Modulation of skin collagen metabolism by irradiation: collagen synthesis is increased in irradiated human skin

The importance of hypoxia in radiotherapy for the immune response, metastatic potential and FLASH-RT

PURPOSE

Hypoxia (low oxygen) is a common feature of solid tumors that has been intensely studied for more than six decades. Here we review the importance of hypoxia to radiotherapy with a particular focus on the contribution of hypoxia to immune responses, metastatic potential and FLASH radiotherapy, active areas of research by leading women in the field.

CONCLUSION

Although hypoxia-driven metastasis and immunosuppression can negatively impact clinical outcome, understanding these processes can also provide tumor-specific vulnerabilities that may be therapeutically exploited. The different oxygen tensions present in tumors and normal tissues may underpin the beneficial FLASH sparing effect seen in normal tissue and represents a perfect example of advances in the field that can leverage tumor hypoxia to improve future radiotherapy treatments.

Protective Effect of Fat-Tissue-Derived Products against Ultraviolet Irradiation-Induced Photoaging in Mouse Skin

BACKGROUND

Exposure to ultraviolet radiation causes erythema, inflammation, and photoaging. Mechanical micronization of adipose tissue can concentrate functional cells and has great potential as an alternative for regenerative medicine. Stromal vascular fraction gel is produced by means of a series of mechanical processes of lipoaspirates and can be injected intradermally. This study aimed to assess the therapeutic effect of stromal vascular fraction gel on photoaging skin.

METHODS

A photoaging model was established in nude mice. Photoaging mice received treatments of stromal vascular fraction gel, fat, tretinoin, or phosphate-buffered saline. Photoaging skin was characterized by histologic and immunohistochemical analyses. Expression of collagen synthesis-related or photoaging-related genes was assessed.

RESULTS

Stromal vascular fraction gel, fat, and tretinoin reversed photoaging, whereas stromal vascular fraction gel demonstrated the greatest therapeutic effect. Treatment with stromal vascular fraction gel restored intradermal fat tissue content and increased dermal collagen density. Injection of stromal vascular fraction gel had the strongest effect on stimulating fibroblasts and increasing the expression of transforming growth factor β1 (TGF-β1), propeptide of type-I procollagen, and Smad 2, decreasing the expression of Smad 3, compared with fat and tretinoin. Expression of photoaging-related genes was significantly reduced, whereas expression of fibulin-5 was significantly increased after stromal vascular fraction gel treatment.

CONCLUSIONS

Stromal vascular fraction gel demonstrated remarkable therapeutic effects in reversing photoaging skin. Stromal vascular fraction gel can be injected intradermally and survive within dermal layer after grafting. This product increased TGF-β1expression and activated fibroblasts to produce propeptide of type I procollagen, thus increasing the amount of collagen I, leading to thickening of the dermis of photoaging skin.

Initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin

BACKGROUND

Calvaria skin has a reduced thickness, and its initial damage produced by irradiation was scarcely reported. We aimed to identify the initial effects of x-ray irradiation in the rat calvaria skin.

METHODS

After approval by the Animal Ethical Committee, calvaria skin sections of five Wistar rats per time point were evaluated on days 4, 9, 14, and 25 following a single 15-Gy x-ray irradiation of the head. The control group was composed of five rats and evaluated on day 4. Sections were assessed using hematoxylin-eosin and Masson's trichrome staining for morphology, inflammation, and fibrosis. Fibrosis was also evaluated by the collagen maturation index from Picrosirius red staining and by cell proliferation using the immunohistochemistry, after 5-bromo-2-deoxyuridine intraperitoneal injection.

RESULTS

In irradiated rats, we observed a reduction in epithelial cell proliferation (p = 0.004) and in matrix metalloproteinase-9 expression (p < 0.001), an increase in the maturation index, and with a predominance in the type I collagen fibers, on days 9 and 14 (1.19 and 1.17, respectively). A progressive disorganization in the morphology of the collagen fibers at all time points and changes in morphology of the sebaceous gland cells and hair follicle were present until day 14.

CONCLUSIONS

The initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin was a change in the normal morphology of collagen fibers to an amorphous aspect, a temporary absence of the sebaceous gland and hair follicles, and without a visible inflammatory process, cell proliferation, or fibrosis process in the dermis.

Effects of Peritoneal Dialysis Solutions on the Secretion of Growth Factors and Extracellular Matrix Proteins by Human Peritoneal Mesothelial Cells

♦ Objective

To compare the effects of different peritoneal dialysis solutions (PDS) on secretion of vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGFβ1), procollagen I C-terminal peptide (PICP), procollagen III N-terminal peptide (PIIINP), and fibronectin by cultured human peritoneal mesothelial cells (HPMC).

♦ Design

Using M199 culture medium as control, commercial PDS containing 1.5% or 4.25% glucose and 40 mmol/L lactate [Dianeal 1.5 (D 1.5) and Dianeal 4.25 (D 4.25), respectively; Baxter Healthcare, Deerfield, Illinois, USA]; PDS containing 1.5% or 4.25% glucose with 25 mmol/L bicarbonate and 15 mmol/L lactate [Physioneal 1.5 (P 1.5) and Physioneal 4.25 (P 4.25), respectively; Baxter]; and PDS containing 7.5% icodextrin [Extraneal (E); Baxter] were tested. Growth-arrested and synchronized HPMC were continuously stimulated for 48 hours by test PDS diluted twofold with M199, TGFβ1 1 ng/mL, or different concentrations of icodextrin. VEGF, TGFβ1, and fibronectin secreted into the media were analyzed by ELISA, and PICP and PIIINP by radioimmunoassay.

