[Association between periodontitis and mild cognitive impairment: a clinical pilot study].

Objective: To evaluate the association between periodontitis and mild cognitive impairment (MCI), and explore the potential local oral risk factors for MCI. Methods: The study included 70 middle-aged and elderly subjects (44 females and 26 males) with periodontal disease who were first diagnosed by the Department of Periodontology or referred by the Department of Geriatrics in Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from January 2021 to January 2022. In this study, the control group consisted of periodontal disease patients without cognitive impairment, and the case group (MCI group) consisted of those diagnosed with MCI referred by the geriatrics specialists. Full-mouth periodontal examinations of all subjects were performed and periodontal indicators were recorded by periodontists, while digital panoramic radiographs were taken. The severity of periodontitis was defined according to the 1999 classification, and the staging and grading of periodontitis were defined according to the 2018 American Academy of Periodontology and European Federation of Periodontology classification. The mini-mental state examination scale was chosen by geriatricians to evaluate the cognitive function of the included subjects. The cubital venous blood was drawn to detect the expression levels of inflammatory factors such as hypersensitive C-reactive protein (hs-CRP), interleukin (IL)-1ß, IL-6 and tumor necrosis factor-α(TNF-α) in serum. Independent-samples t test and chi-square test were used to analyze the differences in population factors, periodontal-related indexes and serum inflammatory factors between the two groups (α=0.05). Odds ratios (OR) for MCI according to the severity of periodontitis and main periodontal clinical indexes were calculated by binary Logistic analysis. Results: Thirty-nine subjects were included in the control group and thirty-one in the MCI group. The age of the study population was (58.3±6.2) years (range: 45-70 years). The comparison between two groups showed that the control group was with higher educational background (χ²=9.45, P=0.024) and 2.6 years younger than the MCI group [(57.1±6.0) years vs. (59.7±6.3) years, t=-1.24, P=0.082]. The number and proportion of moderate to severe periodontitis in control group were significantly lower compared to those in MCI group (17 cases with 43.6% vs. 23 cases with 74.2%, χ²=6.61, P=0.010), and the OR of moderate to severe periodontitis adjusted by age and educational background was 3.00 (95%CI: 1.01-8.86, P=0.048). Compared with the grading (χ²=5.56, P=0.062) of periodontitis, staging had a greater impact on MCI (χ²=7.69, P=0.041), moreover the proportion of MCI in stage Ⅰ grade A periodontitis was significantly lower than any other type of periodontitis (χ²=13.86, P=0.036). In addition, less presence of deep periodontal pockets [probing depth (PD)≥6 mm] (17.9% vs. 41.9%, χ²=4.87, P=0.027), fewer number of PD≥4 mm (6.48±6.70 vs. 11.03±8.91, t=-2.44, P=0.017), lower plaque index (1.42±0.56 vs. 1.68±0.57, t=-1.91, P=0.059) and gingival index (1.68±0.29 vs. 1.96±0.30, t=-3.93, P<0.001) were in the control group than in the MCI group. However, there were no significant differences between the two groups in the levels of serum inflammatory factors, such as hs-CRP, IL-1ß, IL-6 and TNF-α (P>0.05). Conclusions: It appears a strong correlation between moderate to severe periodontitis and the incidence of MCI in middle-aged and elderly people. Moreover, deep and increased number of periodontal pockets, poor oral hygiene, and severe gingival inflammation can be potentially associated risk factors for MCI.

[Preliminary study on the relationship between different blood glucose levels and periodontitis in patients with diabetes mellitus type 2].

