The effect of supra- and subphysiologic testosterone levels on ligature-induced bone loss in rats--a radiographic and histologic pilot study

Testosterone Promotes Nerve Tethering and Acellular Biomaterial Perineural Fibrosis in a Rat Wound Repair Model

Objective: Nerve scarring after traumatic or iatrogenic exposure can lead to impaired function and pain. Nerve-adjacent biomaterials promoting a regenerative tissue response may help reduce perineural fibrosis. Our prior work suggests that testosterone may promote fibrotic skin scarring, but it is unknown how testosterone alters nerve fibrosis or shifts the response to biomaterials. Approach: Sterilized Lewis rats received either testosterone cypionate (+T) or placebo (-T) biweekly. Fifteen days later, wounds were created over the sciatic nerve and covered with an acellular matrix (AM) or closed via primary closure (PC). At day 42, force gauge testing measured the force required to mobilize the nerve, and wound tissue was analyzed. Results: Nerve mobilization force was greater in +T versus -T wounds (p < 0.01). Nerves tore before gliding in 60% of +T versus 6% of -T rats. Epidermal gap (p < 0.01), scar width (p < 0.01), and cross-sectional scar tissue area (p = 0.02) were greater in +T versus -T rats. +T versus -T rats expressed less Col-3 (p = 0.02) and CD68 (p = 0.02). Nerve mobilization force trended nonsignificantly higher for PC versus AM wounds and for +T versus -T wounds within the AM cohort. Innovation: Testosterone increases nerve tethering in the wound healing milieu, altering repair and immune cell balances. Conclusion: Testosterone significantly increases the force required to mobilize nerves in wound beds and elevates histological markers of scarring, suggesting that testosterone-induced inflammation may increase perineural adhesion. Testosterone may reduce the potential anti-tethering protective effect of AM. Androgen receptor antagonism may represent a therapeutic target to reduce scar-related nerve morbidity.

Testosterone replacement relieves ligature-induced periodontitis by mitigating inflammation, increasing pro-resolving markers and promoting angiogenesis in rats: A preclinical study

OBJECTIVES

This study aimed to evaluate the inflammatory profile as well as the resolution of inflammation in a ligature-induced periodontal inflammation in rats with depletion and/or supraphysiological testosterone replacement.

DESIGN

Sixty male rats (Holtzman) were used in the present study. Study groups were created as following: (1) Sham (no testicle removal); (2) Orchiectomy (OCX), 3) OCX + Testosterone (OCX + T); (4) Sham + Ligature (SH + L); (5) OCX+L; and 6) OCX + T + L. The surgeries were performed on day 1, and testosterone was administered weekly since day 1. On day 15, a cotton ligature was placed around the lower first molars and maintained for 15 days. Morphological changes in periodontal tissues were determined by histopathological analysis. Immunohistochemistry (factor VIII) and immunoenzymatic assay were performed to evaluate angiogenesis process and (pro- and anti-) inflammatory markers, respectively.

RESULTS

Ligature promoted a marked inflammatory gingival infiltrate and bone loss (P < 0.05). Supraphysiological testosterone treatment increased the percentage of blood vessels, extracellular matrix and fibroblasts in the presence and absence of periodontal inflammation (P < 0.05). A high dose of testosterone increased factor VIII+ blood vessels and IL-10 expression in inflamed gingival tissue, while PGE₂, LXA₄ and MPO were reduced as a result of supraphysiological testosterone administration (P < 0.05).

CONCLUSIONS

These results, in our experimental model, suggest that supraphysiological testosterone treatment stimulated gingival tissue repair during ligature-induced periodontitis, and it seems to be related to an anti-inflammatory and pro-resolutive mechanism resulting by the modulatory effect on PGE₂ and IL-10 related to an enhanced angiogenesis.

