Long-term efficacy of microbiology-driven periodontal laser-assisted therapy.

Periodontitis represents a highly prevalent health problem, causing severe functional impairment, reduced quality of life and increased risk of systemic disorders, including respiratory, cardiovascular and osteoarticular diseases, diabetes and fertility problems. It is a typical example of a multifactorial disease, where a polymicrobial infection inducing chronic inflammation of periodontal tissues is favoured by environmental factors, life style and genetic background. Since periodontal pathogens can colonise poorly vascularised niches, antiseptics and antibiotics are typically associated with local treatments to manage the defects, with unstable outcomes especially in early-onset cases. Here, the results of a retrospective study are reported, evaluating the efficacy of a protocol (Periodontal Biological Laser-Assisted Therapy, Perioblast™) by which microbial profiling of periodontal pockets is used to determine the extent and duration of local neodymium-doped yttrium aluminium garnet (Nd:YAG) laser irradiation plus conventional treatment. The protocol was applied multicentrically on 2683 patients, and found to produce a significant and enduring improvement of all clinical and bacteriological parameters, even in aggressive cases. Microbiome sequencing of selected pockets revealed major population shifts after treatment, as well as strains potentially associated with periodontitis in the absence of known pathogens. This study, conducted for the first time on such a large series, clearly demonstrates long-term efficacy of microbiology-driven non-invasive treatment of periodontal disease.

Comparison of periodontal microbiological patterns in Italian spouses.

PURPOSE: The aim of this study is to evaluate whether periodontopathogens are transmitted from husband to wife or vice versa. MATERIALS AND METHODS: We tested the microbiological profile of 9 couples married for at least 10 years suffering from periodontitis. The microbiological analysis provides the quantification by Real-Time PCR of six main periodontopathogens, including P. gingivalis, T. denticola, T. forsythia, F. nucleatum ssp. polymorphum, P. intermedia, A. actinomycetemcomitans and genotype of P. gingivalis FimA in 90 subgingival plaque samples. RESULTS: The microbiological profiles highlighted a quite similar composition of oral microbial flora among husband and wife. Statistical results revealed a very high Pearson correlation values for the microbiological profiles in all 9 spouses. Additionally, five couples out of nine showed statistically similar values for the microbiological profile as determined by the Wilcoxon rank Sign test. We provided also a strong validation for the horizontal transmission of oral pathogens in the detection of the same genotype of P. gingivalis FimA in the spouses. CONCLUSIONS: The presence of periodontitis in one member of the couple is a strong indicator of risk for the colonization of the spouse by periodontophatic bacteria. This study confirms that periodontal disease can be transmitted suggesting the importance of an early detection of oral pathogens in familial pattern of periodontitis to clarify the source of infection in order to assess correct prevention protocols based on potential infectivity within spouses.

VDR TaqI polymorphism is associated with chronic periodontitis in Italian population.

AIM: The aim of this study is to investigate the relationship between a vitamin D receptor polymorphism and the diagnosis of periodontal disease in non-smoker Italian patients with aggressive and chronic periodontitis. MATERIALS AND METHODS: DNA was obtained from the internal cheek mucosa of 115 patients with chronic periodontitis, 58 with aggressive periodontitis and 65 healthy controls. Allelic discrimination was performed using TaqMan SNP Genotyping Assays. Genotype and allele frequencies were calculated. RESULTS: Comparisons between diseased patients and healthy controls showed significant differences. Moreover, calculating the odds ratio, individuals with the TT genotype, was more susceptible than individuals with tt to chronic periodontitis and individuals with Tt to aggressive periodontitis. Interestingly, the dominant model (TT + Tt vs. tt) was applicable to chronic periodontitis, whilst for aggressive periodontitis the recessive model (TT vs. Tt + tt) gave the highest odds ratio. CONCLUSIONS: These data indicated that VDR TaqI polymorphism is differentially associated with development of chronic periodontitis and aggressive periodontitis in Italian population. The study of VDR polymorphisms may therefore be essential for the prevention of periodontitis and for a pre-treatment periodontal and/or for implant assessment. Moreover VDR TaqI polymorphism could be useful to discriminate between aggressive and chronic forms of periodontal disease.

PON1 activity and genotype in patients with arterial ischemic stroke and in healthy individuals.

