Ciprofloxacin accelerates aortic enlargement and promotes dissection and rupture in Marfan mice

OBJECTIVE

Aortic aneurysm and dissection are major life-threatening complications of Marfan syndrome. Avoiding factors that promote aortic damage is critical in managing the care of these patients. Findings from clinical and animal studies raise concerns regarding fluoroquinolone use in patients at risk for aortic aneurysm and dissection. Therefore, we examined the effects of ciprofloxacin on aortic aneurysm and dissection development in Marfan mice.

METHODS

Eight-week-old Marfan mice (Fbn1C1041G/+) were given ciprofloxacin (100 mg/kg/d; n = 51) or vehicle (n = 59) for 4 weeks. Mice were monitored for 16 weeks. Aortic diameters were measured by using ultrasonography, and aortic structure was examined by using histopathologic and immunostaining analyses.

RESULTS

Vehicle-treated Fbn1C1041G/+ mice showed progressive aortic enlargement, with aortic rupture occurring in 5% of these mice. Compared with vehicle-treated Fbn1C1041G/+ mice, ciprofloxacin-treated Fbn1C1041G/+ mice showed accelerated aortic enlargement (P = .01) and increased incidences of aortic dissection (25% vs 47%, P = .03) and rupture (5% vs 25%, P = .005). Furthermore, ciprofloxacin-treated Fbn1C1041G/+ mice had higher levels of elastic fiber fragmentation, matrix metalloproteinase expression, and apoptosis than did vehicle-treated Fbn1C1041G/+ mice.

CONCLUSIONS

Ciprofloxacin accelerates aortic root enlargement and increases the incidence of aortic dissection and rupture in Marfan mice, partially by suppressing lysyl oxidase expression and further compromising the inherited defect in aortic elastic fibers. Our findings substantiate that ciprofloxacin should be avoided in patients with Marfan syndrome.

Intraluminal infusion of Penta-Galloyl Glucose reduces abdominal aortic aneurysm development in the elastase rat model

BACKGROUND

An abdominal aortic aneurysm (AAA) is a progressive chronic dilatation of the abdominal aorta with terminally rupture when the aortic wall is so weakened that aortic wall stress exceeds wall strength. No effective medical treatment exists so far. We aimed to test whether intraluminal admission of Penta-Galloyl Glucose (PGG) treatment in a rodent AAA model could hold the potential to inhibit aneurysmal progression.

METHOD

Male Sprague Dawley rats had either intraluminal elastase infused for AAA induction or saline to serve as controls. In two independent experimental series, elastase was used to induce AAA followed by an intraluminal PGG (directly or by a drug eluting balloon) treatment. All rats were followed for 28 days and euthanized. In both series, maximal infrarenal aortic diameter was measured at baseline and at termination as a measure of AAA size. In series 2, maximal internally AAA diameter was followed by ultrasound weekly. AAA tissues were analyzed for elastin integrity by millers stain, collagen deposition by masson trichrome staining. In other AAA tissue samples the mRNA level of CD45, lysyloxidase (LOX), lysyloxidase like protein 1 (LOXL1) were determined by qPCR.

RESULTS

Direct administration of PGG significantly reduced AAA expansion when compared to controls. PGG treatment resulted in a higher number and more preserved elastic fibers in the aneurysmal wall, while no significant difference was seen in the levels of CD45 and LOX mRNA levels. The drug eluting balloon (DEB) experiment showed no significant difference in AAA size observed neither macroscopically nor ultrasonically. Also the aneurysmal mRNA levels of CD45, LOX and LOXL1 were unchanged between groups.

CONCLUSION

A significant reduced expansion of AAAs was observed in the PGG group, suggesting PGG as a drug to inhibit aneurysmal progression, while administration through a DEB did not show a promising new way of administration.

Effects of tadalafil to prevent injury on corpus cavernosum after vascular or nervous peri-prostatic bundle injury. Experimental model in rats

PURPOSE

To evaluate the effects of tadalafil (TD) in preventing histological alterations of the corpus cavernosum caused by isolated lesions of cavernous nerve (ILCN) and artery (ILCA) in rats.

METHODS

Fifty male Wistar rats were randomly assigned in five groups: G1: control; G2: bilateral ILCN; G3: bilateral ILCA; G4: ILCN+TD; G5: ILCA+TD. The cavernous bodies were submitted to histomorphometry, immunohistochemistry and biochemical analysis.

RESULTS

Nerve density was significantly higher in G2 and G4 compared to control (22.62±2.84 and 19.53±3.47 vs. 15.72±1.82; respectively, p<0.05). Smooth muscle density was significantly lower in G2 and G3 in comparison to G1 (12.87±1.90 and 18.93±1.51 vs. 21.78±1.81, respectively; p<0.05). A significant decrease in the sinusoidal lumen area was observed in G2 compared to controls (5.01±1.62 vs. 9.88±3.66, respectively; p<0.05) and the blood vessel density was increased in G2 and G3 (29.32±4.13 e 20.80±2.47 vs. 10.13±2.71, p<0.05). Collagen density was higher in G3 compared to G1 (93.76±15.81 vs. 64.59±19.25; p<0.05).

CONCLUSIONS

Histomorphometric alterations caused by ILCN were more intense than those produced by vascular injury, but the collagen analyses showed more fibrosis in animals with ILCA. TD was effective in preventing the majority of the alterations induced by the periprostatic bundle injury.

A reproducible swine model of proximal descending thoracic aortic aneurysm created with intra-adventitial application of elastase

OBJECTIVE

Animal models are required to explore the mechanisms of and therapy for proximal descending thoracic aortic aneurysm (TAA). This study aimed to establish a reproducible swine model of proximal descending TAA that can further explain the occurrence and progression of proximal descending TAA.

METHODS

Eighteen Chinese Wuzhishan miniature pigs (30.32 ± 1.34 kg) were randomized into the elastase group (n = 12) and the control group (n = 6). The elastase group received intra-adventitial injections of elastase (5 mL, 20 mg/mL), and the control group received injections of physiologic saline solution. A 4-cm descending thoracic aortic segment proximal to the left subclavian artery was isolated. The distance between the left subclavian artery and the injection starting point of the descending thoracic aorta was 0.5 cm. Elastic protease was circumferentially injected intra-adventitially into the isolated segment of the aortic wall in the elastase group by a handmade bent syringe. The length of the elastic protease injection was 2 cm. An average of 12 injection points were distributed in this 2-cm aortic segment. Each injection point used about 0.4 mL of elastic protease. The distance between two injection points was about 1.5 cm. All animals underwent digital subtraction angiography preoperatively and 3 weeks after operation. Three weeks after TAA induction, aortas were harvested for biochemical and histologic measurements.

RESULTS

All animals in the elastase group developed TAAs. No aneurysms were observed in the control group. The distance between the left subclavian artery and the TAA was 8.00 ± 4.19 mm. Preoperative and postoperative aortic diameters of the elastase group were 15.42 ± 0.43 mm and 24.53 ± 1.41 mm, respectively (P < .0001). Preoperative and postoperative aortic diameters of the control group were 15.31 ± 0.33 mm and 15.57 ± 0.40 mm, respectively (P = .5211). The changes of aortic structure and composition included reduction of smooth muscle cells and degradation of elastic fibers. Levels of matrix metalloproteinases 2 and 9 were increased in TAA tissue.

CONCLUSIONS

This study established a reproducible large animal model of proximal descending TAA. This model has the same biochemical characteristics as human aneurysms in the aspects of aortic expansion, aortic middle-level degeneration, and changes in the levels of matrix metalloproteinases and provides a platform for further study.

