Extracellular matrix powder protects against bleomycin-induced pulmonary fibrosis

The Salutary Effects of Diminazene, Lisinopril or Valsartan on Cisplatin - Induced Acute Kidney Injury in Rats: A Comparative Study

Nephrotoxicity as a cause of acute kidney injury (AKI) induced by cisplatin (CP), limits its usefulness as an anticancer agent. Diminazene, an angiotensin converting enzyme 2 activator, exhibited renoprotective properties on rat models of kidney diseases. This research aims to investigate the salutary effect of diminazene in comparison with lisinopril or valsartan in CP-induced AKI. The first and second groups of rats received oral vehicle (distilled water) for 9 days, and saline injection or intraperitoneal CP (6 mg/kg) on day 6, respectively. Third, fourth, and fifth groups received intraperitoneal injections of CP on day 6 and diminazene (15 mg/kg/day, orally), lisinopril (10 mg/kg/day, orally), or valsartan (30 mg/kg/day, orally), for 9 days, respectively. 24h after the last day of treatment, blood and kidneys were removed under anesthesia for biochemical and histopathological examination. Urine during the last 24 h before sacrificing the rats was also collected. CP significantly increased plasma urea, creatinine, neutrophil gelatinase-associated lipocalin, calcium, phosphorus, and uric acid. It also increased urinary albumin/creatinine ratio, N-Acetyl-beta-D-Glucosaminidase/creatinine ratio, and reduced creatinine clearance, as well the plasma concentrations of inflammatory cytokines [plasma tumor necrosis factor-alpha, and interleukin-1beta], and significantly reduced antioxidant indices [catalase, glutathione reductase , and superoxide dismutase]. Histopathologically, CP treatment caused necrosis of renal tubules, tubular casts, shrunken glomeruli, and increased renal fibrosis. Diminazine, lisinopril, and valsartan ameliorated CP-induced biochemical and histopathological changes to a similar extent. The salutary effect of the three drugs used is, at least partially, due to their anti-inflammatory and antioxidant effects. Keywords: Cisplatin, Diminazene, ACE2 activator, Lisinopril, Valsartan, Acute kidney injury.

Nephroprotective effects of diminazene on doxorubicin-induced acute kidney injury in rats

This study aimed to investigate the potential protective effects of diminazene, an activator of angiotensin II converting enzyme (ACE2), on kidney function and structure in rats with acute kidney injury (AKI) induced by the anticancer drug doxorubicin (DOX). The impact of diminazene was compared to that of two other drugs: the ACE inhibitor lisinopril and the angiotensin II type 1 (AT1) receptor blocker valsartan. Rats were subjected to a single intraperitoneal injection of DOX (13.5 mg/kg) on the 5th day, either alone or in combination with diminazene (15 mg/kg/day), lisinopril (10 mg/kg/day), or valsartan (30 mg/kg/day) for 8 consecutive days. Various markers related to kidney function, oxidative stress, and inflammation were measured in plasma and urine. Additionally, kidney tissues were assessed histopathologically. DOX-induced nephrotoxicity was confirmed by elevated levels of plasma urea, creatinine, and neutrophil gelatinase-associated lipocalin (NGAL). DOX also led to increased urinary N-acetyl-β-D-glucosaminidase (NAG) activity and decreased creatinine clearance, albumin levels, and osmolality. Moreover, DOX caused a reduction in renal oxidative stress markers, including superoxide dismutase (SOD), glutathione reductase (GR), and catalase activities, while increasing malondialdehyde (MDA) levels. It also raised plasma inflammatory markers, tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β). Concurrently administering diminazene significantly mitigated these DOX-induced changes, including histopathological alterations like renal tubule necrosis, tubular casts, shrunken glomeruli, and increased renal fibrosis. Similar protective effects were observed with lisinopril and valsartan. These protective effects, at least in part, appear to result from the anti-inflammatory and antioxidant properties of these drugs. In summary, this study suggests that the administration of diminazene, lisinopril, or valsartan had comparable effects in ameliorating the biochemical and histopathological aspects of DOX-induced acute kidney injury in rats.

The molecular mechanisms of extracellular matrix-derived hydrogel therapy in idiopathic pulmonary fibrosis models