OBJECTIVE: Paraoxonase-1 (PON1) is an esterase with antioxidant properties. Low PON1 enzyme activity or specific allelic polymorphisms seem to be associated with the risk of developing coronary artery disease or acute ischemic stroke (AIS). Our objective was to determine the distribution of both PON1 enzyme activity and its genotype in a group of patients with AIS. MATERIALS AND METHODS: PON1 activity and the relative Q192R and L55M polymorphisms in the PON1 gene were assessed on 126 survivors of a first AIS and in 92 healthy subjects. RESULTS: The genotype distribution for PON1 Q192R and L55M polymorphisms was similar in AIS patients and healthy subjects, but patients carrying the QRLL or RRLL genotype combination had lower PON1 enzyme activity compared with healthy subjects with the same genotype. CONCLUSION: We postulate that lower than expected PON1 enzyme activity within specific genotypes might explain the reported association between R and L alleles and the risk of developing AIS.

Do different dialytic techniques have different atherosclerotic and antioxidant activities?

To compare the chronic effect of several dialytic techniques (bicarbonate dialysis, BHD; acetate free biofiltration, AFB; hemodiafiltration, HDF; paired filtration dialysis, PFD) on atherosclerosis and antioxidant activity, three different indices were created. The first (atherosclerotic index = AI) is formed using the sum of three plasma substances: MDA, Hcy, and Cys (malondialdehyde, homocysteine, cysteine). The second (antioxidant activity index = AOAI) is the sum of five erythrocyte (E) parameters: E-GSH, GPx, CAT, SOD, GR (E-glutathione, E-glutathione peroxidase, E-catalase, E-superoxide dismutase, E-glutathione reductase). The third (defense index = DI) is derived from the previous two: (AOAI - AI). The indices were so expressed as AI in mmol/L, AOAI in U/g hemoglobin (Hb), and DI in arbitrary units. These indices were calculated in 20 controls and 51 chronic HD patients (26 female, 25 male) before, during, and after the first session of the week. HD patients were divided according to their dialytic technique: BHD, n = 35; AFB, n = 5 patients; HDF, n = 7 patients; or PFD = 4 patients. All patients had been treated with a given technique for at least 12 months, before entering the study. As expected, HD patients had AI values higher than controls, both before and after the session, with a mean value of 541 (before) and 331 (after), whereas controls had a mean value of 205. The AOAI was lower than controls, both before and after the session, the mean value being 1,122 (before) and 1,582 (after), that of controls being 2,424. In all cases, PFD gave the best "acute" results; at the end of a PFD session, near normal values of AI, AOAI, and DI (defensive index = AOAI - AI) were obtained.

Role of cellulosic and noncellulosic membranes in hyperhomocysteinemia and oxidative stress.

Hyperhomocysteinemia is an independent risk factor for cardiovascular morbidity and mortality in end-stage renal disease (ESRD) with an increased relative risk (RR) of 1% per micromol/L in total homocysteine concentration. In ESRD patients who undergo hemodialysis (HD), the antioxidant system is largely inadequate in correcting the imbalance between generation and scavenging of reactive oxygen species (ROS). To clarify the role of several cellulosic (CMs) and noncellulosic of synthetic membranes (NCMs) upon hyperhomocysteinemia and the oxidative stress, we measured plasma (P) homocysteine (t-HCY), plasma lipid peroxidation (LPO), and erythrocyte (E) concentration of several antioxidant enzymes in 20 normal subjects, in 35 HD patients treated with CMs, and in 29 patients treated with NCMs. Before, during, and after the first session of the week (at times 0', 120', end, 30' after HD end), blood samples were drawn. Plasma (P) homocysteine (t-HCY), cysteine (CYS), malondialdehyde (MDA), erythrocyte (E)-glutathione (GSH), glucose-6-phosphodehydrogenase (G6PD), glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), and superoxide-dismutase (SOD) were determined. The dialytic procedure significantly decreased the three plasma parameters, but none normalized (as a mean). The E-enzymes scavenging ROS (lower than normal before session) increased throughout the session, but the normal range of activity was never reached. Different membranes have shown different effects. When these effects on P and E spaces were pooled, we were able to classify the membranes as follows. In a general sense, cellulosic membranes are less effective than synthetic membranes both on lipoperoxides (LPO) and antioxidant activity (AOA). Among synthetic membranes, PMMA is the best membrane both for plasma values and lesser enzymatic derangement during the session. A practical system for classifying the anti-atherosclerotic action and antioxidant activity of dialytic membranes is proposed.

Dialysis kinetics of homocysteine and reactive oxygen species.

