Density Of Elastic Fibers Research Articles

Postnatal overnutrition affects metabolic and vascular function reflected by physiological and histological changes in the aorta of adult Wistar rats

ABSTRACTRigorous nutritional care during early life leads to healthy adulthood. Cardiovascular and metabolic disorders, the most prevalent clinical challenges worldwide, are epidemiologically linked to poor nutritional habits throughout life. We aimed to understand whether postnatal overnutrition (PO) initiated during lactation affects metabolic markers and vascular function later in life. To test this hypothetical effect, we studied a PO Wistar rat model based on adjusting litter size at the third day of age to three pups and eight for the control group (C). Systemic parameters such as body weight and food intake were significantly increased in adult rats, measured up to 36 weeks. Moreover, fat mass, triglycerides, insulin and systolic blood pressure were all significantly increased in the PO group. Furthermore, we assessed whether these alterations would affect morphological and functional parameters in isolated vessels. Consistent with systemic alterations of the vasculature, contraction of thoracic aortic rings, determined by dose-response curves to norepinephrine (NE), was significantly reduced in PO rats. Histological stains revealed that the relative area of collagen was higher and the elastic fiber density was lower in the distal rings of PO rats. Altogether, our results highlight the critical importance of having a healthy neonatal nutrition to prevent harmful metabolic and vascular alterations during adulthood.

Histologic and biochemical alterations predict pulmonary mechanical dysfunction in aging mice with chronic lung inflammation.

Both aging and chronic inflammation produce complex structural and biochemical alterations to the lung known to impact work of breathing. Mice deficient in surfactant protein D (Sftpd) develop progressive age-related lung pathology characterized by tissue destruction/remodeling, accumulation of foamy macrophages and alteration in surfactant composition. This study proposes to relate changes in tissue structure seen in normal aging and in chronic inflammation to altered lung mechanics using a computational model. Alterations in lung function in aging and Sftpd -/- mice have been inferred from fitting simple mechanical models to respiratory impedance data (Zrs), however interpretation has been confounded by the simultaneous presence of multiple coexisting pathophysiologic processes. In contrast to the inverse modeling approach, this study uses simulation from experimental measurements to recapitulate how aging and inflammation alter Zrs. Histologic and mechanical measurements were made in C57BL6/J mice and congenic Sftpd-/- mice at 8, 27 and 80 weeks of age (n = 8/group). An anatomic computational model based on published airway morphometry was developed and Zrs was simulated between 0.5 and 20 Hz. End expiratory pressure dependent changes in airway caliber and recruitment were estimated from mechanical measurements. Tissue elements were simulated using the constant phase model of viscoelasticity. Baseline elastance distribution was estimated in 8-week-old wild type mice, and stochastically varied for each condition based on experimentally measured alteration in elastic fiber composition, alveolar geometry and surfactant composition. Weighing reduction in model error against increasing model complexity allowed for identification of essential features underlying mechanical pathology and their contribution to Zrs. Using a maximum likelihood approach, alteration in lung recruitment and diminished elastic fiber density were shown predictive of mechanical alteration at airway opening, to a greater extent than overt acinar wall destruction. Model-predicted deficits in PEEP-dependent lung recruitment correlate with altered lung lining fluid composition independent of age or genotype.

Evidence for age-dependent air-space enlargement contributing to loss of lung tissue elastic recoil pressure and increased shear modulus in older age.

As a normal part of mature aging, lung tissue undergoes microstructural changes such as alveolar air-space enlargement and redistribution of collagen and elastin away from the alveolar duct. The older lung also experiences an associated decrease in elastic recoil pressure and an increase in specific tissue elastic moduli, but how this relates mechanistically to microstructural remodeling is not well-understood. In this study, we use a structure-based mechanics analysis to elucidate the contributions of age-related air-space enlargement and redistribution of elastin and collagen to loss of lung elastic recoil pressure and increase in tissue elastic moduli. Our results show that age-related geometric changes can result in reduction of elastic recoil pressure and increase in shear and bulk moduli, which is consistent with published experimental data. All elastic moduli were sensitive to the distribution of stiffness (representing elastic fiber density) in the alveolar wall, with homogenous stiffness near the duct and through the septae resulting in a more compliant tissue. The preferential distribution of elastic proteins around the alveolar duct in the healthy young adult lung therefore provides for a more elastic tissue.NEW & NOTEWORTHY We use a structure-based mechanics analysis to correlate air-space enlargement and redistribution of elastin and collagen to age-related changes in the mechanical behavior of lung parenchyma. Our study highlights that both the cause (redistribution of elastin and collagen) and the structural effect (alveolar air-space enlargement) contribute to decline in lung tissue elastic recoil with age; these results are consistent with published data and provide a new avenue for understanding the mechanics of the older lung.