♦ Results

Dianeal 1.5, D 4.25, and P 4.25, but not P 1.5 and E, significantly increased VEGF secretion compared with control M199. D 4.25- and P 4.25-induced VEGF secretion was significantly higher than induction by D 1.5 and P 1.5, respectively, suggesting that high glucose may be involved in the induction of VEGF. Physioneal 1.5- and P 4.25-induced VEGF secretion was significantly lower than induction by D 1.5 and D 4.25, respectively, suggesting a role for glucose degradation products (GDP) in VEGF production. TGFβ1 secretion was significantly increased by D 4.25 and E. Icodextrin increased TGFβ1 secretion in a dose-dependent manner. All PDS tested significantly increased secretion of PIIINP compared with control. D 1.5- and D 4.25-induced PIIINP secretion was significantly higher than P 1.5, P 4.25, and E. Physioneal 4.25-induced PIIINP secretion was significantly higher than P 1.5, again implicating high glucose and GDP in PIIINP secretion by HPMC. There was no significant increase in PICP or fibronectin secretion using any of the PDS tested. Addition of TGFβ1 1 ng/mL into M199 control significantly increased VEGF, PICP, PIIINP, and fibronectin secretion by HPMC.

♦ Conclusions

The present study provides direct evidence that HPMC can secrete VEGF, TGFβ1, and PIIINP in response to PDS, and that HPMC may be actively involved in the development and progression of the peritoneal membrane hyperpermeability and fibrosis observed in long-term PD patients. This study also suggests that both high glucose and GDP in PDS may play important roles in inducing VEGF and PIIINP production/secretion by HPMC.

Incidence of Morphea following Adjuvant Irradiation of the Breast in 2,268 Patients

Background

Morphea of the breast is an autoimmune reaction of the subcutaneous connective tissue which can be triggered by exposure to ionizing radiation. The literature suggests incidence rates of 1:500 to 1:3,000 which, however, do not seem to match the very small number of cases reported.

Objectives

The aim of the present study was to determine the incidence of morphea following irradiation of the breast in order to generate more evidence about the frequency of this serious and mutilating complication.

Method

Retrospective analysis of patient data who underwent adjuvant radiotherapy in the period 2009-2018 following breast-conserving surgery and who made use of the recommended radiooncology follow-up examinations in 2018. Analysis was done by descriptive statistics.

Results

Of a total of 5,129 patients who had undergone radiotherapy over a 10-year period, follow-up data were available in 2,268 patients. In 2,236 patients (98.6%) the breast had been irradiated using conventional fractionation schemes with a total dose of 50-50.4 Gy; 32 (1.4%) were given a total dose of 40.05 Gy in 15 fractions. During the observation period, 6 patients were diagnosed with morphea (4 unilateral and 2 bilateral) by punch biopsies resulting in a cumulative incidence proportion of 0.26% (95% CI: 0.24-0.28), translating into 1 case for every 378 irradiated patients.

Conclusions

In the case studies reported to date, morphea is described as a very rare complication. In contrast, our data suggest a cumulative incidence of 1:378, which is higher than other authors have estimated. This leads us to suspect that in a large number of patients, morphea is incorrectly diagnosed as an infection (in the early stages) and radiation-induced fibrosis (in later stages).

The Multiple Applications and Possible Mechanisms of the Hyperbaric Oxygenation Therapy

Hyperbaric Oxygenation Therapy (HBOT) is used as an adjunctive method for multiple diseases. The method meets the routine treating and is non-invasive, as well as provides 100% pure oxygen (O2), which is at above-normal atmospheric pressure in a specialized chamber. It is well known that in the condition of O2 deficiency, it will induce a series of adverse events. In order to prevent the injury induced by anoxia, the capability of offering pressurized O2 by HBOT seems involuntary and significant. In recent years, HBOT displays particular therapeutic efficacy in some degree, and it is thought to be beneficial to the conditions of angiogenesis, tissue ischemia and hypoxia, nerve system disease, diabetic complications, malignancies, Carbon monoxide (CO) poisoning and chronic radiation-induced injury. Single and combination HBOT are both applied in previous studies, and the manuscript is to review the current applications and possible mechanisms of HBOT. The applicability and validity of HBOT for clinical treatment remain controversial, even though it is regarded as an adjunct to conventional medical treatment with many other clinical benefits. There also exists a negative side effect of accepting pressurized O2, such as oxidative stress injury, DNA damage, cellular metabolic, activating of coagulation, endothelial dysfunction, acute neurotoxicity and pulmonary toxicity. Then it is imperative to comprehensively consider the advantages and disadvantages of HBOT in order to obtain a satisfying therapeutic outcome.

Radiation-induced morphea-a rare but severe late effect of adjuvant breast irradiation : Case report and review of the literature

Background

Radiation-induced morphea (RIM) is a circumscribed localized scleroderma that occurs most often in the breast. After an asymptomatic period of one month to several years, the symptoms (circumscribed inflammation, edema, sclerosis) often arise suddenly and cannot be clinically distinguished from a local recurrence in the form of inflammatory carcinoma.

Case

We present a case of a 74-year-old woman who developed this rare and serious local side-effect in connective tissue following neoadjuvant CDK 4/6 inhibitor abemaciclib (Verzenio®) and aromatase inhibitor anastrozole (Arimidex®) therapy and subsequent radiation therapy of the breast.

