Tissue Collagen Content Research Articles

Current Literature Review.

Current Literature Review.

Enamel Matrix Derivative Promotes Healing of a Surgical Wound in the Rat Oral Mucosa.

Enamel matrix proteins (EMPs) play a role in enamel formation and the development of the periodontium. Sporadic clinical observations of periodontal regeneration treatments with enamel matrix derivative (EMD), a commercial formulation of EMPs, suggest that it also promotes post-surgical healing of soft tissues. In vitro studies showed that EMD stimulates various cellular effects, which could potentially enhance wound healing. This study examines the in vivo effects of EMD on healing of an oral mucosa surgical wound in rats. A bilateral oral mucosa wound was created via a crestal incision in the anterior edentulous maxilla of Sprague-Dawley rats. Full-thickness flaps were raised, and, after suturing, EMD was injected underneath the soft tissues on one side, whereas the EMD vehicle was injected in the contralateral side. Animals were sacrificed after 5 or 9 days, and the wound area was subjected to histologic and immunohistochemical analysis of the epithelial gap, number of macrophages, blood vessels, proliferating cells, and collagen content in the connective tissue (CT). Gene expression analysis was also conducted 2 days post-surgery. EMD had no effect on the epithelial gap of the wound. On both days 5 and 9, EMD treatment increased significantly the number of blood vessels and the collagen content. EMD also enhanced (by 20% to 40%) the expression of transforming growth factors β1 and β2, vascular endothelial growth factor, interleukin-1β, matrix metalloproteinase-1, versican, and fibronectin. EMD improves oral mucosa incisional wound healing by promoting formation of blood vessels and collagen fibers in CT.

Quantitative Assessment of Optical Properties in Healthy Cartilage and Repair Tissue by Optical Coherence Tomography and Histology

Quantification of the OCT signal is an important step toward clinical implementation of a diagnostic tool in cartilage imaging. Discrimination of structural cartilage differences in patients with osteoarthritis is critical, yet challenging. This study assesses the variation in the optical attenuation coefficient ( $\mu_{{\rm OCT}}$ ) between healthy cartilage, repair tissue, bone, and layers within repair tissue in a controlled setting. OCT and histology were used to assess goat talus articular surfaces in which central osteochondral defects were created. Exact matches of OCT and histology were selected for research. $\mu_{{\rm OCT}}$ measurements were taken from healthy cartilage, repair tissue, and bone. Measured $\mu_{{\rm OCT}}$ in healthy cartilage was higher compared to both repair tissue and bone tissue. Two possible mechanisms for the difference in attenuation were investigated. We studied morphological parameters in terms of nucleus count, nucleus size, and inter-nucleus distance. Collagen content in healthy cartilage and repair tissue was assessed using polarization microscopy. Quantitative analysis of the nuclei did not demonstrate a difference in nucleus size and nucleus count between healthy cartilage and repair tissue. In healthy cartilage, cells were spaced farther apart and had a lower variation in local nuclear density compared to the repair tissue. Polarization microscopy suggested higher collagen content in the healthy cartilage compared to the repair tissue. $\mu_{{\rm OCT}}$ measurements can distinguish between healthy cartilage, repair tissue, and bone. Results suggest that cartilage OCT attenuation measurements could be of great impact in clinical diagnostics of osteoarthritis.

