Search Results (72)

Background/Objectives: Nerve injuries cause functional loss and psychosocial issues due to prolonged rehabilitation. Recently, 3D-modeled nerve conduits have been used to aid in surgical planning. This study investigated the impact of 3D-bioprinted PLA, chitosan, alginate, and collagen conduits on nerve regeneration in a rat sciatic nerve crush injury model. Methods: This study, conducted at Kütahya University of Health Sciences, involves 50 rats were divided into four groups: (1) sham-operated controls, (2) sciatic nerve injury without treatment, (3) injury treated with a PLA conduit, and (4) injury treated with 3D-printed tubes composed of chitosan and alginate. The procedures were performed, blood was collected, and the rats were sacrificed after two months. Weekly checks for infection, scar healing, and motor responses were performed. Results: Rats with nerve conduits showed less macroscopic scarring. Weekly assessments of motor nerve recovery showed no movement restrictions in limbs treated with PLA conduits, graft conduits, or conduits bridging retracted nerve stumps, based on responses to stimulus checks. An infection developed in the sciatic nerve and surrounding muscle tissue of one rat with a bio-graft conduit, prompting histopathological examination to investigate its cause. Conclusions: This proof-of-principle study demonstrates the feasibility of using 3D-printed biocompatible nerve conduits for peripheral nerve repair, providing a basis for future, more comprehensive investigations. Full article

Cannabidiol (CBD) and tetrahydrocurcumin (THC) have demonstrated anti-inflammatory activity as well as generating new lymph vessels. We present the formulations and evaluations of CBD and THC loaded in hydrogels for the treatment of lymphedema to promote angiogenesis of lymph vessels and an anti-inflammatory response. Six CBD-THC hydrogel formulations were prepared and evaluated. The hydrodynamic particle sizes were 302.0–545.1 nm and the zeta potentials were from −58.80 to −33.63 mV. The hydrogel pHs were 6.43–6.54. The hydrogel formulations were non-toxic for both CBD (<25 µg/mL) and THC (<12.5 µg/mL). It was observed that high-molecular-weight hyaluronic acid in hydrogel affected collagen production. Hydrogel formulations at 2 µg/mL of CBD and 1 µg/mL of THC induced human dermal lymphatic endothelial cell tube formation. CBD-THC hydrogel formulations showed a notable ability to induce angiogenesis, which suggested its potential effectiveness in promoting new lymphatic vessel formation. Moreover, CBD-THC hydrogels showed anti-inflammatory properties. Further research is needed to ensure these treatments effectively enhance lymphatic repair. Full article

Objectives: This study sought to determine the platelet function and viscoelastic blood properties in the pre- and postoperative period using three different point-of-care (POC) devices (Multiplate^®, Siemens PFA-200^® and ROTEM^®). We aimed to investigate the association between preoperative POC test results and bleeding outcomes. Postoperative changes in blood hemostatic properties were also evaluated, as well as the agreement between two platelet function analyzers and rotational thromboelastometry parameters. Methods: The study was conducted in a prospective observational fashion. Patients undergoing elective coronary artery bypass graft surgery (CABG) were enrolled. Hemostatic blood properties were assessed using three different POC devices; two platelet function analyzers were used: (1) Impedance aggregometry (Multiplate^®) with the arachidonic acid (ASPI) test and adenosine diphosphate (ADP) test. (2) The Siemens INNOVANCE^® PFA-200 System with the following assays: the PFA Collagen/EPI test, PFA Collagen/ADP test, and the INNOVANCE^® PFA P2Y test. Viscoelastic blood properties were assessed using ROTEM^® delta (TEM Innovations GmbH, Munich, Germany). POC tests were performed simultaneously at two different time points: (1) before surgery and (2) on postoperative day 4, respectively. The primary outcome was defined as amounts of perioperative bleeding and transfusion requirements, classified according to the universal definition for perioperative bleeding (UDPB) score. Results: The study recruited a total number of 63 patients undergoing elective isolated coronary artery bypass graft surgery (CABG). Based on the packed red blood cell (PRBC) transfusion requirements, patients with excessive bleeding were not just only frequently transfused (87.5% vs. 48.9%, p = 0.007) but were also transfused with higher amounts of PRBCs (1338.75 mL ± SD 1416.49 vs. 289.36 mL ± 373.07, p < 0.001). The FIBTEM A30 results significantly correlated with excessive bleeding (Correlation Coefficient Rho = −0.280, p = 0.028). Regression analysis revealed FIBTEM A 30 as a strongest predictor of 24 h chest tube output (CTO) (R Square 0.108, p = 0.009). The receiver operating characteristics curve (ROC) analysis showed that a preoperative FIBTEM A30 < 10.86 mm predicted excessive bleeding with 94% sensitivity and 50% specificity (ROC AUC 68.4%). The multiplate ASPI test results were significantly higher (35.24 AUC ± SD 22.24 vs. 19.43 AUC ± SD 10.74) and the proportion of Aspirin responders was significantly lower (42.4% vs. 76.7%, p = 0.006) in patients considered to have insignificant bleeding. On postoperative day 4, we found platelet hyperreactivity in the ASPItest coupled with a ROTEM-documented shift towards hypercoagulability. Conclusions: Modern hemostatic management and perioperative antiplatelet therapy (APT) administration/discontinuation management should be guided by thromboelastometry and platelet function testing. Prospective interventional trials are necessary to validate such an approach in multicentric studies. Full article

