Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The limitation of available islets for transplantation is a major obstacle for the treatment of diabetes through islet therapy. However, islet monolayers expanded ex vivo may provide a source of progenitor cells and a model to help understand islet development from precursor cell types. The existence of progenitor cells within the islets is highly likely, yet, to date, no fully defined or characterized postnatal stem cell has been isolated, expanded or marked. Our study evaluates the expression of progenitor markers, including the haematopoietic stem cell marker c-Kit, in epithelial monolayers derived from postnatal rat islets through immunofluorescence and RT-PCR, and the ability of precursor-rich monolayers to reform islet-like structures. Islets formed confluent monolayers when cultured on a type I collagen gel which lacked endocrine phenotypes but were positive for cytokeratin 20 and contained an increased proportion of proliferating c-Kit-expressing cells, with the proportion reaching a maximum of 45+/-6% at 8 weeks of culture. Evaluation of transcription factors at the mRNA level revealed constant PDX-1, ngn3 and Pax4 expression, while undifferentiated cell markers, such as Oct4 and alpha-fetoprotein, were also detected frequently after 4 weeks of culture. Changing the extracellular matrix protein to laminin-rich Matrigel, the monolayers re-formed islet-like clusters that secreted insulin in a glucose-responsive fashion. Our data show that islets can be expanded ex vivo to form epithelial monolayers with rich undifferentiating cell populations that are characterized by cells expressing the progenitor markers. These monolayers are capable of extensive proliferation and retain plasticity to form new islet cells, and c-Kit-expressing cells may play an important role in new islet cluster formation.
 ...
PMID:Phenotypic analysis of c-Kit expression in epithelial monolayers derived from postnatal rat pancreatic islets. 1522 36

Factors affecting bone turnover in premature infants are not entirely clear but certainly are different from those influencing bones of adults and children. To identify fetal and maternal factors that might influence bone turnover, we prospectively studied 50 infants (30 preterm and 20 full-term) born at Ain Shams University Obstetric Hospital in Cairo, Egypt. Maternal parity and medical history and infant's weight, gestational age, gender and anthropometrical measurements were recorded. Cord blood samples were collected and serum type I collagen C-terminal propeptide (PICP) was assessed as a marker for fetal bone formation. First morning urine samples were collected and pyridinoline cross-links of collagen (Pyd) were measured as an index for bone resorption. Serum PICP was higher in premature infants when compared with full-term infants (73.30 +/- 15.1 versus 64.3 +/- 14.7, p = 0.022) and was higher in male premature infants when compared with females (81.64 +/- 9.06 versus 66.0 +/- 15.7, p = 0.018). In a multiple regression model using PICP as the dependent variable and controlling for different infant and maternal conditions, PICP significantly correlated with infant gender (r = 8.26 +/- 4.1, p = 0.05) maternal parity (r = -2.106 +/- 0.99, p = 0.041) and diabetes (r = 22.488 +/- 8.73, p = 0.041). Urine Pyd tended to increase in premature infants (612 +/- 308 versus 434 +/- 146, p = 0.057) and correlated significantly with gestational age (r = -63.93 +/- 19.55, p = 0.002). Therefore, bone formation (PICP) is influenced by fetal age and gender, as well as maternal parity and diabetes. Bone resorption (Pyd) is mostly dependent on gestational age only. Further in-depth studies are needed to enrich management of this vulnerable population.
 ...
PMID:Gestational age, sex and maternal parity correlate with bone turnover in premature infants. 1577 20

