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1.
Diabetes Ther ; 14(10): 1639-1658, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37468684

ABSTRACT

INTRODUCTION: Preference for quality of life is important in deciding the treatment strategy for patients with type 2 diabetes mellitus. This study aimed to assess the effect of omarigliptin on patients' psychological attitudes and responses compared with daily dipeptidyl peptidase-4 inhibitors (DPP4is) by measuring the burden of pharmacotherapy using the Diabetic Treatment Burden Questionnaire (DTBQ). METHODS: Patients with type 2 diabetes mellitus who were taking daily DPP-4is were enrolled and randomized to a group that switched to omarigliptin or a group that continued daily DPP4is and were monitored for 12 weeks. The primary endpoint was the change in the DTBQ score from baseline to week 12. The secondary endpoints included changes in blood test results, medication preferences and medication adherence. RESULTS: The DTBQ total score significantly decreased from baseline to week 12 in both groups; however, no significant intergroup differences were observed. The DTBQ subscale, implementation and flexibility burden scores significantly decreased in the group that switched to omarigliptin, although no significant intergroup difference in the change was observed. DTBQ scores and medication preferences were associated with improvements in the DTBQ scores. CONCLUSION: Although this study failed to demonstrate the improvement of DTBQ total score by switching from daily DPP4is to omarigliptin compared with continuing the daily DPP4is, the DTBQ subscale score implementation and flexibility burden score were significantly improved only in the group that switched to omarigliptin, suggesting the possibility of switching from daily DPP4is to omarigliptin to decrease the patients' medication burden. TRIAL REGISTRATION: jRCTs031200437.

2.
J Obes Metab Syndr ; 31(4): 345-349, 2022 Dec 30.
Article in English | MEDLINE | ID: mdl-36530067

ABSTRACT

Background: This study aimed to investigate the effectiveness at 1 and 3 months of using a smaller rice bowl for diet therapy among Japanese men with type 2 diabetes. Methods: A parallel-group randomized controlled trial was conducted at a medical clinic in Japan. The participants were men with type 2 diabetes mellitus, aged 20-80 years, with glycosylated hemoglobin <8.5%, and who ate rice one or more times per day at home. The intervention group (36 men) received a small rice bowl from which to eat the usual diet therapy, and the control group (38 men) received only the usual diet therapy. Results: The changes in weight and body mass index among the intervention group at 1 month were significantly higher than those in the control group. There were no significant differences between the two groups at 3 months. Conclusion: The effects of using a small rice bowl were minor and short-term.

4.
Diabetol Int ; 12(3): 293-300, 2021 Jul.
Article in English | MEDLINE | ID: mdl-34150438

ABSTRACT

AIMS: We investigated the impact of actual waiting time and perceived waiting time on treatment satisfaction in patients with diabetes receiving outpatient care. METHODS: Three hundred and thirty-six outpatients diagnosed with diabetes mellitus or impaired glucose tolerance were selected and the time they spent in reception, blood collection, consultation, and accounting were recorded to measure the time they spent waiting in the hospital (actual waiting time). Simultaneously, we conducted a questionnaire survey that included questions on their perceptions of the waiting time (perceived waiting time) and satisfaction with treatment (DTSQ). RESULTS: No significant relationship was found between actual waiting time and DTSQ score, although associations were observed with perceived waiting time. The patients who felt the overall waiting time was long scored 23.0, those who felt it was short scored 26.0, and those who felt it was very short scored 34.0, with those who felt the waiting time was long having a significantly lower score (p = 0.004, p < 0.001, respectively) and those who felt it was short having a significantly lower score than those who felt it was very short (p = 0.008). In addition, more patients who felt the waiting time was long expressed dissatisfaction with the responses of doctors and staff than those who felt the waiting time was short. CONCLUSIONS: These results suggest that in addition to reducing actual waiting times, shortening perceived waiting times by improving the responses of medical staff could help to increase patient satisfaction.