Objective: To determine the correlation between the diabetes mellitus control and periodontitis. Methods: This study was a cross-sectional survey using stratified system sampling model design. The target population was the patients with diabetes investigated from May to July 2018 in Huangpu District of Shanghai. In the present study, severe periodontitis was defined as at least at two sites in different quadrants with probing depth (PD)≥6 mm and clinical attachment loss (CAL)≥ 5 mm. Edentulous induced by periodontitis were also classified as severe periodontitis and the others were classified as non-severe periodontitis subjects. Diabetes control levels were divided into the following three groups: poorly controlled group [glycated hemoglobin (HbA1c)>7.5% and fasting blood glucose (FPG)>7.0 mmol/L], well controlled group (6.5%≤HbA1c≤7.5％ or 6.1 mmol/L≤FPG≤7.0 mmol/L) and ideally controlled group (HbA1c<6.5% and FPG<6.1 mmol/L). SPSS 25.0 was used for statistical analysis. Chi square test was used for demographic data and frequency distribution, α=0.05, two-sided test. Ordinal regression model was used for PD and diabetes control status to balance confounding factors (including age, gender, education and smoking status). After matching the propensity scores between severe periodontitis group and non-severe periodontitis group, logistic regression analysis was used to analyze the level of diabetes control and periodontitis. Results: A total of 5 220 adults over the age of 18 with a medical history of diabetes participated in the survey, of which 3 064 subjects with diabetes mellitus type 2 (T2DM) who were given both oral and laboratory examinations and were included in this study. Statistics showed that the prevalence of moderate and severe periodontitis was 10.57% (324/3 064). In the severe periodontitis group, 79.01% (256/324) of the subjects were over 65 years old, 55.56% (180/324) were male, 58.33% (189/324) had lower education level than high school level, and 21.91% (71/324) were smokers, which were significantly higher than those in the non-severe periodontitis group (P<0.01). In different T2DM status groups, the percentage of severe periodontitis increased with the aggravation of T2DM status. In severe periodontitis group, the proportion of patients with poor glycemic control was higher. T2DM patients with poor glycemic control accounted for 68.52% (222/324) in severe periodontitis group, which was significantly higher than the proportion of non-severe periodontitis group of 60.99% (1 671/2 740) (P<0.05). The regression coefficient of PD was 0.191, and PD had a significant negative effect on the level of blood glucose (P<0.01). There was a significant positive correlation between diabetes glycemic control and severe periodontitis (OR=2.800, P<0.05). Conclusions: In Huangpu District of Shanghai, among T2DM patients, the age of severe periodontitis group was higher than that of non-severe periodontitis group, most of them were male, with lower education level and higher proportion of smoking. The severity of diabetes was related to periodontitis and the proportion of severe periodontitis was higher in patients with poor glycemic control.

Genetic-dietary regulation of serum paraoxonase expression and its role in atherogenesis in a mouse model.

In an effort to identify genetic factors contributing to atherogenesis, we have studied inbred strains of mice that are susceptible (C57BL/6J) and resistant (C3H/HeJ) to diet-induced aortic fatty streak lesions. When maintained on a low-fat diet, HDL isolated from both strain C57BL/6J (B6) and C3H/HeJ (C3H) mice protect against LDL oxidation in a coculture model of the artery wall. However, when maintained on an atherogenic diet high in fat and cholesterol, the HDL isolated from B6 mice lose the capacity to protect, whereas HDL from C3H mice protect equally well. Associated with the loss in the ability of HDL to protect is a decrease in the activity of serum paraoxonase, a serum esterase carried on HDL that has previously been shown to protect against LDL oxidation in vitro. The levels of paraoxonase mRNA decreased in B6 mice upon challenge with the atherogenic diet but increased in C3H, indicating that paraoxonase production is under genetic control. In a set of recombinant inbred strains derived from the B6 and C3H parental strains, low paraoxonase mRNA levels segregated with aortic lesion development, supporting a role for paraoxonase in atherogenesis.

Exon-intron organization and chromosomal localization of the mouse monoglyceride lipase gene.

Monoglyceride lipase (MGL) functions together with hormone-sensitive lipase to hydrolyze intracellular triglyceride stores of adipocytes and other cells to fatty acids and glycerol. In addition, MGL presumably complements lipoprotein lipase in completing the hydrolysis of monoglycerides resulting from degradation of lipoprotein triglycerides. Cosmid clones containing the mouse MGL gene were isolated from a genomic library using the coding region of the mouse MGL cDNA as probe. Characterization of the clones obtained revealed that the mouse gene contains the coding sequence for MGL on seven exons, including a large terminal exon of approximately 2.6 kb containing the stop codon and the complete 3' untranslated region. Two different 5' leader sequences, diverging 21 bp upstream of the predicted translation initiation codon, were isolated from a mouse adipocyte cDNA library. Western blot analysis of different mouse tissues revealed protein size heterogeneities. The amino acid sequence derived from human MGL cDNA clones showed 84% identity with mouse MGL. The mouse MGL gene was mapped to chromosome 6 in a region with known homology to human chromosome 3q21.