Conclusions

Little is known about risk factors and pathogenesis of RIM. Here we describe the first case of RIM following immunotherapy. The diagnosis is based on clinical appearance and histopathological examination. Treatment should be initiated in the inflammatory stage in order to prevent or delay irreversible fibrosis and atrophy of the breast.

Serum N-Terminal Type III Procollagen Propeptide: An Indicator of Growth Hormone Excess and Response to Treatment in Feline Hypersomatotropism

Background

N‐terminal type III procollagen propeptide (PIIINP) is a biomarker of soft tissue proliferation. Hypersomatotropism (HS) is associated with soft tissue proliferation.

Hypothesis

Serum PIIINP is increased in cats with HS and decreases with effective treatment, and may be an additional tool in the diagnosis and treatment of feline HS.

Animals

Cats with uncomplicated diabetes mellitus (DM; n = 30) and with HS‐induced DM (HSDM; n = 30). Pre‐ and posttreatment samples were available from 5 cats undergoing radiotherapy (RT) and 16 cats undergoing hypophysectomy (HPX).

Methods

Retrospective and prospective cross‐sectional study. Analytical performance of a serum PIIINP ELISA was assessed and validated for use in cats. PIIINP and insulin‐like growth factor 1 (IGF‐1) radioimmunoassays (RIA) were performed pre‐ and post‐treatment in cats with DM and HSDM. PIIINP and IGF‐1 were compared between cats treated by RT and HPX.

Results

Serum PIIINP concentrations were significantly higher (P < .001) in HSDM cats (median, 19.6 ng/mL; range, 1.7–27.9) compared to DM cats (median, 5.0 ng/mL; range, 2.1–10.4). A cut‐off of 10.5 ng/mL allowed differentiation between DM and HSDM cats with 87% sensitivity and 100% specificity (area under the curve [AUC], 0.91; 95% confidence interval [CI], 0.82‐1). After RT, PIIINP increased significantly (P = .043) with no significant change in IGF‐1 concentrations. After HPX, serum PIIINP (P = .034) and IGF‐1 concentrations (P < .001) decreased significantly.

Conclusion and clinical importance

PIIINP concentrations are increased in cats with untreated HSDM compared to those with DM, demonstrating the effect of excess GH on soft tissue. PIIINP concentrations decreased after HPX in most HSDM cats.

Stimulation of triple negative breast cancer cell migration and metastases formation is prevented by chloroquine in a pre-irradiated mouse model

Background

Some triple negative breast cancer (TNBC) patients are at higher risk of recurrence in the first three years after treatment. This rapid relapse has been suggested to be associated with inflammatory mediators induced by radiation in healthy tissues that stimulate cancer cell migration and metastasis formation. In this study, the ability of chloroquine (CQ) to inhibit radiation-stimulated development of metastasis was assessed.

Methods

The capacity of CQ to prevent radiation-enhancement of cancer cell invasion was assessed in vitro with the TNBC cell lines D2A1, 4T1 and MDA-MB-231 and the non-TNBC cell lines MC7-L1, and MCF-7. In Balb/c mice, a single mammary gland was irradiated with four daily doses of 6 Gy. After the last irradiation, irradiated and control mammary glands were implanted with D2A1 cells. Mice were treated with CQ (vehicle, 40 or 60 mg/kg) 3 h before each irradiation and then every 72 h for 3 weeks. Migration of D2A1 cells in the mammary gland, the number of circulating tumor cells and lung metastasis were quantified, and also the expression of some inflammatory mediators.

Results

Irradiated fibroblasts have increased the invasiveness of the TNBC cell lines only, a stimulation that was prevented by CQ. On the other hand, invasiveness of the non-TNBC cell lines, which was not enhanced by irradiated fibroblasts, was also not significantly modified by CQ. In Balb/c mice, treatment with CQ prevented the stimulation of D2A1 TNBC cell migration in the pre-irradiated mammary gland, and reduced the number of circulating tumor cells and lung metastases. This protective effect of CQ was associated with a reduced expression of the inflammatory mediators interleukin-1β, interleukin-6, and cyclooxygenase-2, while the levels of matrix metalloproteinases-2 and −9 were not modified. CQ also promoted a blocking of autophagy.

Conclusion

CQ prevented radiation-enhancement of TNBC cell invasion and reduced the number of lung metastases in a mouse model.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2393-z) contains supplementary material, which is available to authorized users.

New perspectives on the conservative management of osteoradionecrosis of the mandible: A literature review

Over the last decades, several therapeutic options were considered in the treatment of the osteoradionecrosis (ORN) of the mandible, including supportive measures, ultrasound therapy, corticosteroids, hyperbaric oxygen, surgical resection with reconstruction, and, more recently, drugs capable of reversing the fibroatrophic process. Once established, the ORN does not spontaneously disappear and a standard treatment has not yet been defined. The clear clinical effectiveness of hyperbaric oxygen therapy (HBOT) varies according to the literature and there are some economic/logistic issues to be considered; the triplet tocopherol/pentoxifylline/clodronate demands greater evidence from randomized clinical trials and also resilience from the patient, given the long treatment duration and its possible side effects. Controversy around the ideal treatment of the initial stage ORN of the mandible persists. More rigorous randomized prospective trials are essential. The purpose of this article was to review the relevant literature on the physiopathology of ORN of the mandible and discuss the new perspectives of its conservative treatment. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1708-1716, 2016.