Tetrahydropalmatine attenuates irradiation induced lung injuries in rats

AimsThe lung is a major organ targeted by irradiation (R) in cancer radiotherapy of the thoracic region. Irradiation induced lung injury (RILI) is a common major obstacle in thoracic cancer radiotherapy. Tetrahydropalmatine (THP) has been shown to have a protective effect against oxidative stress. This study was designed to investigate the potential radioprotective effect of THP against RILI and to elucidate the underlying mechanisms. Materials and methodsSprague–Dawley rats were treated with THP and R. THP was delivered 1h before R. Using TUNEL staining to explore the effectiveness of THP displayed on R induced pulmonary cells apoptosis. Lung histopathologic findings, bronchoalveolar lavage fluid (BALF) levels of total cell counts, protein and inflammatory cytokines, fibrotic factors (hydroxyproline content), apoptotic mediators (caspase-3 and cytochrome c) and malondialdehyde (MDA) were also evaluated after R. Key findingsTHP significantly ameliorates the deleterious effects of R. Further studies showed that THP decreased lung injury by inhibiting the pulmonary cells apoptosis; reduced lung inflammation by decreasing BALF cells recruitment and lowering BALF protein levels; reduced pulmonary fibrosis by decreasing collagen content of lung tissues. THP also ameliorated oxidative modification of rat lungs as evidenced by levels of lipid peroxidation. BALF cytokine analysis, moreover, pointed to a mitigation of the chronic inflammatory profile of irradiated lungs as a result of the protective effect of THP treatment. SignificanceTHP can effectively attenuate RILI through anti-apoptosis, anti-fibrosis and anti-inflammation mechanisms.

MP86-14 TREATMENT OF DIABETES MELLITUS-INDUCED ERECTILE DYSFUNCTION USING ENDOTHELIAL PROGENITOR CELLS GENETICALLY MODIFIED WITH HUMAN TELOMERASE REVERSE TRANSCRIPTASE

You have accessJournal of UrologySexual Function/Dysfunction: Basic Research & Pathophysiology I1 Apr 2016MP86-14 TREATMENT OF DIABETES MELLITUS-INDUCED ERECTILE DYSFUNCTION USING ENDOTHELIAL PROGENITOR CELLS GENETICALLY MODIFIED WITH HUMAN TELOMERASE REVERSE TRANSCRIPTASE Yan Zhang, Tao Wang, Jun Yang, Rui Li, Zhi Chen, Shaogang Wang, Jihong Liu, and Zhangqun Ye Yan ZhangYan Zhang More articles by this author , Tao WangTao Wang More articles by this author , Jun YangJun Yang More articles by this author , Rui LiRui Li More articles by this author , Zhi ChenZhi Chen More articles by this author , Shaogang WangShaogang Wang More articles by this author , Jihong LiuJihong Liu More articles by this author , and Zhangqun YeZhangqun Ye More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.2322AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Erectile dysfunction (ED) is one of the most common complications of diabetes mellitus (DM). The efficacy of treatments for diabetes mellitus-induced erectile dysfunction (DMED) is quite poor, and stem cell therapy is emerging as a useful method. This study evaluated the possibility and mechanisms of DMED treatment with endothelial progenitor cells (EPCs) genetically modified to express human telomerase reverse transcriptase (hTERT). METHODS Rat EPCs were isolated and transfected with hTERT (EPCs-hTERT). Proliferation capacity, intracellular reactive oxygen species, paracrine character and resistance to oxidative stress of EPCs-hTERT were assessed in vitro. Diabetes was induced via an intraperitoneal injection of streptozotocin. Twenty-four male DMED rats were subjected to four treatments: DMED (DMED group), EPCs (EPCs group), EPCs transfected with control lentivirus (EPC-control group) and EPCs-hTERT (EPCs-hTERT group). A group of health rats were used as a normal control group. Intracavernosal pressure (ICP) was measured using electrical stimulation for each group after 2 weeks of EPC injections. Masson's trichrome staining was performed to determine collagen content in penile tissues. The degree of apoptosis was assessed using western blotting analysis for terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) signaling pathway was detected. RESULTS EPCs-hTERT secreted more growth factors than EPCs and EPCs-control. EPC resistance to oxidative stress and proliferation was dramatically improved by hTERT transfection. The ICP/mean arterial pressure (MAP) ratio induced by electrical stimulation was markedly increased in the EPCs-hTERT group compared with the EPCs and EPCs-control group. Immunofluorescence demonstrated increased cell survival in penile tissues after EPCs-hTERT implantation. The smooth muscle/collagen ratio was markedly increased in the EPCs-hTERT group. TGF-β1 and p-Smad expression decreased significantly in DMED rats after EPCs-hTERT treatment. The degree of apoptosis in penile tissues of the EPCs-hTERT group was considerably reduced, as demonstrated by the decreased Bax/Bcl-2 ratio. NOS expression and NO and cGMP concentrations increased significantly in the EPCs-hTERT group. CONCLUSIONS The enhanced paracrine effect, resistance to oxidative stress and EPCs-hTERT proliferation contributed to the improvement of erectile function in DMED rats. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e1111 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Yan Zhang More articles by this author Tao Wang More articles by this author Jun Yang More articles by this author Rui Li More articles by this author Zhi Chen More articles by this author Shaogang Wang More articles by this author Jihong Liu More articles by this author Zhangqun Ye More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Protective Effects of Myrtol Standardized Against Radiation-Induced Lung Injury