Osteoporosis and Alveolar Bone Health in Periodontitis Niche: A Predisposing Factors-Centered Review

Periodontitis is a periodontal inflammatory condition that results from disrupted periodontal host-microbe homeostasis, manifested by the destruction of tooth-supporting structures, especially inflammatory alveolar bone loss. Osteoporosis is characterized by systemic deterioration of bone mass and microarchitecture. The roles of many systemic factors have been identified in the pathogenesis of osteoporosis, including endocrine change, metabolic disorders, health-impaired behaviors and mental stress. The prevalence rate of osteoporotic fracture is in sustained elevation in the past decades. Recent studies suggest that individuals with concomitant osteoporosis are more vulnerable to periodontal impairment. Current reviews of worse periodontal status in the context of osteoporosis are limited, mainly centering on the impacts of menopausal and diabetic osteoporosis on periodontitis. Herein, this review article makes an effort to provide a comprehensive view of the relationship between osteoporosis and periodontitis, with a focus on clarifying how those risk factors in osteoporotic populations modify the alveolar bone homeostasis in the periodontitis niche.

Supraphysiological testosterone supplementation improves granulation tissue maturation through angiogenesis in the early phase of a cutaneous wound healing model in rats

OBJECTIVE

The aim of this study was to evaluate the effects of both testosterone depletion and supraphysiological testosterone supplementation in the early phase of an animal cutaneous wound healing model in comparison with the physiological hormonal condition.

MATERIAL AND METHODS

Forty rats were distributed into the following four groups: Control, Orchiectomy (OCX), Durateston (Dura) and OCX+Dura. On day 1, the testicles were removed (OCX group) and the rats (Dura group) received a supraphysiological dose (250 mg/kg) of exogenous testosterone weekly. After 15 days a full-thickness excisional skin wound was created in all animals, which was healed by the second intention for 7 days. On day 22, the rats were euthanatized and the wounds were harvested for histopathological evaluation, immunohistochemistry analyses and multiplex immunoassay. One-way ANOVA and post-hoc Tukey tests were performed.

RESULTS

It was found that the supraphysiological testosterone level increased extracellular matrix deposition, promoted higher blood vessel formation and reduced wound contraction (p < 0.05). Additionally, it also stimulated PCNA-positive fibroblasts and KGF-positive cells (p < 0.05), while orchiectomy reduced the expression of IL-6 and TNF-α and increased VEGF and PDGF (p < 0.05) .

CONCLUSION

In conclusion, the results provide evidence that supraphysiological testosterone supplementation plays a positive role in the early phase of cutaneous wound healing, thus improving granulation tissue maturation through the enhancement of angiogenesis.

Association between metabolic and hormonal profile, proinflammatory cytokines in saliva and gingival health in adolescent females with polycystic ovary syndrome

Background

Research studies indicate that polycystic ovary syndrome (PCOS) may increase susceptibility to periodontal disease. The mechanisms that link both conditions are not entirely understood. Thus, the study aimed to investigate the impact of hormonal and metabolic disturbances on the gingival health and salivary levels of tumor necrosis factor (TNF-α), interleukin 1β (IL1-β), and interleukin 6 (IL-6) in adolescent girls with PCOS.

Methods

Thirty-one patients with PCOS and twenty-eight healthy age-mates (as the control group) were enrolled in the study. Individuals with PCOS underwent blood tests for the determination of hormonal and metabolic parameters. Saliva samples were collected to measure salivary testosterone and proinflammatory cytokines in both studied groups. Calibrated dentist assessed oral hygiene and gingival health of all subjects.

Results

Salivary testosterone was significantly higher in the study group (p = 0.0007). The groups did not differ significantly concerning periodontal parameters. Patients with PCOS revealed higher levels of salivary cytokines (p < 0.0001). Gingival index (GI) and the percentage of sites bleeding upon probing (BOP%) were positively correlated with the plaque index (PI) in both groups (r_s ≥ 0.60, p < 0.001), and negatively correlated with salivary testosterone level in the PCOS group (r_s = − 0.44, p = 0.0138 and r_s = − 0.37, p = 0.0424, respectively). BOP% was also positively correlated with body mass index (BMI) in the control group (r_s = 0.40, p = 0.0368) and index of insulin resistance (HOMA-IR) in the study group (r_s = 0.48, p = 0.0068). Salivary testosterone was positively correlated with TNF-α in the control group (r_s = 0.41, p = 0.0321), while in the study group, total testosterone (TT) was positively correlated with IL-6 (r_s = 0.37, p = 0.0400) and free androgen index (FAI) with TNF-α (r_s = 0.36, p = 0.0491).