Genetic contributions to quantitative lipoprotein traits associated with coronary artery disease: analysis of a large pedigree from the Bogalusa Heart Study.

A pedigree of a large family with high prevalence of heart disease is subjected to association and sib-pair linkage analysis to investigate the role of 5 candidate genes in the regulation of lipoprotein metabolism and the development of coronary artery disease. At the 5% nominal significance level, the apolipoprotein B locus (APOB) was found to be linked to high-density lipoprotein cholesterol level (HDL-C), low-density lipoprotein cholesterol level (LDL-C), the ratio HDL-C/LDL-C, and apolipoprotein AI level times this ratio (apoAI x LDL-C/HDL-C). APOB (PvuII) was strongly associated with apolipoprotein B levels (apoB) (P = 0.006) and the VNTR region of the APOB locus showed highly significant association between allele 7 and low triglyceride levels (P = 0.004). No significant linkage results were found with cholesterol ester transfer protein (CETP). At the 1% nominal significance level, CETP [TaqI(B)] showed significant association with LDL-C, apoB, and HDL-C/LDL-C. There was significant linkage of lipoprotein lipase (LPL) with very-low-density lipoprotein cholesterol and the ratio apoAI/HDL-C, and strong association results between LPL (HindIII) and triglyceride levels (P = 0.005). At the 5% nominal significance level, haptoglobin (HPA) was associated with HDL-C, HDL-C/LDL-C, apoAI/HDL-C and apoAI x LDL-C/HDL-C. The apolipoprotein AI locus did not show any significant linkages or associations. The study thus indicated that genetic variation of APOB, LPL, CETP, and lecithin cholesterol acyl transferase (which is linked to HPA and CETP) may play an important role in the regulation of lipoprotein metabolism and could contribute to the risk of coronary artery disease.

Assignment of the human pancreatic colipase gene to chromosome 6p21.1 to pter.

Pancreatic colipase is a 12-kDa polypeptide cofactor for pancreatic lipase (EC 3.1.1.3), an enzyme essential for the absorption of dietary long-chain triglyceride fatty acids. Colipase is thought to anchor lipase noncovalently to the surface of lipid micelles, counteracting the destabilizing influence of intestinal bile salts. Using primers derived from the known amino acid sequence, we have used the polymerase chain reaction to produce a cDNA clone corresponding to the complete coding region of the human procolipase mRNA. Southern blot analysis of genomic DNA from a panel of mouse-human somatic cell hybrids indicated that the colipase gene (CLPS) resides on human chromosome 6. Further analysis of somatic cell hybrids carrying chromosome 6 translocations permitted regional localization of CLPS to the 6p21.1-pter region.

Ubiquinone biosynthesis in eukaryotic cells: tissue distribution of mRNA encoding 3,4-dihydroxy-5-polyprenylbenzoate methyltransferase in the rat and mapping of the COQ3 gene to mouse chromosome 4.

The isolation and sequence of a rat cDNA corresponding to the rat COQ3 gene was recently reported. The COQ3 gene encodes 3,4-dihydroxy-5-polyprenylbenzoate methyltransferase, an enzyme in coenzyme Q biosynthesis. In this study, the rat COQ3 cDNA has been used to examine the expression and chromosomal localization of the COQ3 gene. COQ3 mRNA was detected in every tissue analyzed, consistent with the idea that in most tissues de novo synthesis accounts for the observed levels of Q. Highest levels were present in testis, heart, and skeletal muscle. The rat COQ3 cDNA hybridized to genomic DNA from multiple species, suggesting the conserved nature of the 3,4-dihydroxy-5-polyprenylbenzoate methyltransferase. A single copy of the COQ3 gene appears to be present in rats and mice. By analyzing a restriction fragment length variant in an interspecific backcross, the COQ3 gene was localized to mouse chromosome 4, at a position 3.7 +/- 2.6 cM proximal to the marker D4Mit4. The map position of the gene, designated Coq3, places it in close proximity to the mouse vacillans or vc mutation. The symptoms exhibited by the vc mice are similar to those reported for Q deficiencies in humans.

