João Requicha | Universidade de Trás-os-Montes e Alto Douro (UTAD) (original) (raw)

Papers by João Requicha

Genomic Medicine in Periodontal Disease: Old Issue, New Insights

Journal of Veterinary Dentistry, Jun 28, 2022

Genetic variability is the main cause of phenotypic variation. Some variants may be associated wi... more Genetic variability is the main cause of phenotypic variation. Some variants may be associated with several diseases and can be used as risk biomarkers, identifying animals with higher susceptibility to develop the pathology. Genomic medicine uses this genetic information for risk calculation, clinical diagnosis and prognosis, allowing the implementation of more effective preventive strategies and/or personalized therapies. Periodontal disease (PD) is the inflammation of the periodontium induced mainly by bacterial plaque and is the leading cause of tooth loss. Microbial factors are responsible for the PD initiation; however, several studies support the genetic influence on the PD progression. The main purpose of the present publication is to highlight the main steps involved in the genomic medicine applied to veterinary patients, describing the flowchart from the characterization of the genetic variants to the identification of potential associations with specific clinical data. After investigating which genes might potentially be implicated in canine PD, the RANK gene, involved in the regulation of osteoclastogenesis, was selected to illustrate this approach. A case-control study was performed using DNA samples from a population of 90 dogs – 50 being healthy and 40 with PD. This analysis allowed for the discovery of four new intronic variations that were banked in GenBank (g.85A>G, g.151G>T, g.268A>G and g.492T>C). The results of this study are not intended to be applied exclusively to PD. On the contrary, this genetic information is intended to be used by other researchers as a foundation for the development of multiple applications in the veterinary clinical field.

Animals

Genomic medicine has become a growing reality; however, it is still taking its first steps in vet... more Genomic medicine has become a growing reality; however, it is still taking its first steps in veterinary medicine. Through this approach, it will be possible to trace the genetic profile of a given individual and thus know their susceptibility to certain diseases, namely periodontal disease. This condition is one of the most frequently diagnosed in companion animal clinics, especially in dogs. Due to the limited existing information and the lack of comprehensive studies, the objective of the present study was to systematically review the existing scientific literature regarding genomic medicine in canine periodontal disease and determine which genes have already been studied and their probable potential. This study followed the recommendations of the PRISMA 2020 methodology. Canine periodontal disease allied to genomic medicine were the subjects of this systematic review. Only six articles met all of the inclusion criteria, and these were analyzed in detail. These studies described ...

Veterinary Sciences

The tooth is made up of three mineralized tissues, enamel, dentin, and cementum, which surround a... more The tooth is made up of three mineralized tissues, enamel, dentin, and cementum, which surround a non-mineralized tissue called the dental pulp. Micro-computed tomography (mCT) is an imaging technology based on X-rays that allows non-invasive visualization of objects at a microscopic scale, according to their radiopacity and in three dimensions (3D). Likewise, it allows the subsequent execution of morphological and quantitative analysis of the objects, such as, for example, the determination of the relative mineral density (MD). The present work aimed to describe the MD of feline teeth using mCT. The studied sample consisted of four European Shorthair cats, from which nine canine teeth were extracted per medical indication. These teeth were evaluated through dental radiography before and after their extraction. Using mCT and the CTAn software, the values of the relative mineral density of the root of each tooth and of specific segments corresponding to the coronal, middle, and apica...

The potential of computed tomography in odontometry: application to a Mesolithic dog

Journal of Archaeological Science: Reports

Cytological Characterization of the Oral Cavity of the Inland Bearded Dragon (Pogona vitticeps)

Journal of Herpetological Medicine and Surgery

Cytological analyses of the oral cavity are necessary for the identification and correct evaluati... more Cytological analyses of the oral cavity are necessary for the identification and correct evaluation of lesions in this anatomical region. Literature on this subject in reptiles is scarce, in contrast to other species kept as pets. The main objective of this descriptive study was to evaluate the normal cytological characteristics of the oral cavity of inland bearded dragons (Pogona vitticeps). Twenty-eight clinically healthy inland bearded dragons, including juveniles and adult males and females, from private collections were evaluated. Oral samples from the tongue and palate were obtained from each animal. Slides were stained with modified Wright–Giemsa stain and analyzed under an optical microscope. The contents of the slides were mostly hypocellular, with no evidence of microbiological overgrowth or inflammation, and showed mostly keratinized squamous cells; basal epithelial cells were seldom observed. Occasionally, goblet cells were observed in tongue samples, but were rare in pa...

