Unique osteogenic profile of bone marrow stem cells stimulated in perfusion bioreactor is Rho-ROCK-mediated contractility dependent.

The fate determination of bone marrow mesenchymal stem/stromal cells (BMSC) is tightly regulated by mechanical cues, including fluid shear stress. Knowledge of mechanobiology in 2D culture has allowed researchers in bone tissue engineering to develop 3D dynamic culture systems with the potential for clinical translation in which the fate and growth of BMSC are mechanically controlled. However, due to the complexity of 3D dynamic cell culture compared to the 2D counterpart, the mechanisms of cell regulation in the dynamic environment remain relatively undescribed. In the present study, we analyzed the cytoskeletal modulation and osteogenic profiles of BMSC under fluid stimuli in a 3D culture condition using a perfusion bioreactor. BMSC subjected to fluid shear stress (mean 1.56 mPa) showed increased actomyosin contractility, accompanied by the upregulation of mechanoreceptors, focal adhesions, and Rho GTPase-mediated signaling molecules. Osteogenic gene expression profiling revealed that fluid shear stress promoted the expression of osteogenic markers differently from chemically induced osteogenesis. Osteogenic marker mRNA expression, type 1 collagen formation, ALP activity, and mineralization were promoted in the dynamic condition, even in the absence of chemical supplementation. The inhibition of cell contractility under flow by Rhosin chloride, Y27632, MLCK inhibitor peptide-18, or Blebbistatin revealed that actomyosin contractility was required for maintaining the proliferative status and mechanically induced osteogenic differentiation in the dynamic culture. The study highlights the cytoskeletal response and unique osteogenic profile of BMSC in this type of dynamic cell culture, stepping toward the clinical translation of mechanically stimulated BMCS for bone regeneration.

Limited dilute lidocaine anesthesia: A useful technique with many practical applications.

BACKGROUND: Limited dilute lidocaine infiltration facilitates a comfortable procedure and a rapid recovery process following a novel intervention for reduction of cellulite. Infiltration of dilute lidocaine has many other practical applications in dermatologic surgery. OBJECTIVES: This article describes a safe, effective technique for local infiltration of limited volume dilute lidocaine anesthesia in a cellulite reduction procedure. METHODS: The limited dilute lidocaine technique was utilized in studies of a novel device designed to reduce the appearance of cellulite by focal release of fibrous septa in a minimally invasive procedure. No sedation was used. A small (27- to 30-gauge) needle was used to deliver anesthesia to the entry sites. Then, a 20-gauge spinal needle was tunneled under the skin in the superficial plane to manually deliver anesthetic along the advancement pathway of the device and marked cellulite targets. RESULTS: During the initial studies, the mean delivered anesthesia volume was 357.2 ml (range, 250-525 ml) or 18.7 mg/kg (range, 11.1-28.4 mg/kg). The mean anesthesia time was 16 min (range, 8-32 min). The mean number of cellulite depressions treated was 19.8 (range, 11-34). Adverse events were closely monitored, and there were no signs of toxicity in any study patients. There were very low levels of discomfort; all patients reported the procedure was tolerable. This technique facilitates a time-efficient procedure and minimizes weeping of excess fluid during recovery. CONCLUSIONS: When administered with care and skill, the limited dilute anesthesia technique is a safe, effective approach for local anesthesia with many practical applications in dermatologic surgery.

Injectable agents affecting subcutaneous fats.

Mesotherapy is an intradermal or subcutaneous injection of therapeutic agents to induce local effects, and was pioneered in Europe during the 1950s. For the past 2 decades, there has been significant interest in the use of mesotherapy for minimally invasive local fat contouring. Based on the theorized lipolytic effects of the agent phosphatidylcholine, initial attempts involved its injection into subcutaneous tissue. With further studies, however, it became apparent that the activity attributed to phosphatidylcholine mesotherapy was due to the adipolytic effects of deoxycholate, a detergent used to solubilize phosphatidylcholine. Since then, clinical trials have surfaced that demonstrate the efficacy of a proprietary formulation of deoxycholate for local fat contouring. Current trials on mesotherapy with salmeterol, a b-adrenergic agonist and lipolysis stimulator, are underway-with promising preliminary results as well.

Laser and Light-Based Aesthetics in Men.

Men represent an important evolving segment of the cosmetic market. With the growing acceptability of cosmetic procedures along with societal and workplace pressure to maintain youthfulness, men increasingly seek the advice of aesthetic practitioners. Despite this so-called "Menaissance," there is a paucity of published literature regarding laser and light treatments of male skin. Herein the differences in male cutaneous physiology are addressed, followed by a review of light-based treatment of conditions largely unique to male skin, pseudofolliculitis barbae, and rhinophyma. Next, the publications related to laser treatment of male skin specifically are examined. We conclude with a discussion of personal observations derived from clinical experience with laser and light-based treatments in men.

Home-use laser and light devices for the skin: an update.

Over the past several years, a number of home-use laser and light skin devices have been introduced for various indications, including photorejuvenation, hair growth, hair removal and acne treatment. Although these devices allow for privacy and a significant cost advantage, they are typically underpowered and afford lower efficacy than their in-office counterparts. A number of these devices have recently received FDA clearance. Although large clinical trials are lacking, dermatologists should familiarize themselves with the various options to help patients assess their clinical value.

PAR1 specifies ciliated cells in vertebrate ectoderm downstream of aPKC.

Partitioning-defective 1 (PAR1) and atypical protein kinase C (aPKC) are conserved serine/threonine protein kinases implicated in the establishment of cell polarity in many species from yeast to humans. Here we investigate the roles of these protein kinases in cell fate determination in Xenopus epidermis. Early asymmetric cell divisions at blastula and gastrula stages give rise to the superficial (apical) and the deep (basal) cell layers of epidermal ectoderm. These two layers consist of cells with different intrinsic developmental potential, including superficial epidermal cells and deep ciliated cells. Our gain- and loss-of-function studies demonstrate that aPKC inhibits ciliated cell differentiation in Xenopus ectoderm and promotes superficial cell fates. We find that the crucial molecular substrate for aPKC is PAR1, which is localized in a complementary domain in superficial ectoderm cells. We show that PAR1 acts downstream of aPKC and is sufficient to stimulate ciliated cell differentiation and inhibit superficial epidermal cell fates. Our results suggest that aPKC and PAR1 function sequentially in a conserved molecular pathway that links apical-basal cell polarity to Notch signaling and cell fate determination. The observed patterning mechanism may operate in a wide range of epithelial tissues in many species.