Periodontal Disease May be Associated With the Occurrence of Diabetic Retinopathy: A Subgroup Analysis of The Survey of the Diabetes Coordination Notebook in Gifu.

AIMS: A questionnaire survey of the prevalence of diabetic retinopathy was recently conducted in Japan. A subgroup analysis to examine the association of periodontal disease with diabetic retinopathy in subjects with diabetes and prediabetes was conducted. METHODS: The association of the presence of periodontal disease with the occurrence of diabetic retinopathy was examined using multivariate logistic regression analysis. RESULTS: Of 27 016 subjects who completed a survey at 217 community pharmacies, 5 572 had diabetes or prediabetes, among whom 522 and 1 421 had retinopathy or periodontal disease, respectively. Therapy duration≥10 years (OR: 2.73, 95% CI: 2.17-3.43, P<0.001), periodontal disease (OR: 2.10, 95% CI: 1.68-2.62, P<0.001) and glycated hemoglobin (HbA1c) ≥ 7.0% (OR: 1.64, 95% CI: 1.32-2.04, P<0.001) were significantly associated with the occurrence of retinopathy, while retinopathy (OR: 2.11, 95% CI: 1.: 69-2.63, P<0.001) and therapy duration ≥10 years (OR: 1.24, 95% CI: 1.06-1.46, P=0.007) were significantly associated with the occurrence of periodontal disease. The prevalence of retinopathy was much higher in diabetic subjects with periodontal disease than in those without it (15.1% vs. 7.8%, P<0.001). Notably, the difference of prevalence of retinopathy between subjects with and without periodontal disease was statistically significant even at HbA1c 6.0-6.9% (15.2% vs. 7.3%, P<0.01). CONCLUSIONS: These findings indicate that the target HbA1c level for diabetes patients with periodontal disease may be set lower than for those without it, and that regular dental visits should be prescribed for the management of periodontal disease and the prevention of diabetic retinopathy.

Evaluation of the Diabetes Regional Coordination Path using the Diabetes Coordination Notebook in community-based diabetes care.

AIMS: A number of epidemiologic surveys have demonstrated that improving lifestyle habits, providing patient education, and regular screening of patients for early diabetic symptoms and complications through multidisciplinary collaboration are crucial for the management of diabetes. METHODS: To evaluate the Diabetes Coordination Notebook and the Diabetes Regional Coordination Path in management of diabetes, 217 community pharmacies conducted a survey by questionnaire in Gifu Prefecture, Japan. RESULTS: A reply to the questionnaire was obtained from 27,016 individuals, of whom 5,572 claimed to have diabetes or prediabetes. The rate of usage of the Diabetes Coordination Notebook and the Diabetes Regional Coordination Path was 40% and 7%, respectively. Interestingly, patients using the Diabetes Regional Coordination Path more frequently visited an ophthalmic clinic (p < 0.001) and a dental clinic (p < 0.05) than those not using it. Furthermore, multivariate logistic regression analysis revealed that use of the Diabetes Regional Coordination Path was the only factor associated with control of HbA1c < 7.0% (OR: 0.613, 95% CI: 0.395-0.951, p = 0.029). CONCLUSIONS: The usage of the Diabetes Regional Coordination Path together with the Diabetes Coordination Notebook is associated not only with regular visits to both an ophthalmic clinic and a dental clinic but also with the maintenance of appropriate HbA1c.

"Force-From-Lipids" mechanosensation in Corynebacterium glutamicum.

