Stevo Najman

Macrophages play an important role in bone regeneration by releasing bioactive factors that regulate the behavior of osteoprogenitor cells. In this in vitro study, we investigated how conditioned media (CM) derived from RAW 264.7 macrophages treated with lipopolysaccharide (LPS; 1 or 100 ng/mL), dexamethasone (DEX; 10⁻⁶ M), or left untreated, modulate the proliferation and osteogenic differentiation of MC3T3-E1 preosteoblasts. Exposure to LPS and DEX produced different patterns of macrophage activation, assessed by microscopic morphology, nitroblue tetrazolium (NBT) reduction, and measurement of TNF-α secretion from macrophages. In the L929 bioassay, no CM was cytotoxic, while effects on MC3T3-E1 proliferation and differentiation varied with macrophage treatment and CM dilution. CM obtained from DEX-treated macrophages elicited the most pronounced pattern of osteogenic activity that included reduced cell proliferation, acquisition of osteoblast-like morphology, enhanced von Kossa staining, and pronounced osteocalcin and osteopontin immunoexpression. CM from untreated macrophages also supported osteogenesis, although to a lesser extent. At 100%, CMs from LPS-treated macrophages supported greater preosteoblast proliferation than other CMs, while their effects on differentiation depended on LPS dose and CM dilution. These findings indicate that macrophage-derived signals differentially modulate preosteoblast proliferation and differentiation depending on their functional state. This study provides a valuable in vitro cell model for the development of immunomodulatory and regenerative strategies in bone tissue engineering and broader applications in wound healing.

This study aimed to assess phytochemical profiles and antioxidant activities of lyophilized black currant fruit juice (BCLJ) and its corresponding waste extract (BCLW) from the Čačanska crna variety, and to evaluate their antiproliferative properties. The main anthocyanins quantified through HPLC-DAD analysis were delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside, with significantly higher levels in BCLW. Antioxidant activity was examined using the DPPH and β-carotene/linoleic acid methods, with BCLW showing superior effects in both. Antiproliferative potential was evaluated by determining the Ki67 index in renal epithelial cells of rats treated with BCLJ or BCLW. Thirty healthy male rats were randomly assigned to five groups (n = 6) and administered BCLJ or BCLW orally for ten days, receiving 100, 200, and 300 mg/kg b.w. of BCLW (BCLW1, BCLW2, and BCLW3 groups, respectively) or 200 mg of BCLJ. Histopathological and immunohistochemical parameters were assessed in rats’ kidneys. Across all epithelial types (cortical proximal tubules, distal medullary proximal tubules, collecting ducts, and urothelial cells of the renal pelvis), the highest Ki67 indices were observed in control animals, particularly in collecting ducts and cortical proximal tubules. The lowest Ki67 values in cortical proximal tubules occurred in the BCLW2 group (p < 0.05 vs. control). These findings suggest that black currant preparations could be valuable functional ingredients.

The aim of this paper is to examine the possibility of using electrospun poly(vinylpyrrolidone) (PVP) fibers as a carrier of the phytoestrogen biochanin A (BCA). PVP fibers were prepared with different BCA content by using electrospinning method at specific process parameters. Produced electrospun PVP– –BCA fibers were characterized by chemical, physical-mechanical and biological methods. SEM, DSC and FTIR analyzes showed that there are no strong interactions between PVP and BCA molecules, neither thermal changes in tested temperature range (50–250°C) and that equal distribution of BCA in the PVP electrospun fibers was achieved. Physico-mechanical tests showed that the physical properties and wetting angle of PVP change in the presence of BCA. Testing of electrospun PVP fibres with and without BCA on L929 fibroblasts in direct contact assay in vitro revealed a significant effect on proliferation and migration of fibroblasts. Biological tests confirmed that the system of electrospun PVP–BCA fibers can become suitable for the treatment of complicated wounds, where in the first stage of treatment the damaged tissue should be removed by the activity of electrospun PVP–BCA fibers. Another possibility of using electrospun PVP– –BCA fibers is for the treatment of facial skin for the exfoliation intent.

Osteoclasts, as the only cells capable of resorbing bone, play a significant role in all processes that take place at the level of bone tissue and are involved in the development of the skeleton, maintenance of its integrity, repair, and regeneration of bones. Therefore, it is not surprising that even small deviations from their normal functioning result in diseases that not only affect skeletal system but also the entire organism. There are a number of rare genetic bone diseases associated with mutations in osteoclast genes that govern their differentiation and function. Specifically, they are known as osteoclast-related diseases, and their main hallmark is either decreased or increased bone resorption. To understand the impact of osteoclast gene mutations on the course of these diseases, it is also necessary to know the cellular and molecular mechanisms underlying osteoclast development and function. Moreover, identification of specific gene mutations as potential therapeutic targets would be an important step in creating personalized gene therapies in the future.