The murine chemokine CXCL11 (IFN-inducible T cell alpha chemoattractant) is an IFN-gamma- and lipopolysaccharide-inducible glucocorticoid-attenuated response gene expressed in lung and other tissues during endotoxemia.

A new murine chemokine was identified in a search for glucocorticoid-attenuated response genes induced in the lung during endotoxemia. The first 73 residues of the predicted mature peptide are 71% identical and 93% similar to human CXCL11/IFN-inducible T cell alpha chemoattractant (I-TAC) (alias beta-R1, H174, IFN-inducible protein 9 (IP-9), and SCYB9B). The murine chemokine has six additional residues at the carboxyl terminus not present in human I-TAC. Identification of this cDNA as murine CXCL11/I-TAC is supported by phylogenetic analysis and by radiation hybrid mapping of murine I-TAC (gene symbol Scyb11) to mouse chromosome 5 close to the genes for monokine induced by IFN-gamma (MIG) and IP10. Murine I-TAC mRNA is induced in RAW 264.7 macrophages by IFN-gamma or LPS and is weakly induced by IFN-alphabeta. IFN-gamma induction of murine I-TAC is markedly enhanced by costimulation with LPS or IL-1beta in RAW cells and by TNF-alpha in both RAW cells and Swiss 3T3 fibroblasts. Murine I-TAC is induced in multiple tissues during endoxemia, with strongest expression in lung, heart, small intestine, and kidney, a pattern of tissue expression different from those of MIG and IP10. Peak expression of I-TAC message is delayed compared with IP10, both in lung after i.v. LPS and in RAW 264.7 cells treated with LPS or with IFN-gamma. Pretreatment with dexamethasone strongly attenuates both IFN-gamma-induced I-TAC expression in RAW cells and endotoxemia-induced I-TAC expression in lung and small intestine. The structural and regulatory similarities of murine and human I-TAC suggest that mouse models will be useful for investigating the role of this chemokine in human biology and disease.

Localization of the gene for high-density lipoprotein binding protein (HDLBP) to human chromosome 2q37.

The high-density lipoprotein binding protein (HDLbp) is a 110-kDa protein that specifically binds HDL molecules and may function in the removal of excess cellular cholesterol. As part of an effort to study the function of the protein and its possible role in cholesterol transport, we report the localization of the gene for HDLbp, designated HDLBP, to human chromosome 2q37 using analysis of somatic cell hybrids and in situ hybridization.

A locus on the X chromosome is linked to body length in mice.

Linkage between body length (anus to nose (AN) length) and three markers on the mouse X Chromosome was found in an interspecific backcross ((C57BL/6J x Mus spretus) F 1x C57BL/6J), designated BSB. A cross of 409 mice were scored for 148 genetic markers distributed on all chromosomes except the Y Chromosome. Statistical analysis revealed highly significant linkage (LOD score 5.5) between body length and a locus in the middle portion of the X Chromosome, the nearest markers being the microsatellite marker DXMit73 and a farnesyl pyrophosphate locus (Fpsl9) 3.1 cM proximal to DXMit73. The locus explains 10% of the variance in AN length and affects both males and females to about the same extent.

Localization of the gene for the DNA-binding protein AP-2 to human chromosome 6p22.3-pter.

A variety of cellular proteins bind to cellular and viral enhancer elements. One such factor, known as AP-2, is a 52-kDa transcription factor identified by its interaction with the SV40 and metallothionein enhancers. In addition, it has been found that AP-2 binds to the SV40 T-antigen. AP-2 activity is mediated by both the state of cellular differentiation and changes in signal transduction pathways, suggesting a potential role of AP-2 in the regulation of diverse cellular processes. As part of an effort to examine the chromosomal organization of cellular genes encoding transcription factors, we report the mapping of the gene encoding AP-2 to human chromosome 6p22.3-24 by analysis of somatic cell hybrids and in situ hybridization to chromosomes.

