Use of a latex biomembrane for bladder augmentation in a rabbit model: biocompatibility, clinical and histological outcomes

Effects of Low-Level Laser Therapy and Purified Natural Latex (Hevea brasiliensis) Protein on Injured Sciatic Nerve in Rodents: Morpho-Functional Analysis

The present study analyzed the effects of low-level laser therapy (LLLT) and the purified natural latex protein (Hevea brasiliensis, F1 protein) on the morpho-function of sciatic nerve crush injuries in rats. One-hundred and eight male Wistar rats were randomly allocated to six groups (n = 18): 1. Control; 2. Exposed (nerve exposed); 3. Injury (injured nerve without treatment); 4. LLLT (injured nerve irradiated with LLLT (15 J/cm2, 780 nm)); 5. F1 (injured nerve treated with F1 protein (0.1%)); and 6. LLLT + F1 (injured nerve treated with LLLT and F1). On the 1st, 7th, 14th, and 56th days after injury, a functional sensory analysis of mechanical allodynia and mechanical hyperalgesia and a motor analysis of grip strength and gait were performed. After 3, 15, and 57 days, the animals were euthanized for morphometric/ultrastructural analyses. The treatments applied revealed improvements in morphometric/ultrastructural parameters compared to the injured group. Sensory analyses suggested that the improvements observed were associated with time progression and not influenced by the treatments. Motor analyses revealed significant improvements in grip strength from the 7th day in the LLLT group and in gait from the 56th day in all treated groups. We concluded that even though the morphological analyses showed improvements with the treatments, they did not influence sensory recovery, and LLLT improved motor recovery.

Natural latex serum: characterization and biocompatibility assessment using Galleria mellonella as an alternative in vivo model

Natural latex serum (NLS) is one of the natural rubber latex fractions from Hevea brasiliensis tree, which is formed by centrifuged serum and is composed of proteins, acids, nucleotides, salts and carbohydrates. The proteins present in NLS have demonstrated several interesting biological properties, including angiogenic, healing, osteogenic, anti-inflammatory, antimicrobial, in addition to inducing neovascularization, bone formation and osseointegration. Thus, we proposed to characterize NLS by physicochemical techniques and to investigate the biocompatibility by toxicological assays and safety test in Galleria mellonella. Infrared spectrum showed vibrational bands characteristic of amide I, II and III that are linked to the protein content, which was confirmed by the High Performance Liquid Chromatography profile and by the Electrophoresis analysis. This material did not exhibit hemolytic (rate <0.5%) and cytotoxic effects (viability >70%) and was able to enhance the proliferation of fibroblasts (>600%) after 3 days. The pronounced proliferative effect observed in fibroblast cells can be explained by the presence of the fibroblast growth factor (FGF) like protein revealed by the Western blot test. Moreover, NLS did not provoke toxic effects (survival ∼ 80%) on the G. mellonella model, indicating that it is a biocompatible and safe material.

In-vivo regeneration of bladder muscular wall with whole decellularized bladder matrix: A novel hourglass technique for duplication of bladder volume in rabbit model

OBJECTIVE

To determine histological aspects of decellularized bladder graft to achieve a double-sized bladder by novel hourglass technique; using rabbit models.

METHODS

Sixteen rabbit bladders were decellularized and underwent laboratory investigations. After making a laparotomy incision and exposure of bladders in another 16 rabbits (partial detrusor myomectomy), they were separated into two groups. The fundus of the decellularized scaffold was anastomosed to the fundus of the native bladder via the serosal layer, and the omentum and a double-J stent were placed in the decellularized bladder by no direct contact with the urine (Group A, n=8). In group B (n=8), the bladder was augmented applying the decellularized bladder that was in contact with the urine. After 6 months, the omentum was brought out of the neck of the engineered bladder and the anastomosis was opened. Biopsies were taken at 1, 3, and 9 months postoperatively.

RESULTS

Cell removal with preservation of extracellular matrix structure was confirmed in decellularized bladders. Histological examination after 1 month demonstrated few cells at the border of the grafts. After 3 months, the region of the graft was indistinguishable from the natural bladder with continuity of transitional epithelium of natural bladder on the decellularized grafted scaffolds. The organization of muscle layers was similar to native bladder muscle layers after 9 months. IHC staining markers were highly expressed after 9 months. Interestingly, bladders had a high fibrosis grade in group B compared with hourglass technique.

CONCLUSION

We confirmed that decellularized bladder may be a reliable scaffold and viable material for bladder augmentation.

Voriconazole-natural latex dressings for treating infected Candida spp. skin ulcers

Aim: This work aimed to develop a membrane based on voriconazole (VCZ)-loaded natural rubber latex (NRL) for treating infected ulcers with Candida spp. and study their interaction, drug release, antifungal activity against Candida parapsilosis and biological characterization. Materials & methods: VCZ-loaded NRL membrane was produced by casting method. Results: Infrared spectrum showed that the incorporation of VCZ into the NRL membrane maintained its characteristics. Its mechanical properties were considered suitable for dermal application. The VCZ was able to release from NRL membrane, maintaining its antifungal activity against C. parapsilosis, besides did not present hemolytic effects. Conclusion: The VCZ-NRL membrane showed good results in mechanical, antifungal and biological assays, representing an interesting alternative to treatment of infected wound with Candida spp.

