Is there any relation of nanobacteria with periodontal diseases?

Tetracycline attenuates calcifying nanoparticles-induced renal epithelial injury through suppression of inflammation, oxidative stress, and apoptosis in rat models

Background

Calcifying nanoparticles (CNPs) has been associated with the occurrence and development of kidney stones, but the exact mechanism is not clear. This study aimed to establish a rat model of CNP-induced renal epithelial injury and assess the efficacy of tetracycline in preventing this injury.

Methods

Kidney stones from patients after percutaneous nephrolithotomy (PCNL) were collected to isolate and culture CNPs. Thirty Sprague-Dawley rats were divided into three groups: the sham group (G1), the CNP group (G2), and the CNP + tetracycline group (G3). Rats in G2 and G3 were given an intravenous injection of CNPs via the tail vein, while rats in G1 were given saline. Meanwhile, rats in G3 were given tetracycline by gavage twice a day at a dose of 25 mg/kg. After 8 weeks, the 24-h urine of all rats was collected, and all rats were sacrificed to obtain blood and kidneys.

Results

The results revealed that in G2, activities of antioxidant enzymes such as superoxide dismutase and catalase were significantly lower than those in G1, while malondialdehyde activity in G2 was significantly higher than that in G1 and both of them were inhibited by tetracycline co-treatment in G3. CNPs significantly increased expression of inflammatory cytokines, including monocyte chemotactic protein 1 and interleukin 6, which were largely alleviated in G3. CNPs significantly increased TUNEL-positive cells and the apoptosis activity of Bcl2-associated X protein but decreased B-cell lymphoma-2 level compared with that in G1, and was limited by tetracycline co-treatment in G3. Furthermore, CNPs led to notable renal tubular epithelial cell damage, hyaline cast formation, desquamation, swelling, vacuolization in histology, all of which were alleviated by tetracycline.

Conclusions

Tetracycline can attenuate CNP-induced renal epithelial injury through suppression of inflammation, oxidative stress, and apoptosis.

Comparison of polymerase chain reaction and immunologic methods for the detection of nanobacterial infection in type-III prostatitis

OBJECTIVE

To compare the results of polymerase chain reaction (PCR) and immunologic methods for the detection of nanobacteria (NB) in the expressed prostatic secretions (EPSs) of patients with type-III prostatitis.

METHODS

In total, 150 patients with type-III prostatitis for whom conventional clinical treatment had failed were selected from September 2009 to April 2010. The EPS of each patient was divided into 3 parts, which were used for PCR analysis, indirect immunofluorescence staining (IIFS), and culture and subsequent indirect immunofluorescence staining (CIIFS).

RESULTS

PCR analysis has a higher sensitivity than IIFS for the detection of NB in EPSs. Of 83 CIIFS-positive EPS samples, 79 (95.2%) were positive by PCR. Of 67 EPS samples that were negative by CIIFS, 60 (89.6%) were negative by PCR. The sensitivity of PCR for the detection of NB compared with the CIIFS method was 95.2%, with a specificity of 89.6%. The positive predictive value was 91.9%, and the negative predictive value was 93.8%. A comparative evaluation showed no statistically significant difference between PCR and CIIFS in the detection of NB in EPSs. A strong agreement in the positive and the negative results obtained by PCR and CIIFS for NB detection was found for all EPS samples.

CONCLUSION

PCR analysis has a higher sensitivity than IIFS for NB detection in type-III prostatitis. PCR can detect nanobacterial infection in type-III prostatitis equally well as CIIFS and offers significant advantages for the rapid, simple, and economical detection of nanobacterial infection in type-III prostatitis.

Clinical implications of calcifying nanoparticles in dental diseases: a critical review

BACKGROUND

Unknown cell-culture contaminants were described by Kajander and Ciftçioğlu in 1998. These contaminants were called nanobacteria initially and later calcifying nanoparticles (CNPs). Their exact nature is unclear and controversial. CNPs have unique and unusual characteristics, which preclude placing them into any established evolutionary branch of life.

AIM

The aim of this systematic review was to assess published data concerning CNPs since 1998 in general and in relation to dental diseases in particular.

MATERIALS AND METHODS

The National Library of Medicine (PubMed) and Society of Photographic Instrumentation Engineers (SPIE) electronic and manual searches were conducted. Nanobacteria and calcifying nanoparticles were used as keywords. The search yielded 135 full-length papers. Further screening of the titles and abstracts that followed the review criteria resulted in 43 papers that met the study aim.

CONCLUSION

The review showed that the existence of nanobacteria is still controversial. Some investigators have described a possible involvement of CNPs in pulpal and salivary gland calcifications, as well as the possible therapeutic use of CNPs in the treatment of cracked and/or eroded teeth.

Relationship between morphological changes and survival status of Clonorchis sinensis eggs and gallstone formation

AIM: To explore the relationship between Clonorchis sinensis (C. sinensis) infection and gallstone formation by observing the morphology and survival status of C. sinensis eggs in gallbladder bile, biliary sludge and gallstones from gallstone patients with C. sinensis infection.

METHODS: Twenty gallstone patients with C. sinensis infection were enrolled in this study. Their gallbladder bile, biliary sludge and gallbladder stones were collected to observe the morphology of C. sinensis eggs using optical microscopy and scanning electron microscopy (SEM). Von Kossa staining and X-ray energy dispersive spectroscopy were used to analyze the calcium content on the surface of eggs and the substance surrounding them. Trypan blue staining was used for evaluating the survival rate of eggs.

