Cannabidiol decreases bone resorption by inhibiting RANK/RANKL expression and pro-inflammatory cytokines during experimental periodontitis in rats

Effects of cannabidiol interactions with Wnt/β-catenin pathway and PPARγ on oxidative stress and neuroinflammation in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease, in which the primary etiology remains unknown. AD presents amyloid beta (Aβ) protein aggregation and neurofibrillary plaque deposits. AD shows oxidative stress and chronic inflammation. In AD, canonical Wingless-Int (Wnt)/β-catenin pathway is downregulated, whereas peroxisome proliferator-activated receptor γ (PPARγ) is increased. Downregulation of Wnt/β-catenin, through activation of glycogen synthase kinase-3β (GSK-3β) by Aβ, and inactivation of phosphatidylinositol 3-kinase/Akt signaling involve oxidative stress in AD. Cannabidiol (CBD) is a non-psychotomimetic phytocannabinoid from Cannabis sativa plant. In PC12 cells, Aβ-induced tau protein hyperphosphorylation is inhibited by CBD. This inhibition is associated with a downregulation of p-GSK-3β, an inhibitor of Wnt pathway. CBD may also increase Wnt/β-catenin by stimulation of PPARγ, inhibition of Aβ and ubiquitination of amyloid precursor protein. CBD attenuates oxidative stress and diminishes mitochondrial dysfunction and reactive oxygen species generation. CBD suppresses, through activation of PPARγ, pro-inflammatory signaling and may be a potential new candidate for AD therapy.

Cannabidiol administration reduces sublesional cancellous bone loss in rats with severe spinal cord injury

Patients with spinal cord injury (SCI) undergo severe loss of bone mineral below the level of lesion, and data on available treatment options after SCI is scarce. The aim of this work was to investigate the therapeutic effect of cannabidiol (CBD), a non-psychoactive cannabis, on sublesional bone loss in a rat model of SCI. The adult male rats were exposed to surgical transection of the cord and treated with CBD for consecutive 14 days. It was found that CBD treatment elevated the serum levels of osteocalcin, reduced the serum levels of collagen type I cross-linked C-telopeptide, and enhanced bone mineral density of tibiae and femurs. Treatment of SCI rats with CBD enhanced bone volume, trabecular thickness, and trabecular number, and reduced trabecular separation in proximal tibiae, and increased ultimate compressive load, stiffness, and energy to max force of femoral diaphysis. Treatment of SCI rats with CBD upregulated mRNA expression of alkaline phosphatase and osteoprotegerin and downregulated mRNA expression of receptor activator of NF-κB ligand and tartrate-resistant acid phosphatase in femurs. Furthermore, treatment of SCI rats with CBD enhanced mRNA expression of wnt3a, Lrp5 and ctnnb1 in femurs. In conclusion, CBD administration attenuated SCI-induced sublesional cancellous bone loss.

Cannabidiol: an alternative therapeutic agent for oral mucositis?

WHAT IS KNOWN AND OBJECTIVE

Chemo- and radiotherapy are therapeutic modalities often used in patients with malignant neoplasms. They kill tumour cells but act on healthy tissues as well, resulting in adverse effects. Oral mucositis is especially of concern, due to the morbidity that it causes. We reviewed the literature on the etiopathogenesis of oral mucositis and the activity of cannabidiol, to consider the possibility of its use for the prevention and treatment of oral mucositis.

METHODS

We searched the PubMed database and selected complete articles published in English that met the inclusion criteria for the period 1998-2016. The search terms 'cannabinoids', 'cannabidiol', 'oxidative stress', 'antioxidants' and 'oral mucositis' were used.

RESULTS AND DISCUSSION

The control of oxidative stress may prevent and alleviate oral mucositis. Studies have demonstrated that cannabidiol is safe to use and possesses antioxidant, anti-inflammatory and analgesic properties.

WHAT IS NEW AND CONCLUSIONS

The literature on the use of cannabidiol in dentistry is still scarce. Studies investigating the use of cannabidiol in oral mucositis and other oxidative stress-mediated side effects of chemotherapy and radiotherapy on the oral mucosa should be encouraged.

Dietary arginine silicate inositol complex inhibits periodontal tissue loss in rats with ligature-induced periodontitis

The purpose of this study was to induce experimental periodontitis in rats previously fed diets containing arginine silicate inositol (ASI) complex and examine the biochemical, immunological, and radiological effects. Fifty two 8-week-old female Sprague Dawley rats were equally divided into four groups. The control group included those fed a standard rat diet with no operation performed during the experiment. The periodontitis, ASI I, and ASI II groups were subjected to experimental periodontitis induction for 11 days after being fed a standard rat diet alone, a diet containing 1.81 g/kg ASI complex, or a diet containing 3.62 g/kg ASI complex, respectively, for 8 weeks. Throughout the 11-day duration of periodontitis induction, all rats were fed standard feed. The rats were euthanized on the eleventh day, and their tissue and blood samples were collected. In the periodontitis group, elevated tissue destruction parameters and reduced tissue formation parameters were found, as compared to the ASI groups. Levels of enzymes, cytokines, and mediators associated with periodontal tissue destruction were lower in rats fed a diet containing ASI complex after experimental periodontitis. These results indicate that ASI complex could be an alternative agent for host modulation.

