Microvascular complications in diabetes are associated with poor long-term diabetes control as measured by HbA1c levels. Glucose fluctuations are related to oxidative stress, endothelial dysfunction, and inflammation, factors traditionally associated with the pathogenesis of vascular damage. Glucose variability has been associated with macrovascular disease in some studies but any association with microvascular disease remains controversial. This overview summarizes recent findings in the field of glucose variability and its possible relationship with retinopathy, nephropathy and neuropathy. It is concluded that randomized prospective follow-up trials could possibly help estimate whether short-term glucose variability should be considered as an independent risk factor for microvascular complications in diabetes.

• Klíčová slova
• Glucose variability, HbA1c variability, Microvascular complications, Type 1 and Type 2 diabetes,
• MeSH
• diabetické angiopatie metabolismus   MeSH
• glykovaný hemoglobin metabolismus   MeSH
• krevní glukóza metabolismus   MeSH
• lidé MeSH
• mikrocévy patologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• glykovaný hemoglobin MeSH
• hemoglobin A1c protein, human MeSH Prohlížeč
• krevní glukóza MeSH

Microvascular diabetes complications are linked to inadequate long-term diabetes control, as indicated by glycated haemoglobin (HbA1c) levels. Fluctuations in glucose levels are connected to oxidative stress, endothelial dysfunction, and inflammation, all of which are traditionally linked to the development of vascular damage. While some studies have linked glucose variability to macrovascular disease, its association with microvascular disease is still debated. The major question is whether short-term glucose variability should be regarded as an independent risk factor for microvascular complications in diabetes. This summary reviews research on glucose variability and its potential connections to diabetic retinopathy, nephropathy, and neuropathy. Current data indicate the need for further research into the parameters of both short-term and long-term glucose variability. These variability parameters may be important for selecting optimal treatment strategies and for estimating the risk of chronic diabetic complications.

• Klíčová slova
• glucose variability, glycated hemoglobin HbA1c, microvascular complications, diabetes mellitus,
• MeSH
• diabetická retinopatie etiologie   metabolismus   MeSH
• diabetické angiopatie * etiologie   patofyziologie   MeSH
• diabetické nefropatie metabolismus   patofyziologie   etiologie   MeSH
• diabetické neuropatie etiologie   patofyziologie   metabolismus   MeSH
• krevní glukóza * metabolismus   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• krevní glukóza * MeSH

AIMS: Glycaemic variability (GV) has been hypothesized to increase the risk of diabetes complications; however, results of clinical studies are contradictory. The effect of GV on cell phenotypes has been investigated in vitro showing that GV may have more deleterious effect on cells that high glucose itself. However, methodology used to study GV in vitro differs significantly between studies and does not reflect in vivo situation. Therefore we aimed to establish clinically relevant an in vitro experimental approach for the study of GV that reflects intra-day glucose fluctuations of subjects with type 1 diabetes mellitus (T1DM) and of healthy subjects and to test how low and high GV affect expression of genes that protects cells from hyperglycaemia-induced damage. METHODS: Human umbilical vein endothelial cells (HUVEC) were cultured 24h in medium with different glucose profiles: high GV, low GV and GV of healthy subjects-profiles created according to CGM of T1DM patients and healthy subjects. These profiles were compared to commonly used 5.5 and 25mmol/l glucose concentrations. Gene expression was determined using quantitative PCR. RESULTS: Our results showed general down-regulation of enzymes that are involved in the protection against hyperglycaemia-induced intracellular changes in both low and high GV compared to normal glycaemia similarly to the decrease induced by continuous hyperglycaemia. Gene expressions did not differ between high and low GV. CONCLUSION: Our data indicate that GV may have similar or even greater effect than continuous hyperglycaemia on the expression of several genes relevant to pathogenesis of diabetes microvascular complications.

• Klíčová slova
• Continuous glucose monitoring, Diabetes complications, Glycaemic variability, Hyperglycaemia, Hypoglycaemia, Pentose phosphate pathway,
• MeSH
• apoptóza účinky léků   MeSH
• biologické markery metabolismus   MeSH
• diabetes mellitus 1. typu komplikace   farmakoterapie   patofyziologie   MeSH
• endoteliální buňky pupečníkové žíly (lidské) účinky léků   metabolismus   MeSH
• glukosa škodlivé účinky   MeSH
• hyperglykemie etiologie   patologie   MeSH
• hypoglykemie etiologie   patologie   MeSH
• krevní glukóza metabolismus   MeSH
• kultivované buňky MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proliferace buněk účinky léků   MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• stanovení celkové genové exprese MeSH
• studie případů a kontrol MeSH
• techniky in vitro MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• biologické markery MeSH
• glukosa MeSH
• krevní glukóza MeSH
• messenger RNA MeSH

• MeSH
• chronické selhání ledvin * terapie   MeSH
• diabetes mellitus 2. typu * komplikace   MeSH
• dialýza ledvin MeSH
• glukosa MeSH
• krevní glukóza MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• dopisy MeSH
• komentáře MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glukosa MeSH
• krevní glukóza MeSH