Conclusions

Gingival health of the examined population was associated primarily with oral hygiene and, to a lesser extent, with the hormonal and metabolic profile. Despite similar periodontal parameters in the both studied groups, patients with PCOS revealed significantly higher levels of proinflammatory cytokines in saliva, which might be the manifestation of the systemic low-grade inflammation associated with PCOS.

Mandibular-related bone metabolism in orchiectomized rats treated with sex hormones

OBJECTIVE

This study aimed to compare the impact of testosterone and estrogen replacement therapy on mandibular bone density and bone-related markers.

DESIGN

Forty male adult rats were randomly allocated to 4 experimental groups (n = 10/group): Sham (Control); Orchiectomy; Orchiectomy plus testosterone replacement; and orchiectomy plus estradiol replacement. Twenty-four days after orchiectomy, the hemi-mandibles were collected and processed for analysis of microhardness in cortical and trabecular bone, radiographic bone density and histomorphometric evaluation. Serum was collected for the analysis of calcium, phosphorus, alkaline phosphatase and magnesium.

RESULTS

The orchiectomy group had the lowest mandibular bone density (p < 0.01) and also their serum levels of alkaline phosphatase were higher than all other experimental groups (p < 0.001). Estradiol replacement significantly reduced microhardness when compared to orchiectomy in cortical bone (p < 0.05). Both testosterone and estrogen replacement reverted orchiectomy impact on this parameter (p < 0.01); and decreased alkaline phosphatase to levels comparable to the Sham-Control group. The effect of estrogen was more pronounced than testosterone, and a statistically significant difference was observed between Sham-Control and testosterone replacement (p < 0.05) but not between Sham-Control and estradiol replacement groups.

CONCLUSION

Our findings demonstrated that both estradiol and testosterone replacement therapies play a role in mandibular bone metabolism, but suggest different pathways.

Sex hormone replacement therapy in periodontology-A systematic review

OBJECTIVE

To analyse whether sex hormone replacement therapy (HRT) improves periodontal parameters and dental implants osseointegration in humans.

MATERIALS AND METHODS

Electronic databases and hand searches were performed from June to August 2018 in SciELO, LILACS and PubMed/MEDLINE. Human observational and interventional studies that evaluated the following parameters were included: clinical attachment loss (CAL), probing pocket depth (PPD), bleeding on probing (BOP), radiographic bone loss (RBL) or osseointegration.

RESULTS

Initial search retrieved 1,282 non-duplicated articles. Fifteen studies were selected after inclusion criteria were applied. All studies were performed in postmenopausal women. Mean differences for PPD reduction ranged from 0.02 to 0.2 mm in HRT-positive patients; mean CAL gain -0.18 to 0.54 mm; mean RBL reduction -0.87 to 0.15 mm; and mean BOP reduction 9%-30.3%. Failure rate of dental implants increased -5.5% to 11.21% when HRT was used.

CONCLUSIONS

Very low but consistent evidence suggests a reduction in BOP and no impact on RBL in postmenopausal women receiving HRT. There are inconsistent reports that suggest that HRT in postmenopausal women: (a) improves or does not impact PPD reduction and CAL gain; and (b) does not impact or increase implant loss. In summary, there is no evidence to support HRT prescription for either men or women for periodontal/implant placement purposes.