Relationship Between Frequent Recreational Cannabis (Marijuana and Hashish) Use and Periodontitis in Adults in the United States: National Health and Nutrition Examination Survey 2011 to 2012

BACKGROUND

Recreational use of cannabis, following its legalization in some countries, poses emergent oral and periodontal health concerns. The objective of this study is to examine the relationship between frequent recreational cannabis (FRC) (marijuana and hashish) use and periodontitis prevalence among adults in the United States.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) 2011 to 2012 were analyzed. Primary outcome (periodontitis) was defined using the Centers for Disease Control and Prevention/American Academy of Periodontology classification as well as continuous measurements of probing depth (PD) and clinical attachment loss (AL). Exposure of interest was self-reported cannabis use, defined as "FRC use" versus "non-FRC use." Bivariate and multivariable regression models were performed using the entire analytical sample (model 1) as well as those who had never used tobacco (never-users) (model 2).

RESULTS

Of 1,938 participants with available cannabis use data and essential covariates, 26.8% were FRC users. Mean number of sites per participant with PD ≥4, ≥6, and ≥8 mm and AL ≥3, ≥5, and ≥8 mm was significantly higher among FRC users than among non-FRC users (mean difference in number of PD sites: 6.9, 5.6, and 5.6; P <0.05; mean difference in number of AL sites: 12.7, 7.6, and 5.6; P <0.05). Average AL was higher among FRC users than among non-FRC users (1.8 versus 1.6 mm; P = 0.004). Bivariate analysis revealed positive (harmful) association between FRC use and severe periodontitis in the entire sample (odds ratio [OR]: 1.7, 95% confidence interval [CI]: 1.3 to 2.4; P = 0.002) as well as in never-smokers (OR: 2.0, 95% CI: 1.2 to 3.5; P = 0.01). This association was retained in multivariable models adjusted for demographics (age, sex, race/ethnicity, and income level), alcohol and tobacco use, diabetes mellitus, and past periodontal treatment (model 1: adjusted OR [aOR]: 1.4, 95% CI: 1.1 to 1.9; P = 0.07; model 2: aOR: 1.9, 95% CI: 1.1 to 3.2; P = 0.03).

CONCLUSION

FRC use is associated with deeper PDs, more clinical AL, and higher odds of having severe periodontitis.

From Phytocannabinoids to Cannabinoid Receptors and Endocannabinoids: Pleiotropic Physiological and Pathological Roles Through Complex Pharmacology

Apart from having been used and misused for at least four millennia for, among others, recreational and medicinal purposes, the cannabis plant and its most peculiar chemical components, the plant cannabinoids (phytocannabinoids), have the merit to have led humanity to discover one of the most intriguing and pleiotropic endogenous signaling systems, the endocannabinoid system (ECS). This review article aims to describe and critically discuss, in the most comprehensive possible manner, the multifaceted aspects of 1) the pharmacology and potential impact on mammalian physiology of all major phytocannabinoids, and not only of the most famous one Δ9-tetrahydrocannabinol, and 2) the adaptive pro-homeostatic physiological, or maladaptive pathological, roles of the ECS in mammalian cells, tissues, and organs. In doing so, we have respected the chronological order of the milestones of the millennial route from medicinal/recreational cannabis to the ECS and beyond, as it is now clear that some of the early steps in this long path, which were originally neglected, are becoming important again. The emerging picture is rather complex, but still supports the belief that more important discoveries on human physiology, and new therapies, might come in the future from new knowledge in this field.

Cannabidiol, neuroprotection and neuropsychiatric disorders

Cannabidiol (CBD) is a non-psychotomimetic phytocannabinoid derived from Cannabis sativa. It has possible therapeutic effects over a broad range of neuropsychiatric disorders. CBD attenuates brain damage associated with neurodegenerative and/or ischemic conditions. It also has positive effects on attenuating psychotic-, anxiety- and depressive-like behaviors. Moreover, CBD affects synaptic plasticity and facilitates neurogenesis. The mechanisms of these effects are still not entirely clear but seem to involve multiple pharmacological targets. In the present review, we summarized the main biochemical and molecular mechanisms that have been associated with the therapeutic effects of CBD, focusing on their relevance to brain function, neuroprotection and neuropsychiatric disorders.

Cannabinoid receptor gene polymorphisms and bone mineral density in Korean postmenopausal women

OBJECTIVE

We investigated the association between single nucleotide polymorphisms in cannabinoid receptor (CNR) genes and bone mineral density (BMD) in Korean postmenopausal women.

METHODS

Seven polymorphisms (rs2023239, rs806379, rs12720071, rs1049353, rs806368, rs2180619, and rs7766029) in the cannabinoid receptor type 1 (CNR1) gene and 16 polymorphisms (rs2501432, rs2502992, rs2501431, rs3003336, rs4649124, rs2502993, rs2229579, rs2229580, rs2229581, rs2229583, rs2229584, rs2229585, rs2229586, rs4237, rs7530595, and rs16828926) in the cannabinoid receptor type 2 (CNR2) gene were analyzed in 405 Korean postmenopausal women. Serum levels of bone turnover markers, osteoprotegerin (OPG), and soluble receptor activator of nuclear factor-κB ligand (sRANKL) were measured, and BMD at the lumbar spine and femoral neck was examined.

