This study investigated the anti-inflammatory effects of Lactobacillus brevis on periodontitis. 21 patients with chronic periodontitis received L. brevis-containing lozenges and were examined before and after treatment. The treatment led to disappearance or improvement of all clinical parameters in all patients. Saliva samples showed decreased levels of nitric oxide, prostaglandin E2, matrix metalloproteinases, and interferon-γ after treatment. In vitro experiments on macrophages suggested the anti-inflammatory effects were due to L. brevis's arginine deiminase preventing nitric oxide generation by competing for the same substrate as nitric oxide synthase. These results provide insights into periodontitis and suggest L.
Anti-inflammatory doc effects of Lactobacillus brevis CD2 on periodontal disease
1. Oral Diseases (2007) 13, 376–385. doi:10.1111/j.1601-0825.2006.01291.x
Ó 2007 The Authors. Journal compilation Ó 2007 Blackwell Munksgaard
All rights reserved
http://www.blackwellmunksgaard.com
ORIGINAL ARTICLE
Anti-inflammatory effects of Lactobacillus brevis (CD2) on
periodontal disease
DN Della Riccia1, F Bizzini1, MG Perilli2, A Polimeni3, V Trinchieri4, G Amicosante2 and MG Cifone1
1
Department of Experimental Medicine, University of L’Aquila, L’Aquila, Italy; 2Department of Biomedical Sciences and
Technologies, University of L’Aquila, L’Aquila, Italy; 3Department of Odontostomatologic Sciences, University ÔLa Sapienza’, Rome,
Italy; 4Department of Infectious and Tropical Diseases, University ÔLa Sapienza’, Rome, Italy
OBJECTIVES: To analyze the anti-inflammatory effects Introduction
of Lactobacillus brevis extracts on periodontitis patients
and to investigate the involved mechanisms in vitro on Lactic acid bacteria (LAB) belong to a variety of genera
activated macrophages. used for milk fermentation. The primary metabolic end
METHODS: Eight healthy subjects and 21 patients with product from carbohydrate metabolism is lactic acid,
chronic periodontitis were enrolled to analyze the effect which in turn preserves milk by providing the acidity
of L. brevis-containing lozenges on periodontitis-associ- necessary for a tart flavor and for changes in the
ated symptoms and signs. Before and after the treat- structure of casein to achieve syneresis and desired
ment, the patients received a complete periodontal functional characteristics. The extensive knowledge on
examination. Saliva samples, collected before and after LAB has opened new possibilities for their application
treatment, were analyzed for metalloproteinase and ni- (for reviews see Konings et al, 2000; Caglar et al, 2005).
¸
tric oxide synthase (NOS) activity, immunoglobulin-A Reports of many investigators have confirmed that LAB
(IgA), prostaglandin E2 (PGE2) and c-interferon (IFN-c) and their products have beneficial effects on the health
levels. Arginine deiminase (AD) and NOS activities were of animals and humans, i.e., protection against enteric
determined through a radiometric assay. Metallopro- infections, use as an oral adjuvant, immunopotentiation
teinases were assayed by zymogram and Western blot- in malnutrition, and prevention of chemically induced
ting, whereas IgA, PGE2 and IFN-c were assayed by tumors (Bodana and Rao, 1990; Roberfroid, 1998;
enzyme-linked imunosorbent assay tests. Dugas et al, 1999; Gorbach, 2000). Almost all genera of
RESULTS: The treatment led to the total disappearance LAB are able to produce bacteriocins that are primarily
or amelioration of all analyzed clinical parameters in all lethal to other strains and species of bacteria form short-
patients. This was paralleled to a significant decrease of lived pores in biologic membranes by interactions with
nitrite/nitrate, PGE2, matrix metalloproteinase, and IFN- different compounds including nisin, lipid II and
c levels in saliva samples. phospholipids, thereby killing the target bacteria (Kon-
CONCLUSION: Our results suggest that the anti- ings et al, 2000). In the attempt to better characterize the
inflammatory effects of L. brevis could be attributed to metabolic features of some LAB strains, our group has
the presence of AD which prevented nitric oxide gen- recently shown the presence of high levels of arginine
eration. Our findings give further insights into the deiminase (AD) in Lactobacillus brevis (Di Marzio et al,
knowledge of the molecular basis of periodontitis and 2001). As bacterial AD may compete with nitric oxide
have a potential clinical significance, giving the experi- synthase (NOS) by using the same substrate, arginine,
mental ground for a new innovative, simple and effica- we decided to investigate the ability of L. brevis extracts
cious therapeutical approach of periodontal disease. to inhibit NOS activity as well other inflammatory
Oral Diseases (2007) 13, 376–385 parameters [c-interferon (IFN-c), prostaglandin E2
(PGE2) and metalloproteinases], known to be associated
Keywords: L. brevis; nitric oxide; metalloproteinases; prostaglan- with NOS induction (Cifone et al, 1999; Goodwin et al,
din E2; c-interferon 1999; Di Marzio et al, 2001; Ishii et al, 2003). In
particular, the chronic periodontal disease was chosen
as the known inflammatory model to test the potential
Corresponding Author: Dr MG Cifone, Department of Experimental in vivo anti-inflammatory effects of L. brevis.