Background/Aims: As a major complication after thoracic radiotherapy, radiation-induced lung injury (RILI) has great impact on long term quality of life and could result in fatal respiratory insufficiency The present study was aimed to evaluate the effects of Myrtol standardized on RILI, and to investigate the underlying mechanism. Methods: A mouse model of radiation-induced lung injury was generated by using thoracic irradiation with a single dose of 16Gy. Mice were orally administrated with Myrtol (25 mg/kg/day) for 4 weeks after irradiation, while prednisone (5 mg/kg/day) was used as a positive control. After then, the body weight and lung coefficient were calculated. The severity of fibrosis was evaluated by observing pulmonary sections after radiation and collagen content in lung tissues was calculated following the hydroxyproline (HYP) assay. Pathological changes were observed in all the groups by using HE staining and Masson staining. The serum levels of TGF-β1, TNF-α, IL-1β, IL-6, and PGE2 were also measured with an ELISA assay. Western blot assay was used to measure the impact of Myrtol on AKT and its downstream signaling pathway, including MMP-2 and MMP-9. The levels of Vimentin and α-SMA were evaluated with an immunofluorescence assay. Results: Treatment with Myrtol standardized, but not prednisone, reduced lung coefficient and collagen deposition in lung tissues, while attenuated histological damages induced by irradiation. Myrtol standardized also reduced the production of MDA, while increased the level of SOD. It was also observed that Myrtol standardized inhibited TGF-β1 and a series of pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, PGE2. While in prednisone group, even though the early pneumonitis was ameliorated, the collagen disposition remained unchanged in latter times. Immunofluorescence analysis also revealed elevation of vimentin and α-SMA in the alveoli after a single dose of 16Gy. Conclusion: The present results suggest Myrtol standardized as an effective agent for attenuating the lung injury induced by irradiation.

Changes in Caspase-3, B Cell Leukemia/Lymphoma-2, Interleukin-6, Tumor Necrosis Factor-α and Vascular Endothelial Growth Factor Gene Expression after Human Umbilical Cord Blood Derived Mesenchymal Stem Cells Transfusion in Pulmonary Hypertension Rat Models.

Background and ObjectivesFailure of vascular smooth muscle apoptosis and inflammatory response in pulmonary arterial hypertension (PAH) is a current research focus. The goals of this study were to determine changes in select gene expressions in monocrotaline (MCT)-induced PAH rat models after human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) transfusion.Materials and MethodsThe rats were separated into 3 groups i.e., control group (C group), M group (MCT 60 mg/kg), and U group (hUCB-MSCs transfusion) a week after MCT injection.ResultsTUNEL assay showed that the U group had significantly lowered positive apoptotic cells in the lung tissues, as compared with the M group. mRNA of caspase-3, B cell leukemia/lymphoma (Bcl)-2, interleukin (IL)-6, tumor necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF) in the lung tissues were greatly reduced at week 4 in the U group. Immunohistochemical staining of the lung tissues also demonstrated a similar pattern, with the exception of IL-6. The protein expression of caspase-3, Bcl-2 VEGF, IL-6, TNF-α and brain natriuretic peptide in the heart tissues were significantly lower in the U group, as compared with the M group at week 2. Furthermore, the protein expression of VEGF, IL-6 and BNP in the heart tissues were significantly lower in the U group at week 4. Collagen content in the heart tissues was significantly lower in the U group, as compared with M group at weeks 2 and 4, respectively.ConclusionhUCB-MSCs could prevent inflammation, apoptosis and remodeling in MCT-induced PAH rat models.