Effect of hyperbaric oxygen treatment on irradiated oral mucosa: microvessel density

The aim of this study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on microvascular tissue and cell proliferation in the oral mucosa. Twenty patients, aged 51-78 years, were allocated randomly to a treatment or a control group. All had a history of radiotherapy (50-70 Gy) to the orofacial region 2-6 years previously. Tissue samples were taken from the irradiated buccal oral mucosa before HBOT and at 6 months after treatment. In the control group, tissue samples were taken on two occasions, 6 months apart. The samples were subjected to immunohistochemistry staining: double staining with CD31 and D2-40 for microvessels, or Ki-67 for the analysis of cell proliferation. Blood vessel density and area were significantly increased after HBOT (P=0.002-0.041). D2-40-positive lymphatic vessels were significantly increased in number and area in the sub-epithelial area (P=0.002 and P=0.019, respectively). No significant differences were observed in the control group. There were no significant differences in Ki-67-expressing epithelial cells between the two groups. It is concluded that the density and area of blood and lymphatic vessels in the irradiated mucosa are increased by HBOT 6 months after therapy. Epithelial cell proliferation is not affected by HBOT.

Quantifying fibrosis in head and neck cancer treatment: An overview

BACKGROUND

Fibrosis is a common late complication of radiotherapy and/or surgical treatment for head and neck cancers. Fibrosis is difficult to quantify and formal methods of measure are not well recognized. The purpose of this review was to summarize the methods available to quantify neck fibrosis.

METHODS

A PubMed search of articles was carried out using key words "neck" and "fibrosis."

RESULTS

Many methods have been used to assess fibrosis, however, there is no preferred methodology. Specific to neck fibrosis, most studies have relied upon hand palpation rating scales. Indentation and suction techniques have been used to mechanically quantify neck fibrosis. There is scope to develop applications of ultrasound, dielectric, bioimpedance, and MRI techniques for use in the neck region.

CONCLUSION

Quantitative assessment of neck fibrosis is sought after in order to compare treatment regimens and improve quality of life outcomes in patients with head and neck cancer.

Pre-irradiation of mouse mammary gland stimulates cancer cell migration and development of lung metastases

Background:

In most patients with breast cancer, radiotherapy induces inflammation that is characterised by an increase of promigratory factors in healthy tissues surrounding the tumour. However, their role in the emergence of the migration phenotype and formation of metastases is still unclear.

Methods:

A single mammary gland of BALB/c mice was irradiated with four doses of 6 Gy given at a 24-h interval. After the last session of irradiation, treated and control mammary glands were either collected for quantification of promigratory and proinflammatory factors or were implanted with fluorescent ubiquitination-based cell cycle indicator (FUCCI)-expressing mouse mammary cancer D2A1 cells. The migration of cancer cells in the mammary glands was monitored by optical imaging. On day 21, mammary tumours and lungs were collected for histology analyses and the quantification of metastases.

Results:

Pre-irradiation of the mammary gland increased by 1.8-fold the migration of cancer cells, by 2-fold the quantity of circulating cancer cells and by 2.4-fold the number of lung metastases. These adverse effects were associated with the induction of interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2).

Conclusion:

The emergence of the metastasis phenotype is believed to be associated with the accumulation of mutations in cancer cells. Our results suggest an alternative mechanism based on promigratory factors from irradiated mammary glands. In clinic, the efficiency of radiotherapy could be improved by anti-inflammatory agents that would prevent the stimulation of cancer cell migration induced by radiation.

Effects of zoledronate on irradiated bone in vivo: analysis of the collagen types I, V and their cross-links lysylpyridinoline, hydroxylysylpyridinoline and hydroxyproline

Radiotherapy can lead to a reduction of bone density with an increased risk of pathological fractures. Bisphosphonates may represent a preventive treatment option by increasing the density of anorganic bone mineral. Yet it is unknown how bisphosphonates act on irradiated collagen cross-links, which play an essential role for the mechanical stability of bone. The aim of this study was to evaluate the effects of zoledronate on bone collagens and their cross-links after irradiation. The right femur of 37 rats was irradiated with a single dose of 9.5 Gy at a high dose rate using an afterloading machine. Half of the rats (n=18) received additionally a single dose zoledronate (0.1 mg/kg body weight). Fourteen and 100 days after irradiation the femora were collected for histologic evaluation and determination of the collagen cross-links lysylpyridinoline, hydroxylysylpyridinoline, and hydroxyproline. The collagen types were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Fourteen days after treatment the lysylpyridinoline levels of all treatment groups were significantly lower compared to the untreated control. After 100 days, in the combined radiotherapy+zoledronate group significantly lower lysylpyridinoline values were determined (p=0.009). Radiotherapy and/or zoledronate did not change significantly the level of hydroxylysylpyridinoline. The concentration of hydroxyproline was 14 days after irradiation significantly higher in the combined treatment group compared to the control. No significant differences were observed 100 days after treatment. Zoledronate does not have the ability to restore the physiological bone collagen cross-link levels after radiotherapy. However, this would be necessary for regaining the physiological mechanical stability of bone after irradiation and therefore to prevent effectively radiation-induced fractures.

"Pharyngocise": randomized controlled trial of preventative exercises to maintain muscle structure and swallowing function during head-and-neck chemoradiotherapy

PURPOSE

Dysphagia after chemoradiotherapy is common. The present randomized clinical trial studied the effectiveness of preventative behavioral intervention for dysphagia compared with the "usual care."