Medicine, University of L’Aquila, Via Vetoio, 10, Coppito 2, 67100 Periodontal disease is a major cause of tooth loss in
L’Aquila, Italy. Tel: 0862 433503, Fax: 0862 433523, E-mail: pres- humans and is one of the most prevalent diseases
med@cc.univaq.it associated with bone loss. Following bacterial coloniza-
Received 19 November 2006; revised 9 January 2006; accepted 30
January 2006 tion, the gingiva becomes inflamed leading, in some cases,
2. Anti-inflammatory effects of L. brevis
DN Della Riccia et al
377
to the destruction of the alveolar bone. Periodontitis has (Centricon 10) from Amicon (Amicon, Millipore Co.,
two distinct but interconnected etiologic components: Bedford, MA, USA). IFN-c (Endogen, Inc., Walburn,
periodontopathic bacteria adjacent to the periodontal MA, USA) and PGE2 Elisa kits (Assay Designs Inc.,
tissues, and host-mediated connective tissue-destructive Ann Arbor, MI, USA) were purchased from TEMA
responses to the causative bacteria and their metabolic ricerca srl (Bologna, Italy). IgAs Elisa kits were
products (Golub et al, 1998). Treatment strategies obtained from IPR (Catania, Italy).
against periodontal diseases have evolved with the aim
of eliminating specific pathogens or suppressing destruc- Preparation of bacterial extracts
tive host response. Although the pathogenesis of the Lactobacillus brevis, obtained from VSL Pharmaceuti-
various forms of this disease is not completely under- cals (Gaithersburg, MD, USA) in a pure lyophilized
stood, several factors are believed to play an important form (108 colony-forming units per gram), was routinely
role, including inflammatory cytokines (McGee et al, grown in MRS broth medium under aerobic conditions.
1998; Graves, 1999), PGE2 (Offenbacher, 1996; Tsai et al, For the determination of AD activity and for in vitro
1998; Kornman, 1999), nitric oxide (Matejka et al, 1999; experiments on macrophages, L. brevis cultures were
Takeichi et al, 2000) and salivary immunoglobulin-A washed and resuspended in 10 ml phosphate-buffered
(IgA) antibodies (Schenk et al, 1993). Moreover, many of solution (PBS), sonicated (30 min, alternating 10 s
the characteristics of periodontal diseases such as inflam- sonication and 10 s pause) with a Vibracell sonicator
mation and attachment loss are associated with proteo- (Sonic and Materials Inc., Danbury, CT, USA), centri-
lytic events. Indeed, oral damage can result from the fuged at 7500 g for 20 min at 4°C and the supernatants
release of an array of proteolytic enzymes by colonizing stored at )20°C until used (bacterial extract). For
bacteria as well as host-derived proteases (Henskens et al, the in vitro experiments, the bacterial extract was
1996; Baron et al, 1999; Korostoff et al, 2000; Travis and added to cell cultures at 0.5 mg/105cells/1 ml)1 (final
Potemba, 2000). Selection of an appropriate delivery concentration).
system is an important factor and, periodontitis being a For gene expression studies, genomic DNA was
Ôlocalized’ disease condition, local drug treatment should isolated from an overnight culture of L. brevis using
be preferred. a WIZARD genomic DNA purification kit (Promega,
The aims of this study were firstly to analyze the Milan, Italy), according to the manufacturer’s
effects of AD-expressing L. brevis-containing lozenges, instructions.
both on the clinical signs of chronic periodontitis
patients and on the NOS activity levels, matrix metal- Arginine deiminase activity
loproteinase (MMP) levels, eicosanoid generation, IgA Arginine deiminase activity was determined in L. brevis
levels, IFN-c levels of the saliva. The mechanisms extracts by measuring the conversion of [3H]-L-arginine to
underlying the anti-inflammatory effect of L. brevis [3H]-L-citrulline. Samples were homogenized by sonica-
extract were investigated in vitro on rat peritoneal tion in homogenization ice-cold buffer (25 mM Tris-HCl,
macrophages activated by lipopolysaccharide (LPS). pH 7.4, 1 mM EDTA, 1 mM EGTA) containing protease
inhibitors (0.2 mM PMSF, 10 lg ml)1 aprotinin,
10 lg ml)1 pepstatin A and 10 l g ml)1 leupeptin). The
Materials and methods
homogenates were centrifuged at 4°C for 20 min at
11 000 g. The supernatants were passed through an
AG50WX-8 Dowex resin (Bio-Rad Laboratories, Mel-
Materials
ville, NY, USA) to remove endogenous arginine. The
Nitrate reductase, L-lactic dehydrogenase (LDH), pyru- protein content was determined by the bicinchoninic acid
vic acid, b-nicotinamide adenine dinucleotide phosphate procedure (BCA; Pierce, Rockford, IL, USA) using BSA
(NADPH), flavin adenine dinucleotide (FAD), flavin as standard. Enzymatic reactions were conducted at 37°C
mononucleotide (FMN), (6R)-5,6,7,8-tetrahydrobiop- for 30 min in 50 mM Tris-HCl, pH 7.4, containing 1 mM
terin (H4B), L-valine, phenylmethanesulfonyl fluoride CaCl2, 1 mM MgCl2, 1 mM L-citrulline (to inhibit the
(PMSF), pepstatin A, leupeptin, aprotinin, ethylene catabolism of [3H]-L-citrulline), 60 mM L-valine, 60 mM
glycol-bis (2-aminoethlether)-N,N,N,‘N’-tetraacetic L-ornithine, 60 mM L-lysine (to inhibit nonspecific argi-
acid (EGTA), ethylenediamine tetraacetic acid (EDTA), nase activity) and 10 lCi ml)1 of [3H]-L-arginine (Amer-
4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid sham, Bukinghamshire, UK). The reaction was stopped
(HEPES), Tris base, gelatin, Triton X-100, Coomassie by the addition of 0.4 ml of stop buffer (50 mM HEPES,
brilliant blue and other chemicals were obtained from pH 5.5, 5 mM EDTA). The samples were spotted onto
Sigma Aldrich srl (Milan, Italy). L-ornithine hydrochlo- TLC plates and developed in chloroform/methanol/
ride and TPA were purchased from Alexis (San Diego, ammonium hydroxide/water (1:4:2:1, by vol) as solvent
CA, USA). L-lisin monohydrochloride was obtained system. After drying, the radiolabeled spots were visual-
from Merck (Merck Bioscience GmbH, Schwalback, ized by autoradiography, after spraying EN3HANCER
Germany). EN3HANCE spray was obtained from (Perkin-Elmer Life and Analytical Sciences). [3H]-argin-
