Regeneration of Critical-Sized Mandibular Defects Using 3D-Printed Composite Scaffolds: A Quantitative Evaluation of New Bone Formation in In Vivo Studies.

Mandibular tissue engineering aims to develop synthetic substitutes for the regeneration of critical size defects (CSD) caused by a variety of events, including tumor surgery and post-traumatic resections. Currently, the gold standard clinical treatment of mandibular resections (i.e., autologous fibular flap) has many drawbacks, driving research efforts toward scaffold design and fabrication by additive manufacturing (AM) techniques. Once implanted, the scaffold acts as a support for native tissue and facilitates processes that contribute to its regeneration, such as cells infiltration, matrix deposition and angiogenesis. However, to fulfil these functions, scaffolds must provide bioactivity by mimicking natural properties of the mandible in terms of structure, composition and mechanical behavior. This review aims to present the state of the art of scaffolds made with AM techniques that are specifically employed in mandibular tissue engineering applications. Biomaterials chemical composition and scaffold structural properties are deeply discussed, along with strategies to promote osteogenesis (i.e., delivery of biomolecules, incorporation of stem cells, and approaches to induce vascularization in the constructs). Finally, a comparison of in vivo studies is made by taking into consideration the amount of new bone formation (NB), the CSD dimensions, and the animal model.

Condylar Position is Maintained in Maxillomandibular Advancement Surgery Utilizing Custom Cutting Guides and Plates.

PURPOSE: The objective of this study is to compare virtual surgical planned (VSP) and postoperative condylar positioning outcomes in patients who underwent maxillomandibular advancement surgery with custom mandibular cutting guides and osteosynthesis plates to establish reliability and effectiveness using these forms of technology. METHODS: An ambispective case series was performed by obtaining preoperative and postoperative computed tomography (CT) scans of obstructive sleep apnea patients who underwent maxillomandibular advancement surgery with VSP and custom printed mandibular cutting guides and plates at the San Francisco Veterans Affairs Healthcare System from February 2019 to October 2021. The primary predictor variables were the use of custom guides and plates compared to VSP over the course of a year. The outcome variable was the maintained condylar position, defined as the mean differences between the VSP and postoperative positioning. The comparison group was the preoperative VSP position. Covariates were planned surgical movements, age, and gender. Measurements were taken bilaterally in sagittal CT sections measuring the condylar positioning within the posterior space, superior space, and anterior space of the glenoid fossae. Similarly, coronal CT section measurements were taken to measure the condylar positioning within the coronal lateral space, coronal central space, and coronal medial space. A Wilcoxon signed rank test was used. RESULTS: This study included 6 male participants (n = 6) aged 32 to 57 years (mean 46.5). The median differences for the posterior space, superior space, and anterior space planned versus postoperative position were 0.25 (0.40), 0.40 (0.35), and 0.40 (0.55) mm, respectively. The median differences for the coronal lateral space, coronal central space, and coronal medial space planned versus postoperative position were 0.30 (0.30), 0.78 (0.70), and 0.40 (0.30) mm, respectively. There was no statistically significant difference in the planned and postoperative condylar position (Wilcoxon signed rank test, P > .5). A qualitative analysis showed little to no displacement or rotation of the condyle in the virtually planned and postoperative condylar positions. CONCLUSIONS: Qualitative and quantitative comparisons of the preoperative virtual surgical planned and the postoperative condylar position with the use of custom-printed mandibular cutting guides and plates support the null hypothesis that there is no difference between planned and postoperative positioning.

Dietary supplements for improving nitric-oxide synthesis.