METHODS AND MATERIALS

A total of 58 head-and-neck cancer patients treated with chemoradiotherapy were randomly assigned to usual care, sham swallowing intervention, or active swallowing exercises (pharyngocise). The intervention arms were treated daily during chemoradiotherapy. The primary outcome measure was muscle size and composition (determined by T(2)-weighted magnetic resonance imaging). The secondary outcomes included functional swallowing ability, dietary intake, chemosensory function, salivation, nutritional status, and the occurrence of dysphagia-related complications.

RESULTS

The swallowing musculature (genioglossus, hyoglossuss, and mylohyoid) demonstrated less structural deterioration in the active treatment arm. The functional swallowing, mouth opening, chemosensory acuity, and salivation rate deteriorated less in the pharyngocise group.

CONCLUSION

Patients completing a program of swallowing exercises during cancer treatment demonstrated superior muscle maintenance and functional swallowing ability.

Irradiation of normal mouse tissue increases the invasiveness of mammary cancer cells

PURPOSE

Treatment of breast tumours frequently involves irradiating the whole breast to reach malignant microfoci scattered throughout the breast. In this study, we determined whether irradiation of normal tissues could increase the invasiveness of breast cancer cells in a mouse model.

MATERIALS AND METHODS

Non-irradiated MC7-L1 mouse mammary carcinoma cells were injected subcutaneously in irradiated and non-irradiated thighs of Balb/c mice. The invasion volume, tumour volume, blood vessel permeability and interstitial volumes were monitored by magnetic resonance imaging (MRI). Slices of normal tissue invaded by cancer cells were examined by histology. Activity of matrix metalloproteinase -2 and -9 (MMP -2 and -9) in healthy and irradiated tissues was determined, and the proliferation index of the invading cancer cells was evaluated.

RESULTS

Three weeks after irradiation, enhancement of MC7-L1 cells invasiveness in irradiated thighs was already detected by MRI. The tumour invasion volume continued to extend 28- to 37-fold compared to the non-irradiated implantation site for the following three weeks, and it was associated with an increase of MMP-2 and -9 activities in healthy tissues. The interstitial volume associated with invading cancer cells was significantly larger in the pre-irradiated sites; while the blood vessels permeability was not altered. Cancer cells invading the healthy tissues were proliferating at a lower rate compared to non-invading cancer cells.

CONCLUSION

Implantation of non-irradiated mammary cancer cells in previously irradiated normal tissue enhances the invasive capacity of the mammary cancer cells and is associated with an increased activity of MMP-2 and -9 in the irradiated normal tissue.

Effect of topical tretinoin on photoaged facial skin: a histometric, immunohistochemical and ultrastructural study

BACKGROUND

Topical tretinoin is a recognized treatment for photoageing.

AIM

To evaluate the microscopic changes induced by topical tretinoin used to treat mild to moderate photodamage in dark-skinned patients aged 30 to 50 years.

PATIENTS AND METHODS

Biopsy specimens were obtained from the facial skin of 11 patients before and after treatment with topical tretinoin. Routine histopathology coupled with histometric computer-assisted image analysis was used to assess epidermal changes. Alcian blue stain was used to measure changes in glycosaminoglycans (GAGs). Immunoperoxidase technique for type I and III collagens and elastin, as well as transmission electron microscopy, were used to measure changes in collagen and elastic fibres.

RESULTS

Epidermal hyperplasia occurs following tretinoin application, which is reversible with continued therapy. GAGs decreased (p < 0.05) after 6 months of tretinoin application but with no significant change thereafter. Quantitatively, there was an insignificant decrease of type I (p = 0.7) and III (p = 0.3) collagens during the first 6 months of tretinoin usage. However, biopsies taken after 10 months revealed a statistically significant increase in collagen I from a mean of 75.2% +/- 9.6 before treatment to 94.2% +/- 4.1 after treatment (p = 0.05). Similarly, the amount of type III collagen increased from a mean of 74.6% +/- 9.96 to 90.6% +/- 2.1 after 10 months of treatment (p = 0.05). On the other hand, the amount of elastin significantly (p = 0.02) decreased from a mean of 54.5% +/- 3.68 before treatment to 43.4% +/- 4.42 after 6 months of tretinoin application but with no significant change thereafter. Such changes were associated ultrastructurally with new collagen deposition and improvement of the quality of elastic fibres.

CONCLUSION

Topical tretinoin benefits facial skin, mainly by increasing collagen I and III and also by improving the morphological appearance of collagen and elastic fibres.

Difference between total and intact assays for N-terminal propeptide of type I procollagen reflects degradation of pN-collagen rather than denaturation of intact propeptide

BACKGROUND

The concentration of N-terminal propeptide of type I procollagen (PINP) in the serum reflects the rate of type I collagen formation. Intact PINP assay measures the trimeric propeptide while total P1NP assay measures both trimeric and monomeric forms. In this study we compared these two assays emphasizing the possible differences.

METHODS

Intact and total PINP were measured from serum in healthy Finnish blood donors (n = 34) and in the patients with chronic renal failure before and after haemodialysis (n = 39). In addition, the serum of a normal man, pooled hospital serum samples and the serum of a patient with haemodialysis treatment were fractioned by gel filtration and trimeric and monomeric forms were located. Fractions were lyophilized and intact and total PINP were measured in each fraction. Samples from bedridden geriatric patients (n = 173) were also measured using intact and total PINP assays and a degradation marker of type I collagen (ICTP).