The composition and biomechanical properties of human cryopreserved aortas, pulmonary trunks, and aortic and pulmonary cusps

Human cryopreserved allografts of pulmonary and aortic heart valves, aortas and pulmonary trunks are used for valve replacement. However, it is unknown how the composition of these allografts relate to their mechanical properties. Our aims were to correlate the histological compositions and passive mechanical properties of aortic and pulmonary valves and to observe the microcracks of aortas and pulmonary trunks. The following parameters were quantified: ultimate stress; ultimate strain; Young’s modulus of elasticity; valve cusp wall thickness; pulmonary and aortic intima-media thickness; area fraction of elastin, collagen and calcification; and length density of elastic fibres. The propagation of experimentally induced microcracks avoided elastic fibres. Ultimate strain was negatively correlated with the area fraction of calcification (r=−0.4) in aortas. Ultimate stress (r=0.27) and Young’s modulus in small deformation (r=0.29) and in large deformation (r=0.32) correlated with wall thickness in valve cusps. Young’s modulus (r=0.34) and ultimate strain (r=0.31) correlated with intima-media thickness. Ultimate strain correlated with the area fraction of elastin (r=−0.40) and collagen in the arteries (r=0.31). As conventional histology does not fully explain the mechanical properties of cryopreserved grafts, both morphological and biomechanical tests should be used complementarily when characterizing the ageing of the grafts.

Idiopathic atrophoderma of Pasini and Pierini: A case study of collagen and elastin texture by multiphoton microscopy

The diagnosis of idiopathic atrophoderma of Pasini and Pierini (IAPP) relies on typicalclinical features, particularly distinctive pigmented ovular/round depressed plaques. Histologic examination often reveals no obvious changes, but patterns of collagen distribution, using multiphoton imaging and second harmonic generation can help track hidden details of tissue organization contributing to atrophy. To identify histologic features that distinguish IAPP from unaffected skin. Eleven patients were included for conventional analyses. Masson trichrome- and Unna-Tanzer orcein-stained sections were evaluated using automated morphometry. Hematoxylin-eosin-stained sections were analyzed by multiphoton imaging using 2-photon excited fluorescence and second harmonic generation. No abnormalities were found under light microscopy or by automated quantification. Multiphoton imaging revealed no difference in optical density of either collagen or elastic fibers in lesioned and unaffected skin; however, horizontal collagen fiber organization in lesion specimens increased toward the lower dermis, whereas elastic fibers featured greater disorganization within the upper dermis. The low number of patients evaluated. The atrophic appearance of IAPP lesions reflects changes in organization, but not in collagen and elastic tissue content. Minute organizational differences that are imperceptible to the experienced pathologist and undetectable by automated analyses were revealed by multiphoton analyses, particularly second harmonic generation, in association with texture analyses.

Effects of castration on penile extracellular matrix morphology in domestic cats.