Perkin-Elmer (Perkin-Elmer Life and Analytical ine and [3H]-citrulline, identified by co-chromatography
Sciences, Boston, MA, USA). Methanol, acetic acid, with unlabeled standards which were revealed with
chloroform and ammonium hydroxide were purchased ninhydrin spray, was scraped, and quantified by liquid
from J.T. Baker (Milan, Italy), Microconcentrators scintillation. Where indicated, bacterial extracts were
Oral Diseases
3. Anti-inflammatory effects of L. brevis
DN Della Riccia et al
378
preincubated for 60 min with 20 mM formamidine any patient, and antibiotics were not taken during the
hydrochloride (Fluka Seelze, Germany), an inhibitor of previous 4 months. No patient was subjected to oral
AD (Weikmann et al, 1978a,b). hygienics. Before and after the treatment with lozenges,
the patients received a periodontal examination including
Arginine deiminase gene PCR amplification plaque index (Silness and Loe, 1964), gingival index,
¨
The oligonucleotides were designed on the bases of bleeding on probing, calculus and temperature sensitivity
nucleotide sequences of AD genes conserved at EMBL scores. All periodontal disease measurements were per-
and GeneBank databases (accession number AJ001330). formed in four quadrants at six sited per tooth for all
For polymerase chain reaction (PCR) experiments the teeth, with the exception of plaque index for which four
following primers were used: primer arcA1 frame sites were examined. The results were expressed as a mean
5¢-ATTTGCACAAACATTACGAGAC and primer value accompanied by standard error of the mean. The
arcA2 reverse 5¢-GTGAAGACTGTATCTAAATG- saliva samples, collected from controls and patients by
CAT. Polymerase chain reaction (PCR) to amplify the spitting into an ice-cooled vessel before and after the
AD-encoding gene, was performed in a 100 ll volume. treatment, were analyzed for MMP and NOS activity (the
The amplification reaction mixture contained 2.5 U of latter determined as nitrite/nitrate levels in the fluid saliva
AmpliTaq Gold DNA polymerase (Perkin-Elmer Life fraction and as citrulline levels in the cellular saliva
and Analytical Sciences), the reaction buffer provided by fraction), and IgA, PGE2, IFN-c. Five patients, four men
the Taq manufacturer (containing 1.5 mM MgCl2), and one women, 29–48 years old (mean age 40 ± 9.6)
200 lM each deoxyribonucleotide triphosphate manifesting periodontitis were also enrolled in the trial
(dNTPs), 0.5 lM each primer, and 1 lg of genomic and treated for 4 days with conventional oral antibiotic
DNA as template. Amplification reactions were carried therapy (spiromycin, 1 · 300 mg day)1) with the aim of
out as follows: 12 min at 95° C for activation of comparing the effects of this conventional treatment with
AmpliTaq Gold DNA polymerase; denaturation at 94° those exerted by the bacterial extracts of L. brevis. All
C for 1 min, annealing at 55° C for 1 min, and extension participants were carefully informed of the aim of the
at 72°C for 1 min, repeated for 30 cycles. A final DNA investigation and were free to withdraw from the study at
extension step at 72°C for 7 min was allowed at the end any time. Written consent was obtained from all patients
of the termal cycling. Direct sequencing of PCR ampl- prior to the collection of samples. The study was approved
icons was performed on both strands by dideoxy-chain by the Institute of Odontoiatric Clinics of the La Sapienza
termination method using a dRhodamina Terminator University, Rome, and was conducted in according with
Cycle Sequencing Ready reaction Kit and the ABI the principles of the Declaration of Helsinki.
PRISM 377 DNA Sequencer (Perkin-Elmer Life and
Analytical Sciences). Sequencing was performed on three Animals
PCR products derived from three independent reactions. Wistar rats (5–6 weeks old) were purchased from
Charles River Breeding Laboratories (Calco, Como,
L. brevis-containing lozenges Italy).
Each lozenge (VSL Pharmaceuticals) was composed of
the following: lyophilized bacteria (200 mg), fructose Rat peritoneal macrophages
(400 mg), mannitole (1020 mg), aspartame (40 mg), talc Rat macrophages were obtained by peritoneal washes
(60 mg), aerosil 200 (10 mg), Peg 6000 (50 mg), mag- with PBS, centrifuged and resuspended in Roswell Park
nesium stearate (20 mg), tartaric acid (100 mg), and Memorial Institute (RPMI) 1640 medium containing
orange flavor (100 mg). 2 mM glutamine, 10% heat-inactivated fetal calf serum
(FCS) and 100 IU ml)1 penicillin and 100 lg ml)1
Healthy volunteers, patients, treatment, and sample streptomycin. The cells were counted and their viability,
collection as assessed by Trypan blue dye exclusion, was routinely
The study was conducted as a double-blind paired- greater than 98%. Two milliliters of cell suspension
comparison study, with treatment assignments random- (4 · 106cell ml)1) was then plated on a 12-well tissue
ized and balanced to a group of eight healthy volunteers culture plate (Falcon; Becton Dickinson, Buccinasco,
(people of our laboratories; male and female, age 24– Milan). The following day, cell cultures were washed
47 years, mean age 33.6 ± 7.96), who were clinically free thrice with medium without FCS and then cultured in
of periodontal disease. Twenty-one patients with chronic the same medium for 18 h with or without LPS
periodontitis, 16 men and five women, 30–51 years old (100 ng ml)1) in the presence or absence of bacterial
(mean age 41.9 ± 7.23) were enrolled to analyze the effect extracts (0.5 mg ml)1). At the end of the treatments, cell
of L. brevis-containing lozenges (4 lozenges/day for pellets were used for NOS activity determination and
4 days) on periodontitis-associated symptoms and signs, supernatants, concentrated 10-fold by Centricon C10
from the clinical point of view. Patients in this study (Amicon, Millipore Co.), were used in zymogram
displayed a range of periodontal disease from moderate to experiments to detect metalloproteinase activity.