Understanding Solar Skin Elastosis-Cause and Treatment

Photoageing, also called actinic ageing, is the main cause of prematurely aged skin. Our expertise in elastic fibers has led us to discover a process triggered in response to ultraviolet (UV) light and which upsets the balance of elastin fibers: there is too much elastin and insufficient lysyl oxidase (LOXL1) enzyme to form functional elastic fibers. This imbalance then leads to an accumulation of nonfunctional elastin, which forms aggregates. In addition to this imbalance, UV rays also induce elafin synthesis by fibroblasts. Known to be a marker of elastotic aggregates, elafin crystallizes the elastin fibers and stimulates the formation of aggregates that cannot be naturally eliminated by the skin. We developed a Hamamelis virginiana leaf extract that was able to restore both the balance between elastin and LOXL1 and to decrease the elafin synthesis to fight and correct the damage. This specific Hamamelis virginiana extract increased LOXL1 expression by twofold and decreased elafin synthesis. As a consequence, elastic fibers became functional and aggregates of unfunctional fibers decreased. The specific Hamamelis extract activity was confirmed in vivo with decreasing wrinkles and improving skin firmness.

Treatment of Annular Elastolytic Giant Cell Granuloma With Topical Tretinoin

<p>Annular elastolytic giant cell granuloma, also known as actinic granuloma, is a rare skin condition with a chronic course that is often resistant to treatment. Literature is sparse, and only a handful of case reports are available to guide treatment decisions. Typical first line treatment options include topical and intralesional steroids, topical pimecrolimus, and cryotherapy. Resistant cases have been treated with cyclosporine, systemic steroids, antimalarials, and oral retinoids. In particular, acitretin and isotretinoin have shown success in three cases. However, these medications can have side effects and require frequent lab monitoring. We present a case of a 47-year-old woman with bilateral forearm lesions consistent with annular elastolytic giant cell granuloma who was successfully treated with topical tretinoin.</p> <p><em>J Drugs Dermatol. 2017;16(7):699-700.</em></p>.

Steroid Hormones Are Key Modulators of Tissue Mechanical Function via Regulation of Collagen and Elastic Fibers

The extracellular matrix (ECM) plays an active and dynamic role that both reflects and facilitates the functional requirements of a tissue. The mature ECM of the nonpregnant cervix is drastically reorganized during pregnancy to drive changes in tissue mechanics that ensure safe birth. In this study, our research on mice deficient in the proteoglycan decorin have led to the finding that progesterone and estrogen play distinct and complementary roles to orchestrate structural reorganization of both collagen and elastic fibers in the cervix during pregnancy. Abnormalities in collagen and elastic fiber structure and tissue mechanical function evident in the cervix of nonpregnant and early pregnant decorin-null mice transiently recover for the remainder of pregnancy only to return 1 month postpartum. Consistent with the hypothesis that pregnancy levels of progesterone and estrogen may regulate ECM organization and turnover, expressions of factors required for assembly and synthesis of collagen and elastic fibers are temporally regulated, and the ultrastructure of collagen fibrils and elastic fibers is markedly altered during pregnancy in wild-type mice. Finally, utilizing ovariectomized nonpregnant decorin-null mice, we demonstrate structural resolution of collagen and elastic fibers by progesterone or estrogen, respectively, and the potential for both ECM proteins to contribute to mechanical function. These investigations advance understanding of regulatory factors that drive specialized ECM organization and contribute to an understanding of the cervical remodeling process, which may provide insight into potential complications associated with preterm birth that impact 9.6% of live births in the United States.

Synergistic Effect of Hydrogen Peroxide and Elastase on Elastic Fiber Injury In Vitro

This laboratory has previously shown that hyperoxia enhances airspace enlargement in a hamster model of elastase-induced emphysema. To further understand the mechanism responsible for this finding, the effect of oxidants on elastase activity was studied in vitro, using a radiolabeled elastic fiber matrix derived from rat pleural mesothelial cells. Matrix samples were treated with either 0.1%, 1%, 3%, or 10% hydrogen peroxide (H2O2) for 1 hr, then incubated with 1.0 μg/ml porcine pancreatic elastase for 2 hrs. Radioactivity released from the matrix was used as a measure of elastolysis. Results indicate that sequential exposure to H2O2 and elastase markedly enhanced elastolysis compared to enzyme treatment alone. A 22% increase in elastolysis was seen with 0.1% H2O2 (325 vs. 396 cpm; P < 0.05), whereas samples pretreated with 1%, 3%, and 10% H2O2 showed increases of 53% (274 vs. 420 cpm; P < 0.05), 71% (381 vs. 653 cpm; P < 0.01), and 38% (322 vs. 443 cpm; P < 0.01), respectively. Exposure to various concentrations of H2O2 alone (0.1% to 10%) produced only minimal elastolysis (<20 cpm). However, 1% H2O2 was capable of degrading peptide-free desmosine and isodesmosine, suggesting that exposure to this oxidant may reduce the stability of the elastic fiber matrix. With regard to lung diseases such as emphysema, H2O2 and other oxidants derived from inflammatory cells or the environment could possibly act as priming agents for elastase-mediated breakdown of elastic fibers, resulting in amplification of lung injury.

The effects of elastic fiber protein insufficiency and treatment on the modulus of arterial smooth muscle cells

Elastic fibers are critical for the mechanical function of the large arteries. Mechanical effects of elastic fiber protein deficiency have been investigated in whole arteries, but not in isolated smooth muscle cells (SMCs). The elastic moduli of SMCs from elastin (Eln-/-) and fibulin-4 (Fbln4-/-) knockout mice were measured using atomic force microscopy. Compared to control SMCs, the modulus of Eln-/- SMCs is reduced by 40%, but is unchanged in Fbln4-/- SMCs. The Eln-/- SMC modulus is rescued by soluble or α elastin treatment. Altered gene expression, specifically of calponin, suggests that SMC phenotypic modulation may be responsible for the modulus changes.

Elastin in large artery stiffness and hypertension

Large artery stiffness, as measured by pulse wave velocity, is correlated with high blood pressure and may be a causative factor in essential hypertension. The extracellular matrix components, specifically the mix of elastin and collagen in the vessel wall, determine the passive mechanical properties of the large arteries. Elastin is organized into elastic fibers in the wall during arterial development in a complex process that requires spatial and temporal coordination of numerous proteins. The elastic fibers last the lifetime of the organism but are subject to proteolytic degradation and chemical alterations that change their mechanical properties. This review discusses how alterations in the amount, assembly, organization, or chemical properties of the elastic fibers affect arterial stiffness and blood pressure. Strategies for encouraging or reversing alterations to the elastic fibers are addressed. Methods for determining the efficacy of these strategies, by measuring elastin amounts and arterial stiffness, are summarized. Therapies that have a direct effect on arterial stiffness through alterations to the elastic fibers in the wall may be an effective treatment for essential hypertension.

Therapeutic effects of hyaluronan on smoke-induced elastic fiber injury: does delayed treatment affect efficacy?

Aerosolized hyaluronan (HA) has been previously shown to prevent cigarette smoke-induced airspace enlargement and elastic fiber injury in mice when given concurrently with smoke. In the present study, a more stringent test of the therapeutic potential of HA was performed by delaying treatment with this agent for 1 month. After treatment with cigarette smoke for 3 h per day for 5 days per week for 1 month, mice (DBA/2J) began receiving aerosolized HA (0.1%) for 1 h prior to smoke exposure (controls were given aerosolized water). The results indicate that much of the damage to the lung elastic fibers occurred within the first several months of smoke exposure, as measured by levels of desmosine and isodesmosine (DID) in bronchoalveolar lavage fluid (BALF). In contrast to previously published studies, where concurrent administration of aerosolized HA significantly reduced BALF DID levels within 3 months of smoke exposure, the same effect was not seen until 6 months when HA treatment was delayed. However, despite the prolonged breakdown of elastic fibers in the current study, a significant reduction in airspace enlargement was observed after only 2 months of HA treatment. These findings provide further support for testing this agent in patients with pre-existing chronic obstructive pulmonary disease.