Evidence in Practice of Tissue Healing with Latex Biomembrane: Integrative Review

Wound healing is a perfectly coordinated cascade of cellular, molecular, and biochemical events which interact in tissue reconstitution. Chronic diseases such as pressure ulcers (PU) and diabetes mellitus (DM) are considered risk factors for wound healing. Patients with such diseases often have higher sepsis, infection, and complication rates, since they have revascularization inhibition and low growth factor expression. Thus, latex biomembrane (LBM), a biocompatible material, derived from the latex of the rubber tree (Hevea brasiliensis) appears to create tendencies as an angiogenic-inducing tissue healing agent and as biomaterial, resulting from its structural qualities and its low cost when compared to conventional treatments. Therefore, this work aims at summarizing the results, experiments, and scientific findings that certify or recommend the use of LBM as a new technique to be applied effectively in the treatment of wounds. An integrative review was held in the BIREME, LILACS, Burns, MEDLINE, PubMed, and SciELO databases, from 2000 to 2016, using the following descriptors: "healing," "diabetes mellitus," "wounds," and "latex membrane." As a result, 600 experiments (out of 612) presented satisfactory results; however, 33% of the cases received explicit recommendations, 11% required more studies on the subjects, and 1% was denied. On the other hand, half of the studies did not expressly endorse its use, despite presenting satisfactory results. The LBM was characterized as a good therapeutic alternative in cases of wounds, including chronic diseases, such as diabetes mellitus and PU, due to its relevant potential for wound healing stimulation, acceleration of cell tissue mending and revascularization, or the reestablishment of angiogenic functions (creation of new blood vessels). The LBM was also confirmed to be safe as a biocompatible material whose structural qualities (elasticity, adaptability, impermeability, and possibility of suture), devoid of toxicity, allowed interaction between tissues and presented no hypersensitivity inducer and no antimicrobial effect.

Effects of bacterial cellulose gel on the anorectal resting pressures in rats submitted to anal sphincter injury

The aim of this study is to evaluate if a gel of bacterial cellulose gel can revert the loss of anal resting pressure after anorectum sphincter injury in rat model, elected as a model to simulate fecal incontinence. Thirty-nine animals were equally divided into three groups: Control (CG), Sphincter injury plus Saline injection (SG) and Sphincter injury plus Bacterial Cellulose Gel injection (BCG). Anal pressure at rest was assessed for all animal in the three groups using anorectum manometry. Saline and Gel groups were subject to anorectum sphincter injury to reduce the anal pressure at rest. Fifteen days later Saline or Gel was injected into the anorectum, according to their groups. Sixty days later first manometry, the anorectum of all animals were removed and processed histologically. The CG group showed maintenance of their mean anorectal resting pressure levels; SG presented a fall in their mean anorectal resting pressure. The BCG presented a significant elevation of the mean anorectal resting pressure levels, surpassing the pressure of CG. The gel of bacterial cellulose remained at the injection site and was neovascularized, colonized by fibroblasts and dense conjunctive tissue. Those data suggest that BC can be used as a future filling agent treatment for fecal incontinence in clinical trial protocols.

Novel membranes from physico-chemically modified deproteinized natural rubber latex: development, characterisation and drug permeation

Novel blend membranes from physico-chemically modified deproteinized natural rubber latex for drug release applications.

Morphometric and high resolution scanning electron microscopy analysis of low-level laser therapy and latex protein (Hevea brasiliensis) administration following a crush injury of the sciatic nerve in rats

This study evaluated the effect of low-level laser therapy (LLLT; 15 J/cm(2)) and a latex protein (F1) on a crush injury of the sciatic (ischiadicus) nerve. Seventy-two rats (male, 250 g) were divided into 6 groups: CG, control; EG, exposed nerve; IG, injured nerve without treatment; LG, injured nerve with LLLT; HG, injured nerve with F1; and LHG, injured nerve with LLLT and F1. After 4 or 8 weeks, the animals were euthanized and samples of the sciatic nerve were collected for morphometric and high-resolution scanning electron microscopy (HRSEM) analysis. After 4 weeks, the morphometry revealed improvements in the treated animals, and the HG appeared to be the most similar to the CG; after 8 weeks, the injured groups showed improvements compared to the previous period, and the results of the treatment groups were more similar to one another. At HRSEM after 4 weeks, the treated groups were similar and showed improvement compared to the IG; after 8 weeks, the LHG and HG had the best results. In conclusion, the treatments resulted in improvement after the nerve injury, and this recovery was time-dependent. In addition, the use of the F1 resulted in the best morphometric and ultrastructural findings.