Objectives This study was undertaken to verify the possible modifications caused by hormonal deprivation in the extracellular matrix in the penises of neutered cats. Methods Twenty-seven penises from domestic shorthair cats were collected: 14 samples from intact cats and 13 from neutered cats. Sections were stained with Weigert's resorcin-fuchsin, hematoxylin and eosin, and picrosirius red. Histomorphometric analysis was performed using light microscopy and image analysis software. The following parameters were analyzed: density of the elastic fibers and collagen fibers in the corpus spongiosum; density of the elastic fibers in the tunica albuginea of the corpus cavernosum and the tunica albuginea of the corpus spongiosum; luminal area of the urethra; area of the corpus spongiosum; area of the corpus cavernosum; and thickness of the urethral epithelium. The data were analyzed using the Shapiro-Wilk test to verify the normal distribution, and groups were compared using Student's t-test; P <0.05 indicated statistically significant differences. Results Significant differences were observed between intact cats and neutered cats in the density of elastic fibers in the tunica albuginea of the corpus cavernosum (8.13% ± 1.38% vs 3.11% ± 0.66%), tunica albuginea of the corpus spongiosum (4.37% ± 1.08% vs 3.30% ± 1.01%) and corpus spongiosum (6.28% ± 3.03% vs 4.10% ± 2.19%), and density of collagen fibers in the corpus spongiosum (34.11% ± 10.86% vs 44.21% ± 12.72%). Conclusions and relevance The results show a significant decrease in the density of the elastic fibers and a significant increase of the density of the collagen fibers in the corpus spongiosum in neutered animals. This suggests that the compliance of the periurethral region is reduced, and these changes could be a predisposing factor for urethral obstructive disease.

The Histopathological Findings of Patients Who Underwent Blepharoplasty Due to Dermatochalasis

ABSTRACTPurpose: To assess changes in lymphatic vessels, collagen, and elastic fiber structure in excised tissues with dermatochalasis (DC). Methods: In this prospective histopathological study, 70 upper eyelid skins of 35 patients operated on for dermatochalasis were compared with 10 eyelid skins of 10 patients operated on for other diagnoses. In histopathological examination, the two groups of patients were compared with respect to number of lymphatic vessels, largest lymphatic vessel diameter, number of elastic fibers, number of macrophages, edema between collagen fibers, and depth of stromal collagen bed. Results: As compared to the control group, the study group had a significantly greater number of dilated lymphatic vessels (p = 0.0001), largest lymphatic vessel diameter (p = 0.02), depth of stromal collagen bed (p = 0.0001), edema space between collagen fibers (p = 0.0001), elastic fiber density (p = 0.0001), and number of macrophages (p = 0.001). Conclusion: According to the results of the present study, in addition to an increase in the diameter and number of lymphatic vessels, a reduction in elastic fibers that are essential for the structure and function of lymphatic system, disarrangement in collagen fibers, stromal edema, and increased number of macrophages play a role in the development of dermatochalasis.

Morphologic Changes in the Dermis After the Single Administration of Autologous Fibroblastic Cells: A Preliminary Study.

Aging is a multifactorial process defined by an accumulation of damage in all tissues and organs, including the skin, throughout the lifespan of an individual. The reduction of both cellular and extracellular matrix components of the dermis during the aging process is followed by the alteration of the morphology of the skin tissue. This study was conducted to assess skin morphology in men before and 3 months after the intradermal injection of autologous fibroblastic cells. Tissue biopsies were surgically obtained before and 3 months after the treatment with autogenously harvested fibroblasts expanded invitro, as well as after injection of phosphate-buffered saline. The thickness of collagen fiber bundles and number of fibroblasts in the dermis were analyzed in morphometric studies. The morphologic evaluation, using different methods of staining has been performed to analyze of extracellular matrix proteins, including collagen and reticular fibers, fibrillin-1-rich microfibrils, elastic fibers, and hyaluronic acid. After administration of the cells, we found a noticeable increase in the number of fibroblasts within the dermis, a significant enlargement in diameter of the collagen fiber bundles, and an improvement in the density of reticular fibers, fibrillin-1-rich microfibrils, and elastic fibers compared with the initial, steady-state condition. The administration of autogenous fibroblasts could be an effective and safe adjunctive therapy to conventional health care treatment to prevent and reduce the age-related accumulation of dermal tissue damage.

Short-term esmolol attenuates remodeling of the thoracic aorta in hypertensive rats by decreasing concentrations of ADMA down-regulated by oxidative stress

Esmolol produces early regression of left ventricular hypertrophy and improves coronary artery remodeling, although the impact of short-term treatment with this beta-blocker on remodeling in large arteries has not yet been studied. We hypothesized that even a short (48h) course of esmolol might alter remodeling of the aorta in the spontaneously hypertensive rat (SHR). Fourteen-month-old male SHRs were treated intravenously with vehicle (SHR, n=8) or esmolol (SHR-E, n=8) (300μg/kg/min). Age-matched, vehicle-treated male Wistar-Kyoto rats (WKY, n=8) served as controls. After 48h, we studied the structure, volume density of elastic fibers, and passive mechanical properties of the aorta. Determination of asymmetrical dimethylarginine concentrations and total protein carbonyls in the aorta were analyzed. Esmolol significantly attenuated abnormal aortic wall thickness, cross-sectional area, wall-to-lumen ratio, volume density of elastic fibers, and wall stiffness. The protective effect of esmolol could be related to a decrease in asymmetrical dimethylarginine levels after down-regulation by oxidative stress. These findings could play a key role in the selection of antihypertensive therapy in patients with hypertension and aortic remodeling.