Idiopathic Pulmonary Fibrosis (IPF) is a progressively debilitating lung condition characterized by oxidative stress, cell phenotype shifts, and excessive extracellular matrix (ECM) deposition. Recent studies have shown promising results using decellularized ECM-derived hydrogels produced through pepsin digestion in various lung injury models and even a human clinical trial for myocardial infarction. This study aimed to characterize the composition of ECM-derived hydrogels, assess their potential to prevent fibrosis in bleomycin-induced IPF models, and unravel their underlying molecular mechanisms of action. Porcine lungs were decellularized and pepsin-digested for 48 h. The hydrogel production process, including visualization of protein molecular weight distribution and hydrogel gelation, was characterized. Peptidomics analysis of ECM-derived hydrogel contained peptides from 224 proteins. Probable bioactive and cell-penetrating peptides, including collagen IV, laminin beta 2, and actin alpha 1, were identified. ECM-derived hydrogel treatment was administered as an early intervention to prevent fibrosis advancement in rat models of bleomycin-induced pulmonary fibrosis. ECM-derived hydrogel concentrations of 1 mg/mL and 2 mg/mL showed subtle but noticeable effects on reducing lung inflammation, oxidative damage, and protein markers related to fibrosis (e.g., alpha-smooth muscle actin, collagen I). Moreover, distinct changes were observed in macroscopic appearance, alveolar structure, collagen deposition, and protein expression between lungs that received ECM-derived hydrogel and control fibrotic lungs. Proteomic analyses revealed significant protein and gene expression changes related to cellular processes, pathways, and components involved in tissue remodeling, inflammation, and cytoskeleton regulation. RNA sequencing highlighted differentially expressed genes associated with various cellular processes, such as tissue remodeling, hormone secretion, cell chemotaxis, and cytoskeleton engagement. This study suggests that ECM-derived hydrogel treatment influence pathways associated with tissue repair, inflammation regulation, cytoskeleton reorganization, and cellular response to injury, potentially offering therapeutic benefits in preventing or mitigating lung fibrosis.

The effect of diminazene, an angiotensin-converting enzyme 2 activator, on adenine-induced chronic kidney disease in rats

The present study investigated the effect of diminazene, lisinopril, or valsartan on adenine-induced chronic kidney disease (CKD) in rats. The animals were divided into five groups (n = 6). The first and second groups received normal diet and adenine in the feed at a dose of 0.25% w/w for 35 days, respectively. The third, fourth, and fifth groups were treated as the second group but also received diminazene (15 mg/kg/day), lisinopril (10 mg/kg/day), and valsartan (30 mg/kg/day), respectively, for 35 days. Adenine significantly increased plasma urea, creatinine, neutrophil gelatinase-associated lipocalin (NGAL), calcium, phosphorus, and uric acid. In addition, adenine increased urinary albumin/creatinine ratio and N-Acetyl-β-D-glucosaminidase (NAG)/creatinine ratio and reduced creatinine clearance. Adenine also significantly increased the plasma concentrations of inflammatory cytokines (plasma tumor necrosis factor-alpha [TNF-α] and interleukin-1beta [IL-1β]) and significantly reduced antioxidant indices (catalase, glutathione reductase [GR], and superoxide dismutase [SOD]). Histopathologically, renal tissue from adenine-treated rats showed necrosis of renal tubules, tubular casts, shrunken glomeruli, and increased renal fibrosis. All drugs ameliorated adenine-induced biochemical and histopathological changes. The protective effect of the three drugs used is, at least partially, due to their anti-inflammatory and antioxidant effects. Our results show that administration of diminazene, lisinopril, or valsartan had a comparable effect on the reversal of the biochemical and histopathological indices of adenine-induced CKD in rats.

Functional acellular matrix for tissue repair

In view of their low immunogenicity, biomimetic internal environment, tissue- and organ-like physicochemical properties, and functionalization potential, decellularized extracellular matrix (dECM) materials attract considerable attention and are widely used in tissue engineering. This review describes the composition of extracellular matrices and their role in stem-cell differentiation, discusses the advantages and disadvantages of existing decellularization techniques, and presents methods for the functionalization and characterization of decellularized scaffolds. In addition, we discuss progress in the use of dECMs for cartilage, skin, nerve, and muscle repair and the transplantation or regeneration of different whole organs (e.g., kidneys, liver, uterus, lungs, and heart), summarize the shortcomings of using dECMs for tissue and organ repair after refunctionalization, and examine the corresponding future prospects. Thus, the present review helps to further systematize the application of functionalized dECMs in tissue/organ transplantation and keep researchers up to date on recent progress in dECM usage.

Investigating the Immunomodulatory Potential of Dental Pulp Stem Cell Cultured on Decellularized Bladder Hydrogel towards Macrophage Response In Vitro

Mesenchymal stem cells (MSCs) possess immunomodulatory properties and capacity for endogenous regeneration. Therefore, MSC therapy is a promising treatment strategy for COVID-19. However, the cells cannot stay in the lung long enough to exert their function. The extracellular matrix from porcine bladders (B-ECM) has been shown not only to regulate cellular activities but also to possess immunoregulatory characteristics. Therefore, it can be hypothesized that B-ECM hydrogel could be an excellent scaffold for MSCs to grow and could anchor MSCs long enough in the lung so that they can exhibit their immunomodulatory functions. In this study, ECM degradation products and a co-culture system of MSCs and macrophages were developed to study the immunomodulatory properties of ECM and MSCs under septic conditions. The results showed that B-ECM degradation products could decrease pro-inflammatory and increase anti-inflammatory cytokines from macrophages. In an in vivo mimicking co-culture system, MSCs cultured on B-ECM hydrogel exhibited immunomodulatory properties at both gene and protein levels. Both B-ECM degradation products and MSC conditioned medium supported the wound healing of alveolar epithelial cells. The results from the study could offer a basis for investigation of immunomodulation by ECM and MSCs before conducting in vivo experiments, which could later be applied in regenerative medicine.

