Effect of estrogen administration on middle cerebral arterial viscoelastic properties in aged female rats

ABSTRACT PURPOSE: To develop a model for studying cerebrovascular disease prevention in elderly women. METHODS: Sixty 18-month-old Sprague Dawley (SD) rats were randomly divided into an estrogen administration group (EA, n=30) and a non-administration group (NA, n=30); thirty 4-month-old SD rats were allocated to a control group. The EA group received estradiol benzoate starting on the 5th day of a 34-day breeding period, and the serum levels of estradiol (E2), estrogen receptor (ER), and malondialdehyde (MDA) were measured. The MCA of each group was then sampled for viscoelastic experiments. RESULTS: The serum levels of E2 and MDA in the EA group showed significant differences compared to those in the control group (p<0.05), while the difference in ER between the EA and control groups was not significant (p>0.05). The decrease in MCA stress at 7,200 s and the increase in strain at 7,200 s in the EA group showed no significant differences compared to the control group (p>0.05). CONCLUSION: Estradiol administration inhibited the formation of lipid peroxidation products and restored middle cerebral arterial viscoelasticity in aged female rats.

A Phase III, Randomized, Double-Blind, Matched-Pairs, Active-Controlled Clinical Trial and Preclinical Animal Study to Compare the Durability, Efficacy and Safety between Polynucleotide Filler and Hyaluronic Acid Filler in the Correction of Crow's Feet: A

The Rejuran(R) is a new filler product made from purified polynucleotides. Here we present data from an animal study and a clinical trial to examine the durability, efficacy and safety of the Rejuran(R) on crow's feet. For the animal study, 25 mice were divided into three groups: Group 1 received phosphate buffered saline (PBS); Group 2 were treated with Yvoire(R); and Group 3 were treated with Rejuran(R). The durability and efficacy of each treatment were assessed by microscopy and staining. In the clinical trial, 72 patients were randomized to receive Rejuran(R) treatment for crow's feet on one side and Yvoire-Hydro(R) on the contralateral side, at a ratio of 1:1. Repeated treatments were performed every two weeks for a total of three times, over a total of 12 weeks' observation. All injections and observations of efficacy and safety were performed by the same two investigators. In the animal study, the Rejuran(R) group showed similar durability and inflammatory response to the Yvoire(R) group. Upon efficacy assessment, the Rejuran(R) group showed the greatest elasticity and collagen composition, and a significant difference in skin surface roughness and wrinkle depth. In the clinical trial, the primary and secondary objective efficacy outcome measure showed no statistical significance between the two groups, and in safety outcomes there were no unexpected adverse effects. Our data suggest that the Rejuran(R), as a new regenerative filler, can be useful to reduce wrinkles, by showing evidence for its efficacy and safety.

Mechanical evaluation of the resistance and elastance of post-burn scars after topical treatment with tretinoin

OBJECTIVE: After burn injuries, scarred skin lacks elasticity, especially in hypertrophic scars. Topical treatment with tretinoin can improve the appearance and quality of the skin (i.e., texture, distensibility, color, and hydration). The objective of this prospective study was to examine the effects of treatment with 0.05 percent tretinoin for one year on the biomechanical behavior and histological changes undergone by facial skin with post-burn scarring. Setting: Tertiary, Institutional. METHOD: Fifteen female patients who had suffered partial thickness burns with more than two years of evolution were selected. Skin biopsies were obtained initially and after one year of treatment. The resistance and elastance of these skin biopsies were measured using a mechanical oscillation analysis system. The density of collagen fibers, elastic fibers, and versican were determined using immunohistochemical analysis. RESULTS: Tretinoin treatment significantly lowered skin resistance and elastance, which is a result that indicates higher distensibility of the skin. However, tretinoin treatment did not significantly affect the density of collagen fibers, elastic fibers, or versican. CONCLUSION: Topical tretinoin treatment alters the mechanical behavior of post-burn scarred skin by improving its distensibility and thus leads to improved quality of life for patients.

Do Acute Changes in Heart Rate by Isoproterenol Affect Aortic Stiffness in Patients with Hypertension?

BACKGROUND: Increased aortic stiffness is a independent risk factor of cardiovascular disease in patients with hypertension. Acute changes of the heart rate (HR) have been reported not to affect the aortic stiffness in pacing. However, it is unknown whether acute changes in HR caused by sympathomimetics can affect the aortic stiffness in patients with hypertension. We investigated the effect of acute changes in HR produced by isoproterenol on the aortic stiffness in 17 hypertensive patientss (mean age: 59 +/- 9 years). METHODS: All vasoactive drugs were discontinued at least 3 days before the study. The carotid-tofemoral pulse wave velocity (PWV) was measured by the foot-to-foot method. The pulse waves were recorded at the baseline and at every increase of HR by 5 to 10 bpm with a gradual increase of the dose of isoproterenol. The blood pressures and HR were measured simultaneously. For the analysis, HR, PWV, compliance (C), and compliance index (Ci) were converted as percent changes (delta) from the baseline values. Percent changes of the parameters of the aortic stiffness, i.e., delta PWV, delta C, and delta Ci, were grouped by every 10% increase in delta HR. RESULTS: There was no significant difference among groups in delta PWV, delta C and delta Ci (p> 0.05 for each of the group). The regression analysis showed no significant correlation of delta HR with delta PWV and delta C (r=0.18, 0.13 respectively, p> 0.05 for each). delta Ci had a poor correlation with delta HR (r=0.22, p< 0.05). However, only 4.6% of delta Ci could be referred to delta HR (r2=0.046). CONCLUSION: Aortic stiffness was not affected by acute changes in HR produced by isoproterenol which suggests that it is not necessary to consider acute changes in HR when measuring aortic PWV.