Atherosclerosis in the circle of Willis: Spatial differences in composition and in distribution of plaques

Background and aimsIntracranial atherosclerosis is one of the main causes of ischemic stroke. However, the characteristics of intracranial arteries and atherosclerosis have rarely been studied. Therefore, we systematically investigated atherosclerotic changes in all arteries of the Circle of Willis (CoW). MethodsSixty-seven CoWs obtained at autopsy from randomly chosen hospital patients (mean age, 67.3 ± 12.5 years), of which a total of 1220 segments were collected from 22 sites. Atherosclerotic plaques were classified according to the revised American Heart Association classification and were related to local vessel characteristics, such as the presence of an external and internal elastic lamina and the elastic fibre density of the media. Results181 out of the 1220 segments had advanced plaques (15%), which were mainly observed in large arteries such as the internal carotid, middle cerebral, basilar and vertebral artery. Only 11 out of 1220 segments (1%) showed complicated plaques (p < 0.001). Six of these were intraplaque hemorrhages (IPH) and observed only in patients who had cardiovascular-related events (p = 0.015). The frequency of characteristics such as the external elastic lamina and a high elastin fibre density in the media was most often associated with the vertebral artery. Only 3% (n = 33) of the CoW arteries contained calcification (p < 0.001), which were mostly observed in the vertebral artery (n = 13, 12%). ConclusionsAdvanced atherosclerotic plaques in the CoW are relatively scarce and mainly located in the 4 large arteries, and mostly characterized by an early and stable phenotype, a low calcific burden, and a low frequency of IPH.

Frequency of cutis laxa-like clinical features and elastolysis in scleromyxedema: a retrospective clinicopathologic study of 19 patients with scleromyxedema.

Cutis laxa-like features were observed in a subset of patients with scleromyxedema. Given this observation, clinical and histopathologic features of scleromyxedema were reviewed in correlation with elastic tissue staining. We retrospectively reviewed clinical records and histopathologic features from patients with scleromyxedema seen at our institution from 1992 through 2013. We also evaluated available skin biopsies with an elastin stain and assessed whether dermal elastin fibers were diminished in density or were fragmented (or both). Nineteen patients with scleromyxedema and 34 skin biopsies were identified. Alcian blue (mucin) stain was used to grade mucin deposition as weakly positive (24%), positive (44%) and markedly positive (32%). Eight patients (42%) had clinical findings of cutis laxa, which were often observed in conjunction with areas of papular eruption or induration. Elastic tissue fibers were normal in 9 of 34 skin specimens (26%), 18 of 34 specimens (53%) had diminished elastic fiber density and 7 of 34 (21%) had markedly decreased density. The elastic tissue was fragmented in 25 specimens (74%). A cutis laxa-like clinical presentation and decreased elastic tissue density on skin biopsy were consistent findings. Dermatologists and dermatopathologists should be aware of these previously unreported clinical and histopathologic findings.

Assessment of collagen and elastic fibres in various stages of oral submucous fibrosis using Masson's trichrome, Verhoeff vangieson and picrosirius staining under light and polarizing microscopy