Morphological and morphometric analyses of crushed sciatic nerves after application of a purified protein from natural latex and hyaluronic acid hydrogel

Hyaluronic acid hydrogels (HAHs) have been used as a carrier of substances and factors in the repair of nervous tissue. Natural latex protein (Hevea brasiliensis, F1) has shown positive effects in treating various types of tissues, including peripheral nerves. This study evaluated the F1 associated with a HAH in a controlled crush injury (axonotmesis) of the sciatic nerve in Wistar rats. The samples were photomicrographed for morphometric and quantitative analyzes using ImageJ 1.47k software (NIH, Bethesda, MD). Morphological, quantitative (myelin area/nerve area ratio and capillary density) and morphometric (minimum nerve fiber diameter, G-Ratio) data revealed an improvement in the recovery of the sciatic nerve with the application of HAH and the combination of HAH and F1 after 4 and 8 weeks of nerve injury. The most efficacious results were observed with the combination of both substances, F1 and HAH, revealing the regenerative capacity of this new biomaterial, which was hardly tested on nerve tissue.

Augmentation cystoplasty using decellularized vermiform appendix in rabbit model

PURPOSE

The aim of this study was to produce a decellularized rabbit vermiform appendix (sacculus rotundus) and investigate its feasibility in bladder augmentation or appendicovesicostomy. The superiority of sacculus rotundus over other tissues is its unique mechanical properties as well as its abundant collagen content.

MATERIALS AND METHODS

The acellular matrix of vermiform appendix underwent different laboratory investigations prior to transplantation. We divided 12 rabbits into 3 groups: group I underwent bladder augmentation cystoplasty by detubularized acellular matrix. Group II underwent implantation of the tapered (tubularized) acellular matrix just beneath the seromuscular part of the bladder without connection to the bladder urothelium. Group III underwent the same procedure as group II plus reimplantation of tapered and tubularized acellular matrix (simulating an appendicovesicostomy). The distal end of the transplanted graft was connected to the bladder mucosal opening and was intubated by a 5Fr double blind ended feeding tube catheter. Biopsies were taken 3, 12, and 36months post-operatively for further histological and immunohistochemical analyses.

RESULTS

The results of the examinations performed prior to transplantation, revealed a decellularized structure resembling the native tissue with intact extracellular matrix, normal pits and appropriate gaps that will be suitable for further cell seeding. Histopathology examination of the biopsies after transplantations confirmed successful cell seeding with urothelial lining in groups I and III, while the inner lumen in group II showed no urothelial lining.

CONCLUSION

The results suggest that we can prospect to perform bladder reconstruction by the application of this method without complications of previously reported augmentation cystoplasty. In the current study we used the bladder as a natural bioreactor for autologous recellularization which may pave the road for clinical application in acellular matrix augmentation cystoplasty.

Natural Rubber Latex: Study of a Novel Carrier for Casearia sylvestris Swartz Delivery

Natural rubber latex (NRL) from Hevea brasiliensis has showed interesting biomedical properties as improving wound healing, cell adherence, tissue formation, and angiogenesis. It is used for biosynthesis of nanoparticles, sensors and prosthesis and for drug delivery systems (for drugs, plant extracts, and nanoparticles). To enhance its wound healing properties was incorporated Casearia sylvestris Swartz extract, whose pharmacological activity includes anti-inflammatory, analgesic, antiseptic, antiulcer, and antitumor due to its casearins and phenols. Results showed the prolonged release of its compounds (35 days) and the mechanism of release is super case II (n>1) by Korsmeyer-Peppas model. Although SEM shows different sizes of clusters at the surface, the release is homogeneous through the biomembrane. FTIR shows no interaction between the matrix and the extract, with computation of the presence of some casearins.

Expression of VEGF and collagen using a latex biomembrane as bladder replacement in rabbits

OBJECTIVE

To investigate the VEGF expression and collagen deposition using a latex biomembrane as bladder replacement in rabbits.

MATERIALS AND METHODS

After partial cystectomy, a patch of a non-vulcanized latex biomembrane (2 x 2 cm) was sewn to the bladder of rabbits with 5/0 monofilament polydioxanone sulfate sutures in a watertight manner. Groups of 5 animals were killed at 15, 45 and 90 days after surgery and the bladder was removed. Sections of 5µm were cut and stained with picrosirius-red in order to estimate the amount of extracellular matrix in the graft. To confirm the presence of VEGF in tissues, protein expression was determined by immunohistochemistry.

RESULTS

No death, urinary leakage or graft extrusion occurred in any group. All bladders showed a spherical shape. A progressive reduction in the amount of collagen occurred in the graft area and was negatively and linearly correlated with time (p < 0.001). VEGF expression was higher in grafted areas when compared to controls at 15 and 45 days after surgery and decreased with time (p < 0.001).

CONCLUSION

The latex biomembrane as a matrix for partial bladder replacement in rabbits promotes temporary collagen deposition and stimulates the angiogenic process.