5.
J Diabetes Investig ; 12(1): 82-90, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32562376

ABSTRACT

AIMS/INTRODUCTION: We investigated the effect of FreeStyle LibreTM on glycemic control in Japanese type 2 diabetes patients treated with basal-bolus insulin therapy. MATERIALS AND METHODS: This prospective, 90-day single-arm study enrolled 94 adults with type 2 diabetes treated with insulin. A 14-day masked baseline phase was followed by an 11-week treatment phase during which participants used the device to monitor glucose levels. The primary end-point was time spent in hypoglycemia (<70 mg/dL) for baseline versus study end (days 76-90). Secondary end-points included other measures of glycemic control, along with patient satisfaction using the Japanese Diabetes Treatment and Satisfaction Questionnaire. RESULTS: Time spent in hypoglycemia was low at baseline (0.51 ± 0.93 h/day) and did not significantly decrease at study end (0.47 ± 0.63 h/day, P = 0.6354). Time in range, time in hyperglycemia and estimated A1c all improved versus baseline (by +1.7 ± 3.0 h/day, -1.6 ± .4 h/day and -0.4 ± 0.8%, respectively, P < 0.0001 in each). Finger stick tests fell from 2.9 ± 1.3 to 1.9 ± 1.4/day, and mean scanning frequency during the intervention phase was 11.3/day. The mean treatment satisfaction score increased by 11.8 ± 5.3 (P < 0.0001). Two severe hypoglycemia-related adverse events were reported; one of which was possibly related to the device. Three participants reported mild device-related skin trauma, site discomfort or subcutaneous bleeding. CONCLUSIONS: Use of FreeStyle Libre by Japanese type 2 patients diabetes treated with basal-bolus insulin therapy showed a low baseline of hypoglycemia, and enabled improved glycemic control and treatment satisfaction.


Subject(s)
Biomarkers/blood , Blood Glucose Self-Monitoring/methods , Diabetes Mellitus, Type 2/drug therapy , Glycemic Control , Hypoglycemia/epidemiology , Hypoglycemic Agents/administration & dosage , Insulin/administration & dosage , Blood Glucose/analysis , Diabetes Mellitus, Type 2/pathology , Female , Follow-Up Studies , Humans , Hypoglycemia/chemically induced , Hypoglycemia/pathology , Hypoglycemic Agents/adverse effects , Insulin/adverse effects , Insulin Infusion Systems , Japan/epidemiology , Male , Middle Aged , Prognosis , Prospective Studies
7.
Diabetes Ther ; 9(3): 1001-1019, 2018 06.
Article in English | MEDLINE | ID: mdl-29600503

ABSTRACT

INTRODUCTION: To measure the burden of pharmacotherapy on patients with type 2 diabetes mellitus (T2DM), we developed the Diabetes Treatment Burden Questionnaire (DTBQ), a patient-administered questionnaire composed of 18 questions, and evaluated its reproducibility and validity. METHODS: We enrolled 240 patients with T2DM under pharmacotherapy over 20 years of age at seven institutes in Japan. Their physicians filled out report forms on patient backgrounds, and the patients answered both the DTBQ and the Diabetes Treatment Satisfaction Questionnaire (DTSQ). For evaluation of reproducibility, 48 of the enrolled subjects completed a 2nd DTBQ at home after leaving the medical institutes. RESULTS: Statistical analyses were performed for two sets of subjects, the validity analysis set (N = 236) and the reproducibility analysis set (N = 47). Factor analysis found a simple structure in the DTBQ item scores using a three-factor model with varimax rotation; the three subscales were designated as "implementation burden", "flexibility burden", and "blood glucose control burden". All intraclass correlation coefficients for the subscale scores were 0.8 or higher, indicating high reproducibility. Negative correlations were observed between the DTSQ satisfaction score and the DTBQ subscale scores. Moreover, as the dosing frequency of diabetic medicines increased, the DTBQ total score (total burden score) also became higher. Likewise, expected associations were observed between patient backgrounds and DTSQ scores. CONCLUSION: The DTBQ has adequate reproducibility and validity as a measurement scale for treatment burden on T2DM patients. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN) 000026382. FUNDING: Eli Lilly Japan.