Substrate coated with autologous decellularized extracellular matrix facilitates in vitro spreading of spheroid from adipose-derived stem cells through regulating ERK1/2-MMP2/9 pathway

Adipose-derived stem cells (ADSCs) are easily available and play an important role in regenerative medicine. In recent years, Cell spheroid models have been in the spotlight because of their various advantages and physiological proximity. Promoting the spreading of ADSCs spheroids may improve the therapeutic effect the transplanted ADSCs. In this study, we prepared autologous decellularized extracellular matrix (d-ECM) and ADSCs spheroids, and investigated in vitro spreading of the spheroids on the d-ECM-coated substrate. In addition, the effect of d-ECM powder (ECM-P) on the aggregation of ADSCs was analyzed in a three-dimensional (3D) culture system. The results showed that d-ECM accelerated the spreading of spheroids, and promoted the migration and proliferation of the surrounding monolayer cells, accompanied by ERK1/2 activation and an increase in the expression of MMP2 and MMP9. In addition, ECM-P facilitated the aggregation of free cells in 3D culture in a concentration-dependent way. The spheroid spreading and cell aggregation were both prevented by ERK1/2 selective inhibitor PD98059. Our data suggest that the d-ECM substrate and its derivant may regulate the transformation between ADSCs spheroids and the monolayer or free cells, and ERK1/2 signalling pathway may be involved in these processes.

Effect of flaxseed on systemic inflammation and oxidative stress in diabetic rats with or without chronic kidney disease

Background

Diabetes mellitus (DM) and chronic kidney disease (CKD) are common causes of morbidity and mortality. Flaxseed contains several bioactive compounds that have been shown to possess anti-inflammatory and antioxidative properties. The aim of the present study was to investigate the possible effect of flaxseed in diabetic rats with adenine–induced CKD.

Methods

Male Wister rats (n = 48) were randomly divided into seven equal groups and treated for 33 consecutive days as follows: G1: control. G2 adenine, G3: streptozotocin (STZ), G4: flaxseed, G5: adenine+flaxseed, G6: STZ+flaxseed, G7: adenine+STZ+flaxseed). DM or CKD were experimentally induced by a single intraperitoneal injection of streptozotocin (STZ) or by adenine via oral gavage, respectively.

Results

Rats fed adenine alone exhibited several changes including decreased body weight, increased food and water intake and urine output, increased urinary albumin/creatinine ratio. They also showed an increase in plasma urea and, creatinine, indoxyl sulfate, neutrophil gelatinase-associated lipocalin and cystatin C, and a decrease in renalase activity. These were associated with significant changes in inflammatory and oxidative biomarkers, e.g., increase in 8-isoprostane, 8 -hydroxy -2-deoxy guanosine and decrease in antioxidant enzymes, as well as increase in interleukins 1β and 6, and NF-κB, and a decrease in interlukin-10. Histopathologically, there was increased tubular necrosis and fibrosis. Concomitant administration of adenine and STZ further worsened the renal damage induced by adenine alone. Flaxseed significantly ameliorated the changes caused by adenine and STZ, given either singly or in combination.

Conclusion

These findings suggest that flaxseed is a potential therapeutic agent in attenuating the progression of CKD in diabetes.

Protective Effects of Extracellular Matrix-Derived Hydrogels in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive disease with significant gas exchange impairment owing to exaggerated extracellular matrix (ECM) deposition and myofibroblast activation. IPF has no cure, and although nintedanib and pirfenidone are two approved medications for symptom management, the total treatment cost is exuberant and prohibitive to a global uninsured patient population. New therapeutic alternatives with moderate costs are needed to treat IPF. ECM hydrogels derived from decellularized lungs are cost-effective therapeutic candidates to treat pulmonary fibrosis because of their reported antioxidant properties. Oxidative stress contributes to IPF pathophysiology by damaging macromolecules, interfering with tissue remodeling, and contributing to myofibroblast activation. Thus, preventing oxidative stress has beneficial outcomes in IPF. For this purpose, this review describes ECM hydrogel's properties to regulate oxidative stress and tissue remodeling in IPF.

The Effect of Metformin in Diabetic and Non-Diabetic Rats with Experimentally-Induced Chronic Kidney Disease

This work aimed to investigate whether treatment with the antidiabetic drug metformin would affect adenine-induced chronic kidney disease (CKD) in non-diabetic rats and rats with streptozotocin (STZ)-induced diabetes. Rats were randomly divided into eight groups, and given either normal feed, or feed mixed with adenine (0.25% w/w, for five weeks) to induce CKD. Some of these groups were also simultaneously treated orally with metformin (200 mg/kg/day). Rats given adenine showed the typical signs of CKD that included detrimental changes in several physiological and traditional and novel biochemical biomarkers in plasma urine and kidney homogenates such as albumin/creatinine ratio, N-acetyl-beta-D-glucosaminidase, neutrophil gelatinase-associated lipocalin, 8-isoprostane, adiponectin, cystatin C, as well as plasma urea, creatinine, uric acid, indoxyl sulfate, calcium, and phosphorus. Several indices of inflammation and oxidative stress, and renal nuclear factor-κB and nuclear factor erythroid 2-related factor 2 levels were also measured. Histopathologically, adenine caused renal tubular necrosis and fibrosis. The activation of the intracellular mitogen-activated protein kinase signaling pathway was inhibited in the groups that received metformin and STZ together, with or without adenine induced-CKD. Induction of diabetes worsened most of the actions induced by adenine. Metformin significantly ameliorated the renal actions induced by adenine and STZ when these were given singly, and more so when given together. The results suggest that metformin can be a useful drug in attenuating the progression of CKD in both diabetic and non-diabetic rats.

