Yohei Tanaka

Differential Long-Term Stimulation of Type I versus Type III Collagen After Infrared Irradiation

BACKGROUND The dermis is composed primarily of type I (soft) and type III (rigid scar‐like) collagen. Collagen degradation is considered the primary cause of skin aging. Studies have proved the efficacy of infrared irradiation on collagen stimulation but have not investigated the differential long‐term effects of infrared irradiation on type I and type III collagen. OBJECTIVE To determine differential long‐term stimulation of type I and type III collagen after infrared (1,100–1,800 nm) irradiation. METHODS AND MATERIALS In vivo rat tissue was irradiated using the infrared device. Histology samples were analyzed for type I and III collagen stimulation, visual changes from baseline, and treatment safety up to 90 days post‐treatment. RESULTS Infrared irradiation provided long‐term stimulation of type I collagen and temporary stimulation of type III collagen. Treatment also created long‐term smoothing of the epidermis, with no observed complications. CONCLUSIONS Infrared irradiation provides safe, consistent, long‐term stimulation of type I collagen but only short‐term stimulation in the more rigid type III collagen. This is preferential for cosmetic patients looking for improvement in laxity and wrinkles while seeking smoother, more youthful skin. The authors have indicated no significant interest with commercial supporters.

Long-term histological comparison between near-infrared irradiated skin and scar tissues

Background and objective: Our previous histological studies indicated that near-infrared (NIR) irradiation stimulates collagen proliferation in rat and human skin for 3 months. High collagen density in the dermis and smoothing of the epidermis were observed in irradiated rat skin, and appeared to last up to 6 months. Epidermal smoothness in irradiated rat skin seems to resemble scarring. Here, we performed a long-term histological comparison between NIR (1100 to 1800 nm) irradiated skin and scar tissues. Materials and methods: Rat skin was irradiated using a NIR device. Scar tissues were harvested from wounded areas and were compared with irradiated skin. Histological changes up to 180 days post-treatment were evaluated with hematoxylin and eosin, Azan-Mallory staining, and collagen type I and III staining. Results: In nonirradiated control skin, the dermis showed a low density of type I and III collagen, the surface of the epidermis was rough, and no significant changes were observed over time. In irradiated skin, both type I and III collagen increased significantly, and persisted up to 180 days. The density of type I collagen was significantly higher than that of type III collagen, whereas type I and III collagen of the control group did not differ significantly. Epidermis was thickened for 30 days, and epidermal smoothness persisted up to 180 days. In scar tissues, the density of type III collagen was higher than that of type I collagen. The number of fibroblasts remained high and the glial fibrils were dense until 180 days after injury compared with irradiated skin. Significant increases in both type I and III collagen and epidermal flattering persisted until 180 days. Conclusions: NIR irradiation induced high collagen density in the dermis, resulting in long-term epidermal smoothness without scar formation. Results indicated that NIR irradiation provides safe, consistent, and long-term effects of skin rejuvenation.

Non-thermal cytocidal effect of infrared irradiation on cultured cancer cells using specialized device

As infrared penetrates the skin, thermal effects of infrared irradiation on cancer cells have been investigated in the field of hyperthermia. We evaluated non‐thermal effects of infrared irradiation using a specialized device (1100–18000 nm with filtering of wavelengths between 1400 and 1500 nm and contact cooling) on cancer cells. In in vitro study, five kinds of cultured cancer cell lines (MCF7 breast cancer, HeLa uterine cervical cancer, NUGC‐4 gastric cancer, B16F0 melanoma, and MDA‐MB435 melanoma) were irradiated using the infrared device, and then the cell proliferation activity was evaluated by 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium (MTS) assay. Proliferation of all the cancer cell lines was significantly suppressed by infrared irradiation. Total infrared output appeared to be correlated with cell survival. Increased temperature during infrared irradiation appeared not to play a role in cell survival. The maximum temperature elevation in the wells after each shot in the 20 and 40 J/cm2 culture was 3.8°C and 6.9°C, respectively. In addition, we have shown that infrared irradiation significantly inhibited the tumor growth of MCF7 breast cancer transplanted in severe combined immunodeficiency mice and MDA‐MB435 melanoma transplanted in nude mice in vivo. Significant differences between control and irradiated groups were observed in tumor volume and frequencies of TUNEL‐positive and Ki‐67‐positive cells. These results indicate that infrared, independent of thermal energy, can induce cell killing of cancer cells. As this infrared irradiation schedule reduces discomfort and side effects, reaches the deep subcutaneous tissues, and facilitates repeated irradiations, it may have potential as an application for treating various forms of cancer. (Cancer Sci 2010)

Non-thermal DNA damage of cancer cells using near-infrared irradiation.