Structural analysis of gubernaculum testis in cryptorchid patients submitted to treatment with human chorionic gonadotrophin

OBJECTIVES

To make a histological and stereological analysis of gubernaculum testis elastic system fibers, collagen and striated muscle cells in patients with cryptorchidism treated with human chorionic gonadotrophin (hCG).

MATERIALS AND METHODS

Gubernacula tissue samples were obtained from 12 patients with cryptorchidism. Patients' ages ranged from 1 to 3 years (mean 1.8). Of the 12 patients, 6 were treated with hCG. The samples were stained with Masson's trichrome to highlight muscle fibers and collagen, and Weigert's resorcin-fuchsin to highlight the elastic system fibers. The volumetric density of these components was determined by stereological methods.

RESULTS

The volumetric density of collagen was increased in patients treated with hCG, ranging from 85.62% to 94.48%, while in patients not submitted to hCG treatment the volume density ranged from 52.12% to 89.46% (p=0.0052). The volumetric density of the elastic system fibers was higher in patients treated with hCG, ranging from 9.62% to 19.62%, while patients not submitted to hCG treatment the volume density of elastic system fibers was between 10.38% and 12.38% (p=0.0030). The volume density of striated muscle fibers in patients treated with hCG ranged from 4.76% to 39.16%, while and in patients not treated hCG it ranged from 3.24% to 11.14% (p=0.0052).

CONCLUSION

Gubernacular components alter significantly when submitted to treatment with hCG. Patients who underwent hCG treatment and had no complete testicular migration had an increase in the concentration of elastic and striated muscle fibers and a decrease in the volumetric density of collagen.

The development of abdominal aortic aneurysms in mice is enhanced by benzo(a)pyrene

Cigarette smoking has been strongly associated with abdominal aortic aneurysm (AAA), but the components of tobacco smoke involved in AAA have not been identified. Benzo(a)pyrene (BaP) is an important constituent in cigarette smoke capable of induction of alterations strikingly similar to the pathological changes seen during AAA development. We therefore hypothesized that BaP exposure contributes to the development of AAA. In this study, C57/B6J mice were treated with vehicle, angiotensin II (AngII) (0.72 mg/kg/day), BaP (10 mg/kg/week), or the combination of AngII and BaP, for 5 weeks, and then examined for incidence of AAA and pathological changes of the aortic wall. Results showed that incidence of AAA formation in C57/B6J mice treated with BaP and AngII was significantly higher than that in AngII-treated mice (7 of 12 compared to 2 of 12). Further, five mice in the group treated with AngII/BaP and one in the group treated with AngII exhibited AAA rupture and hematoma. BaP caused macrophage infiltration, disarray of elastic lamella, and loss of vascular smooth muscle cells (VSMCs). We conclude that BaP aggravates AAA formation and rupture in C57/B6J mice by promoting macrophage infiltration, degeneration of elastic lamella, and loss of VSMCs in the aortic wall.

Dietary iron deficiency compromises normal development of elastic fibers in the aorta and lungs of chicks

Elastic fibers play a key role in the structure and function of numerous organs that require elasticity. Elastogenesis is a complex process in which cells first produce a microfibrillar scaffold, composed of numerous structural proteins, upon which tropoelastin assembles to be cross-linked into polymeric elastin. Recently, it was demonstrated that low concentrations of free iron upregulate elastin gene expression in cultured fibroblasts. The present studies were conducted to assess whether low-iron diets would affect the deposition of elastic fibers in an in vivo model. One-day-old chicks were fed semipurified diets containing 1.3 (low), 12 (moderate), and 24 (control) mg/kg of iron. After 3 wk, chicks in the low-iron group were underweight and anemic. Their aortas were smaller with significantly thinner walls than control chicks, yet elastin or collagen content did not decrease relative to total protein. They also demonstrated a significantly lower stress-strain resistance than the controls. Electron microscopy demonstrated that aortic and lung smooth muscle cells were vacuolated and surrounded by loose extracellular matrix and disorganized elastic lamellae with diffuse and fragmented networks of elastic fibers and microfibrils. Immunohistology demonstrated that fibrillin-3 (FBN3) was disorganized and markedly reduced in amount in aortas of the low-iron chicks. Elastin messenger RNA levels were not downregulated in the tissues from the low-iron-fed chicks; however, there was a significant reduction in expression of the FBN1 and FBN3 genes compared with control chicks. The studies indicate that iron deficiency had a pronounced negative effect on elastic fiber development and suggests that fibrillin may have an important role in this pathology.

Sequelae from inadvertent long-term use of potent topical steroids

We report a case of a 53-year-old African American woman with an unusual example of striae caused by topical steroid usage and discuss the widespread usage of these products.

Versican, a major hyaluronan-binding component in the dermis, loses its hyaluronan-binding ability in solar elastosis

Versican interacts with hyaluronan (HA) at its N-terminus and with fibrillin-1 at its C terminus. As versican in the dermis connects microfibrils to the HA-rich matrix for viscoelasticity, dermal diseases may involve destruction of these complexes. A recombinant versican protein, rVN, covering the HA binding region (HABR) of human versican and a polyclonal antibody, 6084, against rVN were prepared and characterized. Blotting analyses of skin extracts with 6084 and biotin-conjugated HA revealed that versican was a major HA-binding component in the dermis. Matrix metalloprotease-12, which is expressed in areas of solar elastosis, degraded versican and abrogated its HA-binding ability. Immunohistochemical analyses revealed that the elastic materials in solar elastosis lesions were negative for 6084, but positive for 2B1, an antibody recognizing the C-terminus of versican, indicating loss of the HABR in the aggregated elastic fibers. This loss of the HA-binding ability of versican followed by HA exclusion may be responsible for the pathological and phenotypical changes observed in solar elastosis.

Remodeling of the human dermis after application of salicylate silanol

Recently, a controlled double-blind study in patients with photo-aged facial skin demonstrated the beneficial role of oral intake of silanol for skin, hair and nails. The aim of our pilot study was to investigate histologic alterations in human skin after injection of silanol. Seven healthy female caucasian volunteers with a moderate degree of photoaged skin received ten sessions of weekly injections of 0.1% salicylate silanol in the left ventral lateral forearm. The histologic features of punch biopsies of the treated area and the nontreated contralateral arm were compared and the collagen and elastic fibers quantified. Texture analysis was performed on digitalized microscopic images by analyzing the Sarkar fractal dimension or amplitudes (inertia values) after Fast Fourier transformation. The treated area revealed a statistically significant increase of the density of both collagen and elastic fibers. Texture analysis showed more compact and homogeneously distributed collagen fibers after silicon injection. Our results suggest that the application of silicon may stimulate the production of collagen and elastic fibers leading to remodeling of the dermal fiber architecture, which may explain the improvement of the skin surface observed in clinical studies.

