Serum Cardiac and Skeletal Muscle Marker Changes in Repetitive Breath-hold Diving

Appreciable biosafety, biocompatibility and osteogenic capability of 3D printed nonstoichiometric wollastonite scaffolds favorable for clinical translation

Background

Alveolar bone destruction due to periodontal disease often requires a bone graft substitute to reconstruct the anatomical structures and biological functions of the bone tissue. Despite significant advances in the development of foreign ion-doped nonstoichiometric wollastonite bioceramics (CaSiO3, nCSi) for alveolar bone regeneration over the past decade, the in vivo biosafety and osteogenesis of nCSi scaffolds remain uncertain. In this study, we developed a customized porous nCSi scaffold to investigate the in vivo biocompatibility and osteogenic properties of nCSi bioceramics.

Methods

Six percent Mg-doped nCSi bioceramic scaffolds were fabricated by digital light processing (DLP), and the scaffold morphology, pore architecture, compressive strength, in vitro biodegradation, and apatite-forming ability of the bioceramic scaffolds were investigated systematically. Subsequently, an alveolar bone defect rabbit model was used to evaluate the biocompatibility and osteogenic efficacy of the nCSi bioceramics. Animal weight, hematological test, blood biochemical test, wet weight of the main organs, and pathological examination of the main organs were conducted. Micro-CT and histological staining were performed to analyze the osteogenic potential of the personalized bioceramic scaffolds.

Results

The nCSi scaffolds exhibited appreciable initial compressive strength (>30 MPa) and mild mechanical decay over time during in vitro biodissolution. In addition, the scaffolds induced apatite remineralization in SBF. Bioceramic scaffolds have been proven to have good biocompatibility in vivo after implantation into the alveolar bone defect of rabbits. No significant effects on the hematological indices, blood biochemical parameters, organ wet weight, or organ histopathology were detected from 3 to 180 days postoperatively. The porous scaffolds exhibited strong bone regeneration capability in the alveolar bone defect model of rabbits. Micro-CT and histological examination showed effective maintenance of bone morphology in the bioceramic scaffold group; however, depressed bone tissue was observed in the control group.

Conclusions

Our results suggest that personalized nCSi bioceramic scaffolds can be fabricated using the DLP technique. These newly developed strong bioceramic scaffolds exhibit good biocompatibility and osteogenic capability in vivo and have excellent potential as next-generation oral implants.

The translational potential of this article

Tissue-engineered strategies for alveolar bone repair require a bone graft substitute with appreciable biocompatibility and osteogenic capability. This article provides a systematic investigation of the in vivo biosafety and osteogenic property of nCSi to further development of a silicate-based bioceramics materials for clinical applications.

Metformin Protects Rat Skeletal Muscle from Physical Exercise-Induced Injury

Metformin (Met) is a drug commonly prescribed in type 2 diabetes mellitus. Its efficacy is due to the suppression of hepatic gluconeogenesis, enhancement of peripheral glucose uptake and lower glucose absorption by the intestine. Recent studies have reported Met efficacy in other clinical applications, such as age-related diseases. Despite the wide clinical use of Met, its mechanism of action on muscle and its effect on muscle performance are unclear. We investigated the effects of Met combined with training on physical performance (PP) in healthy rats receiving Met for 8 weeks while undergoing daily moderate exercise. We evaluated the following: PP through graded endurance exercise test performed before the beginning of the training protocol and 48 h before the end of the training period; blood ALT, AST, LDH and CK-MB levels in order to address muscle damage; and several blood and muscle myokines and the expression of factors believed to be involved in muscle adaptation to exercise. Our data demonstrate that Met does not improve the positive effects of exercise on performance, although it protects myocytes from exercise-induced damage. Moreover, given that Met positively affects exercise-induced muscle adaptation, our data support the idea of the therapeutic application of Met when muscle function and structure are compromised.