The salutary action of melatonin and betaine, given singly or concomitantly, on cisplatin-induced nephrotoxicity in mice

Cisplatin (CP) is commonly used in the treatment of various solid tumors. Its use, however, is hampered by nephrotoxicity. In this study, we compared the effect of betaine and melatonin given singly, with that of a combination of these two agents on CP-induced nephrotoxicity in mice. CP (20 mg/kg, given intraperitoneally on the 8th day of 12 days of the experiment) showed the typical physiological, biochemical, and histologic features of nephrotoxicity. CP-treated mice showed a significant reduction in food intake, body weight, and urine and fecal output. It also induced significant increases in the plasma concentrations of urea, creatinine, uric acid, phosphorous, adiponectin, interleukin-1β, interleukin-6, transforming growth factor -β1, tumor necrosis factor-α, and cystatin C. All these effects were significantly reduced by daily administration of betaine or melatonin at oral doses of 200 mg/kg and 10 mg/kg, respectively. Furthermore, using the two agents in combination caused further significant reductions in the above parameters. These findings suggest that betaine and melatonin concomitant use is likely to provide greater protection against CP-induced nephrotoxicity than when they are given singly, rendering them potentially suitable and safe agents to use in clinical trials to assess their possible beneficial actions in cancer patients receiving CP.

Treatment with a Urinary Bladder Matrix Alters the Innate Host Response to Pneumonia Induced by Escherichia coli

Escherichia coli has become the prominent cause of nosocomial pneumonia in recent years. In the meantime, some strains of E. coli have developed resistance to commonly used antibacterial drugs. The urinary bladder matrix (UBM) is a biologically derived scaffold material that has been used to promote site-appropriate tissue remodeling in a variety of body systems, partially through the modulation of the innate immune response. In this study, we seek to determine UBM efficacy in preventing bacterial pneumonia in mouse lungs using the Gram-negative bacterial strain E. coli. Our results show that the UBM prevented bacterial biofilm formation in both abiotic and biotic conditions through experimentation on polystyrene plates and culture on the apical surface of differentiated airway epithelial cells. Intratracheal treatment with UBM led to host protection from E. coli-induced respiratory infection in a murine pneumonia model. Transcriptomic analysis revealed the involvement of the enhanced host immune response in UBM-treated mice. Additionally, UBM-treated macrophages had an increased iNOS expression and enhanced phagocytosis activity. Therefore, the protection against E. coli-induced infection and the antibacterial function observed by UBM is potentially through both the anti-biofilm activity and enhanced host immunity following UBM treatment. Taken together, our results support further investigation of UBM as an alternative treatment to attenuate bacterial-induced respiratory infection.

Effects of obesity on periodontal tissue remodeling during orthodontic movement

INTRODUCTION

Orthodontic movement triggers a sequence of cellular and molecular events that may be affected by different systemic conditions. This study evaluated the effect of obesity on rat periodontal tissue remodeling induced by mechanical orthodontic force.

METHODS

Thirty-two Holtzman rats were distributed into 4 groups: control, obesity induction (O), orthodontic movement (M), and obesity induction and orthodontic movement (OM). Obesity was induced by a high-fat diet for 90 days. After 15 days of orthodontic movement, the animals were killed. Obesity induction was confirmed by animal body weight, adipose tissue weight, and serologic analysis. Periodontal tissue remodeling was evaluated using microcomputed tomography and histologic analysis. The gene expression of adipokines and cytokines in gingival tissues was evaluated.

RESULTS

An increase in body and adipose tissue weight was observed in the obesity induction groups. The O group presented an increase in lipids and blood glucose. The OM group showed a decrease in bone volume fraction and bone mineral density compared with all other groups and a tendency for more rapid tooth movement than the M group. The OM group showed a higher quantity of inflammatory cells and higher Mmp1 expression than the O group. The O and OM groups showed higher Nampt expression than the control group and lower Nampt expression than the M group.

CONCLUSIONS

Obesity modulates periodontal tissue remodeling during orthodontic movement and results in more inflammation and bone loss than in nonobese animals.

Inhibitory Effect of Topical Cartilage Acellular Matrix Suspension Treatment on Neovascularization in a Rabbit Corneal Model

BACKGROUND

The extracellular matrix (ECM) of articular cartilage has an inhibitory effect on vascularization, yet clinical utilization has been technically challenging. In this study, we aimed to fabricate a biologically functional ECM powder suspension from porcine articular cartilage that inhibits neovascularization (NV).