Action of topical thyroid hormone analogue, triiodothyroacetic acid in reversing glucocorticoid-induced skin atrophy in humans

The present study concerns the effect of topical treatment with a cream formulation of triiodothyroacetic acid (TRIAC) in comparison with a placebo preparation in producing a reversal of skin atrophy induced by long-term employment of topical glucocorticoid therapy in humans. A total of 39 patients with clinically verified skin atrophy due to long-term use of topical potent glucocorticoids were randomized. The changes in skin thickness, elastic fibers, and hyaluronic acid were evaluated by means of sonography and histology. After 8 weeks' treatment, the skin thickness measured by sonography increased by 16% in the epidermis, 8% in the dermis, and epidermis + dermis in the placebo group. In the TRIAC 0.1% group, the corresponding values were 24% ( p=0.063) in the epidermis, 28% ( p=0.042) in the dermis, and 25% ( p=0.039) in the epidermis + dermis. After 8 weeks, in the placebo group, the skin thickness measured by biopsy increased by 5% in the epidermis, epidermis + dermis, and 6% in the dermis. In the TRIAC 0.1% group, the corresponding values were 31% ( p=0.041) in the epidermis, 46% ( p=0.041) in the dermis and 44% ( p=0.043) in the epidermis + dermis. After 8 weeks, the elastic fibers of moderately irregular and thickened fibers increased by 56% in the placebo group and 100% ( p=0.043) in the TRIAC 0.1 group. This study indicates that topical treatment with TRIAC appears to reverse glucocorticoid-induced skin atrophy under the narrow conditions tested.

Effects of ethanol on intracorporeal structures of the rat

OBJECTIVE

Previous studies demonstrated that acute in vitro exposure of corpus cavernosal tissue to ethanol decreased its response to field stimulation and pharmacological stimulation. In the present study we investigated the effects of chronic ethanol consumption on the ultrastructure of cavernosal smooth muscle cells, elastic fibres and collagen content.

MATERIAL AND METHODS

Fourteen adult wistar rats were divided into a control group (n = 7, fed a standard diet and tap water) and an alcoholic group (n = 7, fed a standard diet and 5% (v/v) ethanol in drinking water and by increasing the ethanol concentration for every week, at the end of 6th week 30% (v/v) ethanol concentration was attained. Same dose was given until 12th week. At the end of 12th week blood samples were obtained and the ethanol concentrations were determined. The cavernosal tissues were obtained and immunohistochemical examinations were performed.

RESULTS

Immunohistochemical analysis revealed that chronic ethanol exposure markedly decreased the content of smooth muscle cells, elastic fibres and collagen type 4.

CONCLUSION

Our findings suggest that in this animal model chronic ethanol exposure decreases the percentage of staining for smooth muscle actin, elastin, and collagen type 4 which are the key structures fundamental for erection.

Ellagic and tannic acids protect newly synthesized elastic fibers from premature enzymatic degradation in dermal fibroblast cultures

Progressive proteolytic degradation of cutaneous elastic fibers, that cannot be adequately replaced or repaired by adult dermal fibroblasts, constitutes a major feature of aging skin. Our present investigations, employing monolayer cultures of human dermal fibroblasts and organ cultures of skin biopsies, were aimed at testing whether the hydrophilic tannic acid (TA) and lipophilic ellagic acid (EA) would protect dermal elastin from exogenous and endogenous enzymatic degradation. Results from both culture systems indicated that dermal fibroblasts, maintained with TA or EA, deposit significantly more elastic fibers than untreated control cultures despite the fact that neither polyphenol enhanced transcription of elastin mRNA or cellular proliferation. Results of a pulse and chase experiment showed that pretreatment with both polyphenols enhanced biostability of tropoelastin and newly deposited elastin. Results of in vitro assays indicated that both polyphenols bound to purified elastin and significantly decreased its proteolytic degradation by elastolytic enzymes belonging to the serine proteinase, cysteine proteinase, and metallo-proteinase families. Importantly, both polyphenols also synergistically enhanced elastogenesis induced by selected elastogenic compounds in cultures of dermal fibroblasts. We propose that EA and TA may be useful for preventing proteolytic degradation of existing dermal elastic fibers and for enhancing more efficient elastogenesis in aged skin.

Mouse strain dependence of lung tissue mechanics: Role of specific extracellular matrix composition

This study analyses the differences between C57BL/10 and BALB/c mice in lung tissue micromechanical behaviour and whether specific histological characteristics are related to the mechanical profile. C57BL/10 and BALB/c subpleural lung strips were submitted to multisinusoidal deformation with frequencies ranging between 0.2 and 3.1 Hz. Tissue resistance (R), elastance (E), and hysteresivity (eta) at each frequency were determined before and 30s, 1, 2, and 3 min after acetylcholine (ACh) treatment. BALB/c mice showed higher E and R, at baseline, as well as greater amount of collagen and elastic fibres, and alpha-actin than C57BL/10 mice. However, E, R, and eta augmented with the same magnitude after ACh treatment in both strains. Baseline R was correlated with collagen fibre content and with the volume proportion of alpha-actin, while E was correlated with elastic and collagen fibres, and alpha-actin contents. In conclusion, BALB/c and C57BL/10 mice present distinct tissue mechanical properties that are accompanied by specific extracellular matrix composition and contractile structures.

Inhibition of ultraviolet-B-induced wrinkle formation by an elastase-inhibiting herbal extract: implication for the mechanism underlying elastase-associated wrinkles

BACKGROUND

Previously, we have demonstrated that fibroblast-derived elastase plays an essential role in the increased three-dimensional tortuosity of elastic fibers, contributing to the loss of skin elasticity in UV-B-exposed skin. This decrease in skin elasticity is closely associated with the formation of wrinkles induced by UV exposure.

OBJECTIVE

To further clarify the role of elastase in the formation of wrinkles induced by UV exposure, we assessed the effects of an extract of Zingiber officinale (L.) Rose (which inhibits fibroblast-derived elastase) on the wrinkle formation induced by chronic UV-B irradiation.

RESULTS

Topical application of an extract of Zingiber officinale (L.) Rose to rat or hairless mouse skin significantly inhibited the wrinkle formation induced by chronic UV-B irradiation at a suberythemal dose, which was accompanied by a significant prevention of the decrease in skin elasticity in both types of animal skin. In the rat hind limb skin, consistent with the inhibition of reduced skin elasticity, wrinkle prevention occurred concomitantly with a significant decrease in the curling and three-dimensional tortuosity of dermal elastic fibers.

CONCLUSION

Our results indicate that herbal extracts with an ability to inhibit fibroblast-derived elastase may prove to be effective as anti-wrinkling agents, confirming the important role of elastase in UV-B-induced wrinkle formation.

Elastic fibres and vascular structure in hypertension

Blood vessels are dynamic structures composed of cells and extracellular matrix (ECM), which are in continuous cross-talk with each other. Thus, cellular changes in phenotype or in proliferation/death rate affect ECM synthesis. In turn, ECM elements not only provide the structural framework for vascular cells, but they also modulate cellular function through specific receptors. These ECM-cell interactions, together with neurotransmitters, hormones and the mechanical forces imposed by the heart, modulate the structural organization of the vascular wall. It is not surprising that pathological states related to alterations in the nervous, humoral or haemodynamic environment-such as hypertension-are associated with vascular wall remodeling, which, in the end, is deleterious for cardiovascular function. However, the question remains whether these structural alterations are simply a consequence of the disease or if there are early cellular or ECM alterations-determined either genetically or by environmental factors-that can predispose to vascular remodeling independent of hypertension. Elastic fibres might be key elements in the pathophysiology of hypertensive vascular remodeling. In addition to the well known effects of hypertension on elastic fibre fatigue and accelerated degradation, leading to loss of arterial wall resilience, recent investigations have highlighted new roles for individual components of elastic fibres and their degradation products. These elements can act as signal transducers and regulate cellular proliferation, migration, phenotype, and ECM degradation. In this paper, we review current knowledge regarding components of elastic fibres and discuss their possible pathomechanistic associations with vascular structural abnormalities and with hypertension development or progression.