severe periodontitis. Pocket depth, measured to the
nearest millimeter marking, was >4 mm. Mean loss of Nitrite/nitrate levels
attachment, evaluated by measuring the distance from the In aqueous solution, NO reacts rapidly with O2 and
cemento-enamel junction to the bottom of the probing accumulates in the culture medium as nitrite and nitrate
pocket, was 4.7 mm. No systemic disease was observed in ions. Twenty microliters of saliva samples or superna-
Oral Diseases
4. Anti-inflammatory effects of L. brevis
DN Della Riccia et al
379
tants from macrophage cultures was used for nitrite activity was compared with that of partially purified
measurement by a colorimetric assay based on the Griess gelatinases (MMP-2 and MMP-9) obtained from the
reaction. Briefly, 5 ll of HEPES (50 mM, pH 7.4), 5 ll supernatants of HT1080 human fibrosarcoma cell line
of FAD (5 lM), 10 ll NADPH (0.1 mM), 58 ll of H2O (ICLC HTL98016, Interlab Cell Line Collection, Genova,
and 2 ll of nitrate reductase (0.2 IU ml)1) were added to Italy) stimulated with TPA (10)7M) for 48 h. All
20 ll of samples, which were then incubated for 30 min experiments were conducted with or without EDTA,
at 37° C. At the end of the incubation time 10 ll of serine or cystein proteinase inhibitors. Bands relative to
pyruvic acid (100 mM) and 1 ll of LDH (1500 IU ml)1) enzyme activity were quantified by scanning densito-
were added to the samples. After 10 min of incubation at metry using Molecular Analyst PCTM software for the
37° C, samples were mixed with an equal volume of Bio-Rad model 670 scanning densitometer.
Griess reagent in a microtiter plate and incubated at
room temperature in the dark for 10 min. The OD was Western blot
measured at 550 nm using a micro-enzyme-linked imu- Saliva collected from healthy volunteers and patients
nosorbent assay (ELISA) reader (Easy Reader EAR 400; were centrifuged at 600 g for 15 min and the superna-
Kontron Analytic, London, UK). KNO3 dissolved in tants were assayed for protein using the BCA method
H2O was used as standard and H2O as blank. (Pierce). Twenty-eight microliters of each sample (40 lg
of protein) was mixed with 7 ll of nonreducing PAGE
Nitric oxide synthase activity buffer 5X [0.5 mol/l Tris-HCl (pH 6.8), 28% glycerol,
Nitric oxide synthase activity was determined in both 4.4% SDS, 0.55% bromophenol blue] and separated on
macrophage extracts and cell fraction of salivary sam- an 8.5% polyacrylamide gel. After electrophoresis, SDS
ples by measuring the conversion of [3H]-L-arginine to was removed by washing the gel in 50 mM Tris HCl pH
[3H]-L-citrulline as above described for AD assay. The 7.4, 2% Triton X-100 for 15 min at 37°C and then with
assay, performed with the addition to the reaction buffer the same buffer lacking Triton X-100 for 15 min at 37°C.
of tetrahydrobiopterin (BH4), 2 lM FAD, 2 lM flavin Afterwards, the gel was equilibrated in electrotransfer
adenine mononucleotide, CaCl2 (0.6 mM) and calmod- buffer (25 mM Tris-HCl, 192 mM glycine, 10% meth-
ulin (CAM) (0.1 lM), measures both the calcium- anol) for 20 min and transferred to polyvinyl difluoride
dependent (constitutive) and calcium-independent (PVDF) membrane (Millipore) for 1 h at 4°C at 100V
(inducible) isoenzyme activities. Any activity inhibited using a Mini Trans-Blot Cell apparatus (Bio-Rad
by AG or detected in the absence of Ca/CAM and in the Laboratories, Hercules, CA, USA). Nonspecific binding
presence of the CAM antagonist W13 (100 lM) (to sites were blocked with 10% nonfat dry milk in TBS-T
inhibit endogenous CAM), represented iNOS activity. (TBS and 0.05% Tween 20) for 16 h at 4°C. The
Where indicated, 20 mM formamidine or 10 lM ami- membrane was then incubated for 1 h at 25°C with a
noguanidine (AG) or 500 lM L-NMMA were added to mouse monoclonal antihuman MMP-9 (Calbiochem-
the assay system to measure AD and/or NOS activity. Novabiochem, Darmstadt, Germany) diluted 1:400 in
5% nonfat dry milk in TBS-T. After incubation the
Determination of saliva IFN-c, PGE2, and IgA levels membrane was incubated for 1 h at 25°C with goat
The IFN-c (Endogen Inc., Woburn, MA, USA), PGE2 antimouse-horseradish peroxidase-conjugated IgG (San-
(Assay Designs) and IgA (IPR S.p.A., Catania, Italy) ta Cruz Biotechnology, Santa Cruz, CA, USA) diluted
levels were determined in the fluid saliva fraction using 1:3000 in 2.5% non-fat dry milk in TBS-T. Immunore-
ELISA kits, according to the manufacturer’s instruc- activity was assessed by chemiluminescence reaction
tions. Where indicated, PGE2 levels were also assessed using ECL Western blotting detection system (Pierce).
in macrophage culture medium.