Since the mechanosensitive channel MscCG has been identified as the major glutamate efflux system in Corynebacterium glutamicum, studies of mechanotransduction processes in this bacterium have helped to unpuzzle a long-unresolved mystery of glutamate efflux that has been utilised for industrial monosodium glutamate production. The patch clamp recording from C. glutamicum giant spheroplasts revealed the existence of three types of mechanosensitive (MS) channels in the cell membrane of this bacterium. The experiments demonstrated that the MS channels could be activated by membrane tension, indicating that the channel gating by mechanical force followed the "Force-From-Lipids (FFL)" principle characteristic of ion channels inherently sensitive to transbilayer pressure profile changes in the mechanically stressed membrane bilayer. Mechanical properties of the C. glutamicum membrane are characteristics of very soft membranes, which in the C. glutamicum membrane are due to negatively charged lipids as its exclusive constituents. Given that membrane lipids are significantly altered during the fermentation process in the monosodium glutamate production, MS channels seem to respond to changes in force transmission through the membrane bilayer due to membrane lipid dynamics. In this review, we describe the recent results describing corynebacterial FFL-dependent mechanosensation originating from the particular lipid composition of the C. glutamicum membrane and unique structure of MscCG-type channels.

Corynebacterium glutamicum mechanosensitive channels: towards unpuzzling "glutamate efflux" for amino acid production.

Corynebacterium glutamicum has been utilized for industrial amino acid production, especially for monosodium glutamate (MSG), the food-additive for the "UMAMI" category of taste sensation, which is one of the five human basic tastes. Glutamate export from these cells is facilitated by the opening of mechanosensitive channels in the cell membrane within the bacterial cell envelope following specific treatments, such as biotin limitation, addition of Tween 40 or penicillin. A long-unsolved puzzle still remains how and why C. glutamicum mechanosensitive channels are activated by these treatments to export glutamate. Unlike mechanosensitive channels in other bacteria, these channels are not simply osmotic safety valves that prevent these bacteria from bursting upon a hypo-osmotic shock. They also function as metabolic valves to continuously release glutamate as components of a pump-and-leak mechanism regulating the cellular turgor pressure. Recent studies have demonstrated that the opening of the mechanosensitive channel, MscCG, mainly facilitates the efflux of glutamate and not of other amino acids and that the "force-from-lipids" gating mechanism of channels also applies to the MscCG channel. The bacterial types of mechanosensitive channels are found in cell-walled organisms from bacteria to land plants, where their physiological functions have been specialized beyond their basic function in bacterial osmoregulation. In the case of the C. glutamicum MscCG channels, they have evolved to function as specialized glutamate exporters.

Evolutionary specialization of MscCG, an MscS-like mechanosensitive channel, in amino acid transport in Corynebacterium glutamicum.

MscCG, a mechanosensitive channel of Corynebacterium glutamicum provides a major export mechanism for glutamate in this Gram-positive bacterium, which has for many years been used for industrial production of glutamate and other amino acids. The functional characterization of MscCG is therefore, of great significance to understand its conductive properties for different amino acids. Here we report the first successful giant spheroplast preparation of C. glutamicum amenable to the patch clamp technique, which enabled us to investigate mechanosensitive channel activities of MscCG in the native membrane of this bacterium. Single channel recordings from these spheroplasts revealed the presence of three types of mechanosensitive channels, MscCG, MscCG2, and CgMscL, which differ largely from each other in their conductance and mechanosensitivity. MscCG has a relatively small conductance of ~340 pS followed by an intermediate MscCG2 conductance of ~1.0 nS and comparably very large conductance of 3.7 nS exhibited by CgMscL. By applying Laplace's law, we determined that very moderate membrane tension of ~5.5 mN/m was required for half activation of MscCG compared to ~12 mN/m required for half activation of both MscCG2 and CgMscL. Furthermore, by combining the micropipette aspiration technique with molecular dynamics simulations we measured mechanical properties of the C. glutamicum membrane, whose area elasticity module of KA ≈ 15 mN/m is characteristic of a very soft membrane compared to the three times larger area expansion modulus of KA ≈ 44 mN/m of the more elastic E. coli membrane. Moreover, we demonstrate that the "soft" properties of the C. glutamicum membrane have a significant impact on the MscCG gating characterized by a strong voltage-dependent hysteresis in the membrane of C. glutamicum compared to a complete absence of the hysteresis in the E. coli cell membrane. We thus propose that MscCG has evolved and adapted as an MscS-like channel to the mechanical properties of the C. glutamicum membrane enabling the channel to specialize in transport of amino acids such as glutamate, which are major osmolytes helping the bacterial cells survive extreme osmotic stress.

