Periodontal Alteration of the Microcirculation and Hypercholesterolemia: A Possible Correlation?:

Exploring the bi-directional relationship between periodontitis and dyslipidemia: a comprehensive systematic review and meta-analysis

AIM

As periodontitis and dyslipidemia are diseases that occur with high incidence, the relationship between them has attracted much attention. Previous studies on these diseases have tended to focus on lipid parameters and periodontitis, we aimed to investigate the relationship between dyslipidemia and periodontitis.

MATERIALS AND METHODS

A comprehensive search to identify the studies investigating the relationship between dyslipidemia and periodontitis was performed on PubMed, Web of Science and Cochrane Library before the date of August, 2023. Studies were considered eligible if they contained data on abnormal blood lipid parameters and periodontitis. Studies that reported mean differences and 95% confidence intervals or odds ratios were used.

RESULTS

A total of 73 publications were included in the meta-analysis. Hyper total cholesterol (TC), triglycerides (TGs), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) and lower high-density lipoprotein (HDL) levels are risk factors for periodontitis. Periodontal disease is a risk factor for high TG and low HDL levels. Three months after periodontal treatment, the levels of TC, TG and HDL were significantly improved, and statin treatment only improved gingival index (GI) levels compared to that of the dietary control.

CONCLUSIONS

The findings reported here suggest that the mutual promotion of periodontitis and dyslipidemia can be confirmed. Non-surgical periodontal therapy may improve lipid abnormalities. It can't be demonstrated whether systematic application of statins have a better effect on the improvement in periodontal status in patients with dyslipidemia compared to that of the control.

Automated Stabilization, Enhancement and Capillaries Segmentation in Videocapillaroscopy

Oral capillaroscopy is a critical and non-invasive technique used to evaluate microcirculation. Its ability to observe small vessels in vivo has generated significant interest in the field. Capillaroscopy serves as an essential tool for diagnosing and prognosing various pathologies, with anatomic-pathological lesions playing a crucial role in their progression. Despite its importance, the utilization of videocapillaroscopy in the oral cavity encounters limitations due to the acquisition setup, encompassing spatial and temporal resolutions of the video camera, objective magnification, and physical probe dimensions. Moreover, the operator's influence during the acquisition process, particularly how the probe is maneuvered, further affects its effectiveness. This study aims to address these challenges and improve data reliability by developing a computerized support system for microcirculation analysis. The designed system performs stabilization, enhancement and automatic segmentation of capillaries in oral mucosal video sequences. The stabilization phase was performed by means of a method based on the coupling of seed points in a classification process. The enhancement process implemented was based on the temporal analysis of the capillaroscopic frames. Finally, an automatic segmentation phase of the capillaries was implemented with the additional objective of quantitatively assessing the signal improvement achieved through the developed techniques. Specifically, transfer learning of the renowned U-net deep network was implemented for this purpose. The proposed method underwent testing on a database with ground truth obtained from expert manual segmentation. The obtained results demonstrate an achieved Jaccard index of 90.1% and an accuracy of 96.2%, highlighting the effectiveness of the developed techniques in oral capillaroscopy. In conclusion, these promising outcomes encourage the utilization of this method to assist in the diagnosis and monitoring of conditions that impact microcirculation, such as rheumatologic or cardiovascular disorders.

Simvastatin intervention mitigates hypercholesterolemia-induced alveolar bone resorption in rats

Simvastatin promotes bone formation and increases bone mineral density in patients with hyperlipidemia and ameliorates hypercholesterolemia-induced microstructure changes in the jaw bone of animals. However, whether and how treatment with simvastatin can modulate the hypercholesterolemia-induced alveolar bone resorption is unclear. The present study aimed to examine the therapeutic efficacy and potential mechanisms of simvastatin application in hypercholesterolemia-induced alveolar bone resorption. The association between hyperlipidemia and alveolar bone resorption in 100 patients with periodontitis was examined. Additionally, male Sprague-Dawley rats were fed a standard rodent chow (NC) for 32 weeks or a high cholesterol diet (HCD) for 24 weeks. The HCD-fed rats were randomized, continually fed with HCD and treated with vehicle saline (HC) or simvastatin by gavage (5 mg/kg; SIM, n=10/group) for 8 weeks. The morphological changes to alveolar bone resorption in rats were analyzed by linear measurements. The relative levels of osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand RANKL, nuclear factor-κB (NF-κB), microtubule-associated protein 1 light chain 3 (LC3) and p62 in the alveolar bone tissues were determined by reverse transcription-quantitative PCR and/or immunohistochemistry. Sulcus bleeding index (SBI), clinical attachment loss (CAL), probing depth (PD) and the distance of cemantoenamel junction-alveolar bone crest (CEJ-ABC) in patients with hyperlipidemia were significantly greater than that in the controls (P<0.001). The levels of hyperlipidemia were positively correlated with the values of SBI, CAL, PD and CEJ-ABC in this population. Compared with the NC rats, higher levels of alveolar bone resorption, NF-κB expression, higher ratios of RANKL/OPG mRNA transcripts and LC3 to p62 expression were detected in the alveolar bone tissues of HC group. Simvastatin intervention significantly mitigated hypercholesterolemia-induced alveolar bone loss and RANKL mRNA transcription, but increased the ratios of LC3/p62 protein expression in the alveolar bone tissues of rats. Hyperlipidemia is associated with alveolar bone resorption and simvastatin treatment alleviated the hypercholesterolemia-related alveolar bone loss by down-regulating the NF-κB expression.