RESULTS

The correlation between intact and total PINP in controls was 0.89 and their PINP concentrations were similar. In haemodialysis or bedridden geriatric patients, the PINP methods gave significantly different results. In gel filtration studies, intact PINP hardly measured monomeric form even if its concentration was disproportionately increased in haemodialysis patients. In bedridden geriatric patients, the difference of total and intact PINP correlated significantly to degradation marker ICTP.

CONCLUSIONS

Difference between total and intact assays for PINP seem to reflect degradation of pN-collagen rather than denaturation of intact propeptide.

Increased excretion of collagen crosslinks in irradiated patients indicates destruction of collagen

PURPOSE

In a recent study we showed an instant radiogenic destruction of collagen in dental tissues. The hypothesis of this analysis was that there is a destruction of collagen directly in bone during irradiation. Our intention was to prove this assumption by the analysis of the intraindividual progression of urinary excretion of bone specific collagen crosslinks before, during and after radiotherapy (RT) of secondary malignant bone tumors.

MATERIAL AND METHODS

Forty-six patients were irradiated with a mean dose of 32 Gy (range 30 - 46 Gy). Four urine probes were collected from each patient before, during, at the end and 6 - 8 weeks after RT. Measurement of the mature collagen crosslinks hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) was performed by high performance liquid chromatography (HPLC).

RESULTS

In 43 patients we found increasing HP and LP concentrations by comparing the different chosen time-points. As regards to HP the urine excretion was significantly increased at the end (p = 0.02) and six weeks after RT (p = 0.01) and for LP six weeks after RT (p = 0.01). We observed significantly higher urinary HP levels in patients treated with doses of 35 - 46 Gy as compared to patients treated with 30 Gy (p = 0.05).

CONCLUSIONS

The urinary excretion of HP and LP was increased directly after a course of RT. This finding may reflect either destruction of collagen or increased bone remodeling/resorption after radiotherapy. Either way these findings suggest a relation to the mechanical instability of bone directly after radiotherapy. Future investigations of irradiated patients without osseous metastases will further clarify this matter.

High frequency ultrasound assessment of skin fibrosis: clinical results

Fibrosis is a common late effect of radiotherapy treatment for cancer patients. Current clinical assessment of radiation-induced fibrosis is generally limited to clinician-based rating scales, which are usually not sufficient for quantitative and objective evaluations. Ultrasonic propagation properties of tissues are widely reported to be sensitive to the alterations of tissue compositions and structures. Based on our previous feasibility study, we used four parameters including skin thickness and three ultrasonic parameters of dermal tissues (attenuation slope [beta], integrated attenuation [IA] and integrated backscatter [IBS]) in the frequency range of 10 to 25 MHz for the assessment of skin fibrosis. Experiments were conducted on the forearm and neck skin in patients with postirradiation fibrosis in the neck region. The palpation score and stiffness of the neck soft tissue were also measured as an indication of fibrotic severity. Comparisons of the results between 38 patients and 20 control subjects showed a significantly smaller beta (p = 0.005) and a significantly larger skin thickness (p < 0.004) and IA (p = 0.04) in the neck skins of the patients. However, age-matched comparisons showed there were neither significant differences among patient subgroups with different fibrotic levels assessed using manual palpation or significant correlations between the four parameters and the overall stiffness of the neck soft tissues (p > 0.05). In conclusion, ultrasound tissue characterization may provide additional information for the assessment of postirradiation skin fibrosis in the neck region. Further studies are necessary to investigate the feasibility of applying the current measurement for differentiating the severity of skin fibrosis.

Radiotherapy for rectal carcinoma: an unusual cause of foreskin phimosis

Phimosis of the foreskin secondary to radiotherapy for a pelvic malignancy has not been previously described in the world literature. However, as radiotherapy is ever more widely used in the treatment of various pelvic malignancies, it is important to ensure that this complication is prevented by the use of appropriate penile shielding.

Curcumin protects against radiation-induced acute and chronic cutaneous toxicity in mice and decreases mRNA expression of inflammatory and fibrogenic cytokines

PURPOSE

To determine whether curcumin ameliorates acute and chronic radiation skin toxicity and to examine the expression of inflammatory cytokines (interleukin [IL]-1, IL-6, IL-18, IL-1Ra, tumor necrosis factor [TNF]-alpha, and lymphotoxin-beta) or fibrogenic cytokines (transforming growth factor [TGF]-beta) during the same acute and chronic phases.

METHODS AND MATERIALS

Curcumin was given intragastrically or intraperitoneally to C3H/HeN mice either: 5 days before radiation; 5 days after radiation; or both 5 days before and 5 days after radiation. The cutaneous damage was assessed at 15-21 days (acute) and 90 days (chronic) after a single 50 Gy radiation dose was given to the hind leg. Skin and muscle tissues were collected for measurement of cytokine mRNA.

RESULTS

Curcumin, administered before or after radiation, markedly reduced acute and chronic skin toxicity in mice (p < 0.05). Additionally, curcumin significantly decreased mRNA expression of early responding cytokines (IL-1 IL-6, IL-18, TNF-alpha, and lymphotoxin-beta) and the fibrogenic cytokine, TGF-beta, in cutaneous tissues at 21 days postradiation.