Aerosolized hyaluronan limits airspace enlargement in a mouse model of cigarette smoke-induced pulmonary emphysema

This study was designed to determine if aerosolized hyaluronan (HA) could prevent airspace enlargement and elastic fiber injury in a mouse model of cigarette smoke-induced pulmonary emphysema. Compared to untreated/smoked controls, HA-treated animals showed statistically significant reductions in mean linear intercept (54 versus 65 microm; P < .001) and elastic fiber breakdown products (desmosine and isodesmosine) in bronchoalveolar lavage fluid (0.3 versus 7.0 ng/mL; P < .05). As in previous studies, the aerosolized HA showed preferential binding to elastic fibers, suggesting that it may protect them from injury. These findings support further investigation of the potential use of HA as a treatment for pulmonary emphysema.

Osteopontin expression and adventitial angiogenesis induced by local vascular endothelial growth factor 165 reduces experimental aortic calcification

BACKGROUND

Vascular calcification is a common pathologic and precisely regulated process involving bone-associated proteins such as osteopontin. In this study, we investigated mechanisms by which recombinant human vascular endothelial growth factor 165 protects the arterial wall from severe vascular remodeling, including calcification, a newly discovered biologic action of vascular endothelial growth factor.

METHODS

In a rabbit model of thoracic aortic end-to-end anastomosis that simulates cardiovascular intervention, recombinant human vascular endothelial growth factor 165 at a dose of 0.75 mug (n = 19) or albumin (control; n = 19) was delivered intraluminally and on the serosal surface. Animals were killed, and aortic tissue was evaluated by Western blotting, immunohistochemistry, and immunofluorescence at 4, 8, and 24 hours; 1 week; and 1 month after surgery.

RESULTS

All controls revealed extensive aortic medial calcification at 1 month, whereas calcification was significantly reduced or absent with vascular endothelial growth factor treatment. Compared with controls, vascular endothelial growth factor treatment resulted in an earlier infiltration of macrophages in the vessel media (at 8 hours: 5.7 +/- 2.3 macrophages per high-power field in control vs 32.1 +/- 7.5 in vascular endothelial growth factor-treated aortas; P < .001), whereas controls showed an increase in macrophages starting at 1 week (24.1 +/- 6.9 vs 4.3 +/- 1.8; P < .001). Osteopontin expression was transiently increased and detected in macrophages and endothelial cells in vascular endothelial growth factor-treated vessels, and adventitial microvascular density was significantly increased by 1 week (9.5 +/- 0.43 vs 25.0 +/- 1.3; P < .001).

CONCLUSIONS

Our data suggest that exogenous vascular endothelial growth factor is capable of increasing adventitial angiogenesis and shifting macrophage infiltration and osteopontin expression in the media to an earlier time point, thereby promoting prompt repair and diminishing vascular remodeling and calcification after acute vascular injury.

Elastin degradation and calcification in an abdominal aorta injury model: role of matrix metalloproteinases

BACKGROUND

Elastin calcification is a widespread feature of vascular pathology, and circumstantial evidence exists for a correlation between elastin degradation and calcification. We hypothesized that matrix metalloproteinase (MMP)-mediated vascular remodeling plays a significant role in elastin calcification.

METHODS AND RESULTS

In the present studies, we determined that short-term periadventitial treatment of the rat abdominal aorta with low concentrations of calcium chloride (CaCl2) induced chronic degeneration and calcification of vascular elastic fibers in the absence of aneurysm formation and inflammatory reactions. Furthermore, the rate of progression of calcification depended on the application method and concentration of CaCl2 applied periarterially. Initial calcium deposits, associated mainly with elastic fibers, were persistently accompanied by elastin degradation, disorganization of aortic extracellular matrix, and moderate levels of vascular cell apoptosis. Application of aluminum ions (known inhibitors of elastin degradation) before the CaCl2-mediated injury significantly reduced elastin calcification and abolished both extracellular matrix degradation and apoptosis. We also found that MMP-knockout mice were resistant to CaCl2-mediated aortic injury and did not develop elastin degeneration and calcification.

CONCLUSIONS

Collectively, these data strongly indicate a correlation between MMP-mediated elastin degradation and vascular calcification.

Can Exogenously Administered Hyaluronan Improve Respiratory Function in Patients With Pulmonary Emphysema?

While most attempts at developing a treatment for pulmonary emphysema have focused on the use of elastase inhibitors to reduce elastic fiber damage and the loss of alveoli, this laboratory has developed a method of preventing such injury by the intratracheal administration of hyaluronan (HA). Animals treated with HA prior to the induction of experimental emphysema develop significantly less disease than untreated controls. The protective effect of HA may be related to its ability to bind to lung elastic fibers, thereby preventing their breakdown by elastases. Although clinical trials involving nebulized HA are not expected to yield a measurable treatment effect for at least several years, it is proposed that the special ability of this polysaccharide to retain water may increase the elasticity of lung elastic fibers, producing a relatively rapid improvement in pulmonary mechanics. Such an outcome might speed the development of this potential treatment for pulmonary emphysema.

Protective effect of a vegetable extract from Lupinus albus (LU 105) on human gingival elastic fibers degradation by human leukocyte elastase

The aim of this study was to determine if a vegetable extract from seeds of Lupinus albus (LU 105) has the capacity to inhibit human leukocyte elastase and/or protect gingival elastic fibers against proteolytic degradation. LU105 was extracted from seeds of L albus and is freely soluble in water. In this study the ex-vivo elastolytic activity of human leukocyte elastase and the potential inhibitory effect of LU 105 were determined using human gingival cryostat tissue sections and computerized morphometric analysis. The gingival tissue sections pre-treated or not with LU 105 were submitted to the action of human leukocyte elastase or submitted to the simultaneous action of human leukocyte elastase and LU 105, and then analyzed using automated image analysis. In such conditions, LU 105 at 0.1%, 0.01%, and 0.001% developed a dose dependent protection of gingival elastic fibers against enzymatic proteolysis due to human leukocyte elastase, and LU 105 at 0.1% or 0.01% was able to inhibit the elastolytic activity of leukocyte elastase itself. It is proposed that LU 105 is an option for the treatment of gingival inflammation in which leukocyte elastase is involved.

Role of elastin in pathologic calcification of xenograft heart valves

Bioprosthetic heart valves fabricated from glutaraldehyde crosslinked porcine aortic valves often fail because of calcific degeneration. Calcification occurs in both cusp and aortic wall portions of bioprosthetic heart valves. The purpose of this study was to discern the role of different aortic wall components in the calcification process. Thus, we selectively extracted cells and other extracellular matrix proteins from porcine aorta using trypsin/DNase/RNase, cyanogen bromide (CNBr), and sodium hydroxide (NaOH) treatments and subdermally implanted these pretreated aortas in young rats. Total DNA and phospholipid data showed complete removal of cells by CNBr and NaOH treatments, whereas trypsin/DNase/RNase treatment was effective in removing DNA but not phospholipids. As shown by amino acid data and Masson's trichrome staining, collagen was removed in CNBr and NaOH treatments. Control fresh porcine aorta calcified significantly after 21 days of implantation (Ca 26.4 +/- 2.4 microg/mg). Removal of cells and collagen from the aorta by CNBr treatment did not lead to a statistically significant reduction in aortic calcification (Ca 20.8 +/- 3.0 microg/mg). Moreover, partial degradation of elastin fibers caused by NaOH (during extraction) and trypsin treatment (after implantation) of the aorta significantly increased elastin-oriented calcification (Ca 94.4 +/- 9.3 and 58.4 +/- 4.6 microg/mg, respectively). Our results indicate that the elastin component of the aorta may undergo independent calcification irrespective of devitalized cell-mediated calcification observed in glutaraldehyde crosslinked aortas. Our results also demonstrate the importance of studying elastin-oriented calcification in decellularized elastin-rich aortic matrices currently used in tissue-engineering applications.