"Low Testosterone Levels in Body Fluids Are Associated With Chronic Periodontitis"

There is a debate over the association between low testosterone levels in body fluids and the occurrence of chronic periodontitis (CP). The aim of the present systematic review was to assess whether low testosterone levels in body fluids reflect CP. In order to identify studies relevant to the focus question: “Is there a relationship between low testosterone levels in body fluids and CP?” an electronic search without time or language restrictions was conducted up to June 2016 in indexed databases using different keywords: periodontitis, chronic periodontitis, periodontal diseases, testosterone, and gonadal steroid hormones. A total of eight studies were included in the present systematic review. The number of study participants ranged from 24 to 1,838 male individuals with ages ranging from 15 to 95 years. Seven studies measured testosterone levels in serum, two studies in saliva, and one study in gingiva. Four studies reported a negative association between serum testosterone levels and CP. Two studies reported a positive association between decreased testosterone levels in serum and CP. Increased levels of salivary testosterone among patients with CP were reported in one study; whereas one study reported no significant difference in the concentration of salivary testosterone between patients with and without CP. One study identified significant increase in the metabolism of testosterone in the gingiva of patients with CP. Within the limits of the evidence available, the relationship between low testosterone levels and CP remains debatable and further longitudinal studies and control trials are needed.

Androgen receptors and experimental bone loss - an in vivo and in vitro study

Testosterone is a sex hormone that exhibits many functions beyond reproduction; one such function is the regulation of bone metabolism. The role played by androgen receptors during testosterone-mediated biological processes associated with bone metabolism is largely unknown. This study aims to use a periodontal disease model in vivo in order to assess the involvement of androgen receptors on microbial-induced inflammation and alveolar bone resorption in experimental bone loss. The impact of hormone deprivation was tested through both orchiectomy and chemical blockage of androgen receptor using flutamide (FLU). Additionally, the direct effect of exogenous testosterone, and the role of the androgen receptor, on osteoclastogenesis were investigated. Thirty male adult rats (n=10/group) were subjected to: 1-orchiectomy (OCX); 2-OCX sham surgery; or 3-OCX sham surgery plus FLU, four weeks before the induction of experimental bone loss. Ten OCX sham-operated rats were not subjected to experimental bone loss and served as healthy controls. The rats were euthanized two weeks later, so as to assess bone resorption and the production of inflammatory cytokines in the gingival tissue and serum. In order to study the in vitro impact of testosterone, osteoclasts were differentiated from RAW264.7 cells and testosterone was added at increasing concentrations. Both OCX and FLU increased bone resorption, but OCX alone was observed to increase osteoclast count. IL-1β production was increased only in the gingival tissue of OCX animals, whereas FLU-treated animals presented a decreased expression of IL-6. Testosterone reduced the osteoclast formation in a dose-dependent manner, and significantly impacted the production of TNF-α; FLU partially reversed these actions. When taken together, our results indicate that testosterone modulates experimental bone loss, and that this action is mediated, at least in part, via the androgen receptor.

Influence of racing on the serum concentrations of acute-phase proteins and bone metabolism biomarkers in racing greyhounds

This study was designed to evaluate the influence of racing on the serum concentrations of the acute-phase proteins (APPs) C-reactive protein (CRP), haptoglobin (Hp) and serum amyloid A (SAA) in 32 endurance-racing greyhounds. The study also aimed to investigate the effect of a 7 km race on the bone biomarkers osteocalcin (OC), bone-specific alkaline phosphatase (b-ALP) and pyridinoline cross-links (PYD). Total white blood cell (WBC) count, and the serum concentrations of cortisol, tumour necrosis factor-α (TNF-α), vitamin D and testosterone were also determined. Blood samples were collected 24 h prior to (T0) and within 2 h of completion of the race (T1). Compared to baseline values, WBC count did not change significantly (P = 0.2300), serum cortisol, Hp and SAA increased, while TNF-α and CRP decreased (P <0.0001 for each). There were no significant differences between the pre- and post-race serum concentrations of OC and PYD (P = 0.9500 and P = 0.2600, respectively), but serum b-ALP increased significantly (P = 0.0004). Serum concentrations of vitamin D and testosterone increased after racing (P = 0.0100 and P <0.0001, respectively). In this study, a 7 km race stimulated an acute-phase response, demonstrated by significant increases in the serum concentrations Hp and SAA in racing greyhounds. Increased serum b-ALP post-race probably indicates a change in bone metabolism and deserves further study.