Nitric oxide (NO) is an essential component of the human body, involved in blood vessel dilation, stimulation of hormone release, signaling and regulation of neurotransmission. Nitric oxide is synthesized by nitric-oxide-synthase-dependent and -independent pathways. Nitric oxide supplementation improves cardiac health, enhances performance during exercise, reduces high blood pressure during pregnancy, reduces erectile dysfunction and improves healing processes and respiratory response. Nitric-oxide-associated benefits are mostly apparent in untrained or moderately trained individuals. L-arginine and L-citrulline supplementation contributes to nitric oxide levels because L-arginine is directly involved in NO synthesis, whereas L-citrulline acts as an L-arginine precursor that is further converted to NO by a reaction catalyzed by NO synthase. L-arginine supplements increase respiratory response and enhance performance during exercise, while L-citrulline with malate and other molecules increase working capacity. Various studies involving beetroot juice have reported a significant increase in plasma nitrite levels, regarded as markers of NO, after intake of beetroot juice. Although NO supplementation may have mild to moderate side-effects, using smaller or divided doses could avoid some of these side-effects. Since nitric oxide supplementation may worsen certain health conditions and may interfere with certain medicines, it should only be taken under medical supervision.

Modern vision of the Mediterranean diet.

The Mediterranean diet is the most well-known and researched dietary pattern worldwide. It is characterized by the consumption of a wide variety of foods, such as extra-virgin olive oil (EVOO), legumes, cereals, nuts, fruits, vegetables, dairy products, fish, and wine. Many of these foods provide several phytonutrients, among which polyphenols and vitamins play an important role. Data from several studies have strongly established that nutrition is a key factor in promoting a healthy lifestyle and preventing many chronic diseases. In particular, a large number of studies have established the protective effects of the Mediterranean diet against several chronic diseases, among which are diabetes, cardiovascular diseases, cancer, aging disorders, and against overall mortality. Animal and human translational studies have revealed the biological mechanisms regulating the beneficial effects of the traditional Mediterranean diet. Indeed, several studies demonstrated that this nutritional pattern has lipid-lowering, anticancer, antimicrobial, and anti-oxidative effects. Moreover, the Mediterranean diet is considered environmentally sustainable. In this review, we describe the composition of the Mediterranean diet, assess its beneficial effects, and analyze their epigenomic, genomic, metagenomic, and transcriptomic aspects. In the future it will be important to continue exploring the molecular mechanisms through which the Mediterranean diet exerts its protective effects and to standardize its components and serving sizes to understand more precisely its effects on human health.

Methodology for clinical research.

A clinical research requires a systematic approach with diligent planning, execution and sampling in order to obtain reliable and validated results, as well as an understanding of each research methodology is essential for researchers. Indeed, selecting an inappropriate study type, an error that cannot be corrected after the beginning of a study, results in flawed methodology. The results of clinical research studies enhance the repertoire of knowledge regarding a disease pathogenicity, an existing or newly discovered medication, surgical or diagnostic procedure or medical device. Medical research can be divided into primary and secondary research, where primary research involves conducting studies and collecting raw data, which is then analysed and evaluated in secondary research. The successful deployment of clinical research methodology depends upon several factors. These include the type of study, the objectives, the population, study design, methodology/techniques and the sampling and statistical procedures used. Among the different types of clinical studies, we can recognize descriptive or analytical studies, which can be further categorized in observational and experimental. Finally, also pre-clinical studies are of outmost importance, representing the steppingstone of clinical trials. It is therefore important to understand the types of method for clinical research. Thus, this review focused on various aspects of the methodology and describes the crucial steps of the conceptual and executive stages.

Dietary supplements for the management of COVID-19 symptoms.

