In Vivo Visualization of Collagen Transdermal Absorption by a Combined Second-harmonic Generation and Two-photon Excited Fluorescence Method

The transdermal administration of collagen is an important method used for wound healing and skin regeneration. However, due to the limitations of previous approaches, the process and degree of collagen transdermal absorption could only be quantitatively and qualitatively assessed in vitro. In the present study, we introduced a novel approach combining second-harmonic generation with two-photon excited fluorescence to visualize the dynamics of collagen transdermal absorption in vivo. The high resolution images showed that the exogenous recombinant human collagen permeated through the epidermis, reached the dermis and formed reticular structures in real time. We also validated these findings through traditional in vitro skin scanning and histological examination. Thus, our approach provides a reliable method of measurement for the real-time evaluation of collagen absorption and treatment effects.

Transdermal Absorption of Methimazole- a Cat’s Tale

Introduction: In modern civilization different kinds of animals live with us as pets. These pets have different diseases and are on medications. Close contact with animals can cause medication adverse reactions or may worsen pre-existing conditions in humans. Here we present an interesting case of hypothyroidism worsened by transdermal absorption of methimazole administered for feline hyperthyroidism. Case History: 66-year-old Caucasian female with past medical history of postoperative hypothyroidism s/p total thyroidectomy secondary to multinodular goiter due to Hashimoto’s thyroiditis with a 0.2 cm papillofollicular microcarcinoma and 0.7 cm follicular adenoma presented for follow up. She complained of weight gain, lethargy and dry skin for the past 4 months. She was on a stable dose of levothyroxine 112 mcg daily for the past year. She took her pill correctly and did not miss any doses. Her other medical problems were impaired fasting glucose, osteopenia and B12 deficiency. Her repeat thyroid function tests showed TSH 11.2 mc IU/ l (0.4 -4) (TSH - 0.538 mc IU/ L 6 months back), T4 - 6.8 mcg/ dl (4.5 - 12) (T4 8.9 6 months back). She had a measurable serum thyroglobulin of 0.4 ng/ml with antithyroglobulin antibody 11 IU/ml (<115) consistent with some residual thyroid tissue despite her history of a “total thyroidectomy”. Due to recent worsening of her symptoms with elevated TSH on background of previous stable levothyroxine requirement, further detailed history was taken. She reported that her cat was suffering from hyperthyroidism, treated with methimazole 10 mg daily. The patient used to cut the pill in half with bare hands and fed it to her pet. She also used to handle wet methimazole that her cat coughed up. Her levothyroxine dose was continued at 112 mcg daily. The patient was advised to use gloves before feeding and wash her hands after feeding her cat. Her symptoms resolved after she took precautions and TSH normalized to 1.170 mc IU/ l with T4 7.6 two months later. Conclusion: Absorption of methimazole by transdermal administration has been shown in cats1. A study by Kasraee et al showed safety of a 5% topical methimazole application for treatment of post inflammatory hyperpigmentation in humans with no change in thyroid function tests2. Our case contradicts this study and indicates that methimazole might be absorbed transdermally in humans. To conclude, more studies are needed to study the effect of transdermal administration of methimazole in humans. References: 1. Hill KE, Mills PC, Jones BR et.al. Percutaneous absorption of methimazole: an in vitro study of the absorption pharmacokinetics for two different vehicles. J Vet Pharmacol Ther. 2015;38(6):581-589. PMID: 25683868 2. Kasraee B et al. Safety of topical methimazole for the treatment of melasma. Transdermal absorption, the effect on thyroid function and cutaneous adverse effects. Skin Pharmacol Physiol. 2008;21(6):300-305. PMID: 18667842

Atmospheric Pressure Plasma Irradiation Facilitates Transdermal Permeability of Aniline Blue on Porcine Skin and the Cellular Permeability of Keratinocytes with the Production of Nitric Oxide

The transdermal delivery system of nutrients, cosmetics, and drugs is particularly attractive for painless, noninvasive delivery and sustainable release. Recently, atmospheric pressure plasma techniques have been of great interest to improve the drug absorption rate in transdermal delivery. Currently, plasma-mediated changes in the lipid composition of the stratum corneum are considered a possible mechanism to increase transdermal permeability. Nevertheless, its molecular and cellular mechanisms in transdermal delivery have been largely confined and still veiled. Herein, we present the effects of cold plasma on transdermal transmission on porcine skin and the cellular permeability of keratinocytes and further demonstrate the production of nitric oxide from keratinocytes. Consequently, argon plasma irradiation for 60 s resulted in 2.5-fold higher transdermal absorption of aniline blue dye on porcine skin compared to the nontreated control. In addition, the plasma-treated keratinocytes showed an increased transmission of high-molecular-weight molecules (70 and 150 kDa) with the production of nitric oxide. Therefore, these findings suggest a promoting effect of low-temperature plasma on transdermal absorption, even for high-molecular-weight molecules. Moreover, plasma-induced nitric oxide from keratinocytes is likely to regulate transdermal permeability in the epidermal layer.