PDRN, polydeoxyribonucleotide, which is used as a tissue-regeneration material, is present in human cells under physiological conditions and stimulates regeneration and metabolic activity. PDRN can be used as a biomaterial for several types of regeneration, including wound healing, to promote cell growth and growth-factor production. The aims of this study were to determine the effect of PDRN derived from human placenta-derived mesenchymal stem cells (hPD-MSCs) on cellular regeneration through A2A receptor signaling and to investigate its therapeutic effects in a mouse model of wound healing. Human PDRN (UNIPlax) was extracted from hPD-MSCs fragmented via a sonication system and evaluated for its effect on the migration of HaCaT cells in an in vitro system and in a wound-healing mouse model in vivo. Compared with the sham treatment, UNIPlax treatment significantly increased the migration of injured HaCaT cells (p < 0.05). Additionally, the tube formation of human umbilical vein endothelial cells (HUVECs) was greater than that of the sham group (p < 0.05), and the effects of this treatment were mediated through the A2A receptor. Furthermore, UNIPlax treatment led to a decrease in wound size; in addition, the area of granulation and the rate of collagen formation at the wound site were significantly greater than those in the sham group in the wound-healing mouse model (p < 0.001). We also confirmed that UNIPlax promoted tissue regeneration and the expression of VEGF through the A2A receptor. Taken together, these findings indicate that UNIPlax has potential for regeneration of damaged tissues, including during wound healing. Full article

The ultrastructure of submandibular gland (SMG) of Bactrian camels was observed by a transmission electron microscope. Routine HE staining, special staining combined with immunohistochemistry, and immunofluorescence techniques were used to study the histochemical characteristics of the submandibular gland and the localisation and distribution characteristics of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR). HE results showed that the submandibular gland of Bactrian camels was composed of mixed serous and mucinous acini glands. The submandibular striated duct was highly developed and connected with intercalated ducts with larger diameter. Intercalated ducts are shorter and directly connected to acini. In AB-PAS staining, it was observed that the inner wall of striated tube was strongly positive for AB staining. The distribution of the reticular fibres around the follicles and ducts of the submandibular gland is distinct, with collagen fibres distributed mainly in the periphery of the ducts and sparse collagen fibres in the periphery of the acini. Immunohistochemistry and fluorescence show that EGF is strongly positive in striated and intercalated ducts, and EGFR is weakly positive in striated and intercalated ducts. Bactrian camel SMGs secrete more acidic mucins, and EGF and EGFR were mainly secreted and play a role in the pipeline system of SMGs. Full article

It is known that ultrashort echo time (UTE) magnetic resonance imaging (MRI) sequences can detect signals from water protons but not collagen protons in short T2 species such as cortical bone and tendons. However, whether collagen protons are visible with the zero echo time (ZTE) MRI sequence is still unclear. In this study, we investigated the potential of the ZTE MRI sequence on a clinical 3T scanner to directly image collagen protons via D₂O exchange and freeze-drying experiments. ZTE and UTE MRI sequences were employed to image fully hydrated bovine cortical bone (n = 10) and human patellar tendon (n = 1) specimens. Then, each specimen was kept in a 30 mL syringe filled with D₂O solution for two days. Fresh D₂O was flushed every 2 h to reach a more complete D₂O–H₂O exchange. Later, the samples were lyophilized for over 40 h and then sealed in tubes. Finally, the samples were brought to room temperature and visualized using the identical 3D ZTE and UTE sequences. All hydrated bone and tendon specimens showed high signals with ZTE and UTE sequences. However, all specimens showed zero signal after the D₂O exchange and freeze-drying procedures. Therefore, similar to UTE imaging, the signal source in ZTE imaging is water. The ZTE sequence cannot directly detect signals from collagen protons in bone and tendons. Full article