The present study was performed to investigate the effects of the antiallergic drug tranilast on the development of diabetic nephropathy in streptozotocin (50 mg/kg)-induced diabetic spontaneously hypertensive rats (SHR). Diabetic SHR were given standard chow or chow containing tranilast at a dose of 1400 mg/kg for 24 weeks. The effects of tranilast on urinary albumin excretion, mesangial expansion, expression of transforming growth factor-beta (TGF-beta) and type I collagen mRNAs, number of anionic sites on the glomerular basement membrane (GBM), and urinary TGF-beta and 8-hydroxy-2'-deoxyguanosine (8-OHdG) excretion were assessed. Tranilast did not affect the blood glucose concentration or blood pressure in diabetic SHR. Urinary albumin excretion rate and creatinine clearance were markedly increased in diabetic SHR. Tranilast treatment decreased albuminuria and hyperfiltration. Tranilast inhibited the diabetes-induced expansion of mesangial and tuft areas, as well as the increase in urinary TGF-beta and 8-OHdG excretion, loss of anionic sites of GBM, and overexpression of TGF-beta as determined immunohistochemically. The levels of TGF-beta and type I collagen mRNA expression were increased in the renal cortex in untreated diabetic SHR at 24 weeks, as determined by real-time quantitative polymerase chain reaction. Tranilast treatment inhibited the up-regulation of TGF-beta and type I collagen mRNA expression by 65 and 36%, respectively, in diabetic SHR. In conclusion, tranilast decreased albuminuria by suppressing glomerular hyperfiltration, mesangial expansion, and loss of the charge barrier via regulation of extracellular matrix gene expression and oxidative stress. Tranilast may be clinically useful in the treatment of diabetic nephropathy.
 ...
PMID:Tranilast prevents the progression of experimental diabetic nephropathy through suppression of enhanced extracellular matrix gene expression. 1585 46

To clarify the pathogenesis of altered bone metabolism in diabetic state and its underlying mechanisms, the bone mineral content and fasting levels of serum intact parathyroid hormone (i-PTH), intact osteocalcin (i-OC), tartrate-resistant acid phosphatase (TRAP) and osteoclastgenesis inhibitory factor/osteoprotegerin (OCIF/OPG) were measured in male type 2 diabetic patients and their age-matched controls. In addition, urine levels of osteoclastic markers, C-telopeptide of type I collagen (CTx), deoxypyridinoline (DPD), and N-telopeptide of type I collagen (NTx) were simultaneously determined. Serum levels of i-PTH and i-OC in diabetic patients were significantly lower than those in the controls. Conversely, serum concentrations of TRAP were significantly elevated in diabetic patients. However, no clear correlation was observed between serum i-OC and TRAP. It was also observed that urinary excretion of CTx, DPD, and NTx was significantly increased in the diabetics as compared with the controls. Unexpectedly, serum levels of OCIF/OPG tended to be higher in the diabetic group, and these values exhibited a significantly positive correlation with those of serum TRAP. There was found a significantly negative correlation between serum TRAP and bone mineral density (BMD) and also between serum OCIF/OPG and bone mineral density. It seems probable that OCIF/OPG has a suppressive role on the increased bone resorption to prevent further loss of the skeletal bone mass in type 2 diabetic patients.
Diabetes Res Clin Pract 2005 May
PMID:Osteoclastic function is accelerated in male patients with type 2 diabetes mellitus: the preventive role of osteoclastogenesis inhibitory factor/osteoprotegerin (OCIF/OPG) on the decrease of bone mineral density. 1586 Feb 39

With decrease of serum PTH in hemodialysis (HD) patients, other factors besides parathyroid hormone (PTH) become important in regulating bone metabolism. We investigated which serum bone metabolic marker is the best to predict the bone mineral density (BMD) reduction in HD patients with serum PTH<180 pg/ml. The bone formation markers, bone alkaline phosphatase (BAP), intact osteocalcin (OC), and N-terminal propeptide of type I collagen (PINP), and the bone resorption markers, deoxypyridinoline (DPD), pyridinoline (PYD), and beta-crossLaps (beta-CTx) were measured in serum from 137 HD patients. BMD of all patients was measured twice, approximately 1.5 years before and 1.5 years after measurement of their markers of bone metabolism. In all 137 HD patients, serum BAP was the only marker significantly higher in those with BMD reduction than in those without. In 42 diabetes mellitus (DM) HD patients with serum PTH<180 pg/ml, hypothetically low bone turnover state, serum BAP was again the only marker to discriminate those with BMD reduction from those without. At serum PTH<60 pg/ml, serum BAP retained tendency toward higher value. These findings suggest that serum BAP might be the most sensitive to identify small changes of bone metabolism in low bone turnover state. Retrospective study confirmed the usefulness of serum BAP in clinical practice by significantly higher values in those with bone loss at PTH<180 pg/ml even in under routine sample handling. In conclusion, serum BAP is a clinically useful bone formation marker to predict the BMD reduction in DM HD patients with low level of PTH.
 ...
PMID:Serum BAP as the clinically useful marker for predicting BMD reduction in diabetic hemodialysis patients with low PTH. 1597 65