Localization of murine macrophage inducible nitric oxide synthase to mouse chromosome 11.

There are at least three distinct nitric oxide (NO) synthase genes. Brain and endothelial NO synthases are constitutively synthesized, while NO synthase is inducible by cytokines in macrophages. We have utilized a backcross of (C57BL/6J x Mus spretus) x C57BL/6J to map the inducible NO synthase (Nos2). We report the chromosomal mapping of Nos2 to mouse chromosome 11, 3.3 cM proximal to Scya2.

Sequence, structure, and chromosomal mapping of the mouse Lgals6 gene, encoding galectin-6.

In the accompanying paper (Gitt, M. A., Colnot, C., Poirier, F., and Barondes, S. H., and Leffler, H. (1998) J. Biol. Chem. 273, 2954-2960), we reported that mouse gastrointestinal tract specifically expresses two closely related galectins, galectins-4 and -6, each with two carbohydrate recognition domains in the same peptide. Here, we report the isolation, characterization, and chromosomal mapping of the complete mouse Lgals6 gene, which encodes galectin-6, and of a fragment of a distinct gene, Lgals4, which encodes galectin-4. The coding sequence of galectin-6 is specified by eight exons. The upstream region contains two putative promoters. Both Lgals6 and the closely related Lgals4 are clustered together about 3.2 centimorgans proximal to the apoE gene on mouse chromosome 7. The syntenic human region is 19q13.1-13.3.

Isolation and sequencing of the rat Coq7 gene and the mapping of mouse Coq7 to chromosome 7.

We recently identified the Saccharomyces cerevisiae COQ7 gene and showed that its product affects one or more monoxygenase steps in the synthesis of ubiquinone. Other investigators have independently isolated the yeast COQ7 gene as CAT5 and identified it as a gene necessary for the derepression of gluconeogenic enzymes in yeast. In the present study, a homolog of the yeast COQ7 (CAT5) gene was isolated from a rat testis cDNA library by functional complementation of a coq7 deletion mutant of S. cerevisiae. The resulting cDNA clones contained a 0.8-kb insert with an open reading frame encoding a 183-amino-acid polypeptide. The rat Coq7 amino acid sequence is 49% identical to that of yeast Coq7p and 58% identical to a C. elegans homolog over a 152-aa region. Sequence homology searches fail to identify any other significant homologies. The Coq7 gene was mapped to mouse chromosome 7, 7.6 +/- 3.6 cM proximal to the marker D7Mit7, by linkage analysis of an interspecific backcross. This region of chromosome 7 containing Coq7 is part of a linkage group conserved between mouse chromosome 7 and human chromosome 11p15.

Cloning of a third mammalian Na+-Ca2+ exchanger, NCX3.

NCX3 is the third isoform of a mammalian Na+-Ca2+ exchanger to be cloned. NCX3 was identified from rat brain cDNA by polymerase chain reaction (PCR) using degenerate primers derived from the sequences of two conserved regions of NCX1 and NCX2. The NCX3 PCR product was used to isolate two overlapping clones totalling 4.8 kilobases (kb) from a rat brain cDNA library. The overlapping clones were sequenced and joined at a unique Bsp106I restriction enzyme site to form a full-length cDNA clone. The NCX3 cDNA clone has an open reading frame of 2.8 kb encoding a protein of 927 amino acids. At the amino acid level, NCX3 shares 73% identity with NCX1 and 75% identity with NCX2 and is predicted to share the same membrane topology as NCX1 and NCX2. Following addition of a poly(A)+ tail to the NCX3 clone, exchanger activity could be expressed in Xenopus oocytes. NCX3 was also expressed in the mammalian BHK cell line. NCX3 transcripts are 6 kb in size and are highly restricted to brain and skeletal muscle. Linkage analysis in the mouse indicated that the NCX family of genes is dispersed, since the NCX1, NCX2, and NCX3 genes mapped to mouse chromosomes 17, 7, and 12, respectively.

Mapping of the glycoprotein 330 (Gp330) gene to mouse chromosome 2.