In patients with chronic renal failure who undergo hemodialysis (HD), the antioxidant system is inadequate to correct the imbalance between the generation and scavenging of reactive oxygen species. To clarify the role of six different membranes on oxidative stress, the authors measured plasma lipid peroxidation and erythrocyte (E) concentrations of several antioxidant enzymes in 30 HD patients: 20 on bicarbonate HD, 4 on paired filtration dialysis, 3 on acetate free biofiltration, and 3 on hemodiafiltration. Before, during, and after the first session of the week (at times 0, 30, 60, and 120 min, end, and 30 min after end of HD), several blood samples were drawn. Plasma (P) homocysteine (HCY), cysteine (CYS), malondialdehyde (MDA), E-glutathione (GSH), glucose-6-phosphodehydrogenase, glutathione reductase (GR), glutathione peroxidase (GP), catalase (CAT), and superoxide dismutase (SOD) were determined. All six membranes (Hemophan [HEMO]; cellulose diacetate [DIAC]; acrylonitrile-69 [AN69]; polymethylmethacrylate [PMMA]; cuprammonium rayon [CURAY]; polysulfone plus hemophan [PS + HEMO]) induced a significant decrease in plasma lipid peroxidation (p < 0.001) and an increase in E-GSH, GR, GR + flavinadenine dinucleotide, GP, and SOD (p < 0.001). Some membranes, however, showed some peculiar effects on reactive oxygen species: HEMO is better than DIAC, as far as P-MDA and P-HCY are concerned; PMMA induces higher changes in E-GR and P-CYS than does HEMO; and patients chronically using PMMA and PS + HEMO membranes show the lowest P-HCY levels both before and after dialytic sessions. Based on these changes, implications as to the effects on vascular disorders could be derived.

Free radicals and oxidative stress challenge dialysis patients: effects of two different membranes.

Patients with end-stage renal disease (ESRD) who undergo hemodialysis manifest pronounced oxidative stress (OS), for the antioxidant system is inadequate to correct the imbalance between generation and scavenging of reactive oxygen species (ROS). To clarify the role of two different membranes on the OS, we measured plasma lipid peroxidation (LPO) and erythrocyte concentration of several antioxidant enzymes on 20 controls and 6 patients on bicarbonate dialysis (BHD). At 7 days intervals, 2 BHD sessions were done on the same 6 hemodialysis patients: the two BHD sessions were similar, except for the membrane used (cuprophan, first study; regenerated cellulose = Bioflux, second study, 7 days later). Before, during, and after each session (0', 30', 60', 120', end, 30' after BHD end), several blood samples were drawn. Lipid peroxidation and erythrocyte glutathione (GSH), superoxide dismutase (SOD), and catalase were spectrophotometrically determined (Bioxytech, France), but for erythrocyte glutathione peroxidase (Gpx) and G-6-PD, Gunzler's and Beutler's methods were used, respectively. Both membranes induce a significant decrease in LPO (p < 0.01) and an increase in erythrocyte SOD (p < 0.05). Bioflux shows some peculiar effects: a significant increase in erythrocyte GSH (p < 0.05) and erythrocyte catalase (p < 0.01) with a gradual increase of erythrocyte SOD and catalase/SOD ratio. Cuprophan, on the contrary, causes a sudden increase in erythrocyte SOD, while erythrocyte catalase decreases. These data support the view that Bioflux induces an OS lower than cuprophan because with the former, increased H2O2 production leads (thanks to catalase and GPx action) to water generation. With cuprophan, instead the reduced SOD/catalase ratio causes a greater H2O2 generation and a lower conversion to water.

The role of erythrocytes in the deperoxidative processes in people on hemodialysis.

The defenses against the production of free radicals and reactive oxygen species (ROS) are to be found in plasma (ascorbate, urate, alpha tocopherol) and in erythrocytes (superoxide dismutase or SOD; catalase or CAT; glutathione peroxidase or GPx). In chronic renal failure, an increased lipid peroxidation and a reduced antioxidant activity seem to be present, but previous reports are conflicting. To clarify the peroxidative status and the defense mechanisms taking place in patients on dialysis, in 30 patients on dialysis (15 men, 15 women) and in 20 control subjects (10 men, 10 women), the following parameters were measured: plasma 4-hydroxinonenal (4-HNE) and erythrocyte reduced glutathione (GSH), SOD, GPx, and glucose-6-phosphate dehydrogenase (G-6-PD). Patients on dialysis, in comparison with control subjects, had 1) increased levels of 4-HNE (p < 0.001); 2) a significant increase in erythrocyte-GSH (p < 0.05); and 3) significant decreases in erythrocyte-SOD (p < 0.001), erythrocyte-G-6-PD (p < 0.005), and the erythrocyte-SOD/GPx ratio (p < 0.001). The dialysis procedure induced a certain reduction in plasma 4-HNE, an increase in erythrocyte-SOD activity, and an important consumption of erythrocyte-GSH, while the erythrocyte-SOD/GPx ratio changed. The current study supports the view that 1) erythrocytes act as small detoxifying packets; 2) in chronic renal failure, the antioxidant system is largely inadequate; and 3) in patients on dialysis, the antioxidant mechanism of erythrocytes in scavenging ROS is effectively exerted during dialysis but remains largely inadequate, as signs of lipid peroxidation persist with time.