The effects of type 1 diabetes on de novo bone formation during tibial distraction osteogenesis (DO) and on intact trabecular and cortical bone were studied using nonobese diabetic (NOD) mice and comparably aged nondiabetic NOD mice. Diabetic mice received treatment with insulin, vehicle, or no treatment during a 14-day DO procedure. Distracted tibiae were analyzed radiographically, histologically, and by microcomputed tomography (microCT). Contralateral tibiae were analyzed using microCT. Serum levels of insulin, osteocalcin, and cross-linked C-telopeptide of type I collagen were measured. Total new bone in the DO gap was reduced histologically (P < or = 0.001) and radiographically (P < or = 0.05) in diabetic mice compared with nondiabetic mice but preserved by insulin treatment. Serum osteocalcin concentrations were also reduced in diabetic mice (P < or = 0.001) and normalized with insulin treatment. Evaluation of the contralateral tibiae by microCT and mechanical testing demonstrated reductions in trabecular bone volume and thickness, cortical thickness, cortical strength, and an increase in endosteal perimeter in diabetic animals, which were prevented by insulin treatment. These studies demonstrate that bone formation during DO is impaired in a model of type 1 diabetes and preserved by systemic insulin administration.
Diabetes 2005 Oct
PMID:Bone formation is impaired in a model of type 1 diabetes. 1618 88

The vitamin D binding protein (DBP) is the major carrier protein for vitamin D metabolites in plasma. Polymorphisms in DBP have been described to be associated with an increased bone fracture risk and diabetes. The present study investigates the influence of both phenotypic and (TAAA)(n)-Alu repeat DBP-polymorphism and DBP-concentration on bone mineral density, body composition, bone turnover- and metabolic markers in a cohort of ambulatory elderly men. We included 211 men (>70 years) in this study. Bone mineral density (BMD) was determined by dual energy X-ray absorptiometry. Bone turnover was assessed by measurement of serum osteocalcin, serum and urinary C-terminal telopeptides of type I collagen and urinary deoxypyridinoline, together with 25(OH)-vitamin D and 1,25(OH)(2)-vitamin D concentrations. DBP-phenotypes were determined electrophoretically and the (TAAA)(n)-Alu repeat polymorphism was determined by polymerase chain reaction. Body composition was estimated using bioelectrical impedance analysis, together with handgrip and arm strength, fasting serum glucose and leptin concentrations. No differences in BMD or bone turnover markers among DBP-phenotypes or (TAAA)(n)-genotypes were observed in this study. Serum 25(OH)-vitamin D was comparable among DBP-variants and did not relate to DBP-concentrations, whereas 1,25(OH)(2)-vitamin D was different among DBP-phenotypes and was correlated positively with DBP-concentrations. DBP-concentrations related positively to body mass index, fat mass, leptin and glucose concentration. The correlation with leptin remained significant after correction for fat mass. Fasting glucose concentrations were different among DBP-phenotypes, whereas no difference was observed between (TAAA)(n)-genotypes. In conclusion, serum 1,25(OH)(2)-vitamin D concentrations are codetermined by DBP-phenotypes and DBP-concentrations. No major effect of DBP-polymorphism was demonstrated on BMD, bone turnover markers or body composition.
 ...
PMID:Vitamin D binding protein, bone status and body composition in community-dwelling elderly men. 1630 86