Dental Pain in Cats: A Prospective 6-Month Study

Journal of Veterinary Dentistry

Dental pathology is among the most ubiquitous diseases in cats of all ages. Dental pain is yet to... more Dental pathology is among the most ubiquitous diseases in cats of all ages. Dental pain is yet to be fully understood in cats and therefore its presence is often missed. To better understand feline dental disease as a pain trigger during routine examination and whether disease severity correlates to the degree of pain, a 6-month prospective study in a cats’ only veterinary hospital in Portugal was conducted. Sixty-four cats that randomly presented for different clinical procedures were evaluated. Dental and periodontal abnormalities (primary dental parameters, PDP), as well as clinical signs related to dental pain (secondary dental parameters, SDP), were assessed. All cats underwent an oral cavity examination, upon which, the Feline Acute Pain Scale from Colorado State University Veterinary Teaching Hospital (CPS), was used in order to assess pain. Six PDP (periodontal disease, gingival index, calculus index, tooth resorption, tooth fracture and missing teeth) and five SDP (mouth di...

Calicivirus and NK Cells in Chronic Feline Gingivostomatitis. What Else?

Journal of Comparative Pathology, 2022

Journal of Archaeological Science: Reports, 2022

Domesticated dogs have been present in the Iberian Peninsula long before other domesticated speci... more Domesticated dogs have been present in the Iberian Peninsula long before other domesticated species, back to the late Palaeolithic period. Their origin is still uncertain, but dogs were already well established during the Chalcolithic period (ca. 5000-4000 BP). This study employed a multidisciplinary approach comprising osteometric, radiographic and palaeogenomic analyses to characterize Chalcolithic Iberian Canis remains. Two Chalcolithic archaeological sites-Leceia, Oeiras, in Portugal, and El Casetón de la Era, Villalba de los Alcores, Valladolid, in Spainwere the main focus of this study. Osteometric and odontometric data from eleven other sites in Iberia were also included. Osteometric results show signs of phenotypic variability, likely the result of human-driven selective pressure. Dental radiographic and dental wear analyses allowed age at death estimation for four individuals (two juvenile and two adults). Three Chalcolithic Iberian dogs had their mitogenomes resequenced and the mitochondrial DNA analysis allowed to assign each individual to two of the major known haplogroups-A and C. Molecular sex infered by the chromosomeX/chromosome1 coverage ratio allowed to identify one female and two males. This study unveils some aspects of the Iberian Chalcolithic dogs: these dogs already exhibited various morphotypes whose profiles might be associated to the performance of certain tasks, as well as mitogenomes of two distinct lineages that help tracking the evolutionary paths of Iberian dogs.

ABSTRACT. Requicha J.F., Pires M. dos A., Albuquerque C.M. & Viegas C.A. [Canine oral cavity neop... more ABSTRACT. Requicha J.F., Pires M. dos A., Albuquerque C.M. & Viegas C.A. [Canine oral cavity neoplasias - Brief review.] Neoplasias da cavidade oral do cao - Breve revisao. Revista Brasileira de Medicina Veterinaria, 37(1):41-46, 2015. Faculdade de Medicina Veterinaria, Universidade Lusofona de Humanidades e Tecnologias, Campo Grande, 1749-024 Lisboa, Portugal e Department of Veterinary Sciences, School of Agriculture and Veterinary Sciences, University of Tras-os-Montes e Alto Douro, P.O. Box 1013, 5001-801 Vila Real, Portugal. E-mail: jfrequicha@gmail.com Oral proliferative lesions are relatively common in domestic carnivores but, fortunately, a lot of these lesions are benign. The oral cavity is place of 6% of all tumours in dogs, being the sixth most important localization of neoplasias in this specie. The non-odontogenic tumors arise from structures of the oral cavity, except from dental tissue, and they are mostly malignant. Odontogenic tumors are those originated from the den...

O Complexo Gengivite-Estomatite-Faringite Felino e uma doenca frequente nestes animais e caracter... more O Complexo Gengivite-Estomatite-Faringite Felino e uma doenca frequente nestes animais e caracteriza-se por uma intensa inflamacao da cavidade oral e das gengivas. Afeta, principalmente, gatos adultos com cerca de 8 anos de idade, nao havendo predisposicao sexual. A etiologia nao e claramente conhecida, mas suspeita-se que determinadas bacterias, alguns virus, a alimentacao, o ambiente e episodios de stresse, ou uma conjugacao destes fatores com fatores geneticos, estejam na origem desta doenca. Atualmente, cre-se que a causa mais importante seja o calicivirus felino. Os sinais clinicos mais frequentemente visualizados sao inapetencia, disfagia, anorexia, ptialismo, halitose e perda de peso. Para a obtencao do diagnostico definitivo realiza-se a pesquisa de calicivirus por PCR (reacao em cadeia da polimerase) e a eletroforese de proteinas para evidenciacao de gamopatia policlonal.