Association between periodontitis and hyperlipidaemia: A systematic review and meta-analysis

To date, it has been reported that periodontitis (PD) may be associated with hyperlipidaemia in clinical practice. However, data on this issue are inconsistent and controversial. The purpose of this meta-analysis was to identify the association between PD and hyperlipidaemia. Here, 21 case-control and eight cross-sectional studies on PD and hyperlipidaemia were included in the random-effects meta-analysis, involving 2060 patients with PD and 2776 healthy controls (HC). Meta-analysis showed that serum triglyceride (TG) and total cholesterol (TC) levels in the PD group were significantly higher than those in the HC group [TG, weighted mean difference (WMD) = 19.4 mg/dL, 95% confidence interval (CI) 13.3-25.5 mg/dL, P = .000; TC, WMD = 15.4 mg/dL, 95%CI 10.2-20.6 mg/dL, P = .000]. Subgroup analysis stratified by study design validated that PD was associated with higher serum TG and TC levels. In addition, compared with the HC group, serum low-density lipoprotein (LDL) in patients with PD showed a markedly higher level (WMD = 11.7 mg/dL, 95% CI 8.3-15.0 mg/dL, P = .000), whereas serum high-density lipoprotein (HDL) in PD group exhibited a significantly lower level (WMD = -4.5 mg/dL, 95%CI -6.4 - -2.7 mg/dL, P = .000). Finally, no significant publication bias was observed and sensitivity analysis also confirmed the stability of our meta-analyses. In conclusion, the accumulated evidence suggests that PD is indeed associated with hyperlipidaemia in humans. More interventions for lowering lipids or increasing HDL may benefit the patients with PD, which need be further investigated in prospective clinical trials.

[Microcirculation impairment in periodontal tissues in patients with chronic generalized periodontitis combined with metabolic syndrome]

Using the method of laser Doppler flowmetry the study of microcirculation in periodontal tissues in patients with moderate chronic generalized periodontitis and metabolic syndrome was carried out. The analysis of microcirculation values proved not only the reduction of blood flow intensity but also the decreased vasoactivity of microvessels essential to maintain normal microcirculation in periodontal tissues, as it provides active modulation of tissue blood flow and its adaptation to local metabolic needs.

[Microcirculation in periodontal tissues assessed by computer capillaroscopy in patients with periodontal disease and metabolic disorders]

The method of capillaroscopy was used to study microcirculation in periodontal tissues in patients with metabolic syndrome and evaluation of vascular disorders in periodontal disease. In addition to visual assessment of the microcirculation morphometric features of microvessels were obtained: capillary diameter, capillary blood flow velocity, density of capillary network. Computer capillaroscopy thus allowed revealing the structural features of microvessels and their distribution in periodontal tissues.

The association between hyperlipidemia and periodontal infection

BACKGROUND

Periodontitis is a local chronic inflammatory condition of the supporting structures of the teeth resulting from a dental plaque biofilm attached to teeth surfaces. Recent studies have indicated that this oral disease may have effects on systemic health.

OBJECTIVES

The aim of the present study was to evaluate the association between periodontitis and hyperlipidemia.

PATIENTS AND METHODS

This case-control study was conducted in Iran during March 2011. In this case-control study, levels of serum lipids in 45 subjects with periodontitis were measured and compared with 45 age, gender and body mass index (BMI) matched controls. Data were analyzed using student t-test and chi-square test with P < 0.05 as the limit of significance.

RESULTS

Mean values of total cholesterol (CHL) (periodontitis group = 218.11 ± 29.77, control group = 162.31 ± 48.24) and triglycerides (TG) (periodontitis group = 209.77 ± 44.30, control group = 125.60 ± 44.16) were significantly higher in the periodontitis group (P < 0.001). High-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol levels were higher in the case group, but this difference was not statistically significant. Frequency of pathological values of CHL and TG were significantly higher in cases compared with the controls (P = 0.002 and P = 0.015, respectively).

CONCLUSIONS

This study indicates that hyperlipidemia may be associated with periodontal disease in healthy individuals; yet whether periodontitis causes an increase in levels of plasma lipids or whether hyperlipidemia is a risk factor for periodontal infection and cardiovascular disease, it needs further investigations.

Hyperlipidemia causes changes in inflammatory responses to periodontal pathogen challenge: implications in acute and chronic infections

OBJECTIVE

In this study, the effect of hyperlipidemia on immune responses to periodontal bacterial infections was investigated.