Evaluation of wound healing activity of cow urine ark in diabetic Wistar albino rats.

Aim:To evaluate wound healing activity of cow urine ark in diabetic rats.Materials and Methods:Streptozotocin-induced diabetic Wistar albino rats were randomly divided into six groups (n = 6). Three groups - diabetic control, active control (glibenclamide), and treatment (cow urine ark) were operated for excision wounds (EWs). Rats in these groups received distilled water 1 ml/day, glibenclamide 0.5 mg/kg body weight/day, and cow urine ark 5.5 ml/kg body weight/day orally till complete healing of the EWs. EWs were evaluated for wound contraction on 3rd, 7th, and 11th day and for reepithelization on 11th day. The other three groups were operated for incision wounds (IW) as well as dead space wounds (DW) in the same animal which received the above agents orally for 11 days. IWs were analyzed for wound breaking strength and DWs were analyzed for dry weight, hydroxyproline content, and histology of granulation tissue.Results:EWs showed significantly increased wound closure in the treatment group as compared to the diabetic as well as active control groups at 3rd (P < 0.001) and 11th (P < 0.05) post-wounding day and to the only diabetic control group at 7th (P < 0.01) post-wounding day. IWs showed significant improvement in wound breaking strength in the treatment as compared to diabetic (P < 0.001) and active control (P < 0.01) groups. DWs showed significant increase in hydroxyproline content of granulation tissue in the treatment as compared to diabetic control (P < 0.001) and active control (P < 0.001) groups. Wound breaking strength and hydroxyproline content also significantly increased in the active control group compared to diabetic control (P < 0.001 and P < 0.05, respectively). Granulation tissue dry weight was significantly increased in treatment and active control groups as compared to diabetic control (P < 0.001).Conclusion:Cow urine ark increases granulation tissue formation as well as collagen content. Wound contraction was also significantly improved. The cow urine ark could be potentially effective in promoting healing of diabetic wounds by increasing granulation tissue formation and collagen content, however, further studies are required for its clinical application.

Effects of Glucagon-Like Peptide-1 on Arteriovenous Fistula Remodelling and Vascular Smooth Muscle Cell Phenotype Switching in Diabetic Rats

This study aimed to determine the potential vascular protective effect of exendin-4, a synthetic glucagonlike peptide (GLP)-1 analogue, on the blood flow and remodelling of arteriovenous (AV) fistulas in a rat model of diabetes. AV fistulas were created in Sprague-Dawley rats with streptozotocin-induced diabetes. The animals were then randomly assigned to receive intraperitoneal injection of vehicle (saline) or exendin-4 for about 2 weeks. The blood flow and vasomotor function of the aortic limb of the fistula were measured. Concentrations of serum norepinephrine and its associate tissue signal proteins, and vascular smooth muscle cell (VSMC) contractile proteins, matrix metalloproteinase (MMP)-2, and collagen expression in the remodelled aorta were examined. Exendin-4 attenuated the contraction response to phenylephrine in isolated arterial segments from treated animals. Treatment with exendin-4 increased serum norepinephrine concentration, reduced aorta tissue α1-receptor expression, and enhanced downstream signal proteins. Additionally, exendin-4 promoted the switching of VSMCs to the synthetic phenotype, which increased tissue collagen content and suppressed tissue abundances of smooth muscle myosin heavy chain type II and desmin in diabetic animals. In conclusion, our study demonstrated that exendin-4 modulates VSMC transition to the synthetic phenotype and enhances the arterial contraction responses, thereby attenuating blood flow in the AV fistula.