Previously, we reported that near‐infrared irradiation that simulates solar near‐infrared irradiation with pre‐ and parallel‐irradiational cooling can non‐thermally induce cytocidal effects in cancer cells. To explore these effects, we assessed cell viability, DNA damage response pathways, and the percentage of mitotic cancer cells after near‐infrared treatment. Further, we evaluated the anti‐cancer effects of near‐infrared irradiation compared with doxorubicin in xenografts in nude mice by measuring tumor volume and assessing protein phosphorylation by immunoblot analysis. The cell viability of A549 lung adenocarcinoma cells was significantly decreased after three rounds of near‐infrared irradiation at 20 J ⁄ cm2. Apoptotic cells were observed in near‐infrared treated cells. Moreover, near‐infrared treatment increased the phosphorylation of ataxia‐telangiectasia mutated (ATM) at Ser1981, H2AX at Ser139, Chk1 at Ser317, structural maintenance of chromosome (SMC) 1 at Ser966, and p53 at Ser15 in A549 cells compared with control. Notably, near‐infrared treatment induced the formation of nucleic foci of γH2AX. The percentage of mitotic A549 cells, as measured by histone H3 phosphorylation, decreased significantly after three rounds of near‐infrared irradiation at 20 J ⁄cm2. Both near‐infrared and doxorubicin inhibited the tumor growth of MDA‐MB435 melanoma cell xenografts in nude mice and increased the phosphorylation of p53 at Ser15, Chk1 at Ser317, SMC1 at Ser966, and H2AX at Ser139 compared with control mice. These results indicate that near‐infrared irradiation can non‐thermally induce cytocidal effects in cancer cells as a result of activation of the DNA damage response pathway. The near‐infrared irradiation schedule used here reduces discomfort and side effects. Therefore, this strategy may have potential application in the treatment of cancer. (Cancer Sci, doi: 10.1111/j.1349‐7006.2012.02310.x, 2012)

Objective assessment of skin rejuvenation using near-infrared 1064-nm neodymium: YAG laser in Asians

Background We reported previously that near-infrared (NIR) irradiation provides long-lasting stimulation of elastin, and is efficient for skin rejuvenation. Many studies have indicated the efficacy of various types of laser, but did not include sufficiently objective evaluation. Therefore, we evaluated the efficacy of NIR laser treatment not only subjectively but also objectively. Methods Fifty Japanese patients were treated with a NIR 1064-nm neodymium: YAG laser. Objective computer assessments were performed by Canfield VISIA Complexion Analysis for improvement of dilated pores, skin texture, and wrinkles. The volunteers then provided subjective assessments. Histological evaluations of elastin were performed by Victoria blue staining up to 90 days post-treatment in four Japanese volunteers. Results Mean pretreatment percentiles of dilated pores, skin texture, and wrinkles were 51.08 ± 24.82, 54.7 ± 26.33, and 58.02 ± 28.61, respectively. Mean post-treatment percentiles of dilated pores, skin texture, and wrinkles were 53.58 ± 23.89, 58.58 ± 24.44, and 62.2 ± 25.39, respectively. All objective computer assessments evaluated by percentiles in dilated pores, skin texture, and wrinkles showed significant improvement after NIR laser treatment. Ninety-six percent, 100%, and 98% of volunteers reported satisfaction with the improvement of dilated pores, skin texture, and wrinkles, respectively. NIR laser treatment appeared to increase the amount of elastin at day 30, which then decreased slightly but was still elevated at day 90 compared with nonirradiated controls on day 0. Thickening of the epidermis was detected on day 30, and epidermal smoothness persisted for up to 90 days. No treatment-related adverse events were observed. Conclusions NIR irradiation increased elastin in the dermis, and achieved skin rejuvenation. The results indicated that NIR irradiation provides safe and effective long-term stimulation of elastin, which is beneficial for improving dilated pores, skin texture, and wrinkles.