METHODS

Sixty male New Zealand white rabbits were equally assigned to normal diet (ND) and high-fat diet (HFD) for 6 weeks. Every six rabbits with ND or HFD were orally inoculated with live Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis three times a week for 8 weeks. Also every six rabbits with ND or HFD rabbits were injected intravenously with A. actinomycetemcomitans and P. gingivalis LPS. Periodontal disease severity was quantified by macroscopic and radiographical evaluation. Serum cytokines were examined by enzyme-linked immunosorbent assay. In vitro, peripheral mononuclear cells were collected and stimulated with LPS. Quantitative real-time polymerase chain reaction was used to determine the changes in gene expression of macrophages.

RESULTS

In the early stages of infection, HFD rabbits were exposed to oral infection and systemic infection developed a weak inflammatory response to the reduced cytokine expression compared with ND rabbits. However, HFD rabbits exhibited higher inflammatory cytokine expression during long-term infections. Moreover, the pronounced changes in inflammatory cytokine expression elicited a significantly increase in bone loss in HFD rabbits with oral infection. Peripheral macrophages harvested from HFD rabbits and exposed to LPS exhibited reduced levels of pro-inflammatory cytokines compared with those from ND rabbits in vitro.

CONCLUSION

These data indicated that hyperlipidemia interfered with immune responses differently. The mechanism is possibly associated with immune paralysis in the acute phase and accumulation of inflammatory mediators in the chronic period.

A non-parametric segmentation methodology for oral videocapillaroscopic images

We aim to describe a new non-parametric methodology to support the clinician during the diagnostic process of oral videocapillaroscopy to evaluate peripheral microcirculation. Our methodology, mainly based on wavelet analysis and mathematical morphology to preprocess the images, segments them by minimizing the within-class luminosity variance of both capillaries and background. Experiments were carried out on a set of real microphotographs to validate this approach versus handmade segmentations provided by physicians. By using a leave-one-patient-out approach, we pointed out that our methodology is robust, according to precision-recall criteria (average precision and recall are equal to 0.924 and 0.923, respectively) and it acts as a physician in terms of the Jaccard index (mean and standard deviation equal to 0.858 and 0.064, respectively).

Periodontal microcirculation in diabetics: an in vivo non-invasive analysis by means of videocapillaroscopy

Background

Diabetes mellitus is today considered a society-wide disease of a chronic/degenerative nature. Among the secondary effects of diabetes, the one that interests the dental surgeon most is diabetic parodontopathy. The aim of this study was to underline and objectify microcirculatory variations at a periodontal mucous level in type 2 diabetics.

Material/Methods

The study enrolled 80 subjects: 40 subjects with a diagnosis of diabetes mellitus type II (18 males and 22 females, between 44 and 85 years of age); and 40 healthy subjects (17 males and 23 females, between 44 and 78 years of age). All the subjects, both diabetic and healthy, were submitted to a videocapillaroscopic examination of the mucosa of the oral cavity.

Results

The measurements concerning the density (expressed in the number of loops/mm²) of the capillary loops presented differences between the healthy subjects and the diabetic subjects. The average periodontal capillary density (DC-P) was clearly superior in diabetic subjects (35.62±10.40 n°loop/mm²) compared to healthy subjects (17.55±3.88 n°loop/mm²). The statistical analysis was performed by means of the Mann Whitney test. The value of P (p=0.000000986), well below the level of significance, demonstrates the high significance of the results obtained.

Conclusions

The increase in capillary density could suggest the presence of active inflammatory phenomena or, more probably, a tendency to a greater susceptibility to inflammatory phenomena. Ultimately, this study shows that there is some peripheral damage to microcirculation at the masticatory mucous level in diabetic subjects and that such alterations can be instrumentally objectified and quantified through the videocapillaroscopic method.

Periodontal status and hyperlipidemia: statin users versus non-users

BACKGROUND

The association between serum lipids and periodontal disease has been studied predominantly in patients with chronic periodontitis with limited data available regarding periodontal status of patients with hyperlipidemia. Meanwhile, the impact of statins on the periodontal health of the population also remains largely underexplored. This study aims to assess the periodontal status among patients with hyperlipidemia and users of statins.

METHODS

In this cross-sectional study, 94 patients with hyperlipidemia (50 receiving statins and 44 receiving non-pharmacologic therapy) and 46 control individuals who were normolipidemic underwent periodontal examination (plaque index, gingival index [GI], probing depth [PD], and clinical attachment level [CAL]). Biochemical parameters measured included serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein cholesterol levels.

RESULTS

PD and GI were significantly higher in patients with hyperlipidemia who were non-statin users compared with the normolipidemic individuals (P <0.001 [PD] and P <0.05 [GI]) and the statin group (P = 0.001 [PD] and P <0.05 [GI]). Periodontal parameters between statin users and the normolipidemic group did not differ significantly. After adjusting for confounders, positive and significant correlations were observed between PD and TG, and TC and LDL, whereas CAL shared correlation with TC and LDL. GI was correlated with TG and TC. Regression analyses revealed that whereas TC was associated significantly with PD (P <0.001), LDL showed significant association with CAL (P = 0.013). TG showed significant association with GI (P = 0.020).

CONCLUSIONS

Our findings suggest that relative to the general population, patients with hyperlipidemia are more prone to periodontal disease. Also, within the limits of this study, statins have a positive impact on periodontal health.