Statistical analysis
Substrate gel electrophoresis (zymogram) The differences in the analyzed parameters between the
SDS-PAGE zymograms containing 0.1% gelatin were control and patient groups were tested by using the
performed as described previously (Thorgeirsson and Student’s t-test. The statistical significance of the differ-
MacKay, 1992) using approximately 2 lg of sample ences in clinical and laboratory parameters between T0
protein from saliva samples or cultured macrophage and T1 was analyzed using the paired sample t-test.
supernatants to reveal the gelanolytic activity. Gelano- The STATPAC program was used to perform statistical
lytic activity secreted by cultured macrophages in basal analysis and statistical difference set at P < 0.05.
or stimulated conditions was analyzed using equal
10-fold concentrated sample volume (10–20 ll). Follow-
ing electrophoresis, gels were rinsed in 50 mM Tris-HCl
Results
(pH 7.4) containing 2% Triton X-100 followed by Arginine deiminase activity in L. brevis extracts
50 mM Tris-HCl (pH 7.4) and incubated overnight for Arginine deiminase activity was analyzed in bacterial
gelatinases, in a buffer containing 50 mM Tris-HCl (pH extracts as described in the Materials and methods
7.4), 0.2 M NaCl, 5 mM CaCl2, and 1% Triton X-100 at section. The enzymatic assay, based on the conversion
37°C. Enzyme activity was detected following staining of L-arginine to L-citrulline in appropriate conditions
with 0.1% Coomassie brilliant blue in a mixture of allowing to exclude NOS and arginase activity, showed
acetic acid:methanol:water (1:3:6), destained in the same that AD activity was present at high levels in L. brevis
mixture without dye and dried. Sample collagenase (Figure 1a). The generation of citrulline by L. brevis
Oral Diseases
5. Anti-inflammatory effects of L. brevis
DN Della Riccia et al
380
(a)
Citrulline (pmol mg–1 prot min–1) (b)
45
40
35
30
25
20
15 665 bp
10
5
0
vis
E
e
ne
Markers
AM
n
bre
idi
idi
-N
uan
am
L.
+L
orm
nog
+F
mi
+A
(c)
5’ aaagaggttt ctagcgatgt cttcgatggc gtccgccgtc
gtccgaggga aaccccaatt gctaagacgt gtcggacaa gacgagctcg
tcgccccctt cgatgtggga ttcgtggttc cggtcgcgcc atacctcaac
ttgccccgca aaccgtgggt ggtggttgat gatgtattcc gtgatcaggg Figure 1 Arginine deiminase expression in
attcacgttg acgggccggg aaagtcatct tgttaatgga gatcccgtca Lactobacillus brevis extracts. (a) Arginine
ccaatggagg cctgcggatc cgcgtgaag taagcgtttg gcattgggtc deiminase activity in bacterial extracts in the
cattaagaac ggccagtccg tattttcgga aacggattgc agatccggtt presence or absence of formamidine, a specific
gggcgatgtc aatgtcagtc ccccgcaccc cttcgatgat cttgtcaacc inhibitor of arginine deiminase, L-NMMA, a
atttcctgcg gggtcatttg ggtagaggta gtcatataag gcgtcgtggg nitric oxide synthase (NOS) inhibitor, and
tggtacccgc aacgtaacca gattcggcga tcatccgg 3’ aminoguanidine, a relatively specific inhibitor
of the inducible form of NOS. The results
represent the mean values of duplicate deter-
(d) L. sakei L DMVEKIMAGVRT NEIDIKSK
minations and are representative of one of
L. brevis MET VDKI I EGVRGTDIDIAQP three experiments. SD values were ever lower
than 10% of mean value. *P < 0.001 when
L. sakei AL I DVSA - - - - - - - - - -- - - - compared with L. brevis extracts alone. (b)
L. brevis DLQSVSENTDWPFLMETDPME
Analysis of arginine deiminase gene, after
L. sakei - - NLYFT RDPAASMGDGLTIN PCR amplification performed on genomic
L. brevis TPNAYFTRDPQAS I GDGI SIN DNA, through 1.2% agarose gel electro-
phoresis. (c) Analysis of the direct sequencing
L. sakei KM - -TFEARQRESMFMEVIMQ of the PCR-obtained fragment amplimer
L. brevis KMETTFPARQRESL I T EYI I N
(arcA1-2). (d) The sequence of a 124 amino
L. sakei HHPRFANQGAQVWRDRDH IDR acid residue encoded by the PCR-obtained
L. brevis HHPRFAGO– VEVWRDRNHESH fragment, corresponding to arginine deimi-
nase protein. The stringent homology (52%)
L. sakei MEGGDEL ILSDKVLAIGIS
L. brevis I EGGDELVLSDHVLAIGVS
with the arginine deiminase of L. sakei is
shown
extract could be attributed to AD activity, as it was 124 amino acid residues which showed several conserved
observed in the absence of NOS cofactors (NADPH, structural elements typical of AD genes. Comparing
FAD, FMN, and BH4) and it was not affected either by amino acids residues of the AD of L. brevis and AD of
L-valine, an arginase inhibitor, or by L-NMMA, a NOS L. sakei (Figure 1d), a stringent homology (52%) was
inhibitor, and aminoguanidine, a relatively specific found. Although the AD gene is scarcely conserved,
inhibitor of the inducible form of NOS. Moreover, the including the internal regions, our results clearly
abrogation of citrulline generation observed in the demonstrated the presence of this gene in L. brevis.