International journal of scientific research, 2017

Muscular spasticity is a clinical sign common on Veterinary Medicine ́s patients with upper motor... more Muscular spasticity is a clinical sign common on Veterinary Medicine ́s patients with upper motor neuron syndrome (UMNS) syndrome and can be explain by neuroanatomy, thus extremely important when adressed from an Animal Rehabilitation point of view, being that these kind of animals are potential future patients of functional neuro-rehabilitation (FNR). Considering its limitation to the functionality and quality of life of patients, Human Medicine invests a lot of work in the full understanting of spasticity. On the other hand this clinical sign is undervalued in Veterinary Medicine. us, the presente article aims to classify muscular spasticity in dogs, introducing a qualitative clinical scale of evaluation, already been proved by neuroscience in Human Medicine. erefore, the main goal of this study was the implementation of the Modified Ashworth Scale (MAS) to Veterinary Medicine. With this method, it becomes possible for all veterinarians in the rehabilitation field to speak the s...

Isabel Pereira was supported by the grant SFRH/BD/ 90066/2012 from FCT. We thank FEDER and NORTE ... more Isabel Pereira was supported by the grant SFRH/BD/ 90066/2012 from FCT. We thank FEDER and NORTE 2020 through the project no 003262 titled iBONE therapies: advanced solutions for bone regeneration and NORTE-01-0145-FEDER-000012. We also thank the funding from FCT (UID/BIO/044469/2013 and UID/BIM/04293/2013) and from FEDER through COMPETE 2020 (POCI-01-0145-FEDER-006684).

Gene, 2018

Periodontal Disease is an infectious and inflammatory disorder triggered mainly by periodontopath... more Periodontal Disease is an infectious and inflammatory disorder triggered mainly by periodontopathogenic bacteria, however, as a multifactorial disease, several factors modulate its progression, namely, genetic factors. Toll-like receptors (TLR) recognize molecular patterns present in pathogens and trigger an immune response against them. Thus, sequences variants in TLR genes seem to have the potential to modify the predisposition to Periodontal Disease and its progression. Based on this fact, TLR9 gene were analysed in a case-control study. DNA was obtained from 90 dogs (50 control and 40 cases) and a fragment of TLR9 gene was amplified by PCR and sequenced. The variants were identified by comparison with the dog wild type sequences. Our results suggest that rs375556098 and rs201959275 polymorphisms in the TLR9 gene are good candidates to become biomarkers of the canine predisposition to Periodontal Disease. It's important to notice that these polymorphic sites exist in Human exactly in the same codon. Since the dog is the best animal model to replicate the pathophysiological mechanisms of human Periodontal Disease, these results can potentially be extrapolated to humans.

Journal of Stem Cell Research & Therapy, 2016

Canine adipose-derived stem cells (cASCs) have great interest for cell-based therapies in Veterin... more Canine adipose-derived stem cells (cASCs) have great interest for cell-based therapies in Veterinary Medicine. As the behaviour of these cells in non-autologous recipients is not deeply characterized, it is mandatory to study them in new animal models previously to canine specie. In this work, cASCs were injected subcutaneously in mice and these cells were detected by immunohistochemistry using vimentin, CD44 and keratin. The local response evaluated by histology did not reveal signals of significant inflammatory reaction neither in the lymph nodes or other organs. This study showed the implantation of cASCs induced a scarce inflammatory response. Hsd:CD1 (ICR) mouse can be proposed as an animal model to study the in vivo behavior of the cASCs and to validate new cASCs-based approaches avoiding or reducing the use of dogs in research.

Journal of Genetics, 2015

Elevated levels of interleukin-1 (IL-1) have been shown to amplify the inflammatory response agai... more Elevated levels of interleukin-1 (IL-1) have been shown to amplify the inflammatory response against periodontopathogenic bacteria. In humans, polymorphisms in the IL1A and IL1B genes are the most well-studied genetic polymorphisms associated with periodontal disease (PD). In contrast to human, there is a lack of knowledge on the genetic basis of canine PD. A casecontrol study was conducted in which a molecular analysis of dog IL1A and IL1B genes was performed. Of the eight genetic variants identified, seven in IL1A gene and one in IL1B gene, IL1A/1_g.388A>C and IL1A/1_g.521T>A showed statistically significant differences between groups (adjusted OR (95% CI): 0.15 (0.03-0.76), P = 0.022; 5.76 (1.03-32.1), P = 0.046, respectively). It suggests that in the studied population the IL1A/1_g.388C allele is associated with a decreased PD risk, whereas the IL1A/1_g.521A allele can confer an increased risk. Additionally, the IL1A/2_g.515G>T variation resulted in a change of amino acid, i.e. glycine to valine. In silico analysis suggests that this change can alter protein structure and function, predicting it to be deleterious or damaging. This work suggests that IL1 genetic variants may be important in PD susceptibility in canines.

