Primary cilia in the pathogenesis of dentigerous cyst: a new hypothesis based on role of primary cilia in autosomal dominant polycystic kidney disease

Primary cilia and hypoxia-associated signaling in developmental odontogenic cysts in relation to autosomal dominant polycystic kidney disease - A novel insight

Developmental cysts are pathological epithelial-lined cavities arising in various organs as a result of systemic or hereditary diseases. Molecular mechanisms involved in the formation of developmental odontogenic cysts (OCs) are not fully understood yet; the cystogenesis of renal cysts originating from the autosomal dominant polycystic kidney disease (ADPKD) has been, however, explored in much greater detail. This narrative review aimed i) to summarize molecular and cellular processes involved in the formation and growth of developmental OCs, especially dentigerous cysts (DCs) and odontogenic keratocysts (OKCs), ii) to find if there are any similarities in their cystogenesis to ADPKD cysts, and, based on that, iii) to suggest potential factors, candidate molecules, and mechanisms that could be involved in the DC formation, thus proposing further research directions. Here we suggest a possible association of developmental OCs with primary cilia disruption and with hypoxia, which have been previously linked with cyst formation in ADPKD patients. This is illustrated on the imagery of tissues from an ADPKD patient (renal cyst) and from developmental OCs, supporting the similarities in cell proliferation, apoptosis, and primary cilia distribution in DC/OKC/ADPKD tissues. Based on all that, we propose a novel hypothesis of OCs formation suggesting a crucial role of mutations associated with the signaling pathways of primary cilia (in particular, Sonic Hedgehog). These can lead to excessive proliferation and formation of cell agglomerates, which is followed by hypoxia-driven apoptosis in the centers of such agglomerates (controlled by molecules such as Hypoxia-inducible factor-1 alpha), leading to cavity formation and, finally, the OCs development. Based on this, we propose future perspectives in the investigation of OC pathogenesis.

Primary Cilia: The New Face of Craniofacial Research

The primary cilium is a solitary, sensory organelle that extends from the surface of nearly every vertebrate cell, including craniofacial cells. This organelle converts chemical and physical external stimuli into intracellular signaling cascades and mediates several well-known signaling pathways simultaneously. Thus, the primary cilium is considered a cellular signaling nexus and amplifier. Primary cilia dysfunction directly results in a collection of diseases and syndromes that typically affect multiple organ systems, including the face and teeth. Despite this direct connection, primary cilia are largely unexplored in craniofacial research. In this review, I briefly summarize craniofacial abnormalities tied to the primary cilium and examine the existing information on primary cilia in craniofacial development and repair. I close with a discussion on preliminary studies that motivate future areas of exploration that are further supported by studies performed in long bone and kidney cells.

Diagnóstico de quiste dentígero en sacos foliculares de terceros molares incluídos

Objetivo: establecer el tipo de patología más frecuente asociada a terceros molares incluidos, extraídos en las clínicas de cirugía oral de la Facultad de Odontología de la Universidad Nacional de Colombia y la frecuencia de aparición de quistes dentígeros, rango de edad, sexo y la región anatómica en que predominan. Métodos: se revisaron 17 sacos foliculares de 11 pacientes atendidos en las clínicas de cirugía oral entre agosto del 2018 y febrero 2019. Resultados: se recolectaron 7 biopsias de 5 pacientes masculinos  y 10 de 7 pacientes femeninos, con edades comprendidas entre los 17 a 24 años (media: 20.40), se realizó estudio histopatológico con hematoxilina-eosina, los datos obtenidos se analizaron para determinar frecuencia, edad, sexo y patología asociada. Se encontraron 15 casos que mostraron cambios quísticos diagnosticados como quistes dentígeros y  2 casos diagnosticados como saco folicular. Conclusiones: aunque la muestra es pequeña, este estudio da indicios que los sacos foliculares asociados a terceros molares incluídos están  altamente implicados en la formación de quistes dentígeros.

Evaluación radiográfica de la estabilidad en medidas cefalométricas de pacientes Clase III sometidos a cirugía ortognática bimaxilar*

Objetivo: evaluar cefalométricamente en los planos sagital y vertical la estabilidad de pacientes con maloclusión clase III sometidos a cirugía ortognática bimaxilar. Métodos: estudio longitudinal en 20 pacientes (11 mujeres), con un promedio de 22.5 años y diagnóstico de hipoplasia del tercio medio facial y prognatismo mandibular, tratados con ortodoncia y cirugía ortognática bimaxilar. Se realizaron tres radiografías cefálicas laterales por cada paciente: una previa al procedimiento quirúrgico (T1), otra a los 8 meses posquirúrgicos (T2) y a los 18 meses posquirúrgicos (T3). Se evaluaron los cambios en el plano X y Y en los tres tiempos, realizando las pruebas estadísticas pertinentes con el fin de observar diferencias. Resultados: se encontraron medidas más estables en el maxilar superior en sentido vertical y sagital, mientras que la mandíbula es menos estable a los movimientos quirúrgicos, principalmente en sentido vertical (diferencias estadísticamente significativas p<0.05) Conclusión: la cirugía ortognática bimaxilar en casos de clase III es muy estable (especialmente en el maxilar); dicha estabilidad fue definida solamente con medidas cefalométricas, sin tener en cuenta variables como la función o las características clínicas de los pacientes.

Hepatic ischemia/reperfusion injury disrupts the homeostasis of kidney primary cilia via oxidative stress

Acute kidney injury (AKI) is a major complication of hepatic surgeries. The primary cilium protrudes to the lumen of kidney tubules and plays an important role in renal functions. Disruption of primary cilia homeostasis is highly associated with human diseases including AKI. Here, we investigated whether transient hepatic ischemia induces length change and deciliation of kidney primary cilia, and if so, whether reactive oxygen species (ROS)/oxidative stress regulates those. HIR induced damages to the liver and kidney with increases in ROS/oxidative stress. HIR shortened the cilia of kidney epithelial cells and caused them to shed into the urine. This shortening and shedding of cilia was prevented by Mn(III) tetrakis(1-methyl-4-pyridyl) porphyrin (MnTMPyP, an antioxidant). The urine of patient undergone liver resection contained ciliary proteins. These findings indicate that HIR induces shortening and deciliation of kidney primary cilia into the urine via ROS/oxidative stress, suggesting that primary cilia is associated with HIR-induced AKI and that the presence of ciliary proteins in the urine could be a potential indication of kidney injury.

A luminescent lanthanide approach towards direct visualization of primary cilia in living cells

A simple and direct imaging tool (HGEu001) for primary cilia based on long-lived europium luminescence is firstly presented.

From bone abnormalities to mineral metabolism dysregulation in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic cause of kidney failure. It is a systemic disorder, not only affecting the kidneys, but also associated with cyst formation in other organs such as the liver, spleen, pancreas, and seminal vesicles. Other extra-renal symptoms may consist of intracranial arterial aneurysms, cardiac valvular defects, abdominal and inguinal hernias and colonic diverticulosis. Very little is known regarding bone involvement in ADPKD; however, recent evidence has revealed the potential role of fibroblast growth factor 23 (FGF23). FGF23 is an endocrine fibroblast growth factor acting in the kidney as a phosphaturic hormone and a suppressor of active vitamin D with key effects on the bone/kidney/parathyroid axis, and has been shown to increase in patients with ADPKD, even with normal renal function. The aim of this review is to provide an overview of bone and mineral abnormalities found in experimental models and in patients with ADPKD, and to discuss the possible role of FGF23 in this disease.