presence of formamidine, a specific inhibitor of AD,
definitively established that the conversion of arginine to Clinical evaluation
citrulline was due to the presence of high levels of this The scores for gingival inflammation, plaque, tartar,
enzyme in L. brevis extracts. temperature sensitivity, and bleeding on probing before
The presence of AD in L. brevis was further con- and after the treatment with L. brevis lozenges are
firmed through the structural analysis of the gene reported in Table 1. All clinical parameters that were
encoding the enzyme. A couple of primers designed on analyzed reached statistically significant differences
the basis of consensus sequences known to be an between patients before treatment (T0) and the same
internal region of the AD encoding gene was used to after treatment with L. brevis containing lozenges (T1).
attempt PCR amplification. The PCR, performed on On the mean, gingival inflammation was rated as
genomic DNA of L. brevis, yielded an amplimer of moderate/diffuse by 20 patients at enrollment, and mild
665 bp (Figure 1b) which was subjected to direct by one subject. After treatment, almost all patients
sequencing. The sequencing of the PCR fragment, showed no gingival inflammation; two individuals
named arcA1-2, resulted in a completely identified complained of a mild inflammation, while just one
478 bp sequence (Figure 1c) encoding a polypeptide of patient had a still moderate gingival inflammation. The
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6. Anti-inflammatory effects of L. brevis
DN Della Riccia et al
381
Table 1 Effect of the treatment with Lactobacillus brevis-containing
HT1080
lozenges on gingival inflammation, plaque and calculus, temperature
sensitivity, and bleeding in periodontitis patients Healthy controls
T0 T1 P-value
250
Gingival inflammation 2.24 ± 0.12 0.14 ± 0.10 <0.0001 150
Plaque 2.10 ± 0.14 1.10 ± 0.12 <0.0001 92 100
Calculus 1.62 ± 0.21 1.29 ± 0.16 <0.0001
75
Temperature sensitivity 2.29 ± 0.14 0.43 ± 0.11 <0.0001 72
Bleeding 1.38 ± 0.19 0.05 ± 0.05 <0.0001 50
37
tolerability was considered as very good by all patients.
Overall, the clinical evaluation of both the dentist and
the patient overlapped, and the results confirmed
recovery in 18 patients and improvement in three
individuals. The antibiotic treatment for 4 days did 250
150
not significantly modify signs and symptoms (data not 92 100
shown), as expected. 75
72
Effects of L. brevis-containing lozenges on saliva sample 50
NOS activity, PGE2, IFN-c, and IgA levels 37
The levels of nitrites and nitrates and those of PGE2,
IFN-c, and IgA, determined in the fluid saliva fraction
of healthy controls and periodontitis patients, as
described in Materials and methods in an unblinded
HT1080
fashion, are reported in Table 2. Periodontitis patients’
saliva had a significantly higher level of nitrites/nitrates Patients
when compared with normal subjects (P < 0.01). In the
same Table are also reported the results obtained when Figure 2 Salivary matrix metalloproteinase (MMP) activity in healthy
periodontitis patients’ saliva was analyzed for nitrite/ subjects and periodontitis patients. Gelatinase activity in the soluble
nitrate levels before (T0) and after (T1) treatment with salivary fractions of representative healthy subjects and periodontitis
L. brevis-containing lozenges. In all patients, the treat- patients is shown. The electrophoretic mobility of MMP-9 and MMP-
2, obtained from supernatants of HT1080 cell, is indicated on the left-
ment was associated with a significant reduction in hand side. Molecular weights of the standard are indicated on the right
nitrite and nitrate levels. Similar results were obtained
when the conversion of radiolabeled arginine to citrul-
line was analyzed in the cell saliva fraction (data not
shown). In addition the PGE2 and IFN-c levels were amounts of MMPs than the control samples, thus
significantly higher in patients with periodontitis than in confirming previous reports. Figure 2 shows gelatinase
controls (P < 0.01). Interestingly, treatment with activity present in five different control salivary samples
L. brevis-containing lozenges was associated with a (panel a) as well as in five different patients’ salivary
strong decrease in the levels of these inflammation- samples (panel b), representative of all examined cases.
associated molecules (P < 0.01). In contrast, IgA levels, Enzymatic activity was compared with that of gelatin-
which were significantly reduced in patients compared ases obtained from the supernatants of the HT1080 cell
with controls (P < 0.05), were not significantly mod- line stimulated with tissue plasminogen activator (TPA)
ified by the treatment. (10)7 M) for 48 h (the 72 kDa type IV collagenase,
gelatinase A, MMP-2, and the 92 kDa type IV collag-
Effects of L. brevis-containing lozenges on saliva sample enase, gelatinase B, MMP-9). The zymogram of healthy
MMP activity and levels control salivas (Figure 2a) shows bands with relative
The measurements of MMP activity in the soluble molecular weights of 92 kDa, of about 120 kDa and
fraction of saliva samples disclosed that the salivary higher than 200 kDa. Aside from a band of about
samples of periodontitis patients contained higher 37 kDa, little or no enzymatic activity was visible at
Table 2 Effect of the treatment with Lactobacillus brevis-containing lozenges on laboratory parameters in periodontitis patients
Samples Nitrite/nitrate (lM) PGE2 (ng ml)1) IFN-c (pg ml)1) IgA (lg ml)1)
HC 4.33 ± 1.31 P < 0.0001 0.32 ± 0.08 10.06 ± 0.84 885.62 ± 118.28
T0 38.86 ± 6.07* P < 0.0001 1.64 ± 0.1* 28.23 ± 2.11* 309.76 ± 143.06*P < 0.05
T1 9.39 ± 1.47** 0.46 ± 0.07** 8.82 ± 4.74**1.04 466.51 ± 237.1
HC, healthy controls; T0, before treatment; T1, after treatment. *P ¼ T0 vs HC; **P ¼ T1 vs T0.