Background/Objectives: Cyclophosphamide (CP) is widely used for treating various cancers and autoimmune diseases, but it causes damage to reproductive organs due to oxidative stress (OS) and inflammation. Boric acid (BA) has antioxidant properties that may help reduce OS, which is critical for preserving uterine functionality, particularly for cancer patients considering pregnancy after cryopreservation. This study aimed to determine whether BA could diminish CP-induced toxicity in the uterus and fallopian tubes (FT) using CP-induced toxicity in a rat model. Methods: Forty female Wistar rats, aged 18–20 weeks, were divided into four groups as follows: control, oral BA (OBR), CP, and CP plus OBR (CP + OBR). The toxicity was induced in the CP and CP + OBR groups with an initial dose of 200 mg/kg CP, followed by 8 mg/kg daily for 14 days. Rats in the OBR and CP + OBR groups received 20 mg/kg/day of BA. After the 16-day experiment, tissues were collected for analysis. Results: Histopathological and immunohistochemical assessments of IL-6 and HIF-1α expressions were used to evaluate inflammation and OS. The control, OBR, and CP + OBR groups maintained normal tissue features, while the CP group showed epithelial cell shedding, vacuolization, degenerative endometrial glands, lymphocyte infiltration, and reduced collagen fiber density. Elevated HIF-1α and IL-6 expressions in the uterus and FT indicated significant OS and inflammation. Conclusions: The study concluded that BA supplementation in CP-treated rats effectively reduced CP-induced uterine and FT damage, suggesting the potential protective role of BA in managing CP-associated toxicity. Full article

Angiogenesis, the formation of new blood vessels, is a fundamental process in both physiological repair mechanisms and pathological conditions, including cancer and chronic inflammation. Hydrogels are commonly used as in vitro models to mimic the extracellular matrix (ECM) and support endothelial cell behavior during angiogenesis. Mesenchymal stem cells further augment cell and tissue growth and are therefore widely used in regenerative medicine. Here we examined the combination of distinct hydrogel types—fibrin, collagen, and human platelet lysate (HPL)—on the formation of capillaries in a co-culture system containing human umbilical vein endothelial cells (HUVECs) and bone marrow-derived mesenchymal stem cells (BM-MSCs). The mechanical properties and structural changes of the hydrogels were characterized through scanning electron microscopy (SEM) and nanoindentation over 10 days. Fibrin and HPL gels sustained complex network formations, with HPL gels promoting even vascular tube formation of up to 10-fold capillary caliber. Collagen gels supported negligible angiogenesis. Our results suggest that HPL gels in combination with MSC-EC co-culture may be employed to obtain robust vascularization in tissue engineering. This study provides a comparative analysis of fibrin, collagen, and HPL hydrogels, focusing on their ability to support angiogenesis under identical conditions. Our findings demonstrate the superior performance of HPL gels in promoting robust vascular structures, highlighting their potential as a versatile tool for in vitro angiogenesis modeling. Full article

Pig skeletal muscle-derived stem cells (SK-MSCs) were transplanted onto the common peroneal nerve with a collagen tube as a preclinical large animal experiment designed to address long nerve gaps. In terms of therapeutic usefulness, a human family case was simulated by adjusting the major histocompatibility complex to 50% and 100% correspondences. Swine leukocyte antigen (SLA) class I haplotypes were analyzed and clarified, as well as cell transplantation. Skeletal muscle-derived CD34+/45− (Sk-34) cells were injected into bridged tubes in two groups (50% and 100%) and with non-cell groups. Therapeutic effects were evaluated using sedentary/general behavior-based functional recovery score, muscle atrophy ratio, and immunohistochemistry. The results indicated that a two-Sk-34-cell-transplantation group showed clearly and significantly favorable functional recovery compared to a non-cell bridging-only group. Supporting functional recovery, the morphological reconstitution of the axons, endoneurium, and perineurium was predominantly evident in the transplanted groups. Thus, Sk-34 cell transplantation is effective for the regeneration of peripheral nerve gap injury. Additionally, 50% and 100% SLA correspondences were therapeutically similar and not problematic, and no adverse reaction was found in the 50% group. Therefore, the immunological response to Sk-MSCs is considered relatively low. The possibility of the Sk-MSC transplantation therapy may extend to the family members beyond the autologous transplantation. Full article