Background: Oral Submucous Fibrosis (OSMF) is a collagen related disorder seen in habitual betel-quid chewers. This is a high risk precancerous condition which clinically presents vertical palpable fibrous bands in buccal mucosa, generalized fibrosis of oral soft tissues with restricted mouth opening. Present study was undertaken to ascertain the changes occurring in collagen type I & III and elastic fibres in OSMF in relation to orientation, density and thickness. Study Methods: The study was performed on 15 cases in each group such as Stage I OSMF, Stage II OSMF, Stage III OSMF and normal oral mucosa (NOM). The biopsied samples were routinely processed for paraffin embedding; stained with Hematoxylin and Eosin as well as special stains like Masson's Trichrome (MT), Verhoeff Van Gieson (VVG) and Picrosirius red (PSR) and examined under light and polarized microscope respectively. MT stain demonstrated all types of collagen fibers collectively while PSR stain under polarized microscopy demonstrated collagen type I and type III separately with enhanced birefringence. VVG stain demonstrated very fine black colored elastic fibers, thus changes taken place could be accurately ascertained with progression of the disease. Results: Change in the orientation of collagen type I has been observed in stage II and stage III of OSMF from haphazard to parallel in relation to surface epithelium, while no change was noted in type III collagen fibres as well as elastic fibres in any stage of OSMF, and remained haphazardly arranged. Increased density of type I collagen was observed with increasing stage of OSMF from moderately dense to dense, while decrease in density of type III collagen was noticed in stage III than in stage II OSMF from moderately dense to sparse. The density of elastic fibres was decreasing from dense in stage I to sparse in stage III. Thickness of collagen type I was increasing with increasing grades while type III collagen and elastic fibres remained unchanged. Conclusion: The alterations in orientation, density and thickness of collagen fibres and density of elastic fibres in various grades of OSMF contribute to the clinical presentation of trismus with progression of the disease. Key Words: Collagen type I, Collagen type III, Elastic fibres, Masson's trichrome stain, Verhoeff Van Gieson stain, Picrosirius red stain

Effects of aging on the architecture of the ileocecal junction in rats.

To evaluate the structural organization of the elastic and collagen fibers in the region of the ileocecal transition in 30 young and old male Wistar rats. Histology, immunohistochemistry (IHC), transmission electron microscopy and scanning electron microscopy were employed in this study. The results demonstrated that there was a demarcation of the ileocecal region between the ileum and the cecum in both groups. The connective tissue fibers had different distribution patterns in the two groups. IHC revealed the presence of nitric oxide synthase, enteric neurons and smooth muscle fibers in the ileocecal junctions (ICJs) of both groups. Compared to the young group, the elderly group exhibited an increase in collagen type I fibers, a decrease in collagen type III fibers, a decreased linear density of oxytalan elastic fibers, and a greater linear density of elaunin and mature elastic fibers. The results revealed changes in the patterns of distribution of collagen and elastic fibers that may lead to a possible decrease in ICJ functionality.

Vascular and ductal elastotic changes in pancreatic cancer.

This study aims to identify and define the type and frequency of elastotic alterations of vessels and ducts in pancreatic ductal carcinoma (PDAC) and evaluate its diagnostic significance. Representative tissue from 36 Whipple specimens, stained with Verhoeff's Van-Gieson, was studied focusing on the density and distribution of elastic fibers in walls of vessels and ducts, in perivascular and periductal tissue and in tumor stroma. Vessels and ducts within the carcinoma, at tumor periphery and in non-tumoral pancreas were grouped and examined separately. Vimentin and α-SMA immunostains were used for the depiction of fibroblasts and myofibroblasts. Histochemistry revealed mild to severe elastotic changes of vessels and ducts in all examined cases. Vascular and ductal elastosis was more prominent within the tumor and diminished at tumor periphery. In tumor stroma and non-tumoral pancreatic tissue mild or no elastosis was identified. α-SMA+ cells were observed in large numbers in tumor stroma and as a ring around carcinomatous structures. There were scant α-SMA+ cells around elastotic and non-elastotic vessels. Conclusively, vascular and ductal elastosis is a tumor-associated phenomenon in PDAC. Its presence is indicative of benignity acquiring a possible diagnostic role.

Implantation of Autologous Adipose Tissue-Derived Mesenchymal Stem Cells in Foot Fat Pad in Rats.