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the ligand-activated nuclear receptor superfamily, and plays an important role in lipid metabolism and glucose homeostasis. The purpose of this study is to determine whether the activation of PPARalpha by fenofbrate would improve diabetes and its renal complications in type II diabetes mellitus. Male C57 BLKS db/db mice and db/m controls at 8 weeks of age were divided to receive either a regular diet chow (db/db, n=8; db/m, n=6) or a diet containing fenofibrate (db/db, n=8; db/m, n=7). Mice were followed for 8 weeks. Fenofibrate treatment dramatically reduced fasting blood glucose (P<0.001) and HbA1c levels (P<0.001), and was associated with decreased food intake (P<0.01) and slightly reduced body weight. Fenofibrate also ameliorated insulin resistance (P<0.001) and reduced plasma insulin levels (P<0.05) in db/db mice. Hypertrophy of pancreatic islets was decreased and insulin content markedly increased (P<0.05) in fenofibrate-treated diabetic animals. In addition, fenofibrate treatment significantly reduced urinary albumin excretion (P<0.001). This was accompanied by dramatically reduced glomerular hypertrophy and mesangial matrix expansion. Furthermore, the addition of fenofibrate to cultured mesangial cells, which possess functional active PPARalpha, decreased type I collagen production. Taken together, the PPARalpha agonist fenofibrate dramatically improves hyperglycemia, insulin resistance, albuminuria, and glomerular lesions in db/db mice. The activation of PPARalpha by fenofibrate in mesangial cells may partially contribute to its renal protection. Thus, fenofibrate may serve as a therapeutic agent for type II diabetes and diabetic nephropathy.
 ...
PMID:PPARalpha agonist fenofibrate improves diabetic nephropathy in db/db mice. 1667 17

Type I collagen, the major organic component of bone matrix, undergoes a series of post-translational modifications that occur with aging, such as the non-enzymatic glycation. This spontaneous reaction leads to the formation of advanced glycation end products (AGEs), which accumulate in bone tissue and affect its structural and mechanical properties. We have investigated the role of matrix AGEs on bone resorption mediated by mature osteoclasts and the effects of exogenous AGEs on osteoclastogenesis. Using in vitro resorption assays performed on control- and AGE-modified bone and ivory slices, we showed that the resorption process was markedly inhibited when mature osteoclasts were seeded on slices containing matrix pentosidine, a well characterized AGE. More specifically, the total area resorbed per slice, and the area degraded per resorption lacuna created by osteoclasts, were significantly decreased in AGE-containing slices. This inhibition of bone resorption was confirmed by a marked reduction of the release of type I collagen fragments generated by the collagenolytic enzymes secreted by osteoclasts in the culture medium of AGE-modified mineralized matrices. This effect is likely to result from decreased solubility of collagen molecules in the presence of AGEs, as documented by the reduction of pepsin-mediated digestion of AGE-containing collagen. We found that AGE-modified BSA totally inhibited osteoclastogenesis in vitro, most likely by impairing the commitment of osteoclast progenitors into pre-osteoclastic cells. Although the mechanisms remain unknown, AGEs might interfere with osteoclastic differentiation and activity through their interaction with specific cell-surface receptors, because we showed that both osteoclast progenitors and mature osteoclasts expressed different AGEs receptors, including receptor for AGEs (RAGEs). These results suggest that AGEs decreased osteoclast-induced bone resorption, by altering not only the structural integrity of bone matrix proteins but also the osteoclastic differentiation process. We suggest that AGEs may play a role in the alterations of bone remodeling associated with aging and diabetes.
 ...
PMID:Non-enzymatic glycation of bone collagen modifies osteoclastic activity and differentiation. 1714 54

The aim of the present study was to evaluate relationships between serum endogenous androgens and urinary concentration of cross-linked N-telopeptides of type I collagen (NTx), a bone resorption marker, in men with type 2 diabetes mellitus because low androgen concentrations are associated with both osteoporosis and cardiovascular disease. Relationships between serum free testosterone and urinary NTx concentrations were investigated in 246 consecutive men with type 2 diabetes mellitus. In addition, relationships between urinary NTx concentration and other variables including age, duration of diabetes, blood pressure, serum lipid concentration, hemoglobin A(1c), and body mass index were evaluated. Urinary NTx concentrations were 27.8 (26.4-29.3) nmol of bone collagen equivalent per millimole of creatinine, correlating inversely with serum free testosterone (r = -0.263, P < .0001). Multiple regression analysis identified serum free testosterone (beta = -.292, P < .0001), hemoglobin A(1c) (beta = .144, P = .0404), and smoking status (beta = .143, P = .0402) as independent determinants of urinary NTx. In conclusion, serum free testosterone concentration correlated inversely with urinary NTx concentration, which may partly account for an observed link between osteoporosis and cardiovascular disease in men with type 2 diabetes mellitus.
 ...
PMID:Association between serum testosterone concentration and collagen degradation fragments in men with type 2 diabetes mellitus. 1769 66


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>