Smoking and skin: a study of the physical qualities and histology of skin in smokers and non-smokers

Tobacco smoke is toxic to cells and could be a factor contributing to accelerated skin ageing. The aim of this study was to provide new information on the possible effects of smoking on the physical qualities of skin and the morphology of elastic fibres. The study population consisted of 98 men, including 47 current smokers and 51 never-smokers. Skin thickness and elasticity were measured from cheek, temple, abdomen, dorsal forearm and non-sun-exposed upper inner arm. Verhoeff-stained punch biopsies from the non-sun-exposed upper inner arm were assessed with a computerized image analyser in a blinded fashion to assess the amount and width of elastic fibres. The thickness of cheek skin was increased in the smokers, but skin thickness in other measured sites did not differ between the groups. The amount and width of elastic fibres in the sun-protected skin of the smokers and non-smokers did not differ significantly, nor did skin elasticity in this or any other region under evaluation, suggesting that smoking alone affects neither the amount and width of dermal elastic fibres nor the elasticity of skin in male smokers.

Aluminum chloride pretreatment of elastin inhibits elastolysis by matrix metalloproteinases and leads to inhibition of elastin-oriented calcification

Calcification of elastin occurs in many pathological cardiovascular diseases including atherosclerosis. We have previously shown that purified elastin when subdermally implanted in rats undergoes severe calcification and aluminum chloride (AlCl(3)) pretreatment of elastin inhibits calcification. In the present study we investigated whether matrix metalloproteinase (MMP) binding to elastin and elastin degradation is prevented by AlCl(3) pretreatment. Subdermal implantation of AlCl(3)-pretreated elastin showed significantly lower MMP-9 and MMP-2 activity surrounding the implant as compared to the control implants. AlCl(3) pretreatment also significantly inhibited elastin implant calcification at the seven-day implant period (AlCl(3)-pretreated 4.07 +/- 1.27, control 23.82 +/- 2.24 microg/mg; p<0.0001). Moreover, elastin gel zymography studies showed that gel pretreatment with AlCl(3) inhibited elastolysis by MMP-9. We also demonstrate significant suppression of MMP-2 activity in aortic wall segments of AlCl(3)-pretreated porcine bioprosthetic heart valve implants as compared to control valve implants in sheep mitral valve replacement studies. AlCl(3) pretreatment also significantly inhibited calcification of elastin in this model. Thus, we conclude that aluminum ion binding to elastin prevents MMP-mediated elastolysis and thus prevents elastin calcification.

DL-penicillamine induced alteration of elastic fibers of periosteum-perichondrium and associated growth inhibition: an experimental study

Perichondrium-periosteum, being of collagen and elastic fiber, is regarded as a bone growth regulating factor. The aim of the present study was to investigate the role of collagen and elastic fibers on bone growth, by interfering with the fiber assembly in growing chicks upon administration of DL-penicillamine (DL-PNA). Our findings demonstrated that DL-PNA determined relevant modifications in the perichondrium-periosteum, as shown by histochemical, histomorphometrical,biochemical and ultrastructural analysis. This chemical has been shown to inhibit the formation of desmosine cross-links in elastin and to induce an increase of elastin associated microfibrils. On the contrary, the collagen network and the biochemical collagen markers were not affected. These changes resulted in a dramatically reduced growth of long bones in comparison with control. Perichondrial-periosteal regulation of bone growth may be mediated by mechanical and biological factors. This study demonstrates a microstructural change in the perichondrium-periosteum with decreased elastin and increased elastic microfibrils content in penicillamine treated chicks. The mechanism linking changes in the perichondrium-periosteum with altered growth still needs to be elucidated.

Effects of antihypertensive therapy on hypertensive vascular disease

Hypertension is associated with alterations in the structure, function, and mechanical properties of large and small arteries. Changes in the endothelium, smooth muscle cell, extracellular matrix, and possibly the adventitia, contribute to complications of hypertension. In large arteries, vascular hypertrophy is found, often with increased stiffness of media components. In small arteries, particularly in mild hypertension, rearrangement of smooth muscle cells around a smaller lumen without changes in media volume (eutrophic remodeling) occurs; in more severe hypertension, hypertrophic remodeling with increased vascular stiffness can be found. Vascular remodeling is accompanied by an increase in the extracellular matrix, particularly collagen deposition. Recent studies have demonstrated that vascular remodeling and endothelial dysfunction of small and large vessels may be normalized by treatment with some antihypertensive agents (angiotensin converting enzyme inhibitors, angiotensin AT(1) receptor antagonists, and long-acting calcium channel blockers). Angiotensin converting enzyme inhibitors have now been shown to improve outcomes in hypertensive patients, an effect that may in part be related to the vascular protective effects reviewed here.

Local photodynamic action of methylene blue favorably modulates the postinterventional vascular wound healing response

PURPOSE

Photodynamic therapy (PDT), the light activation of photosensitizers to produce free radicals, is known to inhibit experimental intimal hyperplasia (IH). However, its clinical application has been limited by the lack of a suitable approach and a clinically appropriate photosensitizer. The aim of this study was to determine the effectiveness of a clinical approach for PDT, while testing its ability to favorably modulate the vascular wound healing response.

METHODS

Rat carotid arteries were balloon-injured (BI), and for PDT, the arteries were irradiated with thermoneutral laser light (lambda = 660 nm, 100 J/cm(2)) after the photosensitizer methylene blue (MB) was delivered locally. Control rats included BI alone and MB after BI alone. Arteries were analyzed after 2 weeks with morphometric evaluation (n = 6) and in situ hybridization for versican and procollagen type I gene expression (digitized image pixel analyses, n = 3).

RESULTS

No IH developed in PDT-treated arteries (0 +/- 0 mm(2); compared with BI, 0.192 +/- 0.006 mm(2); P <.0001). The diameters remained unchanged (PDT, 0.95 +/- 0.04 mm; BI, 0.94 +/- 0.05 mm; uninjured artery, 0.91 +/- 0.06 mm). Arterial injury resulted in an increase of versican and procollagen type I messenger RNA (mRNA) in the adventitia and neointima. In the repopulating cells of the adventitia after PDT, there was a significant decrease in versican mRNA (% of positive pixels per high-power field: PDT, 1.13% +/- 0.39%; BI, 2.93% +/- 0.61%; P <.02), but not in procollagen type I mRNA.

CONCLUSION

The decrease of versican mRNA expression of repopulating cells after PDT reflects favorable healing on a molecular level. Site-specific delivery of MB, a clinically appropriate photosensitizer, followed by PDT represents a suitable method to promote favorable healing after balloon intervention and further supports its role for inhibiting postinterventional restenosis.

Pathological findings of tissue reactivity of gelatin resorcin formalin glue: an autopsy case report of the repair of ventricular septal perforation

A seventy-three-year-old man was treated for ventricular septal perforation with Gelatin Resorcin Formalin (GRF) glue. The patient died of multiple organ failure 36 days after the surgery. In autopsy, macroscopically, the inferior wall was reconstructed successfully by the GRF glue. Furthermore, microscopic study revealed the excellent growth of collagen and elastic fiber where the GRF was glued. No infiltration of inflammatory cells was evident. There have been no reports that the safety and efficacy of GRF glue was pathologically proven in an autopsy case.