RESULTS

The CNR2 rs2501431, rs3003336, rs2229579, and rs4237 polymorphisms in CNR genes were associated with lumbar spine BMD. Women with the AA genotype of rs3003336 and rs4237 polymorphisms had significantly lower lumbar spine BMD compared with women with the non-AA genotype. Lumbar spine BMD in women with the TT genotype of CNR2 rs2501431 and rs2229579 polymorphisms was significantly lower than that in women with the non-TT genotype. Significantly higher odds for osteoporosis of the lumbar spine and/or femoral neck were observed in women with the TT genotype of rs2229579 polymorphisms (odds ratio, 3.43; 95% CI, 1.28-9.19) and with the AA genotype of rs4237 polymorphisms (odds ratio, 1.74; 95% CI, 1.03-2.95) compared with those not carrying the genotypes. The adjusted serum levels of bone turnover markers, OPG, sRANKL, or sRANKL × 1,000-to-OPG ratios were not associated with CNR gene polymorphisms.

CONCLUSIONS

Our results suggest that rs2501431, rs3003336, rs2229579, and rs4237 polymorphisms in CNR genes may be genetic factors affecting BMD in Korean postmenopausal women.

Development, optimization and evaluation of tinidazole functionalized electrospun poly(ε-caprolactone) nanofiber membranes for the treatment of periodontitis

The proposed work is focused to alleviate shortcomings in the treatment of periodontitis by electrospinning of a novel biodegradable poly(ε-caprolactone) based nanofiber membrane functionalized with tinidazole.

Eugenol nanocapsule for enhanced therapeutic activity against periodontal infections

Eugenol is a godsend to dental care due to its analgesic, local anesthetic, and anti-inflammatory and antibacterial effects. The aim of the present research work was to prepare, characterize and evaluate eugenol-loaded nanocapsules (NCs) against periodontal infections. Eugenol-loaded polycaprolactone (PCL) NCs were prepared by solvent displacement method. The nanometric size of the prepared NCs was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The in vitro drug release was found to follow a biphasic pattern and followed Michaelis-Menten like model. The percentage cell viability values near to 100 in the cell viability assay indicated that the NCs are not cytotoxic. In the in vivo studies, the eugenol NC group displayed significant difference in the continuity of epithelium of the interdental papilla in comparison to the untreated, pure eugenol and placebo groups. The in vivo performance of the eugenol-loaded NCs using ligature-induced periodontitis model in rats indicated that eugenol-loaded NCs could prevent septal bone resorption in periodontitis. On the basis of our research findings it could be concluded that eugenol-loaded PCL NCs could serve as a novel colloidal drug delivery system for enhanced therapeutic activity of eugenol in the treatment of periodontal infections.

Cannabidiol increases survival and promotes rescue of cognitive function in a murine model of cerebral malaria

Cerebral malaria (CM) is a severe complication resulting from Plasmodium falciparum infection that might cause permanent neurological deficits. Cannabidiol (CBD) is a nonpsychotomimetic compound of Cannabis sativa with neuroprotective properties. In the present work, we evaluated the effects of CBD in a murine model of CM. Female mice were infected with Plasmodium berghei ANKA (PbA) and treated with CBD (30mg/kg/day - 3 or 7days i.p.) or vehicle. On 5th day-post-infection (dpi), at the peak of the disease), animals were treated with single or repeated doses of Artesunate, an antimalarial drug. All groups were tested for memory impairment (Novel Object Recognition or Morris Water Maze) and anxiety-like behaviors (Open field or elevated plus maze test) in different stages of the disease (at the peak or after the complete clearance of the disease). Th1/Th2 cytokines and neurotrophins (brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF)) were measured in the prefrontal cortex and hippocampus of experimental groups. PbA-infected mice displayed memory deficits and exhibited increase in anxiety-like behaviors on the 5dpi or after the clearance of the parasitemia, effects prevented by CBD treatment. On 5dpi, TNF-α and IL-6 increased in the hippocampus, while only IL-6 increased in the prefrontal cortex. CBD treatment resulted in an increase in BDNF expression in the hippocampus and decreased levels of proinflammatory cytokines in the hippocampus (TNF-α) and prefrontal cortex (IL-6). Our results indicate that CBD exhibits neuroprotective effects in CM model and might be useful as an adjunctive therapy to prevent neurological symptoms following this disease.

Protective effects of cannabidiol on lesion-induced intervertebral disc degeneration

Disc degeneration is a multifactorial process that involves hypoxia, inflammation, neoinnervation, accelerated catabolism, and reduction in water and glycosaminoglycan content. Cannabidiol is the main non-psychotropic component of the Cannabis sativa with protective and anti-inflammatory properties. However, possible therapeutic effects of cannabidiol on intervertebral disc degeneration have not been investigated yet. The present study investigated the effects of cannabidiol intradiscal injection in the coccygeal intervertebral disc degeneration induced by the needle puncture model using magnetic resonance imaging (MRI) and histological analyses. Disc injury was induced in the tail of male Wistar rats via a single needle puncture. The discs selected for injury were punctured percutaneously using a 21-gauge needle. MRI and histological evaluation were employed to assess the results. The effects of intradiscal injection of cannabidiol (30, 60 or 120 nmol) injected immediately after lesion were analyzed acutely (2 days) by MRI. The experimental group that received cannabidiol 120 nmol was resubmitted to MRI examination and then to histological analyses 15 days after lesion/cannabidiol injection. The needle puncture produced a significant disc injury detected both by MRI and histological analyses. Cannabidiol significantly attenuated the effects of disc injury induced by the needle puncture. Considering that cannabidiol presents an extremely safe profile and is currently being used clinically, these results suggest that this compound could be useful in the treatment of intervertebral disc degeneration.

RANKL expression in periodontal disease: where does RANKL come from?