Micromechanics and constitutive modeling of connective soft tissues

In this paper, a micromechanical model for connective soft tissues based on the available histological evidences is developed. The proposed model constituents i.e. collagen fibers and ground matrix are considered as hyperelastic materials. The matrix material is assumed to be isotropic Neo-Hookean while the collagen fibers are considered to be transversely isotropic hyperelastic. In order to take into account the effects of tissue structure in lower scales on the macroscopic behavior of tissue, a strain energy density function (SEDF) is developed for collagen fibers based on tissue hierarchical structure. Macroscopic response and properties of tissue are obtained using the numerical homogenization method with the help of ABAQUS software. The periodic boundary conditions and the proposed constitutive models are implemented into ABAQUS using the DISP and the UMAT subroutines, respectively. The existence of the solution and stable material behavior of proposed constitutive model for collagen fibers are investigated based on the poly-convexity condition. Results of the presented micromechanics model for connective tissues are compared and validated with available experimental data. Effects of geometrical and material parameters variation at microscale on macroscopic mechanical behavior of tissues are investigated. The results show that decrease in collagen content of the connective tissues like the tendon due to diseases leads 20% more stretch than healthy tissue under the same load which can results in connective tissue malfunction and hypermobility in joints.

Long-Term Effects of Diesel Exhaust Particles on Airway Inflammation and Remodeling in a Mouse Model.

PurposeDiesel exhaust particles (DEPs) can induce and trigger airway hyperresponsiveness (AHR) and inflammation. The aim of this study was to investigate the effect of long-term DEP exposure on AHR, inflammation, lung fibrosis, and goblet cell hyperplasia in a mouse model.MethodsBALB/c mice were exposed to DEPs 1 hour a day for 5 days a week for 3 months in a closed-system chamber attached to a ultrasonic nebulizer (low dose: 100 µg/m3 DEPs, high dose: 3 mg/m3 DEPs). The control group was exposed to saline. Enhanced pause was measured as an indicator of AHR. Animals were subjected to whole-body plethysmography and then sacrificed to determine the performance of bronchoalveolar lavage and histology.ResultsAHR was higher in the DEP group than in the control group, and higher in the high-dose DEP than in the low-dose DEP groups at 4, 8, and 12 weeks. The numbers of neutrophils and lymphocytes were higher in the high-dose DEP group than in the low-dose DEP group and control group at 4, 8, and 12 weeks. The levels of interleukin (IL)-5, IL-13, and interferon-γ were higher in the low-dose DEP group than in the control group at 12 weeks. The level of IL-10 was higher in the high-dose DEP group than in the control group at 12 weeks. The level of vascular endothelial growth factor was higher in the low-dose and high-dose DEP groups than in the control group at 12 weeks. The level of IL-6 was higher in the low-dose DEP group than in the control group at 12 weeks. The level of transforming growth factor-β was higher in the high-dose DEP group than in the control group at 4, 8, and 12 weeks. The collagen content and lung fibrosis in lung tissue was higher in the high-dose DEP group at 8 and 12 weeks.ConclusionsThese results suggest that long-term DEP exposure may increase AHR, inflammation, lung fibrosis, and goblet cell hyperplasia in a mouse model.