The evolution of biomaterials engineering allowed for the development of products that improve outcomes in the medical–dental field. Bioglasses have demonstrated the ability to either compose or replace different materials in dentistry. This study evaluated the cytotoxicity, biocompatibility, calcium deposition, and collagen maturation of 45S5 bioglass experimental paste and Bio-C Temp, compared to calcium hydroxide (Ca(OH)₂) paste. The 45S5 bioglass and Ca(OH)₂ powder were mixed with distilled water (ratio 2:1); Bio-C Temp is ready-for-use. Dental pulp cells were exposed to the materials’ extracts (1:2 and 1:4 dilutions; 24, 48, and 72 h) for MTT and live/dead analyses. Polyethylene tubes filled with the pastes, or left empty (control), were implanted on the dorsum of 16 rats. After 7 and 30 days (n = 8/period), the rats were euthanized and the specimens were processed for hematoxylin–eosin (H&E), von Kossa (vK), and picrosirius red (PSR) staining, or without staining for polarized light (PL) birefringence analysis. A statistical analysis was applied (p < 0.05). There was no difference in cell viability among Ca(OH)₂, 45S5 bioglass, and the control, across all periods and dilutions (p > 0.05), while Bio-C Temp was cytotoxic in all periods and dilutions compared to the control (p < 0.05). Regarding biocompatibility, there was a reduction in inflammation from 7 to 30 days for all groups, without significant differences among the groups for any period (p > 0.05). The fibrous capsules were thick for all groups at 7 days and thin at 30 days. All materials showed positive structures for vK and PL analysis. At 7 days, the control and 45S5 bioglass showed more immature collagen than the other groups (p < 0.05); at 30 days, 45S5 bioglass had more immature than mature collagen, different from the other groups (p < 0.05). In conclusion, Bio-C Temp presented cytotoxicity compared to the other materials, but the three pastes showed biocompatibility and induced calcium deposition. Additionally, the bioglass paste allowed for marked and continuous collagen proliferation. This study contributed to the development of new biomaterials and highlighted different methodologies for understanding the characteristics of medical–dental materials. Full article

To develop peptide drugs targeting integrin receptors, synthetic peptide ligands endowed with well-defined selective binding motifs are necessary. The snake venom KTS-containing disintegrins, which selectively block collagen α1β1 integrin, were used as lead compounds for the synthesis and structure–activity relationship of a series of linear peptides containing the KTS-pharmacophore and alternating natural amino acids and 3-aminobenzoic acid (MABA). To ensure a better stiffness and metabolic stability, one, two and three MABA residues, were introduced around the KTS pharmacophore motif. Molecular dynamics simulations determined that the solution conformation of MABA peptide 4 is more compact, underwent larger conformational changes until convergence, and spent most of the time in a single cluster. The peptides’ binding affinity has been characterized by an enzyme linked immunosorbent assay in which the most potent peptide 4 inhibited with IC₅₀ of 324 ± 8 µM and 550 ± 45 µM the binding of GST-α1-A domain to collagen IV fragment CB3, and the cell adhesion to collagen IV using α1-overexpressor cells, respectively. Docking studies and MM-GBSA calculations confirmed that peptide 4 binds a smaller region of the integrin near the collagen-binding site and penetrated deeper into the binding site near Trp1. Peptide 4 inhibited tube formation by endothelial cell migration in the Matrigel angiogenesis in vitro assay. Peptide 4 was acutely tolerated by mice, showed stability in human serum, decreased tumor volume and angiogenesis, and significantly increased the survival of mice injected with B16 melanoma cells. These findings propose that MABA-peptide 4 can further serve as an α1β1-integrin antagonist lead compound for further drug optimization in angiogenesis and cancer therapy. Full article

High-grade serous ovarian cancer (HGSOC) is the predominant subtype of ovarian cancer (OC), occurring in more than 80% of patients diagnosed with this malignancy. Histological and genetic analysis have confirmed the secretory epithelial of the fallopian tube (FT) as a major site of origin of HGSOC. Although there have been significant strides in our understanding of this disease, early stage detection and diagnosis are still rare. Current clinical imaging modalities lack the ability to detect early stage pathogenesis in the fallopian tubes and the ovaries. However, there are several microscopic imaging techniques used to analyze the structural modifications in the extracellular matrix (ECM) protein collagen in ex vivo FT and ovarian tissues that potentially can be modified to fit the clinical setting. In this perspective, we evaluate and compare the myriad of optical tools available to visualize these alterations and the invaluable insights these data provide on HGSOC initiation. We also discuss the clinical implications of these findings and how these data may help novel tools for early diagnosis of HGSOC. Full article

