The Era of Biomaterials: Smart Implants?

Conditions, accidents, and aging processes have brought with them the need to develop implants with higher technology that allow not only the replacement of missing tissue but also the formation of tissue and the recovery of its function. The development of implants is due to advances in different areas such as molecular-biochemistry (which allows the understanding of the molecular/cellular processes during tissue repair), materials engineering, tissue regeneration (which has contributed advances in the knowledge of the properties of the materials used for their manufacture), and the so-called intelligent biomaterials (which promote tissue regeneration through inductive effects of cell signaling in response to stimuli from the microenvironment to generate adhesion, migration, and cell differentiation processes). The implants currently used are combinations of biopolymers with properties that allow the formation of scaffolds with the capacity to mimic the characteristics of the tissue to be repaired. This review describes the advances of intelligent biomaterials in implants applied in different dental and orthopedic problems; by means of these advances, it is expected to overcome limitations such as additional surgeries, rejections and infections in implants, implant duration, pain mitigation, and mainly, tissue regeneration.

Atrazine modifies markers of melanocyte maturation and apoptosis in primary skin cultures

Atrazine (ATZ) is part of a group of herbicides called triazines. ATZ is widely used in agricultural areas of Mexico, commonly used for the selective control of weeds in corn and sorghum crops. The exposure to ATZ can have serious human health effects since its use was associated with the development of cutaneous melanoma in an epidemiological study. The aim of this study was to evaluate the expression of maturation and apoptotic markers in primary skin cultures exposed to ATZ. The primary skin cultures were exposed to 0.1, and 10 µM ATZ with or without ultraviolet (UV) radiation and the expression of maturation and apoptotic markers were evaluated by RT-qPCR. We observed a significant increase in all the melanocyte maturation markers in cells exposed to ATZ with or without UV, with SOX-9 and FAK (melanoblast markers) being the highest. Also, the expression of BCL-2 (anti-apoptotic marker) was the most increased gene in cells exposed to ATZ with or without UV. Low concentrations of ATZ and UV radiation induce genetic changes associated with the development of immature melanocytes and activate mechanisms associated with the inhibition of apoptosis characteristics of malignant cell transformation, which will allow proposing new therapeutic targets and generating new restrictions or care in farmers exposed to pesticides such as the ATZ.

Antioxidant activity of kafirin hydrolysates on UVB irradiated human keratinocyte cells and in silico identification

BACKGROUND

Ultraviolet B (UVB) causes photoaging of the skin, the appearance of wrinkles, spots, and alteration of the skin barrier. The main cells in the most superficial layer of the skin are the keratinocytes; these cells play an important role in protecting this organ.

OBJECTIVE

The present study aimed to investigate the antioxidant activity of the hydrolysates from kafirin to inhibit UVB-induced responses in human keratinocytes cells (HaCaT).

METHODS

Kafirin hydrolysates were produced by enzymatic hydrolysis with alcalase. The activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), in the HaCaT cell line in the presence of UVB and the effects of the hydrolysates against the UVB-induced response were evaluated. Furthermore, the peptides that were generated by hydrolysis were identified in silico using the BIOPEP database.

RESULTS

Two protein sequences were identified (α-kafirin and the precursor protein of α-kafirin), in the kafirin extract. A degree of hydrolysis of 18.8% was obtained by hydrolyzing the kafirin extract with alcalase. The kafirin hydrolysates avoided the decrease in endogenous antioxidant enzymes such as SOD, CAT, and GPx reducing the oxidative stress generated by UVB. Using the BIOPEP-UWM database, we found 102 peptide sequences, and it has shown that the peptides have a large amount of hydrophobic amino acids such as proline, alanine, and glutamine, and amino acids with high antioxidant capacity.

CONCLUSION

These results suggest that the kafirin hydrolysates can be used as antioxidant agents to ameliorate UVB-induced skin keratinocytes cells' response in vitro, providing an alternative against UVB-induced photoaging.

Cytokines secretion from human mesenchymal stem cells induced by bovine bone matrix

BACKGROUND

Bovine bone matrix is a natural material that has been used in the treatment of bone lesions. In this study, bovine bone matrix Nukbone® (NKB) was investigated due its osteoconductive and osteoinductive properties. This biomaterial induces CBFA-1 activation and osteogenic differentiation, although the cytokines involved in these processes is still unknown.