Objective assessment of skin tightening in Asians using a water-filtered near-infrared (1,000–1,800 nm) device with contact-cooling and freezer-stored gel

Background Near-infrared has been shown to penetrate deeper than optical light sources independent of skin color, allowing safer treatment for the Asian skin type. Many studies have indicated the efficacy of various types of devices, but have not included a sufficiently objective evaluation. In this study, we used three-dimensional imaging for objective evaluation of facial skin tightening using a water-filtered near-infrared device. Methods Twenty Japanese patients were treated with the water-filtered near-infrared (1,000–1,800 nm) device using a contact-cooling and nonfreezing gel stored in a freezer. Three-dimensional imaging was performed, and quantitative volume measurements were taken to evaluate the change in post-treatment volume. The patients then provided their subjective assessments. Results Objective assessments of the treated cheek volume evaluated by a three-dimensional color schematic representation with quantitative volume measurements showed significant improvement 3 months after treatment. The mean volume reduction at the last post-treatment visit was 2.554 ± 0.999 mL. The post-treatment volume was significantly reduced compared with the pretreatment volume in all patients (P < 0.0001). Eighty-five percent of patients reported satisfaction with the improvement of skin laxity, and 80% of patients reported satisfaction with improvement of rhytids, such as the nasolabial folds. Side effects, such as epidermal burns and scar formation, were not observed throughout the study. Conclusion The advantages of this water-filtered near-infrared treatment are its high efficacy for skin tightening, associated with a minimal level of discomfort and minimal side effects. Together, these characteristics facilitate our ability to administer repeated treatments and provide alternative or adjunctive treatment for patients, with improved results. This study provides a qualitative and quantitative volumetric assessment, establishing the ability of this technology to reduce volume through noninvasive skin tightening.

Facial reanimation by transposition of the masseter muscle combined with tensor fascia lata, using the zygomatic arch as a pulley

We have created a new way of reanimating the face, involving transposition of the masseter muscle combined with tensor fascia lata, and using the zygomatic arch as a trochlea to reconstruct the inferior facial paralysis. We used it on five patients who had facial palsy after excision of malignant parotid tumours. The wide skin defect that exposed the masseter muscle after total parotidectomy was reconstructed with a free flap. This method differs from those of other methods of transposing the masseter muscle in that force is applied at an upper lateral angle. Our method provided dynamic raising of the upper lip, the corner of the mouth, and the nasolabial fold in four patients. We consider it to be useful, particularly for prompt surgical reconstruction of facial palsy after total parotidectomy with a wide defect in the skin of the cheek.