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7. Anti-inflammatory effects of L. brevis
DN Della Riccia et al
382
molecular weights lower than 92 kDa. The profile of
multiple forms of gelatinases found in patients’ saliva is
shown in Figure 2b. In addition to the same bands of 250
controls, a strong gelatinolytic activity at molecular 150
weights lower than 92 kDa could be seen in all patients’
salivas. In some cases (i.e., lanes 2 and 3) the high 100
molecular weight activities of gelatinase were almost 75
absent, being prevailing below 92 kDa. These latter
species mainly migrated with a connecting smear, being
evident as separate bands only at the 37–50 kDa region. 50
The gelatinolytic activity detected by zimogram
appeared to be due to the presence of MMPs, as
protease activity was completely abrogated by the C T0 T1 T0 T1 T0 T1
addition of EDTA, but not by the addition of serine Patient n. 4 5 6
and cysteine proteinase inhibitors to the incubation
buffer (data not shown). The treatment with lozenges led Figure 4 Effects of Lactobacillus brevis-containing lozenges on saliva
sample matrix metalloproteinase levels. Western blot analysis of
to the near disappearance of these MMP bands in all gelatinase expression in one representative healthy control and three
patients’ samples. Figure 3 shows the gelatinolytic activ- periodontitis patients’ saliva samples before and after treatment with
ity of five representative periodontitis patients before lozenges containing L. brevis. C, healthy control; T0, before treatment;
(T0) and after (T1) the treatment with experimental T1, after treatment. Molecular mass markers are indicated on the left-
hand side
lozenges. The profile of multiple forms of gelatinases
was similar in all patients. The treatment led to the near
disappearance of the low molecular weight bands and 92 kDa were detected. Western blotting with specific
restored the control profile of gelatinolytic activity. antibodies against human MMP-2, MMP-3, MMP-1,
Western blot experiments demonstrated that the bands and MMP-8 showed no immunoreactivity, suggesting
revealed by zymograms were due mainly to the enzymatic that these MMPs were not detectable in the saliva of either
activity of MMP-9. Figure 4 shows a Western blot of one controls or patients (data not shown).
representative control and three representative patients
before and after treatment with experimental lozenges. In Effect of L. brevis extracts on macrophage NOS activity
the saliva of patients antibody against MMP-9 revealed Rat peritoneal macrophages incubated in vitro in the
some high molecular weight forms (>200 kDa) together presence of LPS for 18 h were induced to express iNOS
with bands at the 180 kDa region and at 120 kDa. Other activity (Figure 5a). NOS activity was inhibited by the
molecular weights ranging from 92 to 64 kDa and NOS inhibitors AG and L-NMMA. In the presence of
approximately at 54 and 44 kDa were seen in the saliva bacterial extracts, NOS activity disappeared and argin-
of patients with chronic periodontitis. After treatment the ine was converted in citrulline through bacterial AD,
enzymatic pattern resembled that of healthy controls. as demonstrated either by the unsensitivity of this
Indeed, a relevant reduction in high molecular weight conversion to NOS inhibitor treatment (Figure 5a) or
bands was observed and little or no MMP-9 species below by the disappearance of enzymatic activity in the
presence of the AD inhibitor, formamidine (data not
shown). Similar results were obtained with L. fermentum
250 extracts, but not with Streptococcus thermophilus, a
150 LAB in which the AD activity was not detectable (not
100 shown).
92
75 These results suggest that bacterial AD was able to
72 50 totally utilize the arginine present in the medium thus
37 preventing its uptake by macrophages and consequently
NOS activity.
Effect of L. brevis extracts on macrophage PGE2 release
When rat peritoneal macrophages were cultured for up
HT1080
T0 T1 T0 T1 T0 T1 T0 T1 T0 T1
to 18 h with LPS, a gradual accumulation of PGE2 in
the supernatants occurred (fivefold increase over that in
4 5 7 3 6 control cells) (Figure 5b). This effect was almost totally
Patient n. abrogated in the presence of L. brevis extracts as
Figure 3 Effects of Lactobacillus brevis-containing lozenges on saliva occurred when the cells were previously treated with
sample matrix metalloproteinase (MMP) activity. Zymography com- L-NMMA or aminoguanidine.
paring gelatinolitic activities in saliva of five periodontitis patients
before treatment (T0) with gelatinolitic activities in saliva of the same Effect of L. brevis extracts on MMP production by
patients after treatment with L. brevis-containing lozenges (T1). The
electrophoretic mobility of MMP-9 and MMP-2, obtained from macrophages in the presence of LPS
supernatants of HT1080 cell line, is indicated on the left-hand side. To investigate the L. brevis effect on MMP production,
Molecular weights of the standard are indicated on the right-hand side activated rat peritoneal macrophages were treated with
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8. Anti-inflammatory effects of L. brevis
DN Della Riccia et al
383
(a) 3 Control
L. brevis
Citrulline (pmol mg–1 prot min–1)
2.5 LPS
LPS + L. brevis
2
1.5
1
0.5
0
None L-NAME Aminoguanidine Formamidine
LPS + L. brevis
(b) 60 Control (c)
L. brevis
LPS
PGE2 (ng/106 cells)
50
HT 1080
LPS+ L.brevis
L. brevis
Control
Figure 5 Effect of Lactobacillus brevis LPS+ L-NMMA
LPS+ AG
LPS
extracts on LPS-activated macrophages. 40
Effect of L. brevis extracts on iNOS activity
(a), PGE2 levels (b) and MMP activity (c) in 30
rat peritoneal macrophages incubated in vitro MMP9
in the presence or absence of LPS for 18 h. 20
Where indicated, the effect of L-NMMA,
10 MMP2
aminoguanidine (AG), and formamidine is
shown 0
bacterial extracts in the presence or absence of LPS and enzymatic activity (Di Marzio et al, 2001), we checked
cell culture supernatants were analyzed by zymography the presence of the AD gene. The analysis of a fragment
for MMP-9 and MMP-2 levels. Compared with macr- obtained by PCR unambiguously revealed the presence
ophages in culture medium alone, LPS increased MMP- of this gene, thus confirming our previous findings.