Wound repair and regeneration potential of the fruits of Terminalia bellarica

The infection at the wound site is a severe kind of problem and it delays regeneration of epidermis and dermis in the wound and slows wound closure. Due to the secretion of microbial enzymes by wound pathogens, a variety of extracellular matrix proteins were degraded. Synthetic antimicrobial therapy used in the wound management and eradication of pathogens. However, it has many shortcomings such as anti-microbial resistance, cyto-toxicity against host tissue and absence of synergistic activity. In order to overcome these limitations, Pyto-pharmaceuticals extracted from herbal plants were applied to manage the wound infection and treatment. The objective of this work is to evaluate the wound repair and regeneration potential of the fruits of Terminalia bellarica which has a variety of pharmacological activities such as astringent, antiseptic and laxative. The dry fruits of Terminalia bellarica were grounded into powder form using the grinder. Extraction was performed by using Soxhlet apparatus with 95% (v/v) ethanol. The dried extract was dissolved in Dimethyl Sulfoxide (DMSO) and used to assay the antibacterial activity against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853. An ointment was prepared from the ethanol extract (10% w/w) and assessed for its in vivo wound healing potential on infected rat model by rate of healing, bacterial count, biochemical analysis, and expression of matrix metalloproteinase. In addition to that, the collagen content in the granulation tissue was estimated to comment on wound regeneration potential of the fruits of Terminalia bellarica. The treated group has shown significantly improved wound regeneration and well formed epidermis and dermis in the granulation tissue. Furthermore, Assessment of granulation tissue on every fourth day showed significant reduction in bacterial pathogens CFU with significant elevated level of collagen, hexosamine, uronic acid, in the treated group (P&lt;0.05). The reduced level expression of matrix metalloproteinase expression observed in the treated group by gelatin zymography and the synthesis of substantial amount of collagen in the granulation tissue confirms our in vivo assessment. The results showed the antibacterial and wound healing activities of Terminalia bellarica fruits ointment, necessary for the management of infected open dermal wounds. The isolation of bioactive molecules from Terminalia bellarica fruits and its interaction various cells using cell culture studies would be future work.

미세피부침, 절개침법과 봉독 약침 복합 요법의 여드름 흉터 치료 27례 임상 보고

Objectives : Microneedle therapy and Subcision are commonly used for therap eutic modalities of acne scars in Korean medicine. Beevenom could promote the expression of various cytokines, enzymes and receptors related to increasing collagen content of connective tissues. Through this mechanism, we considered that Beevenom pharmacopuncture therapy is applicable to the treatment of acne scars. We investigated twenty-seven patients with acne scars treated by Microneedle therapy and Subcision combined with Beevenom pharmacopuncture therapy and evaluated the clinical effect. Methods : Twenty-seven patients with acne scars were treated by Microneedle therapy and Subcision combined with Beevenom pharmacopuncture therapy and evaluated the clinical effect. for twelve weeks. The severity of .

Treatment with either obestatin or ghrelin attenuates mesenteric ischemia–reperfusion-induced oxidative injury of the ileum and the remote organ lung

To evaluate the effects of exogenous ghrelin or obestatin on intestinal injury and accompanying pulmonary injury, intestinal ischemia–reperfusion (I/R) was induced in rats by obstructing the superior mesenteric artery for 60min, whereas laparotomy was performed in the sham group. At the beginning of the 90-min reperfusion period, the rats were injected with obestatin (100μg/kg), ghrelin (10ng/kg), or saline intravenously (iv). At the end of reperfusion, the blood, ileum, and lung samples were taken for the histological and biochemical assays. In the saline-treated I/R group, the increased serum interleukin (IL)-1β level, high damage scores, and elevated tissue malondialdehyde level and collagen content in both tissues were significantly reduced by obestatin or ghrelin. Increased ileal myeloperoxidase activity of the saline-treated I/R group was reduced by treatment with obestatin or ghrelin, whereas increased pulmonary myeloperoxidase activity was reduced with administration of obestatin. Increased DNA fragmentation in the ileum of the saline-treated I/R group was reduced by both peptides. Elevated luminol–lucigenin chemiluminescence levels and nuclear factor kappa B (NF-κB) messenger RNA (mRNA) expression in the ileum of the saline-treated-I/R group were significantly decreased by obestatin or ghrelin treatment. I/R-induced depletion of the antioxidant glutathione in both ileal and pulmonary tissues was prevented with either obestatin or ghrelin treatment. Administration of either obestatin or ghrelin exerts similar protective effects against I/R-induced ileal and pulmonary injury, thus warranting further investigation for their possible use against ischemic intestinal injury.

Postnatal changes to the mechanical properties of articular cartilage are driven by the evolution of its collagen network.