METHODS

The digested-cartilage acellular matrix (dg-CAM) was prepared by sequential processes of decellularization, enzymatic digestion and pulverization. Physicochemical properties of dg-CAM were compared with that of native cartilage tissue (NCT). Cellular interactions between human umbilical vein endothelial cells (HUVECs) and dg-CAM was evaluated with proliferation, migration and tube formation assays compared with that of type I collagen (COL) and bevacizumab, an anti-angiogenic drug. We then investigated the therapeutic potential of topical administration of dg-CAM suspension on the experimentally induced rabbit corneal NV model.

RESULTS

The dg-CAM released a significantly larger amount of soluble proteins than that of the NCT and showed an improved hydrophilic and dispersion properties. In contrast, the dg-CAM contained a large amount of collagen, glycosaminoglycans and anti-angiogenic molecules as much as the NCT. The inhibitory effect on NV of the dg-CAM was more prominent than that of COL and even comparable to that of bevacizumab in inhibiting the HUVECs. The therapeutic potential of the dg-CAM was comparable to that of bevacizumab in the rabbit corneal NV model by efficiently inhibiting neovessel formation of the injured cornea.

CONCLUSION

The current study developed a dg-CAM having anti-angiogenic properties, together with water-dispersible properties suitable for topical or minimally invasive application for prevention of vessel invasion.

Effect of concomitant treatment of curcumin and melatonin on cisplatin-induced nephrotoxicity in rats

Cisplatin (CP) is a potent anticancer drug used to treat solid tumors. Its use, however, is dose-limited by its nephrotoxicity. We aimed to compare the effect of melatonin and curcumin given singly, with that of a combination of these two agents on CP-induced nephrotoxicity in rats. CP (6 mg/kg, given once intraperitoneally) induced nephrotoxicity as evidenced by several significant adverse physiological, biochemical and histopathological actions that included a reduction in body weight, increased urine production, and significant alterations in some conventional and novel renal damage indices in plasma, urine and kidneys. CP also elevated several pro-inflammatory cytokines and caused renal oxidative/nitrosative stress. Supplementation with either curcumin (200 mg/kg) or melatonin (10 mg /kg) given singly by oral gavage for eight consecutive days prior to CP injection and four days thereafter, significantly mitigated the adverse renal effects of CP, by attenuating the pro-inflammatory and apoptotic mediators and improving antioxidant competence in renal tissues of CP- treated rats. When curcumin and melatonin were given together, the ameliorative effect was augmented in some of the measured indices e.g. tumor necrosis factor alpha, cystatin C, uric acid, phosphorus in plasma and, urine creatinine and creatinine clearance. Renal platinum concertation was reduced more with curcumin than that with melatonin, while the reduction was maximized when both melatonin and curcumin were given. Pending further pharmacological and toxicological studies, a combination of these two agents is likely to be mor effective in mitigating the adverse renal effects of CP administered to cancer patients.

Characterization and Proteomic Analysis of Decellularized Adipose Tissue Hydrogels Derived from Lean and Overweight/Obese Human Donors

While decellularized adipose tissue (DAT) has potential as an "off-the-shelf" biomaterial product for regenerative medicine, it remains to be determined if donor-source body mass index (BMI) impacts the functionality of DAT. This study set out to comparatively characterize lean versus overweight/obese-donor derived DAT hydrogel based on proteome and to analyze their respective effects on adipose stromal/stem cell (ASC) viability, and differentiation in vitro. Decellularized adipose tissue from lean (lDAT) and overweight/obese (oDAT) donors is produced and characterized. Variability in the fibril microstructures is found, with dense fibrotic fiber clusters and large pore area uniquely present in the oDAT samples. Proteomic analysis reveals that lDAT contains a greater proportion of enriched extracellular proteins and a smaller proportion of enriched intracellular proteins relative to oDAT. Biocompatibility studies show that ASCs cultured in lDAT and oDAT hydrogels remain viable. The adipogenic and osteogenic differentiation capability of ASCs seeded in lDAT and oDAT hydrogels is confirmed by an upregulation in marker gene expression and phenotypic analysis. In conclusion, this study establishes that DAT hydrogels derived from lean and overweight/obese adipose donors present similar physicochemical profiles with some distinctive features while comparably supporting the viability and adipogenic differentiation of ASCs in vitro.

Porcine Lung-Derived Extracellular Matrix Hydrogel Properties Are Dependent on Pepsin Digestion Time

Hydrogels derived from decellularized lungs are promising materials for tissue engineering in the development of clinical therapies and for modeling the lung extracellular matrix (ECM) in vitro. Characterizing and controlling the resulting physical, biochemical, mechanical, and biologic properties of decellularized ECM (dECM) after enzymatic solubilization and gelation are thus of key interest. As the role of enzymatic pepsin digestion in effecting these properties has been understudied, we investigated the digestion time-dependency on key parameters of the resulting ECM hydrogel. Using resolubilized, homogenized decellularized pig lung dECM as a model system, significant time-dependent changes in protein concentration, turbidity, and gelation potential were found to occur between the 4 and 24 h digestion time points, and plateauing with longer digestion times. These results correlated with qualitative scanning electron microscopy images and quantitative analysis of hydrogel interconnectivity and average fiber diameter. Interestingly, the time-dependent changes in the storage modulus tracked with the hydrogel interconnectivity results, while the Young's modulus values were more closely related to average fiber size at each time point. The structural and biochemical alterations correlated with significant changes in metabolic activity of several representative lung cells seeded onto the hydrogels with progressive decreases in cell viability and alterations in morphology observed in cells cultured on hydrogels produced with dECM digested for >12 and up to 72 h of digestion. These studies demonstrate that 12 h pepsin digest of pig lung dECM provides an optimal balance between desirable physical ECM hydrogel properties and effects on lung cell behaviors.