CONCLUSION

Curcumin has a protective effect on radiation-induced cutaneous damage in mice, which is characterized by a downregulation of both inflammatory and fibrogenic cytokines in irradiated skin and muscle, particularly in the early phase after radiation. These results may provide the molecular basis for the application of curcumin in clinical radiation therapy.

Plasminogen activator inhibitor-I–related regulation of procollagen I (α1 and α2) by antitransforming growth factor-β1 treatment during radiation-impaired wound healing

PURPOSE

Plasminogen activator inhibitor (PAI)-1 mediates transforming growth factor-beta1 (TGF-beta1)-related signaling by stimulating collagen Type I synthesis in radiation-impaired wound healing. The regulation of alpha(I)-procollagen is contradictory in fibroblasts of different fibrotic lesions. It is not known whether anti-TGF-beta1 treatment specifically inhibits alpha(I)-procollagen synthesis. We used an experimental wound healing study to address anti-TGF-beta1-associated influence on alpha(I)-procollagen synthesis.

METHODS AND MATERIALS

A free flap was transplanted into the preirradiated (40 Gy) or nonirradiated neck region of Wistar rats: Group 1 (n = 8) surgery alone; Group 2 (n = 14) irradiation and surgery; Group 3 (n = 8) irradiation and surgery and anti-TGF-beta1 treatment. On the 14th postoperative day, skin samples were processed for fibroblast culture, in situ hybridization for TGF-beta1, immunohistochemistry, and immunoblotting for PAI-1, alpha1/alpha2(I)-procollagen.

RESULTS

Anti-TGF-beta1 significantly reduced TGF-beta1 mRNA (p < 0.05) and PAI-1 expression (p < 0.05). Anti-TGF-beta1 treatment in vivo significantly reduced alpha1(I)-procollagen protein (p < 0.05) and the number of expressing cells (p < 0.05) in contrast to significantly increased (p < 0.05) alpha2(I)-procollagen expression.

CONCLUSION

These results emphasize anti-TGF-beta1 treatment to reduce radiation-induced fibrosis by decreasing alpha1(I)-procollagen synthesis in vivo. alpha1(I)-procollagen and alpha2(I)-procollagen might be differentially regulated by anti-TGF-beta1 treatment. Increased TGF-beta signaling in irradiated skin fibroblasts seemed to be reversible, as shown by a reduction in PAI-1 expression after anti-TGF-beta1 treatment.

Treatment of Radiation-Induced Fibrosis of the Face with Manual Compression Therapy

Radiation-induced fibrosis (RIF) is an uncommon complication of radiation therapy. RIF most often occurs in the extremities; it is rare in the head and neck. Only a few medical treatments for RIF are available, and they have been mediocre at best. We describe a case of RIF of the face that was treated successfully with a nonmedical modality: manual compression therapy.

Trichloroacetic acid peeling versus dermabrasion: a histometric, immunohistochemical, and ultrastructural comparison

BACKGROUND

Trichloroacetic acid (TCA) chemical peel and dermabrasion are beneficial methods for treatment of photoaged skin.

OBJECTIVE

In this study, we evaluated the changes induced by these therapies on various structures of facial skin of nine dark-skinned patients (Fitzpatrick types IV-V; TCA, five patients; dermabrasion, four patients) demonstrating different degrees of photodamage.

METHODS

Routine histopathology coupled with histometric computer-assisted image analysis was used to assess epidermal changes. Alcian blue stain was used to evaluate changes in glycosaminoglycans. Immunoperoxidase techniques with antibodies against types I and III collagen and elastin were used to evaluate quantitatively changes in collagen and elastic fibers, and their ultrastructure was examined by transmission electron microscopy.

RESULTS

Similar histologic, immunohistochemical, as well as ultrastructural changes were observed in the two groups, including epidermal and dermal rejuvenation with new collagen deposition and normalization of the elastic tissue. However, these changes were more prominent in patients treated with dermabrasion than those treated with TCA.

CONCLUSION

The results of this study suggest that beneficial effects of such modalities on facial skin were accomplished primarily by increasing the amounts of collagen I and collagen III and improving the morphologic appearance of collagen and elastic fibers.

Radiation-induced changes in skin type I and III collagen synthesis during and after conventionally fractionated radiotherapy

BACKGROUND AND PURPOSE

To measure local changes of collagen metabolism in irradiated breast skin and systemic changes in serum during and after radiotherapy and correlate these changes with skin thickness, erythema and palpable subcutaneous induration.

PATIENTS AND METHODS

Aminoterminal propeptides of type I and type III procollagens (PINP and PIIINP, respectively) were measured from skin suction blister fluid (SBF) in 21 breast cancer patients with breast conserving surgery and conventionally fractionated radiotherapy (RT) to a total dose of 50Gy. Suction blisters were induced in the operated and contralateral breast skin before RT, at 2.5 weeks, at the end of RT, and at 1, 4, 7, 12 and 24 months post-treatment. Blood samples for serum were taken simultaneously with SBF induction. Skin thickness of the suction blister sites was measured with a high-frequency ultrasound device. The investigated sites were scored for erythema at the end of RT and palpable subcutaneous induration at 1 and 2 years post-treatment.