This preliminary study aimed to investigate an ActiGraft blood clot implant (RedDress Ltd., Pardes-Hanna, Israel) attempting to treat and induce the regeneration of a completely injured peripheral nerve with a massive loss defect. The tibial portion of the sciatic nerve in 11 rabbits was transected, and a 25 mm nerve gap was reconnected using a collagen tube. A comparison was performed between the treatment group (eight rabbits; reconnection using a tube filled with ActiGraft blood clot) and the control group (three rabbits; gap reconnection using an empty tube). The post-operative follow-up period lasted 18 weeks and included electrophysiological and histochemical assessments. The pathological severity score was high in the tube cross sections of the control group (1.33) compared to the ActiGraft blood clot treatment group (0.63). Morphometric analysis showed a higher percentage of the positive myelin basic protein (MBP) stained area in the ActiGraft blood clot group (19.57%) versus the control group (3.67%). These differences were not statistically significant due to the small group sizes and the large intra-group variability. The results of this preliminary study suggest that the application of an ActiGraft blood clot (into the collagen tube) can enable nerve recovery. However, a future study using a larger animal group is required to achieve objective statistical results. Full article

Advancements in regenerative medicine have highlighted the potential of decellularized extracellular matrix (ECM) as a scaffold for organ bioengineering. Although the potential of ECM in major organ systems is well-recognized, studies focusing on the angiogenic effects of pancreatic ECM are limited. This study investigates the capabilities of pancreatic ECM, particularly its role in promoting angiogenesis. Using a Triton-X-100 solution, porcine pancreas was successfully decellularized, resulting in a significant reduction in DNA content (97.1% removal) while preserving key pancreatic ECM components. A three-dimensional ECM hydrogel was then created from this decellularized tissue and used for cell culture. Biocompatibility tests demonstrated enhanced adhesion and proliferation of mouse embryonic stem cell-derived endothelial cells (mES-ECs) and human umbilical vein endothelial cells (HUVECs) in this hydrogel compared to conventional scaffolds. The angiogenic potential was evaluated through tube formation assays, wherein the cells showed superior tube formation capabilities in ECM hydrogel compared to rat tail collagen. The RT-PCR analysis further confirmed the upregulation of pro-angiogenic genes in HUVECs cultured within the ECM hydrogel. Specifically, HUVECs cultured in the ECM hydrogel exhibited a significant upregulation in the expression of MMP2, VEGF and PAR-1, compared to those cultured in collagen hydrogel or in a monolayer condition. The identification of ECM proteins, specifically PRSS2 and Decorin, further supports the efficacy of pancreatic ECM hydrogel as an angiogenic scaffold. These findings highlight the therapeutic promise of pancreatic ECM hydrogel as a candidate for vascularized tissue engineering application. Full article

Micro-computed tomography (microCT) is a common tool for the visualization of the internal composition of organic tissues. Collagen comprises approximately 25–35% of the whole-body protein content in mammals, and the structure and arrangement of collagen fibers contribute significantly to the integrity of tissues. Collagen type I is also frequently used as a key structural component in tissue-engineered and bioprinted tissues. However, the imaging of collagenous tissues is limited by their inherently low X-ray attenuation, which makes them indistinguishable from most other soft tissues. An imaging contrast agent that selectively alters X-ray attenuation is thus essential to properly visualize collagenous tissue using a standard X-ray tube microCT scanner. This review compares various contrast-enhanced techniques reported in the literature for MicroCT visualization of collagen-based tissues. An ideal microCT contrast agent would meet the following criteria: (1) it diffuses through the tissue quickly; (2) it does not deform or impair the object being imaged; and (3) it provides sufficient image contrast for reliable visualization of the orientation of individual fibers within the collagen network. The relative benefits and disadvantages of each method are discussed. Lugol’s solution (I₃K), phosphotungstic acid (H₃PW₁₂O₄₀), mercury(II) chloride (HgCl₂), and Wells–Dawson polyoxometalates came closest to fitting the criteria. While none of the contrast agents discussed in the literature met all criteria, each one has advantages to consider in the context of specific lab capabilities and imaging priorities. Full article