Chondrogenic response in presence of cartilage extracellular matrix nanoparticles

Current studies based on regenerative medicine suggest, decellularized extracellular matrix (DC-ECM) components can regulate cell phenotype. In this regard, it is believed, presence of cartilage extracellular matrix particles in culture condition could produce physical and biochemical supportive cues for chondrogenesis. In this study, DC-ECM nanoparticles with average size of 61.5± 22.4 nm were produced by decellularization and mechanical processing. Homogenous distribution and nanoscale size of yield particles were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) microscopy imaging. Chemical structure preservation of cartilage ECM after decellularization was also confirmed by typical Fourier transform infrared (FTIR) spectrum mapping. The influence these nanoparticles on chondrogenic response of chondrocyte cells was investigated by direct and indirect addition of nanoparticles to culture medium. A clinical devitalized cartilage powder (DV-ECM) was also used as a positive control. Totally, MTS results showed that direct and indirect presence of both DC-ECM and DV-ECM particles in culture medium enhanced cellular metabolic activity except on day one of culture. Furthermore, on day 21, SOX9 and COL2 expression of cultured chondrocytes in the medium containing DC-ECM nanoparticles were up-regulated in comparison to negative control, which was further confirmed by presence more frequent number of larger size lacunae in micromass spheroids. Our findings support the use of ECM nanoparticles as condition supplement in culture medium and injectable biomaterials, especially for cell-based therapies for cartilage regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2463-2471, 2018.

Comparison of two different laser photobiomodulation protocols on the viability of random skin flap in rats

To identify the best low level laser photobiomodulation application site at the same irradiation time to increase the viability of the skin flap in rats. Eighteen male rats (Rattus norvegicus: var. Albinus, Rodentia Mammalia) were randomly distributed into three groups (n = 6). Group I (GI) was submitted to simulated laser photobiomodulation; group II (GII) was submitted to laser photobiomodulation at three points in the flap cranial base, and group III (GIII) was submitted to laser photobiomodulation at 12 points distributed along the flap. All groups were irradiated with an Indium, Galium, Aluminum, and Phosphorus diode laser (InGaAlP), 660 nm, with 50 mW power, irradiated for a total time of 240 s in continuous emission mode. The treatment started immediately after performing the cranial base random skin flap (10 × 4 cm² dimension) and reapplied every 24 h, with a total of five applications. The animals were euthanized after the evaluation of the percentage of necrosis area, and the material was collected for histological analysis on the seventh postoperative day. GII animals presented a statistically significant decrease for the necrosis area when compared to the other groups, and a statistically significant increase in the quantification of collagen when compared to the control. We did not observe a statistical difference between the TGFβ and FGF expression in the different groups evaluated. The application of laser photobiomodulation at three points of the flap cranial base was more effective than at 12 points regarding the reduction of necrosis area.

Matrix Metalloproteinase-1 and Acid Phosphatase in the Degradation of the Lamina Propria of Eruptive Pathway of Rat Molars

The comprehension of dental pathogenesis and disorders derived from eruption failure requires a deep understanding of the molecular mechanisms underlying normal tooth eruption. As intense remodelling is needed during tooth eruption, we hypothesize that matrix metalloproteinase-1 (MMP-1) and acid phosphatase (ACP) play a role in the eruptive pathway degradation. We evaluated MMP-1-immunoexpression and the collagen content in the lamina propria at different eruptive phases. Immunohistochemistry and ultrastructural cytochemistry for detection of ACP were also performed. In the maxillary sections containing first molars of 9-, 11-, 13-, and 16-day-old rats, the birefringent collagen of eruptive pathway was quantified. MMP-1 and ACP-2 immunohistochemical reactions were performed and the number of MMP-1-immunolabelled cells was computed. Data were analyzed by one-way ANOVA and Tukey post-test (p ≤ 0.05). ACP cytochemistry was evaluated in specimens incubated in sodium β-glycerophosphate. In the eruptive pathway of 13- and 16-day-old rats, the number of MMP-1-immunolabelled cells increased concomitantly to reduction of collagen in the lamina propria. Enhanced ACP-2-immunolabelling was observed in the lamina propria of 13- and 16-day-old rats. Fibroblasts and macrophages showed lysosomes and vacuoles containing fragmented material reactive to ACP. MMP-1 degrades extracellular matrix, including collagen fibers, being responsible for the reduction in the collagen content during tooth eruption. The enhanced ACP activity at the mucosal penetration stage indicates that this enzyme plays a role in the degradation of remnant material, which is engulfed by macrophages and fibroblasts of the eruptive pathway. Therefore, enzymatic failure in the eruptive pathway may disturbs tooth eruption.