8.
Intern Med ; 56(19): 2563-2569, 2017 Oct 01.
Article in English | MEDLINE | ID: mdl-28883229

ABSTRACT

Objective We investigated the efficacy, safety, and patient satisfaction of once-weekly DPP-4 inhibitors (DPP-4Is). Methods Either of two once-weekly DPP-4Is, trelagliptin or omarigliptin, was administered alone or in combination with other antidiabetic drugs in 80 outpatients with type 2 diabetes mellitus for 3 months. The HbA1c, glycoalbumin (GA), body weight, and the Diabetes Treatment Satisfaction Questionnaire (DTSQ) scores were evaluated. Results Patients switching from other daily DPP-4Is (n=29) showed no significant changes in the HbA1c or GA levels. However, the HbA1c and GA levels of patients who had been naïve to DPP-4Is (n=37) significantly improved from 9.31±2.53% to 7.02±1.20% (p<0.001) and 26.7±11.8% to 17.3±5.7% (p<0.001), respectively. Several non-serious adverse events were reported, including nausea (n=1), abdominal distension (n=1), and constipation (n=1). In the DTSQs, the total score for six questions on the primary factors representing patient treatment satisfaction was not markedly changed in patients switching from daily to weekly DPP-4Is but was significantly improved from 21.0 to 28.0 (p<0.001) in patients naïve to DPP-4Is. Conclusion These findings suggest that the use of a once-weekly DPP-4I is effective and well-tolerated in diabetes treatment and improves treatment satisfaction.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Dipeptidyl-Peptidase IV Inhibitors/therapeutic use , Heterocyclic Compounds, 2-Ring/therapeutic use , Hypoglycemic Agents/therapeutic use , Outpatients/psychology , Patient Satisfaction/statistics & numerical data , Uracil/analogs & derivatives , Adult , Aged , Aged, 80 and over , Body Weight , Female , Humans , Male , Middle Aged , Uracil/therapeutic use
9.
Nagoya J Med Sci ; 79(3): 323-329, 2017 08.
Article in English | MEDLINE | ID: mdl-28878437

ABSTRACT

The Internet of Things (IoT) allows collecting vast amounts of health-relevant data such as daily activity, body weight (BW), and blood pressure (BP) automatically. The use of IoT devices to monitor diabetic patients has been studied, but could not evaluate IoT-dependent effects because health data were not measured in control groups. This multicenter, open-label, randomized, parallel group study will compare the impact of intensive health guidance using IoT and conventional medical guidance on glucose control. It will be conducted in outpatients with type 2 diabetes for a period of 6 months. IoT devices to measure amount of daily activity, BW, and BP will be provided to IoT group patients. Healthcare professionals (HCPs) will provide appropriate feedback according to the data. Non-IoT control, patients will be given measurement devices that do not have a feedback function. The primary outcome is glycated hemoglobin at 6 months. The study has already enrolled 101 patients, 50 in the IoT group and 51 in the non-IoT group, at the two participating outpatient clinics. The baseline characteristics of two groups did not differ, except for triglycerides. This will be the first randomized, controlled study to evaluate IoT-dependent effects of intensive feedback from HCPs. The results will validate a new method of health-data collection and provision of feedback suitable for diabetes support with increased effectiveness and low cost.


Subject(s)
Blood Glucose/analysis , Diabetes Mellitus, Type 2/blood , Internet , Monitoring, Physiologic/methods , Wearable Electronic Devices , Aged , Female , Glycated Hemoglobin/metabolism , Humans , Male , Middle Aged
10.
Intern Med ; 56(6): 597-604, 2017.
Article in English | MEDLINE | ID: mdl-28321056

ABSTRACT

Objective and Methods An SGLT2 inhibitor (ipragliflozin, dapagliflozin, luseogliflozin, tofogliflozin, or canagliflozin) was administered to 132 outpatients with type 2 diabetes mellitus with or without other antidiabetic drugs for 6 months to evaluate its efficacy, the incidence of adverse events, and its influence on the renal function. Results The patient's mean glycated hemoglobin level significantly improved from 7.52±1.16% to 6.95±0.98% (p<0.001). The body weight of the patients was significantly reduced from 78.0±15.3 kg to 75.6±15.1 kg (p<0.001). The estimated visceral fat area was also significantly reduced from 108.4±44.6 cm2 to 94.5±45.3 cm2 (p<0.001). The waist circumference, blood pressure, serum alanine aminotransferase, γ-glutamyl transpeptidase, and uric acid levels also showed a significant decrease. The urinary albumin/creatinine ratio (U-ACR) was significantly reduced in the patients whose U-ACR levels were 30-300 mg/gCr at the baseline. The mean eGFR significantly decreased in the patients with a pre-treatment eGFR value of ≥90 mL/min/1.73 m2 but remained unchanged in the patients with a pre-treatment value of <90 mL/min/1.73 m2. A total of 13 adverse events were noted, including systemic eruption (n=1), cystitis (n=2), pudendal pruritus (n=2), nausea (n=1), malaise (n=1), a strong hunger sensation and increased food ingestion (n=1), and non-serious hypoglycemia (n=5). Conclusion SGLT2 inhibitors seemed to be useful in the treatment of obese type 2 diabetes mellitus patients. Furthermore, these data suggest that SGLT2 inhibitors may protect the renal function.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/pharmacology , Hypoglycemic Agents/therapeutic use , Intra-Abdominal Fat/drug effects , Sodium-Glucose Transporter 2 Inhibitors , Adult , Aged , Aged, 80 and over , Benzhydryl Compounds/pharmacology , Benzhydryl Compounds/therapeutic use , Blood Pressure/drug effects , Body Composition/drug effects , Body Weight , Canagliflozin/pharmacology , Canagliflozin/therapeutic use , Diabetes Mellitus, Type 2/blood , Female , Glomerular Filtration Rate/drug effects , Glucosides/pharmacology , Glucosides/therapeutic use , Glycated Hemoglobin , Humans , Intra-Abdominal Fat/physiopathology , Kidney Function Tests , Male , Middle Aged , Sorbitol/analogs & derivatives , Sorbitol/pharmacology , Sorbitol/therapeutic use , Thiophenes/pharmacology , Thiophenes/therapeutic use
11.
Stem Cell Res Ther ; 6: 162, 2015 Sep 07.
Article in English | MEDLINE | ID: mdl-26345292

