Quantitative Image Analysis Reveals Distinct Structural Transitions during Aging in Caenorhabditis elegans Tissues

Aging is associated with functional and structural declines in many body systems, even in the absence of underlying disease. In particular, skeletal muscles experience severe declines during aging, a phenomenon termed sarcopenia. Despite the high incidence and severity of sarcopenia, little is known about contributing factors and development. Many studies focus on functional aspects of aging-related tissue decline, while structural details remain understudied. Traditional approaches for quantifying structural changes have assessed individual markers at discrete intervals. Such approaches are inadequate for the complex changes associated with aging. An alternative is to consider changes in overall morphology rather than in specific markers. We have used this approach to quantitatively track tissue architecture during adulthood and aging in the C. elegans pharynx, the neuromuscular feeding organ. Using pattern recognition to analyze aged-grouped pharynx images, we identified discrete step-wise transitions between distinct morphologies. The morphology state transitions were maintained in mutants with pharynx neurotransmission defects, although the pace of the transitions was altered. Longitudinal measurements of pharynx function identified a predictive relationship between mid-life pharynx morphology and function at later ages. These studies demonstrate for the first time that adult tissues undergo distinct structural transitions reflecting postdevelopmental events. The processes that underlie these architectural changes may contribute to increased disease risk during aging, and may be targets for factors that alter the aging rate. This work further demonstrates that pattern analysis of an image series offers a novel and generally accessible approach for quantifying morphological changes and identifying structural biomarkers

Selective area epitaxy of ultra-high density InGaN quantum dots by diblock copolymer lithography

Highly uniform InGaN-based quantum dots (QDs) grown on a nanopatterned dielectric layer defined by self-assembled diblock copolymer were performed by metal-organic chemical vapor deposition. The cylindrical-shaped nanopatterns were created on SiNx layers deposited on a GaN template, which provided the nanopatterning for the epitaxy of ultra-high density QD with uniform size and distribution. Scanning electron microscopy and atomic force microscopy measurements were conducted to investigate the QDs morphology. The InGaN/GaN QDs with density up to 8 × 1010 cm-2 are realized, which represents ultra-high dot density for highly uniform and well-controlled, nitride-based QDs, with QD diameter of approximately 22-25 nm. The photoluminescence (PL) studies indicated the importance of NH3 annealing and GaN spacer layer growth for improving the PL intensity of the SiNx-treated GaN surface, to achieve high optical-quality QDs applicable for photonics devices

Multidisciplinary Consideration of Potential Pathophysiologic Mechanisms of Paradoxical Erythema with Topical Brimonidine Therapy

Rosacea is a chronic inflammatory disease with transient and non-transient redness as key characteristics. Brimonidine is a selective α2-adrenergic receptor (AR) agonist approved for persistent facial erythema of rosacea based on significant efficacy and good safety data. The majority of patients treated with brimonidine report a benefit; however, there have been sporadic reports of worsening erythema after the initial response. A group of dermatologists, receptor physiology, and neuroimmunology scientists met to explore potential mechanisms contributing to side effects as well as differences in efficacy. We propose the following could contribute to erythema after application: (1) local inflammation and perivascular inflammatory cells with abnormally functioning ARs may lead to vasodilatation; (2) abnormal saturation and cells expressing different AR subtypes with varying ligand affinity; (3) barrier dysfunction and increased skin concentrations of brimonidine with increased actions at endothelial and presynaptic receptors, resulting in increased vasodilation; and (4) genetic predisposition and receptor polymorphism(s) leading to different smooth muscle responses. Approximately 80% of patients treated with brimonidine experience a significant improvement without erythema worsening as an adverse event. Attention to optimizing skin barrier function, setting patient expectations, and strategies to minimize potential problems may possibly reduce further the number of patients who experience side effects. Funding: Galderma International S.A.S., Paris, France

Fluid platelet-rich fibrin stimulates greater dermal skin fibroblast cell migration, proliferation, and collagen synthesis when compared to platelet-rich plasma.

BACKGROUND Regenerative therapies in the field of facial aesthetics have become a growing field of interest with many recent advancements made over the past decade to meet the growing worldwide demand. While first versions of platelet-derived concentrates were formulated with anticoagulants (PRP), recent modifications to centrifugation speeds and times have permitted the development of a liquid platelet-rich fibrin (fluid-PRF) without use of anticoagulants. OBJECTIVE To compare this entirely natural platelet concentrate (fluid-PRF) to formally utilized PRP on skin cell behavior and regeneration. METHODS Dermal skin fibroblast was cultivated with either fluid-PRF or PRP and investigated for their ability to promote/influence cell viability, migration, spreading, proliferation, and mRNA levels of known mediators of dermal biology including PDGF, TGF-beta, and fibronectin. RESULTS All platelet concentrates were nontoxic to cells demonstrating high cell survival. Skin fibroblasts migrated over 350% more in fluid-PRF when compared to control and PRP (200% increase). Fluid-PRF also significantly induced greater cell proliferation at 5 days. While both PRP and fluid-PRF induced significantly elevated cell mRNA levels of PDGF, it was observed that TGF-beta, collagen 1, and fibronectin mRNA levels were all significantly highest in the fluid-PRF group. Lastly, fluid-PRF demonstrated a significantly greater ability to induce collagen matrix synthesis when compared to PRP. CONCLUSION The findings from the present study demonstrate greater regenerative potential of fluid-PRF on human skin fibroblasts. Future clinical use of fluid-PRF in the field of facial aesthetics is necessary to further evaluate the potential advantages of anticoagulant removal from platelet concentrates