Utility of extracellular matrix powders in tissue engineering

Extracellular matrix (ECM) materials have had remarkable success as scaffolds in tissue engineering (TE) and as therapies for tissue injury whereby the ECM microenvironment promotes constructive remodeling and tissue regeneration. ECM powder and solubilized derivatives thereof have novel applications in TE and RM afforded by the capacity of these constructs to be dynamically modulated. The powder form allows for effective incorporation and penetration of reagents; hence, ECM powder is an efficacious platform for 3D cell culture and vehicle for small molecule delivery. ECM powder offers minimally invasive therapy for tissue injury and successfully treatment for wounds refractory to first-line therapies. Comminution of ECM and fabrication of powder-derived constructs, however, may compromise the biological integrity of the ECM. The current lack of optimized fabrication protocols prevents a more extensive and effective clinical application of ECM powders. Further study on methods of ECM powder fabrication and modification is needed.

Lung protection by inhalation of exogenous solubilized extracellular matrix

Decellularized extracellular matrix (ECM) contains complex tissue-specific components that work in concert to promote tissue repair and constructive remodeling and has been used experimentally and clinically to accelerate epithelial wound repair, leading us to hypothesize that lung-derived ECM could mitigate acute lung injury. To explore the therapeutic potential of ECM for noninvasive delivery to the lung, we decellularized and solubilized porcine lung ECM, then characterized the composition, concentration, particle size and stability of the preparation. The ECM preparation at 3.2 mg/mL with average particle size <3 μm was tested in vitro on human A549 lung epithelial cells exposed to 95% O2 for 24 hours, and in vivo by tracheal instillation or nebulization into the lungs of rats exposed intermittently or continuously to 90% O2 for a cumulative 72 hours. Our results showed that the preparation was enriched in collagen, reduced in glycosaminoglycans, and contained various bioactive molecules. Particle size was concentration-dependent. Compared to the respective controls treated with cell culture medium in vitro or saline in vivo, ECM inhalation normalized cell survival and alveolar morphology, and reduced hyperoxia-induced apoptosis and oxidative damage. This proof-of-concept study established the methodology, feasibility and therapeutic potential of exogenous solubilized ECM for pulmonary cytoprotection, possibly as an adjunct or potentiator of conventional therapy.

Airway epithelial repair in health and disease: Orchestrator or simply a player?

Epithelial cells represent the most important surface of contact in the body and form the first line of defence of the body to external environment. Consequently, epithelia have numerous roles in order to maintain a homeostatic defence barrier. Although the epithelium has been extensively studied over several decades, it remains the focus of new research, indicating a lack of understanding that continues to exist around these cells in specific disease settings. Importantly, evidence is emerging that airway epithelial cells in particular have varied complex functions rather than simple passive roles. One area of current interest is its role following injury. In particular, the epithelial-specific cellular mechanisms regulating their migration during wound repair remain poorly understood and remain an area that requires much needed investigation. A better understanding of the physiological, cellular and molecular wound repair mechanisms could assist in elucidating pathological processes that contribute to airway epithelial pathology. This review attempts to highlight migration-specific and cell-extracellular matrix (ECM) aspects of repair used by epithelial cells under normal and disease settings, in the context of human airways.

Establishment of a mouse model for pulmonary inflammation and fibrosis by intratracheal instillation of polyhexamethyleneguanidine phosphate

Although several animal models have been developed to study human pulmonary fibrosis, lack of a perfect model has raised the need for various animal models of pulmonary fibrosis. In this study, we evaluated the pulmonary effect of polyhexamethyleneguanidine phosphate instillation into the lungs of mice to determine the potential of these mice as a murine model of pulmonary fibrosis. Intratracheal instillation of polyhexamethyleneguanidine phosphate induced severe lung inflammation manifested by the infiltration of mononuclear cells and neutrophils and increased production of IL-6, TNF-α, CCL2 and CXCL1. The lung inflammation gradually increased until 28 days after polyhexamethyleneguanidine phosphate exposure, and increases of collagen deposition and TGF-β production, which are indicators of pulmonary fibrosis, were seen. Our study showed that intratracheal instillation of polyhexamethyleneguanidine phosphate induces pulmonary inflammation and fibrosis in mice.

Effects of early and late treatments of low-intensity, high-frequency mechanical vibration on bone parameters in rats