The aim of this study was to examine homopolymeric poly(N-isopropylacrylamide), p(NIPAM), hydrogels cross-linked with ethylene glycol dimethacrylate as carriers for sulfanilamide. Using FTIR, XRD and SEM methods, structural characterization of synthesized hydrogels before and after sulfanilamide incorporation was performed. The residual reactants content was analyzed using the HPLC method. The swelling behavior of p(NIPAM) hydrogels of different crosslinking degrees was monitored in relation to the temperature and pH values of the surrounding medium. The effect of temperature, pH, and crosslinker content on the sulfanilamide release from hydrogels was also examined. The results of the FTIR, XRD, and SEM analysis showed that sulfanilamide is incorporated into the p(NIPAM) hydrogels. The swelling of p(NIPAM) hydrogels depended on the temperature and crosslinker content while pH had no significant effect. The sulfanilamide loading efficiency increased with increasing hydrogel crosslinking degree, ranging from 87.36% to 95.29%. The sulfanilamide release from hydrogels was consistent with the swelling results—the increase of crosslinker content reduced the amount of released sulfanilamide. After 24 h, 73.3–93.5% of incorporated sulfanilamide was released from the hydrogels. Considering the thermosensitivity of hydrogels, volume phase transition temperature close to the physiological temperature, and the satisfactory results achieved for sulfanilamide incorporation and release, it can be concluded that p(NIPAM) based hydrogels are promising carriers for sulfanilamide.

Barrier membranes are an essential tool in guided bone Regeneration (GBR), which have been widely presumed to have a bioactive effect that is beyond their occluding and space maintenance functionalities. A standardized calvaria implantation model was applied for 2, 8, and 16 weeks on Wistar rats to test the interactions between the barrier membrane and the underlying bone defects which were filled with bovine bone substitute materials (BSM). In an effort to understand the barrier membrane’s bioactivity, deeper histochemical analyses, as well as the immunohistochemical detection of macrophage subtypes (M1/M2) and vascular endothelial cells, were conducted and combined with histomorphometric and statistical approaches. The native collagen-based membrane was found to have ossified due to its potentially osteoconductive and osteogenic properties, forming a “bony shield” overlying the bone defects. Histomorphometrical evaluation revealed the resorption of the membranes and their substitution with bone matrix. The numbers of both M1- and M2-macrophages were significantly higher within the membrane compartments compared to the underlying bone defects. Thereby, M2-macrophages significantly dominated the tissue reaction within the membrane compartments. Statistically, a correlation between M2-macropahges and bone regeneration was only found at 2 weeks post implantationem, while the pro-inflammatory limb of the immune response correlated with the two processes at 8 weeks. Altogether, this study elaborates on the increasingly described correlations between barrier membranes and the underlying bone regeneration, which sheds a light on the understanding of the immunomodulatory features of biomaterials.

Synthetic bone substitute materials (BSMs) are becoming the general trend, replacing autologous grafting for bone tissue engineering (BTE) in orthopedic research and clinical practice. As the main component of bone matrix, collagen type I has played a critical role in the construction of ideal synthetic BSMs for decades. Significant strides have been made in the field of collagen research, including the exploration of various collagen types, structures, and sources, the optimization of preparation techniques, modification technologies, and the manufacture of various collagen-based materials. However, the poor mechanical properties, fast degradation, and lack of osteoconductive activity of collagen-based materials caused inefficient bone replacement and limited their translation into clinical reality. In the area of BTE, so far, attempts have focused on the preparation of collagen-based biomimetic BSMs, along with other inorganic materials and bioactive substances. By reviewing the approved products on the market, this manuscript updates the latest applications of collagen-based materials in bone regeneration and highlights the potential for further development in the field of BTE over the next ten years.

Guided bone regeneration (GBR) has become a clinically standard modality for the treatment of localized jawbone defects. Barrier membranes play an important role in this process by preventing soft tissue invasion outgoing from the mucosa and creating an underlying space to support bone growth. Different membrane types provide different biological mechanisms due to their different origins, preparation methods and structures. Among them, collagen membranes have attracted great interest due to their excellent biological properties and desired bone regeneration results to non-absorbable membranes even without a second surgery for removal. This work provides a comparative summary of common barrier membranes used in GBR, focusing on recent advances in collagen membranes and their biological mechanisms. In conclusion, the review article highlights the biological and regenerative properties of currently available barrier membranes with a particular focus on bioresorbable collagen-based materials. In addition, the advantages and disadvantages of these biomaterials are highlighted, and possible improvements for future material developments are summarized.