While it is well established that the composition and organisation of articular cartilage dramatically change during skeletal maturation, relatively little is known about how this impacts the mechanical properties of the tissue. In this study, digital image correlation was first used to quantify spatial deformation within mechanically compressed skeletally immature (4 and 8 week old) and mature (1 and 3 year old) porcine articular cartilage. The compressive modulus of the immature tissue was relatively homogeneous, while the stiffness of mature articular cartilage dramatically increased with depth from the articular surface. Other, well documented, biomechanical characteristics of the tissue also emerged with skeletal maturity, such as strain-softening and a depth-dependent Poisson's ratio. The most significant changes that occurred with age were in the deep zone of the tissue, where an order of magnitude increase in compressive modulus (from 0.97MPa to 9.4MPa for low applied strains) was observed from 4 weeks postnatal to skeletal maturity. These temporal increases in compressive stiffness occurred despite a decrease in tissue sulphated glycosaminoglycan content, but were accompanied by increases in tissue collagen content. Furthermore, helium ion microscopy revealed dramatic changes in collagen fibril alignment through the depth of the tissue with skeletal maturity, as well as a fivefold increase in fibril diameter with age. Finally, computational modelling was used to demonstrate how both collagen network reorganisation and collagen stiffening play a key role in determining the final compressive mechanical properties of the tissue. Together these findings provide a unique insight into evolving structure-function relations in articular cartilage.

Determination of collagen content within picrosirius red stained paraffin-embedded tissue sections using fluorescence microscopy

Picrosirius red (PSR) staining is a commonly used histological technique to visualize collagen in paraffin-embedded tissue sections. PSR stained collagen appears red in light microscopy. However it is largely unknown that PSR stained collagen also shows a red fluorescence, whereas live cells have a distinct green autofluorescence. Both emission patterns can be detected using standard filter sets as found in conventional fluorescence microscopes. Here we used digital image addition and subtraction to determine the relative area of the pure collagen and live cell content in heart tissue in a semi-automated process using standard software. This procedure, which considers empty spaces (holes) within the section, can be easily adapted to quantify the collagen and live cell areas in healthy or fibrotic tissues as aorta, lung, kidney or liver by semi-automated planimetry exemplified herein for infarcted heart tissue obtained from the mouse myocardial infarction model.•Use of conventional PSR stained paraffin-embedded tissue sections for fluorescence analysis.•PSR and autofluorescence images are used to calculate area of collagen and area of live cells in the tissue; empty spaces (holes) in tissue are considered.•High throughput analysis of collagen and live cell content in tissue for statistical purposes.

Collagen crosslinking does not dictate stiffness in a transgenic mouse model of skeletal muscle fibrosis

Skeletal muscle fibrosis is characterized by increases in tissue stiffness and collagen content. However, a very weak correlation exists between collagen content and stiffness in skeletal muscle. Recently, it has been hypothesized that collagen crosslinking explains tissue stiffness in fibrotic skeletal muscle. Therefore, we addressed this hypothesis by correlating tissue stiffness with lysyl-pyridinoline, hydroxylysyl-pyridinoline, and pentosidine collagen crosslinks. Stepwise regression revealed that, separate or together, collagen crosslinks did not correlate with tissue stiffness. Our result demonstrates that increased tissue stiffness in skeletal muscle fibrosis is not simply explained by increased collagen crosslinks and/or collagen crosslink density. We suggest that collagen organization may affect tissue stiffness.

Boiling histotripsy of the kidney: Preliminary studies and predictors of treatment effectiveness