Low-intensity, high-frequency mechanical vibration (LHMV) has shown to increase bone formation. However, studies comparing the effectiveness of early- and late-treatments of LHMV to counteract bone loss have not been documented. This study was designed to compare the effects of early- and late-treatments of LHMV (at 30 Hz/0.6 g, 20 min per day/five days per week, for 12 weeks) on bone parameters in ovariectomized (Ovx) rats. Thirty days after ovariectomy, 40 adult rats were randomly divided into four groups: GI (early control group); GII treated with LHMV 3 weeks after Ovx (early treatment); GIII (late control group) and GIV treated with LHMV twelve weeks after Ovx (late treatment). Bone mineral density (BMD) was analyzed before Ovx and after treatments. Then, animals were killed, and the femurs were collected and their length and diaphysis diameter were measured; the distal femurs were taken and processed for histomorphometry and polarized light microscopy for collagen fibers analysis or subjected to immunohistochemistry of cleaved caspase-3 in osteocytes. Statistical analysis was done by ANOVA followed by the Bonferroni post hoc test (p < 0.05). BMD was similar among the groups before Ovx, but after treatments, it was significantly higher in GII and GIV compared with their control groups (p < 0.05). Femur length and cortical bone thickness were similar among the groups, but the diaphysis diameter of GII was higher compared with GI. Trabecular bone area was higher in the vibrated groups, but it was greater in GII (p < 0.05). Also, the vibrated groups showed the higher content collagen fibers and lower presence apoptotic osteocytes (positive caspase-3 immunoreactivity) when compared with the other groups (p < 0.05). These results suggest that both early- and late-treatments with LHMV counteract bone loss, being the early treatment more effective than the late treatment.

Tracheal bioengineering: the next steps. Proceeds of an International Society of Cell Therapy Pulmonary Cellular Therapy Signature Series Workshop, Paris, France, April 22, 2014

There has been significant and exciting recent progress in the development of bioengineering approaches for generating tracheal tissue that can be used for congenital and acquired tracheal diseases. This includes a growing clinical experience in both pediatric and adult patients with life-threatening tracheal diseases. However, not all of these attempts have been successful, and there is ongoing discussion and debate about the optimal approaches to be used. These include considerations of optimal materials, particularly use of synthetic versus biologic scaffolds, appropriate cellularization of the scaffolds, optimal surgical approaches and optimal measure of both clinical and biologic outcomes. To address these issues, the International Society of Cell Therapy convened a first-ever meeting of the leading clinicians and tracheal biologists, along with experts in regulatory and ethical affairs, to discuss and debate the issues. A series of recommendations are presented for how to best move the field ahead.

NF-kB overexpression and decreased immunoexpression of AR in the muscular layer is related to structural damages and apoptosis in cimetidine-treated rat vas deferens

BACKGROUND

Cimetidine, histamine H2 receptors antagonist, has caused adverse effects on the male hormones and reproductive tract due to its antiandrogenic effect. In the testes, peritubular myoid cells and muscle vascular cells death has been associated to seminiferous tubules and testicular microvascularization damages, respectively. Either androgen or histamine H2 receptors have been detected in the mucosa and smooth muscular layer of vas deferens. Thus, the effect of cimetidine on this androgen and histamine-dependent muscular duct was morphologically evaluated.

METHODS

The animals from cimetidine group (CMTG; n=5) received intraperitoneal injections of 100 mg/kg b.w. of cimetidine for 50 days; the control group (CG) received saline solution. The distal portions of vas deferens were fixed in formaldehyde and embedded in paraffin. Masson´s trichrome-stained sections were subjected to morphological and the following morphometrical analyzes: epithelial perimeter and area of the smooth muscular layer. TUNEL (Terminal deoxynucleotidyl-transferase mediated dUTP Nick End Labeling) method, NF-kB (nuclear factor kappa B) and AR (androgen receptors) immunohistochemical detection were also carried out. The birefringent collagen of the muscular layer was quantified in picrosirius red-stained sections under polarized light. The muscular layer was also evaluated under Transmission Electron Microscopy (TEM).

RESULTS

In CMTG, the mucosa of vas deferens was intensely folded; the epithelial cells showed numerous pyknotic nuclei and the epithelial perimeter and the area of the muscular layer decreased significantly. Numerous TUNEL-labeled nuclei were found either in the epithelial cells, mainly basal cells, or in the smooth muscle cells which also showed typical features of apoptosis under TEM. While an enhanced NF-kB immunoexpression was found in the cytoplasm of muscle cells, a weak AR immunolabeling was detected in these cells. In CMTG, no significant difference was observed in the birefringent collagen content of the muscular layer in comparison to CG.

CONCLUSIONS

Cimetidine induces significant damages in the epithelium; a possible antiandrogenic effect on the basal cells turnover should be considered. The cimetidine-induced muscle cells apoptosis confirms the susceptibility of these cells to this drug. The parallelism between enhanced cytoplasmic NF-kB immunolabeling in the damaged muscular tissue and muscle cell apoptosis suggests that this drug may avoid the translocation of NF-kB to the nucleus and interfere in the control of NF-kB-mediated smooth muscle cell apoptosis. The decreased immunoexpression of ARs verified in the damaged muscular tissue reinforces this possibility.

Perspectives on whole-organ assembly: moving toward transplantation on demand

There is an ever-growing demand for transplantable organs to replace acute and chronically damaged tissues. This demand cannot be met by the currently available donor organs. Efforts to provide an alternative source have led to the development of organ engineering, a discipline that combines cell biology, tissue engineering, and cell/organ transplantation. Over the last several years, engineered organs have been implanted into rodent recipients and have shown modest function. In this article, we summarize the most recent advances in this field and provide a perspective on the challenges of translating this promising new technology into a proven regenerative therapy.