Repair of UVA-induced elastic fiber and collagen damage by 0.05% retinaldehyde cream in an ex vivo human skin model

BACKGROUND

Cellular effects of UV exposure are implicated in cutaneous aging. UV radiations induce structural and cellular changes in all the compartments of skin.

AIM

To study the antiaging efficacy of a cream containing 0.05% retinaldehyde with an ex vivo technique using human skin in order to approximate in vivo metabolic conditions.

METHODS

Human skin explants were maintained alive in organ culture for 18 days and subjected to UVA exposure, thus simulating skin photoaging. Retinaldehyde cream was then applied to the surface of the epidermis for 2 weeks and the results were compared with those of nontreated skin explants. Dermal repair was analyzed histologically with quantification of collagen and elastic fibers, and biochemically by the measure of newly synthesized collagen as shown by adding tritiated proline to the culture medium.

RESULTS

UVA exposure induced significant alterations of collagen and elastic fibers as shown by morphometric analysis. In all UVA-exposed and then retinaldehyde-treated skin specimens, collagen and elastic fibers were restored to the level of nonexposed skin. UVA exposure induced a decrease in collagen synthesis, whereas in retinaldehyde-treated UVA-exposed skin the synthesis was similar to that of unexposed skin.

CONCLUSION

It has been shown that retinaldehyde has many of the properties of tretinoin in its biological and beneficial effects on photoaging. We have verified some of these previous observations, especially on dermal connective tissue, by obtaining significant repair of elastic fibers and collagen alteration induced by UVA exposure.

Three months use of third-generation oral contraceptives does not affect artery wall properties

In several studies, artery wall properties have been shown to differ between men and women. It has been hypothesized that these differences may result from hormonal influences but, in a previous study, we were unable to detect any influence of the menstrual cycle on artery wall properties. Therefore, we investigated the differences in artery wall properties, if any, between the menstrual cycle and the use of a third-generation oral contraceptive for 3 months. We investigated the right common carotid (CCA) and femoral (CFA) arteries of normotensive young (18-25-y-old) women volunteers (n = 14). The arterial cross-sectional distensibility and compliance coefficients were determined by means of a specially designed ultrasonic wall-tracking device and automatic brachial artery cuff blood-pressure measurements. The menstrual cycles and the cycles during oral contraceptive use (30 microg ethinylestradiol and 75 microg gestodene) were monitored by ultrasonographic evaluation and the assessment of plasma levels of 17beta-oestradiol and progesterone. The distensibility and cross-sectional compliance coefficients of both the CCA and CFA did not differ significantly between the menstrual cycle and the use of oral contraceptives, despite different ovarian hormone levels. Brachial arterial blood pressure was also not affected. We conclude that 3 months use of a third-generation oral contraceptive does not influence the wall properties of peripheral arteries and cannot explain the observed difference between genders. The absence of a rise in blood pressure and the low androgenic profile of this specific oral contraceptive may have contributed to our findings.

Action of chondroitinase ABC on epidurally transplanted nucleus pulposus in the rabbit

STUDY DESIGN

After autotransplanting the nucleus pulposus into the epidural space of rabbits, chondroitinase ABC was administered, and the effect of chondroitinase ABC was examined.

OBJECTIVES

To examine whether chondroitinase ABC accelerates resolution of the nucleus pulposus transplanted into the epidural space.

SUMMARY OF BACKGROUND DATA

No previous reports exist on the effect of chondroitinase ABC on the nucleus pulposus in the epidural space.

METHODS

In Study 1, autotransplantation of the nucleus pulposus into the epidural space was performed in rabbits. Histologic change was observed. In Study 2, dry weight, deoxyribonucleic acid content, and the amount of glycosaminoglycans of autotransplanted nucleus pulposus were quantified and compared with the respective values in the control group, chondroitinase-ABC-injected group, and phosphate-buffered saline-injected group. In Study 3, granulocytes obtained from the blood of a rabbit treated with chondroitinase ABC or phosphate-buffered saline were added to the nucleus pulposus taken from the same rabbit.

RESULTS

In chondroitinase ABC group, inflammatory cells tended to infiltrate earlier than those in the control group (Study 1). The dry weight of recollected nucleus pulposus in the chondroitinase ABC group was significantly less than in the other groups. Deoxyribonucleic acid content in the nucleus pulposus tended to be larger in the chondroitinase ABC group, although no significant difference in content compared with that in the other groups was found. Regarding the residual glycosaminoglycans in the transplanted nucleus pulposus, the amount of chondroitin sulfate markedly decreased in the chondroitinase ABC group (Study 2). The number of granulocytes infiltrating the nucleus pulposus was distinctly large in the chondroitinase ABC group (Study 3).

CONCLUSION

Chondroitinase ABC can enhance resolution of the nucleus pulposus in the epidural space.

Augmented effects of methionine and cholesterol in decreasing the elastic lamina while thickening the aortic wall in the rat aorta

1. Patients with an elevated plasma level of either homocysteine or cholesterol are at increased risk of cardiovascular disease. Both methionine, the precursor of homocysteine, and cholesterol are found primarily in the same foods; therefore we investigated the effect of methionine feeding alone, cholesterol feeding alone, and both, on the thickness of the aortic wall and the aortic elastic lamina of normotensive animals.2. Twenty normotensive rats were divided into four groups of five animals. The following diet was administered for 15 weeks: normal chow; normal chow supplemented with 2% methionine; normal chow supplemented with 2% cholesterol; normal chow supplemented with 2% methionine+2% cholesterol.3. The results showed a 3-fold decrease (P<0.003) in the aortic elastic lamina in the 2% methionine group and a 2.5-fold decrease in the 2% cholesterol group compared with the normal chow group. There was a 9-fold (P<0.0003) decrease in the 2% methionine+2% cholesterol group compared with the normal chow group. Furthermore, feeding with methionine plus cholesterol significantly increased aortic wall thickness compared with the methionine group, cholesterol group or control.4. These results demonstrate an augmented effect of cholesterol plus methionine in the deterioration of the aortic elastic lamina, and furthermore, the combination of these two agents increases the thickness of the aortic wall. The results indicate a more important role for these two agents in combination than for either agent alone.

Saccular aneurysm induction by elastase digestion of the arterial wall: a new animal model

OBJECTIVE

To develop a rabbit aneurysm model that is more realistic in gross appearance and histological features than previous models and to enable the development of a larger animal model.

METHODS

Ten rabbits received porcine pancreatic elastase, five at the right common carotid artery bifurcation and five others at the right superior thyroid artery origin. One control animal received collagenase and another received papaverine, each at the right superior thyroid artery origin. The agents were topically delivered to the arterial adventitia with a microsyringe after surgical exposure of the targeted arteries. The arteries were monitored for aneurysm growth with a video camera for up to 3 hours and were then removed and processed for histology.

RESULTS

Saccular aneurysms developed in one of five animals after elastase application at the carotid bifurcation and in all five animals receiving elastase at the superior thyroid artery origin. Among the six aneurysms, recurrent minor hemorrhages occurred in four, thrombosis of the aneurysm sac in three, and rupture causing severe bleeding in one. Histological sections revealed thin-walled aneurysms composed only of collagen fibers and some cellular elements. No saccular dilation resulted from papaverine application. Collagenase application resulted in a hemorrhagic-thrombotic lesion in the arterial wall but no aneurysm formation.

CONCLUSION

Arterial saccular aneurysms were induced in rabbits by topical application of elastase with an easy and efficient method. These aneurysms are histologically similar to natural aneurysms, and their arterial nature renders them more authentic than those of surgical models. This aneurysm model may serve as a foundation for further aneurysm research.