9 activity, whereas MMP-2 was not detectable. The Nitric oxide is known to be an important inflamma-
presence of L. brevis extract in the culture medium led to tory mediator, and is involved in the pathophysiology of
a relevant decrease in MMP-9 activity, either when several inflammatory disorders. An increase in NO
added alone or in the presence of stimuli. Similarly, a production has been also demonstrated in periodontitis
total inhibition of MMP activity was observed in the as its role in the inflammatory response of periodontal
presence of iNOS inhibitors. A representative zymogra- tissues has been suggested (Matejka et al, 1998, 1999;
phy is illustrated in Figure 5c. Enzymatic activity was Lappin et al, 2000; Hirose et al, 2001; Kendall et al,
compared with that of partially purified gelatinases 2001; Lohinai et al, 2001; Daghigh et al, 2002). These
(MMP-2 and MMP-9) obtained from the supernatants findings are consistent with the hypothesis suggesting
of HT1080 cell line stimulated with TPA (10)7M) for that treatment with agents able to block the production
48 h. The bands revealed by zymograms could be of NO or its effects might be therapeutically valuable for
attributed to MMPs as they disappear with EDTA but periapical lesions (Lohinai et al, 1998; Paquette and
not by the addition of other proteinase inhibitors to the Williams, 2000; Daghigh et al, 2002). Considering the
incubation buffer (data not shown). role of NO in inflammatory events in general and in
periodontitis in particular, we analyzed the potential
beneficial effects of L. brevis-based treatment in patients
Discussion with periodontal disease. Of note, the proposed experi-
Periodontitis is characterized by extensive destruction of mental treatment led to the total disappearance or
the gingival tissues and associated supporting structures amelioration of all analyzed clinical parameters (gingi-
of the teeth. In the present work, we first analyzed the val inflammation, plaque, calculus, temperature sensi-
potential anti-inflammatory action in vivo of L. brevis- tivity, and bleeding on probing) in almost all 21 patients
containing lozenges in 21 adult patients with periodontal (recovery in 18 patients and improvement in three
disease. Previously, our group reported the presence of individuals). The beneficial effects of the treatment on
arginine-deiminase in L. brevis, a strain belonging to clinical signs and symptoms were paralleled by a strong
LAB (Di Marzio et al, 2001). The presence of high levels and statistically significant decrease in oral NOS activ-
of this enzyme, which metabolize arginine to citrulline ity. Besides its direct role as an inflammatory modulator,
and ammonia, aids L. brevis extracts to inhibit NO NO represents a multifunctional messenger molecule
generation, by competing with NOS for the same able to modulate the production of inflammatory
substrate, arginine. To confirm the presence of AD in cytokines (Cifone et al, 1999), PGE2 (Goodwin et al,
L. brevis, previously shown through the assay of 1999), and MMPs (Maeda et al, 1998; Tronc et al, 2000;
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9. Anti-inflammatory effects of L. brevis
DN Della Riccia et al
384
Hirai et al, 2001). On the other hand, inflammatory exclude the possibility that L. brevis extract-based
cytokines such as IFN-c, tumor necrosis factor-a and treatment, besides the anti-inflammatory effects repor-
interleukin-1-a have been shown to be significantly ted here, is also able to antagonize the growth of specific
higher in periodontitis patients than in healthy controls periodontopathic pathogens.
(Takeichi et al, 2000; Hirose et al, 2001; Tervahartiala Taken together, our findings give further insights into
et al, 2001; Ukai et al, 2001). Moreover, the generation the knowledge of the molecular basis of periodontitis
of PGE2, a potent eicosanoid lipid mediator derived and have a potential clinical significance, representing
from phospholipase-released arachidonic acid that is the experimental ground for a new innovative, simple
involved in numerous homeostatic biologic functions and efficacious therapeutical approach of periodontal
and inflammation, has been shown to be strongly disease.
incremented in periodontal lesions (Cavanaugh et al,
1998; Leibur et al, 1999; Paquette and Williams, 2000;
Acknowledgements
Tsilingaridis et al, 2003). Furthermore, MMP levels
have been previously shown to play a critical role in the The authors thank Gasperina De Nuntiis (Department of
inflammatory process leading to alveolar bone and Experimental Medicine, University of L’Aquila, L’Aquila,
connective tissue loss in periodontal disease (Makela Italy) for technical assistance and Miss Florence Pryen for
et al, 1994; Ding et al, 1995; Ejeil et al, 2003; Sorsa et al, careful language revision of the manuscript. This work was
2004). Indeed, one of the most salient features of financially supported by grant ÔPROGETTO DI INTERESSE
GENERALE DI ATENEO’ from the University of L’Aquila.
periodontitis and gingivitis is the increase in the levels of
bacterial and host-derived proteolytic enzymes in oral
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