Testosterone regulates bone response to inflammation

This study evaluated the alveolar bone response to testosterone and the impact of Resolvin D2 (RvD2) on testosterone-induced osteoblast function. For the in vivo characterization, 60 male adult rats were used. Treatments established sub-physiologic (L), normal (N), or supra-physiologic (H) concentrations of testosterone. Forty rats were subjected to orchiectomy; 20 rats received periodical testosterone injections while 20 rats received testicular sham-operation. Four weeks after the surgeries, 10 rats in each group received a subgingival ligature around the lower first molars to induce experimental periodontal inflammation and bone loss. In parallel, osteoblasts were differentiated from neonatal mice calvariae and treated with various doses of testosterone for 48 h. Cell lysates and conditioned media were used for the determination of alkaline phosphatase, osteocalcin, RANKL, and osteoprotegerin. Micro-computed tomography linear analysis demonstrated that bone loss was significantly increased for both L and H groups compared to animals with normal levels of testosterone. Gingival IL-1β expression was increased in the L group (p<0.05). Ten nM testosterone significantly decreased osteocalcin, RANKL, and OPG levels in osteoblasts; 100 nM significantly increased the RANKL:OPG ratio. RvD2 partially reversed the impact of 10 nM testosterone on osteocalcin, RANKL, and OPG. These findings suggest that both L and H testosterone levels increase inflammatory bone loss in male rats. While low testosterone predominantly increases the inflammatory response, high testosterone promotes a higher osteoblast-derived RANKL:OPG ratio. The proresolving mediator RvD2 ameliorates testosterone-derived downregulation of osteocalcin, RANKL, and OPG in primary murine osteoblasts suggesting a direct role of inflammation in osteoblast function.

Anabolic steroids affect human periodontal health and microbiota

OBJECTIVES

This study aims to evaluate periodontal microbiological differences between systemically healthy nonsmoker males taking anabolic androgenic steroids (AASs) and non-AAS users and to find associations between disease severity and AAS use.

METHODS

Ninety-two men practicing bodybuilding were included in the study. They were divided into AAS users and a matched control nonuser group and subgrouped based on their most severe periodontal condition. Pooled subgingival samples from each individual were cultured to evaluate specific periodontopathogen infection.

RESULTS

AAS users had significantly higher prevalence of severe periodontitis. AAS users had greater gingival inflammation and clinical attachment loss of ≥ 3 mm than nonusers (odds ratio (OR) = 2.4; p = 0.09; 95 % confidence interval (CI) 0.8-6.4). AAS users were 4.9 times more likely to be infected with Prevotella intermedia than AAS nonusers (OR = 4.9; p = 0.003; 95 % CI 1.6-14.7). The OR of presenting subgingival Aggregatibacter actinomycetemcomitans was 8.2 times higher in AAS users (OR = 8.2; p = 0.03; 95 % CI 0.9-70.8). AAS users were 5.6 times more likely to present subgingival Candida spp. than nonusers (OR = 5.6; p = 0.02; 95 % CI 1.1-27.1). AAS users were 14.8 times more likely to present subgingival Candida parapsilosis than nonusers (OR = 14.8; p < 0.0001; 95 % CI 3.1-69.2). The likelihood of AAS users presenting subgingival Candida tropicalis was 4.3 times higher than nonusers (OR = 4.3; p = 0.03; 95 % CI 1.1-16.9). A. actinomycetemcomitans was mostly isolated in individuals with severe periodontitis and was associated with subgingival Porphyromonas gingivalis, P. intermedia, and Candida spp.

CONCLUSIONS

AAS use may increase the risk for severe periodontitis and may cause a subgingival selection of certain Candida species. Specific periodontopathogens, such as Candida dubliniensis and Candida albicans, seem to be negatively affected by AAS use. The higher risk for disease progression in AAS users may be explained by the significantly higher proportions of A. actinomycetemcomitans, P. gingivalis, P. intermedia, and Candida species as compared to controls.

CLINICAL SIGNIFICANCE

Data on the influence of AAS on subgingival periodontopathogens and disease progression are scarce. Higher proportions of specific periodontopathogens are plausible in AAS users. AAS users had a higher prevalence of severe periodontitis, gingival inflammation, and clinical attachment loss. Men taking AAS are at greater risk of periodontitis and specific periodontopathogen infection.