Comparison of topical therapy for striae alba (20% glycolic acid/0.05% tretinoin versus 20% glycolic acid/10% L-ascorbic acid)

BACKGROUND

Topical treatment of striae rubra with 0.1% tretinoin and laser treatment of striae rubra and alba with the 585-nm pulsed dye laser are proven therapeutic options. However, little efficacy has been shown for treatment of striae alba topically, and the laser is currently not a suitable treatment option for darker ethnic skin types.

OBJECTIVE

The purpose of this study was to demonstrate that selected commercial topical agents can improve the appearance of striae alba.

METHODS

Ten patients of varying skin types (I-V) having straie distensae alba on the abdomen or thighs were selected to evaluate the effectiveness of two topical treatment regimens. Patients were placed on daily topical application of 20% glycolic acid (MD Forte) to the entire treatment area. In addition, the patients applied 10% L-ascorbic acid, 2% zinc sulfate, and 0.5% tyrosine to half to the treatment area and 0.05% tretinoin emollient cream (Renova) to the other half of the treatment area. The creams were applied on a daily basis for 12 weeks. Improvement was evaluated at 4 and 12 weeks in an objective unblinded fashion at the follow-up visits, a objective blinded fashion by visual grading at the conclusion of the study, and in an objective blinded fashion with profilometry. Additionally, histopathologic analysis was performed.

RESULTS

Analysis of these data reveals: 1) both regimens can improve the appearance of stretch marks; 2) these topical therapy regimens are safe and effective in study patients with minimal irritation; 3) elastin content within the reticular and papillary dermis can increase with topical 20% glycolic acid combined with 0.05% tretinoin emollient cream therapy; 4) both regimens increased epidermal thickness and decreased papillary dermal thickness in treated stretch marks when compared with untreated stretch marks; 5) combined epidermal and papillary dermal thickness in stretch marks treated with either topical regimen approaches that of normal skin; and 6) profilometry can objectively measure differences in skin texture associated with striae treatments when compared to controls, however, it is not sensitive enough to justify comparison or quantitative improvements between similarly effective treatments.

Mechanical role of elastin-associated microfibrils in pig aortic elastic tissue

The contribution of microfibrils to the mechanical performance of the meshwork of elastic tissue in mature pig aorta was investigated by comparing the properties of autoclaved tissue containing elastin and microfibrils with autoclaved tissue that had been treated with dithiothreitol (DTT) or hot alkali to remove the microfibrils from the elastin. The uniaxial tensile stress-strain curve of the autoclaved tissue was linear to a strain of 0.6 or 0.7 and increased nonlinearly up to the breaking strain. The nonlinearity at high strains could not be accounted for by nonGaussian behavior and was attributed to the progressive alignment of the elastic fibers with strain. Removal of the microfibrils with DTT or treatment with calcium reduced the modulus at low strains by 12% and 4% respectively and increased the modulus at high strains, suggesting that the microfibrils have the capacity to change the orientation of the elastin fibers, possibly transmitting some of the load from one elastin fiber to another. Our findings suggest two possible roles for the microfibrils in vivo: distributing the load throughout the elastic fibers of the arterial wall and direct load bearing. The modulus and the breaking stress of the rings decreased linearly with the duration of alkali treatment starting immediately. By 45 min the modulus had dropped by 30% and the breaking stress by 50%, even though the amino acid content of the extract gave little evidence of elastin hydrolysis. Alkali treatment should not be used on autoclaved pig aortic tissue to be used for mechanical testing.

Preferential binding of lysozyme to elastic fibres in pulmonary emphysema

BACKGROUND

Lysozyme is increased in inflammatory reactions and is a component of the extracellular matrix, but its possible role in lung diseases such as emphysema and interstitial fibrosis has not been investigated.

METHODS

To characterise differences in lysozyme content among normal, emphysematous, and fibrotic human lungs, tissue sections obtained from necropsy specimens were immunostained with rabbit polyclonal anti-human lysozyme antibody using the labelled streptavidin-biotin peroxidase method. The immunostained sections were evaluated semi-quantitatively (grading the degree of immunostaining on a scale of 0-4). To determine if degradation of the extracellular matrix affects lysozyme binding, hyaluronidase-treated normal lung tissues were incubated with egg white lysozyme, immunostained with the lysozyme antibody, which crossreacts with egg white lysozyme, and evaluated for degree of staining.

RESULTS

Lysozyme immunostaining was significantly increased in lungs with pulmonary emphysema compared with normal or fibrotic tissues (3.4 versus 1.6 and 1.9, respectively; p < 0.05) and was preferentially associated with interstitial elastic fibres. Hyaluronidase-treated lung tissues incubated with lysozyme showed increased immunostaining for this protein compared with untreated controls (1.9 versus 1.2; p < 0.05).

CONCLUSIONS

The results suggest that damage to elastic fibres and/or the surrounding extracellular matrix increases lysozyme binding. It is hypothesised that attachment of lysozyme to elastic fibres may interfere with their repair and possibly enhance the progression of pulmonary emphysema.

Tenascin expression in elastotic cuffs of invasive ductal carcinoma of the breast

We studied immunohistochemically one thousand one hundred and thirty-seven cases of primary invasive breast cancers (NST) and adjacent normal mammary glands for tenascin expression, and compared their elastic content to verify if a relationship exists between tenascin expression and elastosis. Periductal, perivascular and stromal elastosis were graded on a scale from 0 to 3 (absent to massive). All carcinomas showed tenascin expression and elastosis with various histological appearances. In the adjacent breast, teanscon was distributed around the normal ducts or with extasia and uctal hyperplasia without atypia. Digestion of the sections with elastase prior to staining resulted in a loss of the specific staining reactions in all areas where elastosis was present. Tenascin staining was observed in the mesenchyme closely surrounding the neoplastic ducts and the cancer cell nests. Stromal tenascin staining appeared stronger in those carcinomas that exhibited marked desmoplastic reactions. The highly differentiated tumours contained more elastosis in their tumour tissue than the poorly differentiated ones, whereas tenascin expression was stronger in poorly differentiated tumours than well differentiated tumours. A strong staining for tenascin was observed in the elastotic cuff. Tenascin staining did not disappear afterwards with elastase. We did not find a statistically significant correlation between tenascin expression, elastosis and prognostic factors such as size of the tumour, lymph node metastasis, tumour necrosis and age. In our study tenascin proved to be an additional element in elastotic areas even though the significance of an association between elastosis and tenascin is still unknown, as is that of elastosis itself.

Differential distribution of elastic system fibers in control and bronchoconstricted intraparenchymatous airways in the guinea-pig lung

The elastic system fibers were studied at the light microscopic level by using Weigert's resorcin-fuchsin method after oxidation. This study was designed to describe the distribution of these fibers in intrapulmonary guinea-pig airways and to characterize their conformational changes during bronchoconstriction induced by methacholine aerosol. Airways present a palisade of elastic system fibers just beneath the epithelial basement membrane; these fibers are also present in the adventitial connective tissue. Thin fibers link the fibers located in the palisade among themselves and also connect them to those fibers located in the bronchial adventitial tissue, by traversing the airway smooth muscle. During bronchoconstriction, the fibers located beneath the epithelial basement membrane are divided into two components: one follows the epithelial invaginations towards airway lumen, while the other population remains attached through airway smooth muscle to the fibers located in the adventitial connective tissue. At the ultrastructural level, the findings corroborated those of the light microscopy and in addition, disclosed that typical mature elastic fibers and also elaunin fibers attach directly to the basal lamina, a feature that has not been reported previously in other tissues studied. This configuration is compatible with the idea that fibers of the elastic system restrict the mucosal folding during bronchoconstriction, and may also provide energy to restore airway configuration to its normal status after contraction.