Effectiveness of Sodium-Glucose Cotransporter-2 Inhibitor as an Add-on Drug to GLP-1 Receptor Agonists for Glycemic Control of a Patient with Prader-Willi Syndrome: A Case Report.

INTRODUCTION: Diabetes patients with Prader-Willi syndrome (PWS) are obese because of hyperphagia; weight control by dietary modification and medicine is required for glycemic control. There are several recent reports showing the effectiveness of GLP-1 receptor agonists (GLP-1RAs) for diabetes treatment in PWS. CASE REPORT: A 36-year-old Japanese male patient was diagnosed with PWS at 10 years of age. At age 16 years, he was diagnosed with diabetes and began to take several kinds of oral hypoglycemic agents. At age 29 years, his BMI was 39.1 kg/m2 and he was referred to our department for diabetes and obesity treatment. In the present case, the HbA1c was not improved by GLP-1RAs despite a 28-kg BW reduction, which included a 9-kg loss of muscle. Apprehensive of further loss of muscle mass, basal insulin of insulin glargine was administered in addition to GLP-1RAs. Immediately after the addition of tofogliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, the patient's HbA1c decreased dramatically with only about an additional 3% BW reduction. We note an improvement in our case of lipid deposition in the pancreas confirmed by abdominal CT after the improvement of HbA1c. It is unknown whether this improvement of fatty pancreas was a cause or an effect of the improved glycemic control in the present case. CONCLUSION: This finding clearly supports the effectiveness of combining SGLT2 inhibitors with GLP-1RAs for treatment of patients with PWS and non-alcoholic fatty pancreas disease.

NEUROD1-deficient diabetes (MODY6): Identification of the first cases in Japanese and the clinical features.

AIMS: Only a few families with neuronal differentiation 1 (NEUROD1)-deficient diabetes, currently designated as maturity-onset diabetes of the young 6 (MODY6), have been reported, but mostly in Caucasian, and no mutation has been identified by family-based screening in Japanese. Accordingly, the phenotypic details of the disease remain to be elucidated. METHODS: We examined a total of 275 subjects having diabetes suspected to be MODY who were negative for mutations in MODY1-5 referred from 155 medical institutions throughout Japan. So as not to miss low penetrant cases, we examined non-obese Japanese patients with early-onset diabetes regardless of the presence of family history by direct sequencing of all exons and flanking regions of NEUROD1 . Large genomic rearrangements also were examined. RESULTS: Four patients with 3 frameshift mutations and 1 missense mutation, all of which were heterozygous and 3 of which were novel, were identified. Diabetic ketosis was found occasionally in these patients even under conditions of chronic hyperglycemia, for unknown reasons. Although the capacity of early-phase insulin secretion was low in these patients, the insulin secretory capacity was relatively preserved compared to that in hepatocyte nuclear factor (HNF)1A- and HNF1B-MODY. One of the patients and 2 of their diabetic mothers were found to have some mental or neuronal abnormality. CONCLUSIONS: This is the first report of NEUROD1 mutations in Japanese, who have a genetic background of intrinsically lower capacity of insulin secretion. NEUROD1-deficient diabetes appears to be low penetrant, and may occur in concert with other genetic factors.

ATP-dependent modulation of MgtE in Mg2+ homeostasis.

Magnesium is an essential ion for numerous physiological processes. MgtE is a Mg2+ selective channel involved in the maintenance of intracellular Mg2+ homeostasis, whose gating is regulated by intracellular Mg2+ levels. Here, we report that ATP binds to MgtE, regulating its Mg2+-dependent gating. Crystal structures of MgtE-ATP complex show that ATP binds to the intracellular CBS domain of MgtE. Functional studies support that ATP binding to MgtE enhances the intracellular domain affinity for Mg2+ within physiological concentrations of this divalent cation, enabling MgtE to function as an in vivo Mg2+ sensor. ATP dissociation from MgtE upregulates Mg2+ influx at both high and low intracellular Mg2+ concentrations. Using site-directed mutagenesis and structure based-electrophysiological and biochemical analyses, we identify key residues and main structural changes involved in the process. This work provides the molecular basis of ATP-dependent modulation of MgtE in Mg2+ homeostasis.MgtE is an Mg2+ transporter involved in Mg2+ homeostasis. Here, the authors report that ATP regulates the Mg+2-dependent gating of MgtE and use X-ray crystallography combined with functional studies to propose the molecular mechanisms involved in this process.