Serum paraoxonase activity is decreased in uremic patients.

Paraoxonase is a high-density lipoprotein (HDL)-associated enzyme capable of hydrolysing lipid peroxides. We measured the activity of serum paraoxonase together with serum concentrations of a variety of lipid constituents--total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), cholesterol, triglycerides, apolipoproteins A-I and B--in 60 hemodialyzed (HD) patients. We found that the paraoxonase activity was significantly reduced in HD patients compared with 64 healthy controls (mean median and interquartile values: 93, 63, 87 IU/l in HD patients and 151, 120 and 135 IU/l in controls). In patients, the trimodal frequency of distribution of paraoxonase activity showed a shift toward lower levels. The effect of NaCl on enzyme activation was more pronounced in the patient group, as compared with controls, suggesting a higher frequency of the B allozyme (more responsive to NaCl) in this population. We suggest that altered HDL subfraction, present in HD patients, may be the main cause of the widespread depression of paraoxonase. Furthermore, the higher frequency of allozyme B among HD patients might increase the risk of coronary artery disease. In conclusion, paraoxonase activity may be an adjunctive index of altered lipoprotein metabolism with important repercussions on atherosclerosis.

The plasma glutathione peroxidase enzyme in hemodialyzed subjects.

The kidney is probably the major site of production of the plasma enzyme glutathione peroxidase (GSHPx-P). For this study, GSHPx-P activity was determined in 40 healthy people, in 34 patients with differing degrees of renal impairment, and in hemodialysis patients from whom blood samples were withdrawn either before or after each session (18 patients) or throughout the dialysis session (27 patients). Hemodialysis patients were treated by means of different techniques (bicarbonate hemodialysis, hemodiafiltration, and acetate free biofiltration), and different membranes (cuprophane, polyacrylonitrite, and polymethylmethacrylate). The following results were obtained: 1) GSHPx-P activity was significantly decreased in renal impairment patients; 2) GSHPx-P activity negatively correlated with serum creatinine values in renal impairment patients (r = -0.55; p < 0.001); and 3) the enzyme activity slightly increased after the session in hemodialysis patients. The following conclusions can be drawn: GSHPx-P activity could be new index of renal function, because it was decreased in patients with renal failure; the decrease in GSHPx-P activity paralleled the severity of renal impairment, and was maximal in hemodialysis patients; GSHPx-P activity was slightly raised at the end of the hemodialysis session, concomitant with other enzyme activities (aspartate transaminase, alanine transaminase, and alkaline phosphatase) and total protein concentration. This seems to be attributable to the process of water loss rather than other hypothetical mechanisms, such as A) enzyme activation by either peroxide generation during blood-membrane contact, or by the removal of a hypothetical inhibitor; and B) de novo synthesis in the residual renal mass or in other sites of production.

Plasma glutathione peroxidase activity as an index of renal function.

The kidney is a major source of the plasma enzyme glutathione peroxidase. We measured plasma glutathione peroxidase activity in 130 patients affected with different renal diseases at various stages, and compared it with the following indices of kidney function: serum creatinine, creatinine clearance, and urinary excretion of alpha 1-microglobulin, beta 2-microglobulin, albumin and N-acetyl-beta-D-glucosaminidase. Plasma glutathione peroxidase activity appeared significantly reduced in most of the renal diseases considered, and showed a significant correlation with most of the renal function indices. Linear discriminant analysis showed that the set of indices composed of plasma glutathione peroxidase activity, serum creatinine and creatinine clearance allowed the best classification of renal diseases. During treatment with the nephrotoxic aminoglycoside, tobramycin, plasma glutathione peroxidase activity showed an early and progressive decrease. We suggest the measurement of plasma glutathione peroxidase activity as an adjunctive index for the assessment of kidney alterations.