ABSTRACT

INTRODUCTION: Dental pulp stem cells (DPSCs) are mesenchymal stem cells located in dental pulp and are thought to be a potential source for cell therapy since DPSCs can be easily obtained from teeth extracted for orthodontic reasons. Obtained DPSCs can be cryopreserved until necessary and thawed and expanded when needed. The aim of this study is to evaluate the therapeutic potential of DPSC transplantation for diabetic polyneuropathy. METHODS: DPSCs isolated from the dental pulp of extracted incisors of Sprague-Dawley rats were partly frozen in a -80 °C freezer for 6 months. Cultured DPSCs were transplanted into the unilateral hindlimb skeletal muscles 8 weeks after streptozotocine injection and the effects of DPSC transplantation were evaluated 4 weeks after the transplantation. RESULTS: Transplantation of DPSCs significantly improved the impaired sciatic nerve blood flow, sciatic motor/sensory nerve conduction velocity, capillary number to muscle fiber ratio and intra-epidermal nerve fiber density in the transplanted side of diabetic rats. Cryopreservation of DPSCs did not impair their proliferative or differential ability. The transplantation of cryopreserved DPSCs ameliorated sciatic nerve blood flow and sciatic nerve conduction velocity as well as freshly isolated DPSCs. CONCLUSIONS: We demonstrated the effectiveness of DPSC transplantation for diabetic polyneuropathy even when using cryopreserved DPSCs, suggesting that the transplantation of DPSCs could be a promising tool for the treatment of diabetic neuropathy.


Subject(s)
Diabetic Neuropathies/therapy , Muscle, Skeletal/physiology , Nerve Regeneration , Sciatic Nerve/physiology , Stem Cell Transplantation/methods , Animals , Cells, Cultured , Cryopreservation/methods , Dental Pulp/cytology , Mesenchymal Stem Cells/cytology , Rats , Rats, Sprague-Dawley
12.
J Diabetes Investig ; 6(2): 140-9, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25802721

ABSTRACT

AIMS/INTRODUCTION: Recent studies have shown that cell transplantation therapies, such as endothelial precursor cells, bone marrow-derived mononuclear cells (BM-MNCs) and mesenchymal stem cells, are effective on diabetic polyneuropathy through ameliorating impaired nerve blood flow in diabetic rats. Here, we investigated the effects of BM-MNCs transplantation in diabetic polyneuropathy using BM-MNCs derived from adult (16-week-old) diabetic (AD), adult non-diabetic (AN) or young (8-week-old) non-diabetic (YN) rats. MATERIALS AND METHODS: BM-MNCs of AD and AN were isolated after an 8-week diabetes duration. The BM-MNCs were characterized using flow cytometry analysis of cell surface markers and reverse transcription polymerase chain reaction of several cytokines. BM-MNCs or saline were injected into hind limb muscles. Four weeks later, the thermal plantar test, nerve conduction velocity, blood flow of the sciatic nerve and capillary-to-muscle fiber ratio were evaluated. RESULTS: The number of CD29(+)/CD90(+) cells that host mesenchymal stem cells in BM-MNCs decreased in AD compared with AN or YN, and transcript expressions of basic fibroblast growth factor and nerve growth factor in BM-MNCs decreased in AD compared with AN or YN. Impaired thermal sensation, decreased blood flow of the sciatic nerve and delayed nerve conduction velocity in 8-week-diabetic rats were significantly ameliorated by BM-MNCs derived from YN, whereas BM-MNCs from AD or AN rats did not show any beneficial effect in these functional tests. CONCLUSIONS: These results show that cytokine production abilities and the mesenchymal stem cell population of BM-MNCs would be modified by aging and metabolic changes in diabetes, and that these differences could explain the disparity of the therapeutic efficacy of BM-MNCs between young and adult or diabetic and non-diabetic patients in diabetic polyneuropathy.