Periodontitis is an inflammatory disease characterized by periodontal pocket formation and alveolar bone resorption. Periodontal bone resorption is induced by osteoclasts and receptor activator of nuclear factor-κB ligand (RANKL) which is an essential and central regulator of osteoclast development and osteoclast function. Therefore, RANKL plays a critical role in periodontal bone resorption. In this review, we have summarized the sources of RANKL in periodontal disease and explored which factors may regulate RANKL expression in this disease.

Quercetin inhibits inflammatory bone resorption in a mouse periodontitis model

Periodontitis is a disease that leads to bone destruction and represents the main cause of tooth loss in adults. The development of aggressive periodontitis has been associated with increased inflammatory response that is induced by the presence of a subgingival biofilm containing Aggregatibacter actinomycetemcomitans. The flavonoid quercetin (1) is widespread in vegetables and fruits and exhibits many biological properties for possible medical and clinical applications such as its anti-inflamatory and antioxidant effects. Thus, in the present study, the properties of 1 have been evaluated in bone loss and inflammation using a mouse periodontitis model induced by A. actinomycetemcomitans infection. Subcutaneous treatment with 1 reduced A. actinomycetemcomitans-induced bone loss and IL-1β, TNF-α, IL-17, RANKL, and ICAM-1 production in the gingival tissue without affecting bacterial counts. These results demonstrated that quercetin exhibits protective effects in A. actinomycetemcomitans-induced periodontitis in mice by modulating cytokine and ICAM-1 production.

The cannabinoid receptor type 1 is essential for mesenchymal stem cell survival and differentiation: implications for bone health

Significant loss of bone due to trauma, underlying metabolic disease, or lack of repair due to old age surpasses the body's endogenous bone repair mechanisms. Mesenchymal stem cells (MSCs) are adult stem cells which may represent an ideal cell type for use in cell-based tissue engineered bone regeneration strategies. The body's endocannabinoid system has been identified as a central regulator of bone metabolism. The aim of the study was to elucidate the role of the cannabinoid receptor type 1 in the differentiation and survival of MSCs. We show that the cannabinoid receptor type 1 has a prosurvival function during acute cell stress. Additionally, we show that the phytocannabinoid, Δ(9)-Tetrahydrocannabinol, has a negative impact on MSC survival and osteogenesis. Overall, these results show the potential for the modulation of the cannabinoid system in cell-based tissue engineered bone regeneration strategies whilst highlighting cannabis use as a potential cause for concern in the management of orthopaedic patients.

Secreted osteoclastogenic factor of activated T cells (SOFAT), a novel osteoclast activator, in chronic periodontitis

A novel activated human T cell-secreted cytokine, referred as secreted osteoclastogenic factor of activated T cells (SOFAT), that induce osteoclastogenesis in a RANKL-independent manner was recently described. This study evaluated the role of SOFAT in periodontal tissues and periodontitis. Gingival biopsies were harvested from systemically healthy non-periodontitis (n=15) and chronic periodontitis patients (n=15). The mRNA and protein levels of SOFAT were measured by qPCR and by enzyme-linked immunosorbent assay, respectively. Moreover, RAW 264.7 cells were cultured with SOFAT or Receptor activator of nuclear factor-kB ligand (RANKL) and stained for tartrate-resistant acid phosphatase (TRAP). Also, mice received a palatal injection between the first and second upper molar of SOFAT (100 ng/ml) or saline solution (0.9%). The upper jaw was removed, histologically processed and stained with hematoxilin and eosin to observe the presence of osteoclast-like cells. The mRNA and protein levels of SOFAT were significantly higher in the gingival tissue of the periodontitis group when compared to non-periodontitis one (p<0.05). In addition, SOFAT potently induced TRAP-positive multinucleated cell formation by RAW 264.7 cells as well as induced the formation of osteoclast-like cells in the periodontal ligament in mice. The present study demonstrated that SOFAT may play an important role in periodontitis.

Resveratrol decreases periodontal breakdown and modulates local levels of cytokines during periodontitis in rats

BACKGROUND

Resveratrol (3,4',5-trihydroxystilbene) is a naturally occurring product found in numerous plants. Among its biologic properties, resveratrol may promote immunomodulatory effects on the host response. This study investigates the effect of continuous administration of resveratrol on the progression of experimental periodontitis in rats.

METHODS

Periodontitis was induced in rats in one of the first molars chosen to receive a ligature. Animals were assigned to one of two groups: 1) daily administration of the placebo solution (control group) or 2) 10 mg/kg resveratrol (RESV group). The therapies were administered systemically for 30 days: for 19 days before periodontitis induction and then for another 11 days. Then, the specimens were processed for morphometric analysis of bone loss, and the gingival tissue surrounding the first molar was collected for quantification of interleukin (IL)-1β, IL-4, and IL-17 using a multiplexing assay.

RESULTS

Intergroup comparisons of the morphometric outcomes revealed higher bone loss values in ligated molars and unligated teeth in the control group than the RESV group (P <0.05). The immunoenzymatic assay of the gingival tissue showed a lower concentration of IL-17 in the RESV group than the control group (P <0.05), whereas no differences in the IL-1β and IL-4 levels of the groups were observed (P >0.05).

CONCLUSIONS

Continuous administration of resveratrol may decrease periodontal breakdown induced experimentally in rats. In addition, lower levels of IL-17 were found in the RESV group. Future studies are important to confirm the mechanism through which resveratrol exerts its effects.