Non-Thermal Effects of Near-Infrared Irradiation on Melanoma

Malignant melanoma is considered to be the most aggressive form of skin neoplasms. Over the past few decades, the incidence rate of melanoma has steadily risen throughout the world. The risks of developing melanoma consist of intrinsic and environmental factors. Intrinsic factors generally include a family history and an inherited genotype, while the most relevant environmental factor is sun exposure. Exposure to ultraviolet (UV) radiation is the most important environmental carcinogen (Travers et al., 2008) and plays a significant role in the development of melanoma (Wolf et al., 1994). Sunscreens reduce the effects of UV radiation on human skin (Ananthaswamy et al., 1997). Nevertheless, sunscreens have failed to protect against an increase in UV radiation-induced melanomas (Wolf et al., 1994). Various kinds of UV blocking materials, such as sunblocks, films, paints, and fibers are often used to prevent skin damage from UV exposure. Although individuals all over the world use various kinds of sunscreens, unwanted biological influences such as rosasea, erythema ab igne, long-term vasodilation, muscle thinning, and sagging still occur (Tanaka et al., 2010c). Most sunscreens can only block UV and not visible light or near-infrared (NIR) radiation. Sunlight that reaches the human skin contains solar energy composed of 6.8% UV light, 38.9% visible light, and 54.3% infrared (IR) radiation (Kochevar et al., 1999). In addition to natural NIR, human skin is increasingly exposed to artificial NIR from medical devices and from electrical appliances (Schieke et al., 2003; Schroeder et al., 2008). Thus, we are exposed to tremendous amounts of NIR. Both UV and visible light radiation are attenuated by melanin (Anderson & Parrish, 1981), whereas NIR can penetrate deep into human tissue where it can cause photochemical changes (Karu, 1999). We previously reported that NIR penetrates the skin and is absorbed by sweat on the skin surface, water in the dermis (Tanaka et al. 2009a, 2009b), hemoglobin in dilated vessels (Tanaka et al., 2009b, 2011c), myoglobin in the superficial muscle (Tanaka et al., 2010c), bone cortical mass, and is scattered by adipose cells (Tanaka et al., 2011b). NIR irradiation induces strand breaks and cell death by apoptosis (Tirlapur & Konig, 2001) as well as the cell death of cancer cells and bone marrow cells (Tanaka et al., 2010b, 2011b). In addition, NIR irradiation is used as a therapeutic option for the treatment of wound healing

Treatment of skin laxity using multisource, phase-controlled radiofrequency in Asians: visualized 3-dimensional skin tightening results and increase in elastin density shown through histologic investigation.

BACKGROUND A new multisource phase-controlled radiofrequency (MPCRF) device is widely used for skin tightening and rejuvenation in Asia. OBJECTIVE To evaluate the efficacy of MPCRF objectively and histologically. METHODS An MPCRF device with real-time impedance control was evaluated. Ten Japanese patients were treated one side of the face, and the untreated side served as a control. Three-dimensional (3-D) imaging was performed to evaluate the posttreatment volume change. An independent observer assessed the 3-D images. Histologic evaluations of elastin were performed by Victoria Blue staining in 5 Japanese patients. RESULTS Objective assessments evaluated by a 3-D color schematic representation showed improvement in skin laxity after the final treatment in all patients. The treated side improved markedly compared with the untreated side; however, even the untreated side slightly improved. The elastin density was significantly increased compared with controls in all 5 Japanese patients (p = .0013). Induced elastin appeared to be relatively thin elastic fibers without irregular elastic fibers, such as solar elastosis. Side effects were not observed, and the patients reported feeling comfortable throughout the study. CONCLUSION Multisource phase-controlled radiofrequency treatments provide stimulation of elastin and skin-tightening results safely and effectively, and thus are beneficial for improving skin laxity and rhytides.

The Impact of Near-infrared in Plastic Surgery

Many studies regarding near-infrared, have used near-infrared resources without a water filter or a cooling system, and have proven its thermal effects. With these methods near-infrared energy is mainly absorbed in the superficial tissues and cannot be delivered sufficiently to deeper tissues. As solar near-infrared is filtered by atmospheric water, a water filter is essential in order to simulate solar near-infrared. Thus, these approaches could not sufficiently evaluate the effects of incident solar near-infrared that reaches the human tissue. We have clarified that the near-infrared that simulates solar near-infrared non-thermally affects subcutaneous tissues, including muscle. Importantly, the biological effects of near-infrared have both beneficial applications and deleterious effects. Near-infrared induces dermal heating thermally and non-thermally induces collagen and elastin stimulation, which results in skin tightening, and induces long-lasting vasodilation that may prevent vasospasm and may be beneficial for ischemic disorders and flap surgeries. Near-infrared also non-thermally relaxes and weakens dystonic or hypertrophic muscles to reduce wrinkles and myalgia. Its long-lasting induction of subcutaneous adipocytes may have an application in volume augmentation. However, continuous near-infrared exposure may induce photoaging and thinning of superficial muscles, which results in skin ptosis. Protection against near-infrared should be strongly considered, as over half of the solar energy is near-infrared. Although plastic surgeons are not familiar with the effects of near-infrared, its potential appears to be high and significant. This paper reviews the effects of near-infrared and introduces the new findings and applications of the biological effects of near-infrared in the field of plastic surgery.