Verification of P-Glycoprotein Function at the Dermal Barrier in Diffusion Cells and Dynamic “Skin-On-A-Chip” Microfluidic Device

The efficacy of transdermal absorption of drugs and the irritation or corrosion potential of topically applied formulations are important areas of investigation in pharmaceutical, military and cosmetic research. The aim of the present experiments is to test the role of P-glycoprotein in dermal drug delivery in various ex vivo and in vitro platforms, including a novel microchip technology developed by Pázmány Péter Catholic University. A further question is whether the freezing of excised skin and age have any influence on P-glycoprotein-mediated dermal drug absorption. Two P-glycoprotein substrate model drugs (quinidine and erythromycin) were investigated via topical administration in diffusion cells, a skin-on-a-chip device and transdermal microdialysis in rat skin. The transdermal absorption of both model drugs was reduced by P-glycoprotein inhibition, and both aging and freezing increased the permeability of the tissues. Based on our findings, it is concluded that the process of freezing leads to reduced function of efflux transporters, and increases the porosity of skin. P-glycoprotein has an absorptive orientation in the skin, and topical inhibitors can modify its action. The defensive role of the skin seems to be diminished in aged individuals, partly due to reduced thickness of the dermis. The novel microfluidic microchip seems to be an appropriate tool to investigate dermal drug delivery.

Molecular Pharming of the Recombinant Protein hEGF-hEGF Concatenated with Oleosin Using Transgenic Arabidopsis

We set out to assess the NIH/3T3 cell proliferation activity of Arabidopsis oil body-expressed recombinant oleosin–hEGF–hEGF protein. Normally, human epidermal growth factor (hEGF) is purified through complex process, however, oleosin fusion technology provides an inexpensive and scalable platform for its purification. Under a phaseolin promoter, we concatenated oleosin gene to double hEGF (hEGF–hEGF) with plant-preferred codons in the expression vectors and the construct was transformed into Arabidopsis thaliana (Arabidopsis). The transgenic Arabidopsis was validated by RT–PCR and the content of recombinant protein oleosin–hEGF–hEGF was quantified by western blot. Subsequently, the proliferation assay and transdermal absorption were determined by MTT method and immunohistochemical staining, respectively. First, the expression level of hEGF was recorded to be 14.83-ng/μL oil body and due to smaller size transgenic oil bodies expressing the recombinant oleosin–hEGF–hEGF, they were more skin permeable than those of control. Second, via the staining intensity of transgenic oil bodies was greater than EGF at all time points via immunohistochemical staining in transdermal absorption process. Lastly, activity assays of oil bodies expressed oleosin–hEGF–hEGF indicated that they stimulated the NIH/3T3 cell proliferation activity. Our results revealed oil-body-expressed oleosin–hEGF–hEGF was potential new material having implications in the field of medicine.

Advances in Pharmacological Activities of Terpenoids

Terpenoids, the most abundant compounds in natural products, are a set of important secondary metabolites in plants with diverse structures. Terpenoids play key roles in plant growth and development, response to the environment, and physiological processes. As raw materials, terpenoids were also widely used in pharmaceuticals, food, and cosmetics industries. Terpenoids possess antitumor, anti-inflammatory, antibacterial, antiviral, antimalarial effects, promote transdermal absorption, prevent and treat cardiovascular diseases, and have hypoglycemic activities. In addition, previous studies have also found that terpenoids have many potential applications, such as insect resistance, immunoregulation, antioxidation, antiaging, and neuroprotection. Terpenoids have a complex structure with diverse effects and different mechanisms of action. Activities and mechanisms of terpenoids were reviewed in this paper. The development and application prospect of terpenoid compounds were also prospected, which provides a useful reference for new drug discovery and drug design based on terpenoids.