Effects of long-pulsed 1064-nm Nd:YAG laser on telangiectasias and reticular veins: a human in-vivo histological study.

BACKGROUND: Telangiectasias and reticular veins are associated with aesthetic disorders. Sclerotherapy is the gold standard treatment, but long-pulsed 1064-nm Nd:YAG laser (LP1064 laser) is also used. No data on the human histological effects of these lasers are reported. The objective was to test different LP1064 laser parameters and their histological effects on the dermis, collagen, telangiectasias, and reticular veins. METHODS: This was a single-center, prospective, single-arm, case-control, human study. During surgery (dermolipectomy), the abdominal section of 10 female patients was irradiated with 6 different transdermal LP1064 laser parameters after anesthesia. Ten pieces with areas of varying irradiation were evaluated according to the characteristics of the vessels identified by area. In each piece, two irradiation areas were performed per group, totaling 12 irradiation areas per piece, with 120 regions later analyzed at the end of the ten samples. After removing the surgical product, histological sections were extracted, and the dermis, telangiectasias, and reticular veins were analyzed. RESULTS: Histological analysis showed that exposition to six different parameters from LP1064 laser led to significant dermal layer separation and collagen alterations. The effects were inconsistent on the loss of endothelial cells, intravascular thrombus formation, and fusion of vascular walls for both telangiectasias and reticular veins. In reticular veins, effects on intravascular thrombus formation and vascular wall fusion were not observed. CONCLUSIONS: The LP1064 laser in monotherapy with fixed settings did not lead to a consistent vascular lesion to promote immediate occlusion in telangiectasias and reticular veins. This strategy may not work as monotherapy for small vein treatment, but the possible late response to the LP1064 laser cannot be ruled out and require further investigation.

Effect of quercetin on plasma extravasation in rat CNS and dura mater by ACE and NEP inhibition.

The effects of quercetin on substance P-induced plasma protein extravasation (PE) in the rat dura mater, cerebellum, olfactory bulb and cortex and also its modulation by endopeptidases, angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP) were studied. PE was assessed by photometric measurement of extravasated Evans blue. Substance P (SP) and NEP or ACE inhibitors increased the PE in dura mater. Pretreatment with captopril or phosphoramidon potentiated PE induced by SP in the dura mater and cerebellum, respectively. Quercetin increased the PE in the dura mater, cerebellum and cortex. Further results suggested that the PE induced by SP in the dura mater was enhanced by pretreatment with quercetin, similar to that observed with selective peptidase inhibitors. Quercetin-stimulated extravasation in all tissues was abolished by NK-1 receptor blockade. These results suggest that quercetin increases PE in the dura mater and CNS tissues by inhibiting NEP and/or ACE, showing that the effect induced in the dura mater, cerebellum and cortex occurs through endogenous SP accumulation.