of androgens as male hormones and estrogens as female hormones. It is now recognized that a delicate balance of both androgens and estrogens, a process controlled by aromatase, is fundamental for normal testicular development and fertility. While the site-specific actions of these two classes of steroids within the testis are becoming better documented, the role and regulation of estrogen biosynthesis by aromatase within the testis remains unclear. The majority of data comes from a wide range of animal species, particularly genetically modified mouse models; aromatase knockout (ArKO) and overexpressing (AROM+), with limited information on humans, however the existence of congenital aromatase mutations has provided some insight into its effects on individual parameters of the testis. This review dissects out the localization and activity of aromatase in the healthy and diseased testis, addresses the cellular insult to the testis that occurs in its absence and over abundance and proposes potential molecular mechanisms of aromatase regulation in the testis