The foot fat pad (FFP) bears body weight and may become a source of foot pain during aging. This study investigated the regenerative effects of autologous adipose tissue-derived mesenchymal stem cells (AT-MSCs) in the FFP of rats. Fat tissue was harvested from a total of 30 male Sprague-Dawley rats for isolation of AT-MSCs. The cells were cultured, adipogenic differentiation was induced for 1 week, and the AT-MSCs were labeled with fluorescent dye before injection. AT-MSCs (5 × 10(4) in 50 µL of saline) were injected into the second infradigital pad in the right hindfoot of the rat of origin. Saline only (50 µL) was injected into the corresponding fat pad in the left hind paw of each rat. Rats (n = 10) were euthanized at 1, 2, and 3 weeks, and the second infradigital fat pads were dissected for histologic examination. The fluorescence-labeled AT-MSCs were present in the foot pads throughout the 3-week experimental period. On histologic testing, the area of fat pad units (FPUs) in the fat pads that received AT-MSC injections was greater than that in the control fat pads. Although the thickness of septae was not changed by AT-MSC injections, the density of elastic fibers in the septae was increased in the fat pads with implanted AT-MSCs. In this short-term study, the implanted AT-MSCs largely survived and might have stimulated the expansion of individual FPUs and increased the density of elastic fibers in the FFP in this rat model. These data support the development of stem cell therapies for age-associated degeneration in FFP in humans.

Mesenchymal stem cells and their secretome partially restore nerve and urethral function in a dual muscle and nerve injury stress urinary incontinence model.

Childbirth injures muscles and nerves responsible for urinary continence. Mesenchymal stem cells (MSCs) or their secretome given systemically could provide therapeutic benefit for this complex multisite injury. We investigated whether MSCs or their secretome, as collected from cell culture, facilitate recovery from simulated childbirth injury. Age-matched female Sprague-Dawley rats received pudendal nerve crush and vaginal distension (PNC+VD) and a single intravenous (iv) injection of 2 million MSCs or saline. Controls received sham injury and iv saline. Additional rats received PNC+VD and a single intraperitoneal (ip) injection of concentrated media conditioned by MSCs (CCM) or concentrated control media (CM). Controls received a sham injury and ip CM. Urethral and nerve function were assessed with leak point pressure (LPP) and pudendal nerve sensory branch potential (PNSBP) recordings 3 wk after injury. Urethral and pudendal nerve anatomy were assessed qualitatively by blinded investigators. Quantitative data were analyzed using one-way ANOVA and Holm-Sidak post hoc tests with P < 0.05 indicating significant differences. Both LPP and PNSBP were significantly decreased 3 wk after PNC+VD with saline or CM compared with sham-injured rats, but not with MSC or CCM. Elastic fiber density in the urethra increased and changed in orientation after PNC+VD, with a greater increase in elastic fibers with MSC or CCM. Pudendal nerve fascicles were less dense and irregularly shaped after PNC+VD and had reduced pathology with MSC or CCM. MSC and CCM provide similar protective effects after PNC+VD, suggesting that MSCs act via their secretions in this dual muscle and nerve injury.

Histological comparison of two cryopeeling methods for photodamaged skin.

Background. Cryopeeling is a technique that uses cryotherapy not only on actinic keratoses lesions, but also all over the photodamaged skin. Objectives. To investigate the histological changes induced by two cryopeeling methods (liquid nitrogen (LN) and portable system (PS)). Methods. Sixteen patients (n = 16) with multiple actinic keratoses on the forearms were treated with cryopeeling technique using LN for one forearm and PS for the other, randomly. Skin biopsies were taken before and after the procedures. Results. There was no statistical difference between the epidermal and Grenz zone thicknesses or density of elastic fibers after treatments. The amount of melanin pigment was lower after PS treatment (P < 0.05). In a blind analysis of paired pre- and postprocedure slides, it was not possible to identify cases which underwent treatment, both in global analysis of quality of the skin and in specific analysis (considering only the aspect of stratum corneum). Discussion. The results indicate the inconsistency of histological improvement after treatments, and, likely, since the method causes superficial exfoliation, a reliable marker was not found in the analysis. Conclusions. Despite cosmetic benefits on photodamaged skin and efficient treatment of actinic keratoses lesions, cryopeeling was not able to induce measurable histological changes in solar elastosis, epidermal organization, or epidermal and Grenz zone thicknesses. One should keep in mind the possibility of hypopigmentation risk of the method.

