In vitro meat has recently emerged as a new concept in food biotechnology. Methods to produce in vitro meat generally involve the growth of muscle cells that are cultured on scaffolds using bioreactors. Suitable scaffold design and manufacture are critical to downstream culture and meat production. Most current scaffolds are based on mammalian-derived biomaterials, the use of which is counter to the desire to obviate mammal slaughter in artificial meat production. Consequently, most of the knowledge is related to the design and control of scaffold properties based on these mammalian-sourced materials. To address this, four different scaffold materials were formulated using non-mammalian sources, namely, salmon gelatin, alginate, and additives including gelling agents and plasticizers. The scaffolds were produced using a freeze-drying process, and the physical, mechanical, and biological properties of the scaffolds were evaluated. The most promising scaffolds were produced from salmon gelatin, alginate, agarose, and glycerol, which exhibited relatively large pore sizes (~200 μm diameter) and biocompatibility, permitting myoblast cell adhesion (~40%) and growth (~24 h duplication time). The biodegradation profiles of the scaffolds were followed, and were observed to be less than 25% after 4 weeks. The scaffolds enabled suitable myogenic response, with high cell proliferation, viability, and adequate cell distribution throughout. This system composed of non-mammalian edible scaffold material and muscle-cells is promising for the production of in vitro meat.

BackgroundThis manuscript reports the production and preclinical studies to examine the tolerance and efficacy of an autologous cellular gel-matrix integrated implant system (IIS) aimed to treat full-thickness skin lesions.MethodsThe best concentration of fibrinogen and thrombin was experimentally determined by employing 28 formula ratios of thrombin and fibrinogen and checking clot formation and apparent stability. IIS was formed by integrating skin cells by means of the in situ gelification of fibrin into a porous crosslinked scaffold composed of chitosan, gelatin and hyaluronic acid. The in vitro cell proliferation within the IIS was examined by the MTT assay and PCNA expression. An experimental rabbit model consisting of six circular lesions was utilized to test each of the components of the IIS. Then, the IIS was utilized in an animal model to cover a 35% body surface full thickness lesion.ResultsThe preclinical assays in rabbits demonstrated that the IIS was well tolerated and also that IIS-treated rabbit with lesions of 35% of their body surface, exhibited a better survival rate (p = 0,06).ConclusionIIS should be further studied as a new wound dressing which shows promising properties, being the most remarkable its good biological tolerance and cell growth promotion properties.

We previously reported that moderate calorie restriction (CR) has minimal impact on testicular gene expression in young adult rhesus macaques, and no obvious negative impact on semen quality or plasma testosterone levels. We now extend these findings by examining the influence of CR on various aspects of the reproductive axis of older males, including 24-h circulating testosterone levels, testicular gene expression, and testicular morphology. Young adult and old adult male rhesus macaques were subjected to either 30 % CR for 5-7 years, or were fed a standard control diet. Analysis of the 24-h plasma testosterone profiles revealed a significant age-associated decline, but no evidence for CR-induced suppression in either the young or old males. Similarly, expression profiling of key genes associated with testosterone biosynthesis and Leydig cell maintenance showed no significant CR-induced changes in either the young or old animals. The only evidence for CR-associated negative effects on the testis was detected in the old animals at the histological level; when old CR animals were compared with their age-matched controls, there was a modest decrease in seminiferous tubule diameter and epithelium height, with a concomitant increase in the number of depleted germ cell lines. Reassuringly, data from this study and our previous study suggest that moderate CR does not negatively impact 24-h plasma testosterone profiles or testicular gene expression. Although there appear to be some minor CR-induced effects on testicular morphology in old animals, it is unclear if these would significantly compromise fertility.