Curcumin inhibits inflammatory response and bone loss during experimental periodontitis in rats

OBJECTIVE

Curcumin, an active ingredient of turmeric, is proved to be a potential candidate of controlling inflammation and bone resorption, but few reports are on the periodontitis. The purpose of this study was to evaluate whether the intra-gastric administration of curcumin could inhibit the inflammation and alveolar bone resorption in rats following ligature-induced experimental periodontitis.

MATERIALS AND METHOD

Male Wistar rats were randomly divided into three groups: no ligature placement and administration of vehicle, ligature placement and administration of vehicle, ligature placement and administration of curcumin. After the animals were sacrificed, their mandibles were collected for morphological, histological and immunohistochemical analysis; their gingival tissues were collected for cytokine measurements.

RESULTS

Bone resorption was significantly higher in the experimental periodontitis animals treated with vehicle compared with the curcumin-treated group or the control group. Furthermore, receptor activator of nuclear factor-κB ligand (RANKL), receptor activator of nuclear factor-κB (RANK), osteoprotegerin (OPG), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) expression levels were higher in the experimental periodontitis animals treated with vehicle compared with the curcumin treated group or the control group. CONCLUSIONS. Curcumin may decrease alveolar bone loss in the experimental periodontitis rats via suppressing the expression of RANKL/RANK/OPG and its anti-inflammatory properties.

Effects of a Mikania laevigata extract on bone resorption and RANKL expression during experimental periodontitis in rats

Objectives

The Mikania laevigata extract (MLE) (popularly known in Brazil as "guaco") possesses anti-inflammatory properties. In the present study we tested the effects of MLE in a periodontitis experimental model in rats. We also investigated possible mechanisms underlying such effects.

Material and Methods

Periodontal disease was induced by a ligature placed around the mandibular first molars of each animal. Male Wistar rats were divided into 4 groups: non-ligated animals treated with vehicle; non-ligated animals treated with MLE (10 mg/kg, daily); ligature-induced animals treated with vehicle and ligature-induced animals treated with MLE (10 mg/kg, daily). Thirty days after the induction of periodontal disease, the animals were euthanized and mandibles and gingival tissues removed for further analysis.

Results

Morphometric analysis of alveolar bone loss demonstrated that MLE-treated animals presented a decreased alveolar bone loss and a lower expression of the activator of nuclear factor-κB ligand (RANKL) measured by immunohistochemistry. Moreover, gingival tissues from the MLE-treated group showed decreased neutrophil migration myeloperoxidase (MPO) assay.

Conclusions

These results indicate that MLE may be useful to control bone resorption during progression of experimental periodontitis in rats.

The promise and dilemma of cannabinoid therapy: lessons from animal studies of bone disease

The endocannabinoid system plays an important role in numerous physiological processes and represents a potential drug target for diseases ranging from brain disorders to cancer. Recent preclinical studies implicated endocannabinoids and their receptors in the regulation of bone cell activity and in the pathogenesis of bone loss. Cells and intervening nerves in the skeleton express cannabinoid receptors and the machinery for the synthesis and breakdown of endocannabinoids. In healthy adult mice, pharmacological and genetic inactivation of the cannabinoid type 1 receptor (CB1) and putative cannabinoid receptor GPR55 (G protein-coupled receptor 55) inhibit osteoclastic bone resorption and increase bone mass, suggesting that both receptors have a negative role in early bone development. Although no distinct abnormalities in bone development were observed in healthy adult mice deficient in cannabinoid type 2 receptors (CB2), pharmacological blockage of this receptor was effective in suppressing bone loss associated with increased bone turnover, particularly in mouse models of osteoporosis, arthritis and osteolytic bone disease. In the aging skeleton, CB1 deficiency causes accelerated osteoporosis characterized mainly by a significant reduction in bone formation coupled to enhanced adipocyte accumulation in the bone marrow. A similar acceleration of bone loss was also reported in aging CB2-deficient mice but found to be associated with enhanced bone turnover. This perspective describes the role of cannabinoid ligands and their receptors in bone metabolism and highlights the promise and dilemma of therapeutic exploitation of the endocannabinoid system for treatment of bone disorders.

Protective effect of topical Cordia verbenacea in a rat periodontitis model: immune-inflammatory, antibacterial and morphometric assays

BACKGROUND

This study evaluated the effects of C. verbenacea essential oil topically administered in a rat periodontitis model.

METHODS

Periodontitis was induced on rats in one of the mandibular first molars assigned to receive a ligature. Animals were randomly divided into two groups: a) non-treatment group (NT) (n = 18): animals received 1mL of vehicle; b) C. verbenacea group (C.v.) (n = 18): animals received 5mg/Kg of essential oils isolated from C. verbenacea. The therapies were administered topically 3 times daily for 11 days. Then, the specimens were processed for morphometric analysis of bone loss. The ligatures were used for microbiological assessment of the presence of Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Porphyromonas gingivalis using PCR. The gingival tissue was collected to Elisa assay of interleukin (IL)-1α and IL-10 levels.

RESULTS

Bone loss was inhibited by C. verbenacea when compared to the NT group (p < 0.05). A decrease in the levels of IL-1α and increase in the IL-10 amounts was observed in the C.v. group as compared to NT group (p < 0.05). A lower frequency of P. gingivalis was found in C.v. group (p < 0.05).

CONCLUSION

C. verbenacea essential oil topically administered diminished alveolar bone resorption, promoting a positive local imbalance in the pro/anti-inflammatory system and reducing the frequency of detection of P. gingivalis.