13.
J Clin Periodontol ; 39(4): 342-9, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22276937

ABSTRACT

AIM: Periodontal disease is highly prevalent and severe in diabetic patients, and is considered one of the diabetic complications. To elucidate how periodontitis progresses in diabetes, we examined an animal model of periodontitis in diabetic rats. MATERIALS AND METHODS: Two weeks after the induction of diabetes by streptozotocin, surgical nylon thread was ligated around the cervical portion of the unilateral maxillary second molar to induce periodontitis. Periodontitis was evaluated 2 weeks after the ligation by gingival blood flow, mRNA expressions, Western blot analysis, histological examination and micro CT. RESULTS: Ligation-induced severe periodontitis in the diabetic rats, which was apparently shown by the increase of TNF-α and iNOS mRNA expressions and inflammatory cell infiltration in the gingiva and alveolar bone loss. The number of nitrotyrosine, a footprint of nitrosative stress, -positive cells was significantly higher in the periodontitis of the diabetic rats compared with that in the normal rats. Western blot analysis confirmed that the nitrotyrosine was increased in the periodontitis of the diabetic rats. CONCLUSIONS: This is the first study to confirm increased nitrosative stress due to periodontitis in diabetic rats. Nitrosative stress may play a crucial role in the exacerbation of periodontitis in diabetic patients.


Subject(s)
Diabetes Mellitus, Experimental/complications , Nitric Oxide Synthase Type II/metabolism , Periodontitis/enzymology , Reactive Nitrogen Species/metabolism , Tyrosine/analogs & derivatives , Animals , Diabetes Mellitus, Experimental/enzymology , Disease Models, Animal , Enzyme Activation , Male , Periodontitis/complications , Rats , Rats, Sprague-Dawley , Streptozocin , Stress, Physiological , Tyrosine/genetics , Tyrosine/metabolism
14.
Diabetes Res Clin Pract ; 85(3): 293-7, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19581015

ABSTRACT

AIM: Type 1 diabetes (T1D) is associated with autoimmune thyroid disease (AITD). The human leukocyte antigen (HLA) has been extensively studied in these diseases. We aimed to clarify the contribution of AITD on the susceptibility and resistance of the HLA subtype to autoimmune T1D in the Japanese population. METHODS: The frequency of the HLA DR-DQ haplotype was compared between 56 autoimmune T1D patients with AITD and 71 autoimmune T1D patients without AITD, and control subjects. RESULTS: The frequencies of DRB1 0405-DQB1 0401, DRB1 0802-DQB1 0302, and DRB1 0901-DQB1 0303 haplotypes were significantly higher in T1D patients with AITD than in control subjects. The frequencies of DRB1 0101-DQB1 0501, DRB1 0901-DQB1 0303, and DRB1 1302-DQB1 0604 haplotypes were significantly higher in T1D patients without AITD than in control subjects. The frequencies of DRB1 1101-DQB1 0301 and DRB1 1501-DQB1 0602 haplotypes were significantly lower in T1D patients with or without AITD than in control subjects. CONCLUSIONS: Our results suggest that the susceptibility of the HLA subtype to autoimmune T1D differs between T1D with AITD and T1D without AITD, whereas there is no difference between the two groups with regard to HLA subtypes that confer protection against autoimmune T1D.


Subject(s)
Diabetes Mellitus, Type 1/immunology , Genes, MHC Class II , Thyroiditis, Autoimmune/immunology , Adolescent , Adult , Age of Onset , Aged , Aged, 80 and over , Child , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 1/genetics , Female , Graves Disease/genetics , Graves Disease/immunology , HLA-DQ Antigens/genetics , HLA-DQ Antigens/immunology , HLA-DQ beta-Chains , HLA-DR Antigens/genetics , HLA-DR Antigens/immunology , Humans , Japan , Male , Middle Aged , Thyroiditis, Autoimmune/classification , Thyroiditis, Autoimmune/genetics , Young Adult
15.
Diabetes ; 57(11): 3099-107, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18728233