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The clam Eurhomalea lenticularis may be parasitized by digenean trematodes of the family Plagiorchidae, specifically in the gonads (parasitic castration). A quantitative histological analysis of the parasitized gonads demonstrated a significant decrease in gonadal area, in the size of individual acini, and in the numbers of differentiated germ cells compared to unparasitized clams. Castration may be caused by mechanical compression due to trematode sporocyst growth. However, the uniform loss of germ cells in areas without sporocysts suggests that a more generalized mechanism is responsible. We suggest that parasitic castration has a primary effect on the host's neuroendocrine and gametogenic systems that regulate gamete production. KEY WORDS: Bivalve mollusc · Parasitic castration · Histological analysis · Eurhomalea lenticularis · Digenea · Trematode · Central Chile Resale or republication not permitted without written consent of the publisherDis Aquat Org 59: [151][152][153][154][155][156][157][158] 2004 of alteration in the neuroendocrinological system of the clam, we quantified the variation between germ cell number in the presence and absence of sporocysts. MATERIALS AND METHODSSample processing and histology. To determine the prevalence of the parasite, a total of 1702 clams was obtained from June 1995 to February 1998 by diving on a natural bank located at El Algarrobo inlet, central Chile (33°20' S, 71°40' W). They were transported live to the laboratory, and at least 1 random sample of 30 clams was processed each month (1034 in total; the remaining clams were dissected and observed under the stereoscopic microscope to determine the presence of the parasite) using routine histological techniques (Gabe 1968). After 1 h fixation in Bouin Hollande fluid to harden the tissues, serial transverse sections, 5 mm thick, were made of the visceral mass containing the gonad. After fixation in fresh fixative for 48 h, the thick sections were washed in tap water for 24 h, dehydrated in graded ascending concentrations of ethanol to 100%, cleared in butanol and embedded in Paraplast Plus (Oxford ® ). Histological sections of 5 µm thickness were made at different levels through the tissue at 300 µm intervals, deparaffinized, and rehydrated in a decreasing series of ethanol concentrations, and stained by a trichrome staining method. Briefly, the sections were stained in Harris hematoxylin solution for 75 s and rinsed in running tap water for 10 min, followed by a quick rinse in distilled water. Next, they were stained with a mixture of 0.5% Erythrosin-0.5% Orange G for 30 min, and quickly rinsed in distilled water. They were immersed in 0.5% phosphotungstic acid for 10 min, and again quickly rinsed in distilled water. Finally, they were stained in 1% Aniline blue for 75 s and immediately dehydrated in 3 consecutive baths of 95% ethanol followed by 3 baths in 100% ethanol (Arteta trichrome stain; López et al. 1982). After clearing in xylenes, the slides were coverslipped using Canada balsam (López et al. 1982...

Increasing evidence in animal models and in humans shows that sympathetic nerve activity controls ovarian androgen biosynthesis and follicular development. Thus, sympathetic nerve activity participates in the follicular development and the hyperandrogenism characteristics of polycystic ovary syndrome, which is the most prevalent ovarian pathology in women during their reproductive years. In this study, we mimic sympathetic nerve activity in the rat via "in vivo" stimulation with isoproterenol (ISO), a β-adrenergic receptor agonist, and test for the development of the polycystic ovary condition. We also determine whether this effect can be reversed by the administration of propranolol (PROP), a β-adrenergic receptor antagonist. Rats were treated for 10 days with 125 μg/kg ISO or with ISO plus 5 mg/kg PROP. The ovaries were examined 1 day or 30 days following drug treatment. While ISO was present, the ovaries had an increased capacity to secrete androgens; ISO + PROP reversed this effect on androgen secretory activity. 30 days after treatment, androstenedione secretion reverted to normal levels, but an increase in the intra-ovarian nerve growth factor (NGF) concentration and luteinizing hormone (LH) plasma levels was detected. ISO treatment resulted in follicular development characterized by an increased number of pre-cystic and cystic ovarian follicles; this was reversed in the ISO + PROP group. The lack of change in the plasma levels of progesterone, androstenedione, testosterone, or estradiol and the increased LH plasma levels strongly suggests a local intra-ovarian effect of ISO indicating that β-adrenergic stimulation is a definitive component in the rat polycystic ovary condition.

Cell culture on biopolymeric scaffolds has provided treatments for tissue engineering. Biopolymeric mixtures based on gelatin (Ge), chitosan (Ch) and hyaluronic acid (Ha) have been used to make scaffolds for wound healing. Thermal and physical properties of scaffolds prepared with Ge, Ch and Ha were characterized. Thermal characterization was made by using differential scanning calorimetry (DSC), and physical characterization by gas pycnometry and scanning electron microscopy. The effects of Ge content and cross-linking on thermophysical properties were evaluated by means of a factorial experiment design (central composite face centered). Gelatin content was the main factor that affects the thermophysical properties (microstructure and thermal transitions) of the scaffold. The effect of Ge content of the scaffolds for tissue engineering was studied by seeding skin cells on the biopolymers. The cell attachment was not significantly modified at different Ge contents; however, the cell growth rate increased linearly with the decrease of the Ge content. This relationship together with the thermophysical characterization may be used to design scaffolds for tissue engineering.

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