RESULTS: In gallbladder bile, 88.3% of C. sinensis eggs had typical morphology, while 56.7% of eggs in biliary sludge and 91.5% in stones were deformed (including changes in shape and size, egg cover loss, invisible internal miracidia and adhesion bilirubin on the surface or in their surroundings). Under SEM, egg shell showed an uneven texture shape, and its surface and surroundings were adhered with mucus-like substances in varying degrees. The calcium content of egg surface and surroundings gradually increased from the bile, biliary sludge to stones. The survival rates of eggs in bile, biliary sludge and stones were 86.6%, 42.1% and 11.5%, respectively.

CONCLUSION: In patients infected with C. sinensis, C. sinensis eggs can remain in the gallbladder by their uneven texture-like egg shell and mucus-like substance from the biliary tract. Eggs can be further deformed, degenerated, and even calcified to nucleation, resulting in the formation of biliary sludge and participating in gallstone formation.

Elastic discontinuity due to ectopic calcification in a human fibrous joint

Disease can alter natural ramp-like elastic gradients to steeper step-like profiles at soft-hard tissue interfaces. Prolonged function can further mediate mechanochemical events that alter biomechanical response within diseased organs. In this study, a human bone-tooth fibrous joint was chosen as a model system, in which the effects of bacterial-induced disease, i.e. periodontitis, on natural elastic gradients were investigated. Specifically, the effects of ectopic biomineral, i.e. calculus, on innate chemical and elastic gradients within the cementum-dentin complex, both of which are fundamental parameters to load-bearing tissues, are investigated through comparisons with a healthy complex. Complementary techniques for mapping changes in physicochemical properties as a result of disease included micro X-ray computed tomography, microprobe micro X-ray fluorescence imaging, transmission electron and atomic force microscopy (AFM) techniques, and AFM-based nanoindentation. Results demonstrated primary effects as derivatives of ectopic mineralization within the diseased fibrous joint. Ectopic mineralization with no cementum resorption, but altered cementum physicochemical properties with increasing X-ray attenuation, exhibited stratified concretion with increasing X-ray fluorescence counts of calcium and phosphorus elements in the extracellular matrix in correlation with decreased hygroscopicity, indenter displacement, and apparent strain-relieving characteristics. Disease progression, identified as concretion through the periodontal ligament (PDL)-cementum enthesis, and sometimes the originally hygroscopic cementum-dentin junction, resulted in a significantly increased indentation elastic modulus (3.16±1.19 GPa) and a shift towards a discontinuous interface compared with healthy conditions (1.54±0.83 GPa) (Student's t-test, P<0.05). The observed primary effects could result in secondary downstream effects, such as compromised mechanobiology at the mechanically active PDL-cementum enthesis that can catalyze progression of disease.

Association between calcifying nanoparticles and placental calcification

BACKGROUND

The purpose of this study was to examine the possible contribution of calcifying nanoparticles to the pathogenesis of placental calcification.

METHODS

Calcified placental tissues and distal tissue samples were collected from 36 confirmed placental calcification cases. In addition, 20 normal placental tissue samples were obtained as a control group. All the tissue samples were cultured using special nanobacterial culture methods. The cultured calcifying nanoparticles were examined by transmission electron microscopy (TEM), and their growth was monitored by optical density (OD) at a wavelength of 650 nm. 16S rRNA gene expression of the cultured calcifying nanoparticles was also isolated and sequenced.

RESULTS

Novel calcifying nanoparticles wrapped with electron-dense shells between 50 nm to 500 nm in diameter were observed in the extracellular matrix of calcified placental tissues. They were detected in placental villi and hydroxyapatite crystals, and contained "nucleic acid-like materials". After isolation and four weeks of culture, 28 of 36 calcified placental tissue samples showed white granular precipitates attached to the bottom of the culture tubes. OD(650) measurements indicated that the precipitates from the calcified placental tissues were able to grow in culture, whereas no such precipitates from the control tissues were observed. The 16S rRNA genes were isolated from the cultured calcifying nanoparticles and calcified placental tissues, and their gene sequencing results implied that calcifying nanoparticles were novel nanobacteria (GenBank JF823648).

CONCLUSION

Our results suggest that these novel calcifying nanoparticles may play a role in placental calcification.

Nanobacteria's potential involvement in enamel repair in caries

Dental caries is the accumulation of numerous episodes of demineralization and remineralization, rather than a unidirectional demineralization process. Demineralization and remineralization occur constantly either simultaneously or alternately and whether a lesion will progress or be repaired depends upon the predominant process over periods. Even if fluoride has demonstrated the anti-caries effect by shifting the demineralization/remineralization balance favorably, little is known about non-fluoride action in favor of the balance and the effect of fluoride could not fully explain enamel repair in caries. Recently, in vitro experiments demonstrated enamel repair by synthetic apatite nanocrystals which showed the strong affinity, excellent biocompatibility, mechanical improvement, and a higher resistance to acids than apatite from teeth. This reminds us of a controversial microorganism called nanobacteria (NB) which form nanocrystalline apatite around themselves. Although NB have been detected in some pathological calcifications, epidemiologic literature suggests that they are widespread present in the healthy people blood. Considering the similarity of synthetic nanocrystalline apatite to that of NB and blood circulation communicating with saliva, we put forward a hypothesis that NB may act in enamel surface just like what the synthetic nanocrystalline apatite does in vitro to repair enamel in caries.