ABSTRACT

OBJECTIVE: Mesenchymal stem cells (MSCs) have been reported to secrete various cytokines that exhibit angiogenic and neurosupportive effects. This study was conducted to investigate the effects of MSC transplantation on diabetic polyneuropathy (DPN) in rats. RESEARCH DESIGN AND METHODS: MSCs were isolated from bone marrow of adult rats and transplanted into hind limb skeletal muscles of rats with an 8-week duration of streptozotocin (STZ)-induced diabetes or age-matched normal rats by unilateral intramuscular injection. Four weeks after transplantation, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) productions in transplanted sites, current perception threshold, nerve conduction velocity (NCV), sciatic nerve blood flow (SNBF), capillary number-to-muscle fiber ratio in soleus muscles, and sural nerve morphometry were evaluated. RESULTS: VEGF and bFGF mRNA expression were significantly increased in MSC-injected thigh muscles of STZ-induced diabetic rats. Furthermore, colocalization of MSCs with VEGF and bFGF in the transplanted sites was confirmed. STZ-induced diabetic rats showed hypoalgesia, delayed NCV, decreased SNBF, and decreased capillary number-to-muscle fiber ratio in soleus muscles, which were all ameliorated by MSC transplantation. Sural nerve morphometry showed decreased axonal circularity in STZ-induced diabetic rats, which was normalized by MSC transplantation. CONCLUSIONS: These results suggest that MSC transplantation could have therapeutic effects on DPN through paracrine actions of growth factors secreted by MSCs.


Subject(s)
Bone Marrow Cells/metabolism , Diabetic Neuropathies/surgery , Mesenchymal Stem Cell Transplantation/methods , Mesenchymal Stem Cells/metabolism , Animals , Bone Marrow Cells/cytology , Cells, Cultured , Diabetes Mellitus, Experimental/complications , Diabetic Neuropathies/etiology , Diabetic Neuropathies/pathology , Enzyme-Linked Immunosorbent Assay , Fibroblast Growth Factor 2/genetics , Fibroblast Growth Factor 2/metabolism , Male , Mesenchymal Stem Cells/cytology , Muscle, Skeletal/metabolism , Nerve Growth Factor/metabolism , Nerve Growth Factors/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Reverse Transcriptase Polymerase Chain Reaction , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolism
16.
Exp Neurol ; 213(2): 381-7, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18675804

ABSTRACT

BACKGROUND: Schwann cells (SCs) have been supposed to play prominent roles in axonal regeneration under various diseases. Here, to evaluate the direct interaction between SCs and dorsal root ganglion (DRG) neurons under a diabetic condition, the effects of Schwann cell-conditioned media on neurite outgrowth of DRG neurons were investigated. METHODS: Immortalized mouse Schwann cells (IMS) were cultured under 5.5 mM glucose (NG) or 30 mM glucose (HG) conditions for 4 days. IMS-conditioned media (IMS-media) were added to the culture media of neurons isolated from 8-week-old DDY mice. Neurons were cultured for 48 h with or without mouse recombinant NGF (mrNGF) or nerve growth factor (NGF) neutralizing antibody. The concentrations of NGF in IMS-media by ELISA and neurite outgrowth by a computed image analysis system were evaluated. RESULTS: Neurite outgrowth was significantly enhanced by IMS-media (IMS-media (-): 177+/-177 microm, IMS-media (+): 1648+/-726). The neurite outgrowth cultured with IMS-media obtained under the HG condition was significantly reduced compared with that under the NG condition (NG: 1474+/-652, HG: 734+/-331). The NGF concentrations were significantly lower in IMS-media under the HG condition than in those under the NG condition. The accelerated neurite outgrowth by IMS-media was inhibited by NGF neutralizing antibody. CONCLUSIONS: These results suggest that SCs play important roles in neurite outgrowth of DRG neurons, and that the decreased NGF secretion by SCs under the diabetic condition would cause a defect of axonal regeneration, resulting in the development of diabetic neuropathy.


Subject(s)
Ganglia, Spinal/metabolism , Glucose/administration & dosage , Nerve Growth Factors/metabolism , Neurites/metabolism , Neurons/metabolism , Schwann Cells/metabolism , Animals , Cell Line, Transformed , Cells, Cultured , Ganglia, Spinal/drug effects , Ganglia, Spinal/growth & development , Male , Mice , Neurites/drug effects , Neurons/drug effects , Schwann Cells/drug effects
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