Complementary glucagonostatic and insulinotropic effects of DPP-4 inhibitors in the glucose-lowering action in Japanese patients with type 2 diabetes.

The dipeptidyl peptidase-4 (DPP-4) inhibitors have a low risk of causing hypoglycemia as monotherapy. However, insulin administration is frequently required, particularly in patients with type 2 diabetes and with reduced insulin secretory capacity. The effects of adding DPP-4 inhibitors were evaluated using continuous glucose monitoring (CGM) in Japanese patients with type 2 diabetes who were insufficiently controlled by basal insulin with biguanide. The effects of adding DPP-4 inhibitors on blood glucose and plasma insulin and glucagon levels were evaluated. Δ glucagon showed a significant association with post-prandial glucose increase in the group with diminished insulin secretory capacity, C-peptide index (CPI) <0.8 (p = 0.016), while Δ C-peptide reached significant association in the group with relatively intact insulin secretory capacity, CPI ≥0.8 (p = 0.017). The mean plasma glucose levels and M values were similarly improved in patients treated with the three DPP-4 inhibitors. Hypoglycemia did not occur in any of the DPP-4 inhibitor groups. In conclusion, complementary glucagonostatic and insulinotropic effects of adding DPP-4 inhibitors are involved in the glucose-lowering action of Japanese patients with type 2 diabetes according to their insulin secretory capacity. Such combination therapy may well be a superior therapeutic option for the treatment of diabetes in Japanese patients who often exhibit reduced insulin secretory capacity.

L-Glutamate secretion by the N-terminal domain of the Corynebacterium glutamicum NCgl1221 mechanosensitive channel.

The Corynebacterium glutamicum NCgl1221 mechanosensitive channel mediates L-glutamate secretion by sensing changes in membrane tension caused by treatments such as biotin limitation and penicillin. The NCgl1221 protein has an N-terminal domain (1-286 a.a.) homologous to the Escherichia coli MscS and a long C-terminal domain (287-533 a.a.) of unknown function. In order to investigate the role of the C-terminal domain in L-glutamate secretion, we constructed a series of C-terminally truncated mutants of NCgl1221. We found that the N-terminal domain, homologous to E. coli MscS, retained the ability to cause L-glutamate secretion in response to the treatment. Electrophysiological analysis confirmed that the N-terminal domain mediated L-glutamate secretion. 3D homology modeling has suggested that the N-terminal domain of NCgl1221 has an extra loop structure (221-232 a.a.) that is not found in most other MscS proteins. The mutant NCgl1221, deleted for this loop structure, lost the ability to secrete L-glutamate. In addition, we found that mutant NCgl1221 lacking the C-terminal extracytoplasmic domain (420-533 a.a.) produced L-glutamate without any inducing treatment. These results suggest that the N-terminal domain is necessary and sufficient for the excretion of L-glutamate in response to inducing treatment, and that the C-terminal extracytoplasmic domain has a negative regulatory role in L-glutamate production.

Glutamate is excreted across the cytoplasmic membrane through the NCgl1221 channel of Corynebacterium glutamicum by passive diffusion.

The NCgl1221 gene, which encodes a mechanosensitive channel, has been reported to be critically involved in glutamate (Glu) overproduction by Corynebacterium glutamicum, but direct evidence of Glu excretion through this channel has not yet been provided. In this study, by electrophysiological methods, we found direct evidence of Glu excretion through this channel by passive diffusion. We found that the introduction into Phe-producing Escherichia coli of mutant NCgl1221 genes that induce Glu overproduction by C. glutamicum improved productivity. This suggests a low-substrate preference of this channel, indicates its potential as a versatile exporter, and more broadly, indicates the potential of exporter engineering.