Boiling histotripsy (BH), an ultrasound technique to mechanically homogenize tissue, has been described in ex vivo liver and myocardium. As a noninvasive, non-thermal based approach, BH may have advantages over clinically available thermal ablative technologies for renal masses. We aimed to characterize BH exposures in human and porcine ex vivo kidneys using a 7-element 1 MHz transducer (duty factor 1–3%, 5–10 ms pulses, 98 MPa in situ shock amplitude, 17 MPa peak negative). Lesions were successfully created in both species, demonstrating focally homogenized tissue above treatment thresholds (pulse number) with stark transition between treated and untreated cells on histologic assessment. Human tissue generally required more pulses to produce similar effect compared to porcine. Similarly, kidneys displayed tissue specific resistance to BH with increasing resistance from cortex to medulla to the collecting system. Tissue properties that predict resistance to renal BH were evaluated demonstrating correlation between tissue collagen content and tissue resistance. Subsequently, the impact of intervening abdominal wall and ribs on lesion generation ex vivo was evaluated. “Transabdominal” and “transcostal” treatment required approximately 5- and 20-fold greater acoustic power, respectively, to elicit boiling vs. no intervening tissue. [Work supported by NIH T32DK007779, R01EB007643, K01EB015745 and NSBRI through NASA NCC 9-58.]

Effects on Exposed Articular Cartilage During Open Surgical Procedures: A Comparison of Various Fluids in an Animal Model

The aim of this study was to assess the potential detrimental effects of the operating room environment on exposed healthy articular cartilage and to evaluate tissue hydration treatment strategies for preserving chondrocyte viability and extracellular matrix composition in this environment. With institutional Animal Care and Use Committee approval, femoral and tibial condyles (n = 36; 6 per specimen) were harvested from canine cadavers (n = 6) immediately after euthanasia and placed on a draped operating table under standard surgical lighting for a timed 2-hour period. Each condyle was randomly assigned to one of 6 groups (n = 6 per group): no-treatment control, hyaluronic acid (HA), saline sponge, saline drip, culture media (Dulbecco's modified Eagle's medium [DMEM]) sponge, or culture media drip. Full-thickness cartilage sections were collected from each specimen immediately after harvest (time 0) and immediately after 2-hour exposure (time 2H), and processed to determine chondrocyte viability, tissue water content, and extracellular matrix composition (glycosaminoglycan [GAG] and collagen content). Chondrocyte viability was significantly lower (P = .03) after the 2-hour exposure in the control group. HA, saline sponge, and saline drip treatment groups all had significantly higher (P < .043) chondrocyte viability compared with controls at time 2H. Water content was significantly lower (P < .01) after the 2-hour exposure in the control group. Further, the water content in the control group was significantly lower than all treatment groups at time 2H (P < .001). No significant differences in tissue collagen or GAG content were observed within groups between time points or among groups at either time point. Canine articular cartilage did not demonstrate any reduction in chondrocyte viability or tissue water content at 2 hours when treated with hyaluronic acid, saline drip, saline-soaked sponge, or DMEM-soaked sponge compared with untreated exposed cartilage. Surgeons should consider the use of a hydrating solution for the treatment of exposed articular cartilage during open joint surgery of 2 hours or longer duration.

Targeted delivery of vascular endothelial growth factor improves stem cell therapy in a rat myocardial infarction model

Rebuilding of infarcted myocardium by mesenchymal stem cells (MSCs) has not been successful because of poor cell survival due in part to insufficient blood supply after myocardial infarction (MI). We hypothesize that targeted delivery of vascular endothelial growth factor (VEGF) to MI can help regenerate vasculature in support of MSC therapy in a rat model of MI. VEGF-encapsulated immunoliposomes targeting overexpressed P-selectin in MI tissue were infused by tail vein immediately after MI. One week later, MSCs were injected intramyocardially. The cardiac function loss was moderated slightly by targeted delivery of VEGF or MSC treatment. Targeted VEGF+MSC combination treatment showed highest attenuation in cardiac function loss. The combination treatment also increased blood vessel density (80%) and decreased collagen content in post-MI tissue (33%). Engraftment of MSCs in the combination treatment group was significantly increased and the engrafted cells contributed to the restoration of blood vessels. From the Clinical EditorVEGF immunoliposomes targeting myocardial infarction tissue resulted in significantly higher attenuation of cardiac function loss when used in combination with mesenchymal stem cells. MSCs were previously found to have poor ability to restore cardiac tissue, likely as a result of poor blood supply in the affected areas. This new method counterbalances that weakness by the known effects of VEGF, as demonstrated in a rat model.