Glycoprotein 330 (Gp330) is a member of the low-density lipoprotein receptor gene family that is expressed in the kidney. We have mapped the Gp330 gene to mouse chromosome 2, 4.5 cM proximal to Acra, in an interspecific backcross of (C57BL/6J x Mus spretus) F1 x C57BL/6J.

The L-isoaspartyl/D-aspartyl protein methyltransferase gene (PCMT1) maps to human chromosome 6q22.3-6q24 and the syntenic region of mouse chromosome 10.

We have mapped the genes for the human and mouse L-isoaspartyl/D-aspartyl protein carboxyl methyltransferase (EC 2.1.1.77) using cDNA probes. We determined that the human gene is present in chromosome 6 by Southern blot analysis of DNA from a panel of mouse-human somatic cell hybrids. In situ hybridization studies allowed us to confirm this identification and further localize the human gene (PCMT1) to the 6q22.3-6q24 region. By analyzing the presence of an EcoRI polymorphism in DNA from backcrosses of C57BL/6J and Mus spretus strains of mice, we localized the mouse gene (Pcmt-1) to chromosome 10, at a position 8.2 +/- 3.5 cM proximal to the Myb locus. This region of the mouse chromosome is homologous to the human 6q24 region.

Genetic regulation of cholesterol homeostasis: chromosomal organization of candidate genes.

As part of an effort to dissect the genetic factors involved in cholesterol homeostasis in the mouse model, we report the mapping of 12 new candidate genes using linkage analysis. The genes include: cytoplasmic HMG-CoA synthase (Hmgcs 1, Chr 13), mitochondrial synthase (Hmgcs 2, Chr 3), a synthase-related sequence (Hmgcs 1-rs, Chr 12), mevalonate kinase (Mvk, Chr 5), farnesyl diphosphate synthase (Fdps, Chr 3), squalene synthase (Fdft 1, Chr 14), acyl-CoA:cholesterol acyltransferase (Acact, Chr 1), sterol regulatory element binding protein-1 (Srebf1, Chr 8) and -2 (Srebf2, Chr 15), apolipoprotein A-I regulatory protein (Tcfcoup2, Chr 7), low density receptor-related protein-related sequence (Lrp-rs, Chr 10), and Lrp-associated protein (Lrpap 1, Chr 5). In addition, the map positions for several lipoprotein receptor genes were refined. These genes include: low density lipoprotein receptor (Ldlr, Chr 9), very low density lipoprotein receptor (Vldlr, Chr 19), and glycoprotein 330 (Gp330, Chr 2). Some of these candidate genes are located within previously defined chromosomal regions (quantitative trait loci, QTLs) contributing to plasma lipoprotein levels, and Acact maps near a mouse mutation, ald, resulting in depletion of cholesteryl esters in the adrenals. The combined use of QTL and candidate gene mapping provides a powerful means of dissecting complex traits such as cholesterol homeostasis.

Characterization of the murine mu opioid receptor gene.

The analgesic and addictive properties of morphine and other opioid drugs are thought to result from their interaction with mu opioid receptors. Using a delta opioid receptor cDNA as a probe, we have isolated a murine mu opioid receptor cDNA clone (mMOR). Stable expression of mMOR in Chinese hamster ovary cells conferred high binding affinity for mu receptor ligands including morphine and [D-Ala2,N-methyl-Phe4,Gly5-ol]-enkephalin and low affinity for delta and kappa preferring ligands. Treatment of these cell lines with morphine and other mu agonists inhibited forskolin-induced cAMP accumulation, demonstrating a functional coupling of mMOR to the inhibition of adenylate cyclase. The predicted amino acid sequence of mMOR shares approximately 55% overall amino acid identity with the delta receptor and approximately 97% identity with the recently reported rat mu opioid receptor. Expression of the mu receptor in mouse brain as revealed by in situ hybridization parallels the reported pattern of distribution of mu-selective ligand binding sites. Chromosomal localization (to mouse chromosome 10) and Southern analysis are consistent with a single mu opioid receptor gene in the mouse genome, suggesting that the various pharmacologically distinct forms of the mu receptor arise from alternative splicing, post-translational events, or from a highly divergent gene(s).