Hyperglycemic chorea-ballism or acute exacerbation of Huntington's chorea? Huntington's disease unmasked by diabetic ketoacidosis in type 1 diabetes mellitus.

CONTENT: Hyperglycemic chorea-ballism is predominantly observed in older type 2 diabetic patients, and it is rare in type 1 diabetes and diabetic ketoacidosis (DKA). Huntington's disease (HD) is one of several genetic syndromes associated with diabetes, although the reported prevalence of the association varies. There are few opportunities for most physicians to diagnose early-stage HD. OBJECTIVE: We describe bilateral hyperglycemic chorea-ballism in a 40-yr-old female type 1 diabetes patient with DKA and HD. SETTING: The study was conducted in a tertiary care referral hospital. RESULTS: On admission, the patient exhibited severe involuntary movement of bilateral extremities with DKA, and hyperglycemic chorea-ballism was diagnosed. She recovered from chorea-ballism with admission of fluids and insulin, but mild choreatic movement persisted in the upper extremities. Brain magnetic resonance imaging and DNA analysis revealed HD. Although it has been considered that depletion of striatal γ-aminobutyric acid (GABA) content is rare in DKA, it is largely decreased in HD. Therefore, it is probable that hyperglycemic chorea-ballism or exacerbation of Huntington's chorea resulted from transient depletion of GABA. CONCLUSION: The present case provides important insights on the role of GABA in hyperglycemic chorea-ballism and on the clinical issues associated with HD diagnosis.

Neuroprotective effects of melatonin on the nigrostriatal dopamine system in the zitter rat.

Melatonin has ubiquitous actions, both as a direct free-radical scavenger and as an indirect anti-oxidant. The present study examined in vivo neuroprotective effects of melatonin on the nigrostriatal dopaminergic system in zitter (zi/zi) rat, which displays abnormal metabolism of superoxide leading to age-related degeneration of the dopaminergic system. For up to 9 months after weaning, zi/zi rats had ad libitum access to drinking water containing melatonin. Chronic treatment with melatonin attenuated the decreases of dopamine and its metabolite in zi/zi rat caudate-putamen (CPU). Immunohistochemistry for tyrosine hydroxylase (TH) was consistent with neurochemical data in the CPU and demonstrated substantial sparing of the reduction of TH-immunoreactive neurons in the substantia nigra pars compacta. Quantitative polymerase chain reaction (qPCR) was performed to analyze mRNA expressions of pro-inflammatory cytokines (IL-1ß and TNF-α) and the anti-oxidant enzymes (catalase (CAT), superoxide dismutase (SOD) 1 and 2, and glutathione peroxidase (GPx1)) in the striatum and midbrain in order to examine the neuroprotective effect of melatonin. IL-1ß and TNF-α mRNA expressions were significantly increased in both areas of 3-month-old zi/zi rats, whereas there was a significant decrease in CAT mRNA expression in the striatum of 6-month-old zi/zi rat as compared to age-matched controls. With the exception of the high TNF-α mRNA expression in 3-month-old zi/zi midbrains, chronic treatment of melatonin attenuated expressional changes of IL-1ß, CAT, SOD1, and GPx1. These results suggest that besides its direct scavenger effects, chronic melatonin treatment provides a neuroprotective effect against dopaminergic degeneration by suppressing pro-inflammatory cytokines and up-regulating anti-oxidant enzyme expression.

The protein encoded by NCgl1221 in Corynebacterium glutamicum functions as a mechanosensitive channel.

The function of the NCgl1221-encoded protein of Corynebacterium glutamicum was analyzed using Bacillus subtilis as host because a method for preparing the giant provacuole required for electrophysiological studies has been established. Expression of NCgl1221 in a strain deficient in mscL and ykuT, both of which encode mechanosensitive channels, resulted in an 8.9-fold higher cell survival rate upon osmotic downshock than the control. Electrophysiological investigation showed that the giant provacuole prepared from this strain, expressing NCgl1221, exhibited significantly higher pressure-dependent conductance than the control. These findings show that the NCgl1221-encoded protein functions as a mechanosensitive channel.