Cannabidiol blocks long-lasting behavioral consequences of predator threat stress: possible involvement of 5HT1A receptors

Posttraumatic stress disorder (PTSD) is an incapacitating syndrome that follows a traumatic experience. Predator exposure promotes long-lasting anxiogenic effect in rodents, an effect related to symptoms found in PTSD patients. Cannabidiol (CBD) is a non-psychotomimetic component of Cannabis sativa with anxiolytic effects. The present study investigated the anti-anxiety actions of CBD administration in a model of PTSD. Male Wistar rats exposed to a predator (cat) received, 1 h later, singled or repeated i.p. administration of vehicle or CBD. Seven days after the stress animals were submitted to the elevated plus maze. To investigate the involvement of 5HT1A receptors in CBD effects animals were pre-treated with WAY100635, a 5HT1A receptor antagonist. To explore possible neurobiological mechanisms involved in these effects, 5HT1A receptor mRNA and BDNF protein expression were measured in the hippocampus, frontal cortex, amygdaloid complex and dorsal periaqueductal gray. Repeated administration of CBD prevented long-lasting anxiogenic effects promoted by a single predator exposure. Pretreatment with WAY100635 attenuated CBD effects. Seven days after predator exposure 5HT1A mRNA expression was up regulated in the frontal cortex and hippocampus. CBD and paroxetine failed to prevent this effect. No change in BDNF expression was found. In conclusion, predator exposure promotes long-lasting up-regulation of 5HT1A receptor gene expression in the hippocampus and frontal cortex. Repeated CBD administration prevents the long-lasting anxiogenic effects observed after predator exposure probably by facilitating 5HT1A receptors neurotransmission. Our results suggest that CBD has beneficial potential for PTSD treatment and that 5HT1A receptors could be a therapeutic target in this disorder.

Low dose of propranolol down-modulates bone resorption by inhibiting inflammation and osteoclast differentiation

BACKGROUND AND PURPOSE

Bones are widely innervated, suggesting an important role for the sympathetic regulation of bone metabolism, although there are controversial studies. We investigated the effects of propranolol in a model of experimental periodontal disease.

EXPERIMENTAL APPROACH

Rats were assigned as follows: animals without ligature; ligated animals receiving vehicle and ligated animals receiving 0.1, 5 or 20 mg·kg(-1) propranolol. After 30 days, haemodynamic parameters were measured by cardiac catheterization. Gingival tissues were removed and assessed for IL-1β, TNF-α and cross-linked carboxyterminal telopeptides of type I collagen (CTX) by elisa, or intercellular adhesion molecule 1 (ICAM-1), receptor activator of NF-κ B ligand (RANKL) and osteoprotegerin (OPG) by Western blot analysis. Sections from the mandibles were evaluated for bone resorption. Also, we analysed the ability of propranolol to inhibit osteoclastogenesis in vitro.

RESULTS

Propranolol at 0.1 and 5 mg·kg(-1) reduced the bone resorption as well as ICAM-1 and RANKL expression. However, only 0.1 mg·kg(-1) reduced IL-1β, TNF-α and CTX levels as well as increased the expression of OPG, but did not alter any of the haemodynamic parameters. Propranolol also suppressed in vitro osteoclast differentiation and resorptive activity by inhibiting the nuclear factor of activated T cells (NFATc)1 pathway and the expression of tartrate-resistant acid phosphatase (TRAP), cathepsin K and MMP-9.

CONCLUSIONS AND IMPLICATIONS

Low doses of propranolol suppress bone resorption by inhibiting RANKL-mediated osteoclastogenesis as well as inflammatory markers without affecting haemodynamic parameters.

Evaluation of the effect of an organic extract obtained from Ipomoea alba L. on experimental periodontitis in rats

The aim of this study was to evaluate the effect of an organic extract obtained from Ipomoea alba L. (Convolvulaceae or OE 1493), on experimental periodontal disease in rats. Periodontitis was induced in thirty six Wistar rats: a first mandibular molar was randomly assigned to receive a ligature, whereas the contralateral molar was left unligated. Animals were randomly assigned to two groups and treated topically, three times a day, for 11 days, as follows: Control Group - vehicle-treated (n = 18), and Test Group - OE 1493-treated (n = 18). The rats were sacrificed on the 12th day. Morphometrical measurements from the cementoenamel junction to the bone crest were performed to determine alveolar bone loss, using standardized photographs. Single- and multi-dose acute toxicity assays were carried out after OE 1493 treatment. Morphometrical analysis demonstrated that topically-administered OE 1493 showed no effect on reducing bone loss when compared with the control group (p > 0.05). In addition, OE 1493 did not present toxicity. Within the limits of this investigation, it may be concluded that OE 1493 did not show any positive influence on the progression of ligature-induced periodontitis in rats, when administered according to the regimen used in the present study.

Anti-inflammatory effect of the endocannabinoid anandamide in experimental periodontitis and stress in the rat

OBJECTIVE

Periodontitis is an infectious disease leading to inflammation and destruction of tissue surrounding and supporting the tooth. The progress of the inflammatory response depends on the host's immune system and risk factors such as stress. The aim of the present study was to investigate the role of the endocannabinoid anandamide (AEA) in experimental periodontitis with restraint stress, since the endocannabinoid system is known to modulate the hypothalamo-pituitary-adrenal axis as well as immune functions and has been found in human gingival tissues.

METHODS

Experimental periodontitis was induced by ligature around first inferior molars and immobilization stress for 2 h twice daily for 7 days in a rat model.