The Chemical Composition Characteristics and Health Risk Assessment of Cooking Fume Condensates from Residential Kitchens in Different Regions of China

The aim of this study was to explore the similarities and differences of volatile organic pollutants (VOCs) in cooking fumes (COF) of residential buildings in different regions of China, as well as to evaluate their potential health risks. COF condensates were collected from 10 representative cities in China and analyzed by a GC-MS method. Their effects on α-glucosidase, acetylcholinesterase (AchE), and lactate dehydrogenase (LDH) activities were then detected to evaluate potential health risks. A total of 174 kinds of VOCs, including aldehydes, esters, hydrocarbons, alcohols, and carboxylic acid, were identified. There were 59 identical compounds in the northern and southern regions, and 56 common compounds in spicy and non-spicy regions. Health risk assessment results showed that COF condensate could inhibit the activity of α-glucosidase to varying degrees (61.73-129.25%), suggesting that it had a potential risk of causing hypoglycemia. Daily and 3 and 6 month intakes of COF in minors, adults, and the elderly had both activated and inhibited effects on AchE. The activated effect in the southern and spicy areas was higher than that in northern and non-spicy areas, revealing that different regions and dietary habits had different effects on the risk of neurological diseases caused by changes in AchE activity. For minors, adults, and the elderly, COF had different degrees of activation of LDH at different exposure times and regions. Activation in the northern and non-spicy areas was higher than that in southern and spicy areas, suggesting that the health risks caused by changes in LDH activity levels were significantly increased.

Serum Amino Acid Profile Changes After Repetitive Breath-Hold Dives: A Preliminary Study

Background

The aim of this work was to investigate the serum amino acid (AA) changes after a breath-hold diving (BH-diving) training session under several aspects including energy need, fatigue tolerance, nitric oxide (NO) production, antioxidant synthesis and hypoxia adaptation. Twelve trained BH-divers were investigated during an open sea training session and sampled for blood 30 min before the training session, 30 min and 4 h after the training session. Serum samples were assayed for AA changes related to energy request (alanine, histidine, isoleucine, leucine, lysine, methionine, proline threonine, valine), fatigue tolerance (ornithine, phenylalanine, tyrosine), nitric oxide production (citrulline), antioxidant synthesis (cystine, glutamate, glycine) and hypoxia adaptation (serine, taurine).

Main results

Concerning the AA used as an energy support during physical effort, we found statistically significant decreases for all the investigated AA at T1 and a gradual return to the basal value at T2 even if alanine, proline and theonine still showed a slight significant reduction at this time. Also, the changes related to the AA involved in tolerance to physical effort showed a statistically significant decrease only at T1 respect to pre-diving value and a returned to normal value at T2. Citrulline, involved in NO production, showed a clear significant reduction both at T1 and T2. Concerning AA involved in endogenous antioxidant synthesis, the behaviour of the three AA investigated is different: we found a statistically significant increase in cystine both at T1 and T2, while glycine showed a statistically significant reduction (T1 and T2). Glutamate did not show any statistical difference. Finally, we found a statistically significant decrease in the AA investigated in other hypoxia conditions serine and taurine (T1 and T2).

Conclusions

Our data seem to indicate that the energetic metabolic request is in large part supported by AA used as substrate for fuel metabolism and that also fatigue tolerance, NO production and antioxidant synthesis are supported by AA. Finally, there are interesting data related to the hypoxia stimulus that indirectly may confirm that the muscle apparatus works under strong exposure conditions notwithstanding the very short/low intensity of exercise, due to the intermittent hypoxia caused by repetitive diving.

Capillary Blood Recovery Variables in Young Swimmers: An Observational Case Study

Sport diagnostics is still in pursuit of the optimal combination of biochemical and hematological markers to assess training loads and the effectiveness of recovery. The biochemical and hematological markers selected for a panel should be specific to the sport and training program. Therefore, the aim of this study was to evaluate the usefulness of selected biochemical and hematological variables in professional long-distance and sprint swimming. Twenty-seven participants aged 15–18 years took part in the study. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) activities and creatinine (Cr), C-reactive protein (CRP), ferritin, total bilirubin (TB), direct bilirubin (DB) and iron concentrations were measured for 10 weeks and compared with the traditional sport diagnostic markers of creatine kinase (CK) activity and urea (U) concentration. Additionally, capillary blood morphology was analyzed. An effective panel should consist of measurements of CK and AST activities and urea, TB, DB and ferritin concentrations. These markers provide a good overview of athletes’ post-training effort changes, can help assess the effectiveness of their recovery regardless of sex or competitive distance and are affordable. Moreover, changes in ferritin concentration can indicate inflammation status and, when combined with iron concentration and blood morphology, can help to avoid iron deficiencies, anemia and adverse inflammatory states in swimmers.