RESULTS

In SBF the mean levels of PINP and PIIINP of the operated breast before RT were about 3-4 times higher than those in the contralateral breast due to the operation-related wound healing. The synthesis of PINP in irradiated breast after RT increased 7.7-fold (P < 0.001) 4 months post-irradiation. The PIIINP synthesis was at maximum at 1 month post-irradiation (P < 0.001). Both synthesis stayed elevated until 2 years. The level of PINP correlated significantly with the palpable skin induration at 1 and 2 years (P = 0.038 and P = 0.003, respectively). The skin thickness of the irradiated breast was highest at 4 months post-treatment and significantly elevated until 1 year. The skin thickness correlated with the PINP level until 7 months and with PIIINP between 4 and 18 months. The PINP/PIIINP ratio reached the maximum at 4 months and stayed elevated until 2 years. No change in mean serum level of PINP was found during or after RT.

CONCLUSIONS

We demonstrated a maximum and elevated levels for PINP and PIIINP skin collagen metabolism determined from SBF during the 2 years' follow-up. Elevated levels of PINP and PIIINP correlated with the thickening of the skin and subcutaneous induration but not with erythema.

Different radiation susceptibility among five strains of mice detected by a skin reaction

Published reports about skin reactions to radiotherapy, especially among breast-cancer patients, suggest that there are interindividual differences in the normal tissue response, and genetic factors are thought to be involved in this variation. An analysis of murine strain differences may reveal the mechanism of genetic factors in the extent of normal tissue damage from irradiation for several endpoints. The variation in the radiation susceptibility was observed when the skin of mice from strains A/J, C3H/HeMs, C57BL/6J, C.B.17/Icr-scid and C3H-scid was irradiated with a single dose ranging from 10 to 60 Gy, using Cs-137 gamma rays. The active skin reaction of A/J mice lasted for months. C3H/HeMs mice showed dose-dependent skin damage, and consequently recovered to a state of mild damage within 40 days after local irradiation. The time course of the response in C57BL/6J mice was shorter than in A/J mice. The 2 strains of scid mice exhibited severe damage after irradiation at any dose from 20 to 50 Gy, and did not show any dose dependency. The variation between murine strains in macroscopic and histopathological changes in skin during the progression and resolution of damage caused by irradiation suggests an inter-strain variation in the expression of genes involved in injury, apoptosis, repair, and remodeling.

Elevated expression of extracellular matrix metalloproteinase inducer (CD147) and membrane-type matrix metalloproteinases in venous leg ulcers

BACKGROUND

Matrix metalloproteinases (MMPs) contribute to matrix remodelling in venous leg ulcers. Extracellular MMP inducer (EMMPRIN; CD147) has been reported to increase MMP expression, and membrane type 1 MMP (MT1-MMP) has been implicated in the activation of MMPs.

OBJECTIVES

To examine whether and to what degree EMMPRIN, MMP-2, MT1-MMP and membrane type 2 MMP (MT2-MMP) are expressed in venous leg ulcers as well as the association with MMP activity.

METHODS

EMMPRIN, MMP-2, MT1-MMP and MT2-MMP were analysed by zymography and immunohistochemistry in biopsies from healthy skin and lesional tissue from venous leg ulcers.

RESULTS

Zymography provided direct evidence of increased proteolytic activity of MMP-2 in lesional skin in comparison with healthy controls. Immunostaining showed intense expression of EMMPRIN, MMP-2, MT1-MMP and MT2-MMP in dermal structures of venous leg ulcers, whereas only EMMPRIN and MMP-2 showed elevated expression in perivascular regions. Our findings indicate that venous leg ulcers are characterized by elevated expression of EMMPRIN, MMP-2, MT1-MMP and MT2-MMP. The immunohistological findings of skin alterations reflect the dynamic process of activation of soluble and membrane-bound MMPs, which may be highly induced by EMMPRIN.

CONCLUSIONS

These data suggest for the first time that membrane-bound MMPs may favour enhanced turnover of the extracellular matrix and support unrestrained MMP activity in venous leg ulcers.

Type I collagen turnover and cross-linking are increased in irradiated skin of breast cancer patients

BACKGROUND AND PURPOSE

The effects of radiation therapy on the turnover and structure of type I collagen were studied in irradiated and contralateral skin of 18 breast cancer patients without clinically evident fibrosis.

MATERIALS AND METHODS

The rates of on-going type I collagen synthesis and degradation were assessed by the aminoterminal propeptide of type I procollagen (PINP) and by two different assays (ICTP and SP4) for the carboxyterminal telopeptide of type I collagen in the soluble tissue extracts, respectively. Also, TIMP-1, TIMP-2 and the MMP-2/TIMP-2 complex were measured in the tissue extracts. Insoluble skin matrices, containing the cross-linked type I collagen fibres, were heat-denatured and digested with trypsin. Then, the variants of the carboxyterminal telopeptide of type I collagen were separated by high performance liquid chromatography (HPLC). The major histidinohydroxylysinonorleucine (HHL)-cross-linked variant was quantified by the SP4 assay, and the minor pyridinoline analogue (PA)-cross-linked telopeptide was quantified by the ICTP assay.

RESULTS

Both the synthesis and degradation of type I collagen were increased (r=0.906; P<0.001) on the irradiated side, whereas the concentration of the MMP-2/TIMP-2 complex was decreased. In the insoluble tissue digests, the HHL-cross-linked telopeptides of type I collagen, also, when expressed/tissue hydroxyproline, were increased in the irradiated skin. TIMP-1, TIMP-2 or PA-cross-linked telopeptides of type I collagen showed no differences between the two sides.

CONCLUSIONS

Radiotherapy induces a long-term increase in the turnover of type I collagen and leads to the accumulation of cross-linked type I collagen in skin.