Stereological study of the elastic fiber and smooth muscle cell system in the bovine and buffalo penis

Samples of ten penises of Mediterranean buffaloes and ten penises of Red Sindhi cattle were used. The thickness of the tunica albuginea (TA), distribution of smooth muscle cells (SMC) and volume density (Vv) of elastic system fibers in TA, corpus cavernosum (CC) and corpus spongiosum (CS) were evaluated. The Vv of elastic system fibers in buffalo and bovine penis was respectively 4.07% ±0.88% and 3.36% ±1.21% in TA; 17.32% ±2.21% and 13.14% ±1.27% (CC), 26.58% ±4.31% and 31.36% ±3.67% (CS). The CC of buffalo presented higher Vv of elastic fibers than bovine, while in the CS the Vv of elastic fibers in buffaloes was smaller than in cattle. The TA thickness showed a significant difference among the species studied. The arrangement of SMC in the bovine penises and in the water buffalo suggests that this pattern is common to animals that have fibroelastic penises.

Expression of Hypoxia-inducible Factor-1α, Vascular Endothelial Growth Factor, and Matrix Metalloproteinases 1, 3, and 9 in Hypertrophied Ligamentum Flavum

Immunohistological study. To elucidate the role of matrix metalloproteinases (MMPs), hypoxia-inducible factor-1α (HIF), and vascular endothelial growth factor (VEGF) in the hypertrophied ligamentum flavum (LF) obtained from patients with lumbar spinal stenosis (LSS). The most common spinal disorder in the elderly is LSS, which results in part from LF hypertrophy. Although prior histologic and immunochemical studies have been performed in this area, the pathophysiology of loss of elasticity and hypertrophy is not completely understood. LF samples of 38 patients with LSS were harvested during spinal decompression. Twelve LF samples obtained from patients with disk herniation and no visible degeneration on preoperative magnetic resonance imaging were obtained as controls. Samples were dehydrated and paraffin embedded. For immunohistochemical determination of VEGF, HIF, and MMPs 1, 3, and 9 expression, slices were stained with VEGF, HIF, and MMP antibody dilution. Neovessel density and number of elastic fibers were counted after Masson-Goldner staining. LF hypertrophy and cross-sectional area (CSA) were measured on T1-weighted magnetic resonance imaging. MMPs 1, 3, 9 and VEGF expression were significantly increased in the hypertrophy group (P<0.05). HIF expression was negative in both groups. Vessel density was increased in the hypertrophy group, although this was not statistically significant. The number of elastic fibres was significantly higher in the control group. In the hypertrophy group, LF thickness was significantly increased, whereas CSA was significantly decreased. There was a statistical correlation between LF thickness, CSA, MMP, and VEGF expression in the hypertrophy group (P<0.05). LF hypertrophy is accompanied by increased MMPs 1, 3, 9 and VEGF expression. Neovessel density is increased in hypertrophied LF. HIF is not expressed in hypertrophied LF.

Coexistence of Elastic Fibers with Hyaluronic Acid in the Human Urethral Sphincter Complex: A Histological Study

To promote the prevention and treatment of urethral sphincteric dysfunction, we examined the distribution of elastic fibers around the urethral sphincter complex and the histological localization of hyaluronic acid in relation to elastic fiber architecture. Using elastica-Masson staining as well as biotinated hyaluronic acid binding protein, we examined specimens of the urethral sphincter complex obtained from 14 elderly Japanese cadavers, including 10 men and 4 women. As a control, we also observed other striated muscles in male cadavers. Elastic fibers were densely distributed throughout the submucosal and smooth muscle layers along the entire length of the male urethra, including the prostatic urethra. The levator ani fascia and rhabdosphincter also contained abundant elastic fibers. An intramuscular elastic net was seen in the rhabdosphincter but not in other striated muscles. Strong staining for hyaluronic acid was evident in the submucosa and smooth muscle sphincter of the urethra but not in the levator ani fascia or rhabdosphincter, suggesting that elastic fibers and hyaluronic acid might interact at the former sites. Gender related differences in the distribution of elastic fibers and hyaluronic acid were noted with a much lower density of elastic fibers and hyaluronic acid staining in women than in men. Urethral sites where elastic fibers and hyaluronic acid coexist could be targeted for the prevention and treatment of urethral sphincteric insufficiency. These findings should improve our understanding of the human urethral sphincter complex.