Changes in enzyme activities at the pyruvate node in glutamate-overproducing Corynebacterium glutamicum.

Glutamate is industrially produced by fermentation using Corynebacterium glutamicum. The key factor for efficient glutamate production by this microorganism has been considered to be a metabolic change at the 2-oxoglutarate dehydrogenase (ODH) branch point caused by a decrease in ODH activity under glutamate-overproducing conditions. However, this change would be insufficient because the ODH branch is merely the final branch in the glutamate biosynthetic pathway, and efficient glutamate production requires a balanced supply of acetyl-CoA and oxaloacetate (OAA), which are condensed to form a precursor of glutamate, namely, citrate. Therefore, there must be another (other) change(s) in metabolic flux. In this study, we demonstrated that a decrease in pyruvate dehydrogenase (PDH) activity catalyzes the conversion of pyruvate to acetyl-CoA. It is speculated that carbon flux from pyruvate to acetyl-CoA decreases under glutamate-overproducing conditions. Furthermore, an increase in pyruvate carboxylase (PC) activity, which catalyzes the reaction of pyruvate to OAA, is evident under glutamate-overproducing conditions, except under biotin-limited condition, which may lead to an increase in carbon flux from pyruvate to OAA. These data suggest that a novel metabolic change occurs at the pyruvate node, leading to a high yield of glutamate through adequate partitioning of the carbon flux.

Longitudinal study of patients with idiopathic isolated TSH deficiency: possible progression of pituitary dysfunction in lymphocytic adenohypophysitis.

The relationship between isolated TSH deficiency and hypophysitis was studied. Six patients (five women and one man) with idiopathic isolated TSH deficiency were longitudinally investigated with an interval of 31 to 60 months. Clinical symptoms, laboratory results and endocrine function were investigated as well as pituitary magnetic resonance imaging (MRI) at the start and the end of the study. Clinically, initial symptoms due to hypothyroidism were ameliorated by the thyroid hormone replacement in all patients. Oligomenorrhea newly appeared during the study in three patients, although no other symptoms appeared. Serum fT3 and fT4 levels were within the reference ranges, and serum TSH level and its response to TRH stimulation remained low in all patients. Peak plasma GH level during GRH stimulation was significantly (p<0.03) decreased, at the end of the study as compared with the start. Peak plasma FSH level to LHRH stimulation was significantly (p<0.03) decreased as well as basal FSH level. In contrast, peak of prolactin during TRH stimulation was significantly (p<0.03) increased at the end of the study as compared with the start as well as basal prolactin level. Endocrine features at the end of the study were compatible with those of lymphocytic adenohypophysitis (LAH). MRI of the pituitary gland showed empty sella in one patient and slight swelling in two patients. These findings remained unchanged during the study period. One patient underwent pituitary biopsy, with histological examination showing atypical form of LAH. LAH can cause idiopathic isolated TSH deficiency and can functionally progress to combine dysfunction of the pituitary gland.

Changes in composition and content of mycolic acids in glutamate-overproducing Corynebacterium glutamicum.

Overproduction of glutamate by Corynebacterium glutamicum is induced by biotin limitation or by the supplementation of specific detergents, sublethal amounts of penicillin, or cerulenin. But, it remains unclear why these different treatments, which have different sites of primary action, produce similar effects. In this study, it was found that the cellular content of mycolic acids--characteristic constituents of Corynebacterineae that are synthesized from fatty acids and form a cell surface layer--decreased under all conditions that induced glutamate overproduction. Furthermore, short mycolic acids increased under conditions of biotin limitation and cerulenin supplementation. These results suggest that different treatments produce the same effect that causes defects in the mycolic acid layer. This is perhaps one of the key factors in overproduction of glutamate by C. glutamicum.