RESULTS

Corticosterone plasma levels, locomotor activity, adrenal gland weight and bone loss were increased in periodontitis and stress groups, and there was also less weight gain. The inflammatory parameters such as prostaglandin E(2) (radioimmunoassay), nitric oxide (radioconversion of (14)C-arginine), tumor necrosis factor (TNF)-α (ELISA) and interleukin (IL)-1β (Western blot) measured in the gingival tissue were significantly increased in the periodontitis groups compared to the control group. Local injection of AEA (10(-8)M, 30 µl) decreased corticosterone plasma levels and the content of the cytokines TNF-α and IL-1β in gingival tissue in periodontitis-stress groups. These AEA-induced inhibitions were mediated by CB(1) and CB(2) cannabinoid receptors since the injection of both antagonists together, AM251 (10(-6)M) and AM630 (10(-6)M) in 30 µl, prevented these effects.

CONCLUSION

The endocannabinoid AEA diminishes the inflammatory response in periodontitis even during a stressful situation.

Cannabidiol as an emergent therapeutic strategy for lessening the impact of inflammation on oxidative stress

Oxidative stress with reactive oxygen species generation is a key weapon in the arsenal of the immune system for fighting invading pathogens and initiating tissue repair. If excessive or unresolved, however, immune-related oxidative stress can initiate further increasing levels of oxidative stress that cause organ damage and dysfunction. Targeting oxidative stress in various diseases therapeutically has proven more problematic than first anticipated given the complexities and perversity of both the underlying disease and the immune response. However, growing evidence suggests that the endocannabinoid system, which includes the CB₁ and CB₂ G-protein-coupled receptors and their endogenous lipid ligands, may be an area that is ripe for therapeutic exploitation. In this context, the related nonpsychotropic cannabinoid cannabidiol, which may interact with the endocannabinoid system but has actions that are distinct, offers promise as a prototype for anti-inflammatory drug development. This review discusses recent studies suggesting that cannabidiol may have utility in treating a number of human diseases and disorders now known to involve activation of the immune system and associated oxidative stress, as a contributor to their etiology and progression. These include rheumatoid arthritis, types 1 and 2 diabetes, atherosclerosis, Alzheimer disease, hypertension, the metabolic syndrome, ischemia-reperfusion injury, depression, and neuropathic pain.

Role of RANKL-RANK/osteoprotegerin molecular complex in bone remodeling and its immunopathologic implications

Bone remodeling is a cyclic and continuous physiological process, which ensures the conservation and renewal of the bone matrix. Osteosynthesis of the bone matrix is achieved by osteoblasts and coordinated within this complex machinery of bone remodeling with resorption of extracellular bone matrix performed by osteoclasts. The mismatch between the activities of osteoblasts and osteoclasts has immunopathologic implications associated with either a decrease or increase of bone mass mineral density. The balance of the trimolecular control factor complex composed of osteoprotegerin (OPG), RANKL (osteoprotegerin ligand) and RANK maintains physiologic bone remodeling. This trimolecular complex functions as receptors and ligands and belongs to the superfamily of tumor necrosis factor (TNF). This mini review highlights the complex interplay of the RANKL-RANK/OPG axis and their immunopathologic implications in clinical medicine.

Impact of cannabis sativa (marijuana) smoke on alveolar bone loss: a histometric study in rats

BACKGROUND

Cannabis sativa (marijuana) can interfere with bone physiopathology because of its effect on osteoblast and osteoclast activity. However, its impact on periodontal tissues is still controversial. The present study evaluates whether marijuana smoke affects bone loss (BL) on ligature-induced periodontitis in rats.

METHODS

Thirty male Wistar rats were used in the study. A ligature was placed around one of the mandible first molars (ligated teeth) of each animal, and they were then randomly assigned to one of two groups: control (n = 15) or marijuana smoke inhalation ([MSI] for 8 minutes per day; n = 15). Urine samples were obtained to detect the presence of tetrahydrocannabinol. After 30 days, the animals were sacrificed and decalcified sections of the furcation area were obtained and evaluated according to the following histometric parameters: bone area (BA), bone density (BD), and BL.

RESULTS

Tetrahydrocannabinol was positive in urine samples only for the rats of the MSI group. Non-significant differences were observed for unligated teeth from both groups regarding BL, BA, and BD (P >0.05). However, intragroup analysis showed that all ligated teeth presented BL and a lower BA and BD compared to unligated teeth (P <0.05). The intergroup evaluation of the ligated teeth showed that the MSI group presented higher BL and lower BD (P <0.05) compared to ligated teeth from the control group.

CONCLUSION

Considering the limitations of this animal study, cannabis smoke may impact alveolar bone by increasing BL resulting from ligature-induced periodontitis.

Association of periodontitis with rheumatoid arthritis: a pilot study

BACKGROUND

Similarities exist in the epidemiology and immunopathogenesis of periodontitis and rheumatoid arthritis (RA), but the associations between their respective disease activities and severities are less well documented. We evaluated the prevalence and severity of periodontitis in United States (U.S.) veterans with RA and their relationship to RA disease activity and severity.

METHODS

Patients with RA from an outpatient rheumatology clinic were eligible, and patients with osteoarthritis (OA) served as controls. Dentists, masked to the rheumatologic diagnoses, performed periodontal probing and examined dental panoramic radiographs to assess the presence and severity of periodontitis. Associations of periodontitis with RA were examined using multivariate regression, whereas the association of periodontitis with disease-severity measures in RA was examined using the chi(2) test.