SARS-CoV-2, the etiological agent of COVID-19, caused a pandemic in 2020, which is only recently slowing down. The symptoms of COVID-19 range from cough to fever and pneumonia and may persist beyond the active state of the infection, in a condition called post-COVID syndrome. The aim of this paper is to review the relationship between COVID-19 and nutrition and to discuss to most up-to-date dietary supplements proposed for COVID-19 treatment and prevention. Nutrition and nutritional dysregulations, such as obesity and malnutrition, are prominent risk factors for severe COVID-19. These factors exert anti-inflammatory and proinflammatory effects on the immune system, thus exacerbating or reducing the immunological response against the virus. As for the nutritional habits, the Western diet induces a chronic inflammatory state, whereas the Mediterranean diet exerts anti-inflammatory effects and has been proposed for ameliorating COVID-19 evolution and symptoms. Several vaccines have been researched and commercialized for COVID-19 prevention, whereas several drugs, although clinically tested, have not shown promising effects. To compensate for the lack of treatment, several supplements have been recommended for preventing or ameliorating COVID-19 symptoms. Thus, it is critical to review the dietary supplements proposed for COVID-19 treatment. Supplements containing α-cyclodextrin and hydroxytyrosol exhibited promising effects in several clinical trials and reduced the severity of the outcomes and the duration of the infection. Moreover, a supplement containing hydroxytyrosol, acetyl L-carnitine, and vitamins B, C, and D improved the symptoms of patients with post-COVID syndrome.

Metabolomics application for the design of an optimal diet.

Precision nutrition is an emerging branch of nutrition science that aims to use modern omics technologies (genomics, proteomics, and metabolomics) to assess an individual's response to specific foods or dietary patterns and thereby determine the most effective diet or lifestyle interventions to prevent or treat specific diseases. Metabolomics is vital to nearly every aspect of precision nutrition. It can be targeted or untargeted, and it has many applications. Indeed, it can be used to comprehensively characterize the thousands of chemicals in foods, identify food by-products in human biofluids or tissues, characterize nutrient deficiencies or excesses, monitor biochemical responses to dietary interventions, track long- or short-term dietary habits, and guide the development of nutritional therapies. Indeed, metabolomics can be coupled with genomics and proteomics to study and advance the field of precision nutrition. Integrating omics with epidemiological and clinical data will begin to define the beneficial effects of human food metabolites. In this review, we present the metabolome and its relationship to precision nutrition. Moreover, we describe the different techniques used in metabolomics and present how metabolomics has been applied to advance the field of precision nutrition by providing notable examples and cases.

Physical activity for health.

Physical activity plays a substantial role in maintaining people's good health and mental wellbeing, but that is not all: not only it positively affects the individuals' mental and physical health, but a lack of physical exercise exerts a negative impact also on the overall economy of a nation. In addition, physical inactivity not only increases the risk of non-communicable diseases (NCD), but also contributes significantly to the increased morbidity and mortality in patients suffering from these diseases. On the contrary, physical activity reduces the risk of NCDs - such as cardiovascular diseases, type 2 diabetes, and cancer - in a dose-dependent manner; regular exercise is also associated with many health benefits and delayed mortality. However, understanding the role of physical activity in modern society and creating an awareness in the general population is one of the most important tasks of health and recreation promoters. Correspondingly, there is a dire need to enhance our knowledge, perception, and awareness of physical activity and its impacts on an individual's health, ultimately contributing to developing a healthy society. The current review will focus on the health benefits of the two most widely studied modifiable lifestyle risk factors, physical activity and diet, focusing particularly on the Mediterranean diet.

Ethical considerations regarding animal experimentation.

Animal experimentation is widely used around the world for the identification of the root causes of various diseases in humans and animals and for exploring treatment options. Among the several animal species, rats, mice and purpose-bred birds comprise almost 90% of the animals that are used for research purpose. However, growing awareness of the sentience of animals and their experience of pain and suffering has led to strong opposition to animal research among many scientists and the general public. In addition, the usefulness of extrapolating animal data to humans has been questioned. This has led to Ethical Committees' adoption of the 'four Rs' principles (Reduction, Refinement, Replacement and Responsibility) as a guide when making decisions regarding animal experimentation. Some of the essential considerations for humane animal experimentation are presented in this review along with the requirement for investigator training. Due to the ethical issues surrounding the use of animals in experimentation, their use is declining in those research areas where alternative in vitro or in silico methods are available. However, so far it has not been possible to dispense with experimental animals completely and further research is needed to provide a road map to robust alternatives before their use can be fully discontinued.