Resumo: O hipertiroidismo é agora a doença endócrina mais comum no gato. O motivo pelo aumento an... more Resumo: O hipertiroidismo é agora a doença endócrina mais comum no gato. O motivo pelo aumento anual do número de casos desta doença deverá prender-se com um Maior disponibilidade e utilização correcta dos meios complementares que permitem emitir um diagnóstico definitivo, mas também com o aumento de exposição da população de gatos aos factores predisponentes. Assim, este trabalho, utilizando uma base de dados proveniente de um CAMV na região da Grande Lisboa e um inquérito realizado a 31 Médicos Veterinários (MVs) que exercem a sua prática clínica nesta região do país, visou compreender melhor a abordagem global ao problema. Concluiu-se que, nesta região, a sintomatologia e a idade dos gatos são os principais motivos que levam à suspeita de hipertiroidismo felino e que levam à realização frequente de medições da concentração sérica de T4. No entanto, após um diagnóstico definitivo de hipertiroidismo, a maioria dos MVs não recomenda um tratamento curativo, como por exemplo o iodo radioactivo, o qual é desconhecido da maioria dos profissionais inquiridos, ou a tiroidectomia, mas sim uma abordagem terapêutica visando controlar a doença sem no entanto impedir a sua progressão como sendo o metimazol ou as dietas de prescrição.

New tissue-engineered matrix for periodontal regeneration based on a biodegradable material combined with canine adipose-derived stem cells

Journal of Tissue Engineering and Regenerative Medicine

Periodontal disease (PD) is an inflammatory pathology highly prevalent both in humans and in dogs... more Periodontal disease (PD) is an inflammatory pathology highly prevalent both in humans and in dogs, which is characterized by destruction of the periodontal ligament, cementum and alveolar bone. The development of new therapies, such as Tissue Engineering strategies, is mandatory due to the inefficacy of conventional therapies

Periodontal Tissue Engineering Strategies Based on Nonoral Stem Cells

The Anatomical Record, 2013

Periodontal disease is an inflammatory disease which constitutes an important health problem in h... more Periodontal disease is an inflammatory disease which constitutes an important health problem in humans due to its enormous prevalence and life threatening implications on systemic health. Routine standard periodontal treatments include gingival flaps, root planning, application of growth/differentiation factors or filler materials and guided tissue regeneration. However, these treatments have come short on achieving regeneration ad integrum of the periodontium, mainly due to the presence of tissues from different embryonic origins and their complex interactions along the regenerative process. Tissue engineering (TE) aims to regenerate damaged tissue by providing the repair site with a suitable scaffold seeded with sufficient undifferentiated cells and, thus, constitutes a valuable alternative to current therapies for the treatment of periodontal defects. Stem cells from oral and dental origin are known to have potential to regenerate these tissues. Nevertheless, harvesting cells from these sites implies a significant local tissue morbidity and low cell yield, as compared to other anatomical sources of adult multipotent stem cells. This manuscript reviews studies describing the use of non-oral stem cells in tissue engineering strategies, highlighting the importance and potential of these alternative stem cells sources in the development of advanced therapies for periodontal regeneration.

Canine periodontitis: The dog as an important model for periodontal studies

The Veterinary Journal, 2012

Periodontal disease (PD) refers to a group of inflammatory diseases caused by bacterial plaque in... more Periodontal disease (PD) refers to a group of inflammatory diseases caused by bacterial plaque in the periodontium and ranges from an early stage (gingivitis) to an advanced stage (periodontitis). It is a multifactorial disease that results from the interaction of the host defence mechanisms with the plaque microorganisms. Early detection, diagnosis and treatment are essential in the control of this disease. PD has an enormous impact on human and veterinary medicine due to its high prevalence. The most common animal PD models use dogs and non-human primates, although other animals (rats, mice, hamsters, rabbits, miniature pigs, ferrets, and sheep) have also been employed. Dog models have contributed significantly to the current understanding of periodontology. The most important clinical aspects of canine PD are considered in this review and the various animal models are examined with an emphasis on the role of the dog as the most useful approach for understanding human PD and in the development of new therapeutic and preventive measures.