RESULTS

Sixty-nine patients with RA (57 males and 12 females) and 35 patients with OA (30 males and five females) were studied. Moderate to severe periodontitis was more prevalent in patients with RA (51%) than controls (26%) (P = 0.03), an association independent of age, race, smoking, diabetes mellitus, and gender. Patients with RA who were seropositive for rheumatoid factor (RF) were more likely to have moderate to severe periodontitis (59%) than patients who were RF negative (15%) (P = 0.02). Likewise, patients with RA who were positive for the anti-cyclic citrullinated peptide (CCP) antibodies were more likely to have moderate to severe periodontitis (56%) than patients who were anti-CCP negative (22%) (P = 0.01). There were no associations of periodontitis status with other measures of RA disease activity or severity.

CONCLUSIONS

In a cohort of U.S. veterans, periodontitis was more common and severe in patients with RA compared to patients with OA. Although unrelated to disease activity, the presence of periodontitis in patients with RA was associated with seropositivity for RF and the anti-CCP antibody, which was highly relevant given the associations of these autoantibodies with poor outcomes and disease pathogenesis in RA.

The effects of Delta-tetrahydrocannabinol and cannabidiol alone and in combination on damage, inflammation and in vitro motility disturbances in rat colitis

BACKGROUND AND PURPOSE

Cannabis is taken as self-medication by patients with inflammatory bowel disease for symptomatic relief. Cannabinoid receptor agonists decrease inflammation in animal models of colitis, but their effects on the disturbed motility is not known. (-)-Cannabidiol (CBD) has been shown to interact with Delta(9)-tetrahydrocannabinol (THC) in behavioural studies, but it remains to be established if these cannabinoids interact in vivo in inflammatory disorders. Therefore the effects of CBD and THC alone and in combination were investigated in a model of colitis.

EXPERIMENTAL APPROACH

The 2,4,6-trinitrobenzene sulphonic acid (TNBS) model of acute colitis in rats was used to assess damage, inflammation (myeloperoxidase activity) and in vitro colonic motility. Sulphasalazine was used as an active control drug.

KEY RESULTS

Sulphasalazine, THC and CBD proved beneficial in this model of colitis with the dose-response relationship for the phytocannabinoids showing a bell-shaped pattern on the majority of parameters (optimal THC and CBD dose, 10 mg.kg(-1)). THC was the most effective drug. The effects of these phytocannabinoids were additive, and CBD increased some effects of an ineffective THC dose to the level of an effective one. THC alone and in combination with CBD protected cholinergic nerves whereas sulphasalazine did not.

CONCLUSIONS AND IMPLICATIONS

In this model of colitis, THC and CBD not only reduced inflammation but also lowered the occurrence of functional disturbances. Moreover the combination of CBD and THC could be beneficial therapeutically, via additive or potentiating effects.

Non-psychotropic plant cannabinoids: new therapeutic opportunities from an ancient herb

Delta(9)-tetrahydrocannabinol binds cannabinoid (CB(1) and CB(2)) receptors, which are activated by endogenous compounds (endocannabinoids) and are involved in a wide range of physiopathological processes (e.g. modulation of neurotransmitter release, regulation of pain perception, and of cardiovascular, gastrointestinal and liver functions). The well-known psychotropic effects of Delta(9)-tetrahydrocannabinol, which are mediated by activation of brain CB(1) receptors, have greatly limited its clinical use. However, the plant Cannabis contains many cannabinoids with weak or no psychoactivity that, therapeutically, might be more promising than Delta(9)-tetrahydrocannabinol. Here, we provide an overview of the recent pharmacological advances, novel mechanisms of action, and potential therapeutic applications of such non-psychotropic plant-derived cannabinoids. Special emphasis is given to cannabidiol, the possible applications of which have recently emerged in inflammation, diabetes, cancer, affective and neurodegenerative diseases, and to Delta(9)-tetrahydrocannabivarin, a novel CB(1) antagonist which exerts potentially useful actions in the treatment of epilepsy and obesity.

PPAR-gamma agonist rosiglitazone prevents inflammatory periodontal bone loss by inhibiting osteoclastogenesis

Rosiglitazone (RGZ), an oral anti-hyperglycemic agent used for non-insulin-dependent diabetes mellitus, is a high-affinity synthetic agonist for peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Both in vitro and in vivo experiments have also revealed that RGZ possesses anti-inflammatory properties. Therefore, in the present study, we investigated the anti-inflammatory effects of RGZ in a rat model of periodontal disease induced by ligature placed around the mandible first molars of each animal. Male Wister rats were divided into four groups: 1) animals without ligature placement receiving administration of empty vehicle (control); 2) animals with ligature receiving administration of empty vehicle; 3) animals with ligature receiving administration with oral RGZ (10 mg/kg/day); and 4) animals with ligature receiving administration of subcutaneous RGZ (10 mg/kg/day). Thirty days after induction of periodontal disease, the animals were sacrificed, and mandibles and gingival tissues were removed for further analysis. An in vitro assay was also employed to test the inhibitory effects of RGZ on osteoclastogenesis. Histomorphological and immunohistochemical analyses of periodontal tissue demonstrated that RGZ-treated animals presented decreased bone resorption, along with reduced RANKL expression, compared to those animals with ligature, but treated with empty vehicle. Corresponding to such results obtained from in vivo experiments, RGZ also suppressed in vitro osteoclast differentiation in the presence of RANKL in MOCP-5 osteoclast precursor cells, along with the down-regulation of the expression of RANKL-induced TRAP mRNA. These data indicated that RGZ may suppress the bone resorption by inhibiting RANKL-mediated osteoclastogenesis elicited during the course of experimental periodontitis in rats.