OBJECTIVE

The aim of this work was to determine the influence of NKB on the pro-osteoblastic and anti-osteoblastic cytokines secretion from human mesenchymal stem cells (hMSCs).

METHODS

The hMSCs were cultured onto NKB and cytokines IL-2, IL-4, IL-6, IL-10, IL-12, IFN-γ and TNF-α were analized at 0-14 days by immunoassay. In addition, hemocompatibility of NKB and characterization of hMSCs were evaluated.

RESULTS

NKB induces an increase on pro-osteoblastic cytokine secretion IL-4 and a decrease on anti-osteoblastic cytokine IL-6 secretion, at days 7 and 14 of cell culture. Interestingly, there was no statistical difference between secretion profiles of others cytokines analized.

CONCLUSIONS

The up-regulation of IL-4 and down-regulation of IL-6, and the secretion profiles of other cytokines examined in this work, are findings that will contribute to the understanding of the role of NKB, and similar biomaterials, in bone homeostasis and in the osteoblastic differentiation of hMSCs.

Optimization of Sorghum Kafirin Extraction Conditions and Identification of Potential Bioactive Peptides

The interest in extracting kafirins (KAF), the main storage protein from sorghum grain has recently increased due to its gluten-free content and the significant scientific evidence showing the health benefits of the bioactive peptides from cereal grains in human diets. The objectives were to obtain the highest percentage of KAF extraction using amyloglucosidase as pretreatment to increase the extraction yield and predict the bioactive peptides in the KAF. In this study, pretreatments with amyloglucosidase increased the extraction yield of KAF compared with extraction methods using only ethanol and sodium metabisulfite. Two protein fragment sequences were identified from KAF extract and were evaluated for potential bioactive peptide using the BIOPEP-UWM database, which suggest that KAF proteins from white sorghum may be considered as good precursors of dipeptidyl peptidase-inhibitor, angiotensin-converting enzyme inhibitor, antioxidant and hypotensive peptides following chymotrypsin, thermolysin, and subtilisin and their combination. Average scores aligned using PeptideRanker confirmed KAF proteins' potential sources of bioactive peptides with over 5 peptides scored over 0.8. In addition, 31 unexplored peptide sequences that could have biological activity were identified. Our results suggest that KAF can be used in the peptide productions with potential biological activity and beyond.

<p>Histopathological Diagnosis of Cervical Biopsies: Reduction of Sampling Errors with the Evaluation of a Third Histologic Level</p>

Aim

Cervical cancer (CC) is considered as a major public health problem; this disease affects mainly vulnerable women in poverty, causing a negative effect on a country’s workforce.

Objective

To determine the histopathological diagnosis variation after examining three more levels of cervical biopsy paraffin blocks from patients with HPVI, CIN and CC.

Materials and Methods

A quantitative, retrospective correlational study was performed in a hospital with a second level of health care. We worked with 152 paraffin blocks of CIN (CIN, I, II and III) and cervical cancer samples. Currently, CIN I is considered as a set of low-grade injuries (low-grade squamous intraepithelial lesions, LSIL), while CIN II, CIN III and cancer in situ are considered as high-grade lesions (high-grade squamous intraepithelial lesions, HSIL). A slab was prepared with the 50micron block, which was subsequently cut into 5 microns; later, the same thing was done at two more levels to reevaluate the histopathological diagnosis and correlate it with the initial diagnosis issued by the institution.

Results

During the examination of the additional block levels, a difference was observed from the initial diagnosis: of 32 cases of HPV diagnosis, there were 17 changes to CIN I; of 31 cases of CIN I, there were 4 changes to CIN II; of 30 cases of CIN II, there were 8 changes to CIN III and 1 change to invasive cancer; of 29 cases of CIN III, there were 9 changes to cancer in situ; and finally, of 14 cases of cancer in situ, there was 1 change to invasive cancer. After the statistical analysis, a value of p <0.05 was obtained, which indicated that the differences were statistically significant.

Conclusion

By modifying the histopathological study technique, guidelines can be given to generate a more accurate diagnosis with a more solid base, and thus, a more appropriate and timely treatment can be offered to avoid the development of cervical cancer.

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