AIM: The aim of this pilot study was to acquire insight into the parameters of glycaemic control, especially, (1) the time delay (lag phase) between plasma and tissue glucose concentrations in relation to rise and fall in glucose levels and (2) the rate of glucose increase and decrease. METHODS: Four healthy people (HP), 4 people with type 1diabetes (DM1) and 4 with type 2 diabetes (DM2) underwent concurrent glucose measurements by means of (1) the continuous glucose monitoring system (CGMS-Medtronic), Medtronic-Minimed, CA, USA, calibrated by the glucometer Calla, Wellion, Austria, and, (2) the Beckman II analyser to measure glucose concentrations in venous plasma. Samples were taken on 4 consecutive days in the fasting state and 4 times after consumption of 50 g glucose. Carelink Personal, MS Excel, Maple and Mat lab were applied to plot the evolution of glucose concentration and analyse the results. The time difference between increase and decrease was calculated for HP, DM 1 and DM 2. RESULTS: In DM1and DM2, glucose tolerance testing (GTT) resulted in slower transport of glucose into subcutaneous tissue than in HP where the lag phase lasted up to 12 min. The maximum increase/decrease rates in DM1 and DM2 vs HP were 0.25 vs < 0.1 mmol/L/min. CONCLUSION: CGMS is shown to provide reliable plasma glucose concentrations provided the system is calibrated during a steady state. The analysis of glucose change rates improves understanding of metabolic processes better than standard GTT.

• Klíčová slova
• calibration, continuous glucose monitoring, diabetes mellitus, glucose transport, lag phase,
• MeSH
• časové faktory MeSH
• diabetes mellitus 1. typu metabolismus   MeSH
• diabetes mellitus 2. typu metabolismus   MeSH
• krevní glukóza metabolismus   MeSH
• lidé MeSH
• omezení příjmu potravy metabolismus   MeSH
• pilotní projekty MeSH
• průřezové studie MeSH
• selfmonitoring glykemie MeSH
• subkutánní tkáň metabolismus   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky kontrolované MeSH
• práce podpořená grantem MeSH
• Názvy látek
• krevní glukóza MeSH

the work has been aimed to create an overview of available and used methods and ways to determine the concentration of glucose in body fluids, especially from a technical point of view. It also provides an overview of the clinical features of these methods. The survey found that today's market offers a large number of options and approaches to the issue. There are accurate reference laboratory methods, self-monitoring methods for measuring glucose levels using glucometers, or continuous methods for daily monitoring of blood glucose trends and for insulin pump control. However, it must not be forgotten that the development of full closure of feedback is still not complete today. Individual methods cannot always be compared with each other, precisely because of the focus and the use of these methods. Choosing the right method of blood glucose levels in the body measuring can help patients to manage their diabetes mellitus. The methods listed in the overview are divided in terms of measurement continuity and further according to the invasiveness of the method. Finally, the issues of accuracy in the detection of glycaemia variability and the possibility of further development of these methods are discussed, as it is clear from the survey that the development is focused mainly on continuous methods improving that get to the forefront and also on developing a biosensor that is purely non-invasive and continuous.

• Klíčová slova
• Continuous glucose monitoring (CGM), Glucose monitoring, Glucose selfmonitoring (SMBG), Glycemic control, Non-invasive measurement glucose,
• MeSH
• biosenzitivní techniky * MeSH
• diabetes mellitus 1. typu * MeSH
• glukosa MeSH
• hypoglykemika MeSH
• inzulin MeSH
• krevní glukóza MeSH
• lidé MeSH
• selfmonitoring glykemie metody   MeSH
• tělesné tekutiny * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• glukosa MeSH
• hypoglykemika MeSH
• inzulin MeSH
• krevní glukóza MeSH

Evolution of heterothermy in environments with variable temperatures has allowed bats to survive food scarcity during seasonal climatic extremes by using torpor as a hibernation strategy. The controlled reduction of body temperature and metabolism through complex behavioural and physiological adaptations at organismal, organ, cellular and molecular levels includes the ability of tissues and cells to adapt to temperature alterations. Based on the prediction that cells of different tissues cultured in vitro would differ in their ability to withstand freezing and thawing of the medium, we determined the survival rate of bat-derived cells following exposure to -20 °C for 24 h in media with no cryoprotective agents or medium supplemented by glucose in concentration range 0-3333 mM. Cell survival rates were determined in relation to availability of glucose in the medium, organ origin, cell concentration and bat species. In general, increased glucose helped cells survive at sub-zero temperatures, though concentrations up to 80-fold higher than those found in chiropterans were needed. However, cells in glucose-free phosphate buffered saline also survived, suggesting that other mechanisms may be contributing to cell survival at low temperatures. Highest in vitro viability was observed in nervus olfactorius-derived cell cultures, with high survival rates and rapid re-growth under optimal conditions after exposure to -20 °C. Kidney cells from different bat species showed comparable overall survival rate patterns, though smaller chiropteran species appeared to utilise lower glucose levels as a cryoprotectant than larger species. Our in vitro data provide evidence that cells of heterothermic bats can survive sub-zero temperatures and that higher glucose levels in important tissues significantly improve hibernation survival at extremely low temperatures.

• Klíčová slova
• Cell culture, Cryoprotectant, Glucose, Heterothermy, Hibernation, In vitro model,
• MeSH
• Chiroptera * fyziologie   MeSH
• fyziologická adaptace fyziologie   MeSH
• glukosa metabolismus   MeSH
• hibernace * fyziologie   MeSH
• strnulost * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa MeSH

BACKGROUND: Glucose variability combined with glycosylated hemoglobin (HbA1c) assessments more reliably represents the level of glycemic control. The study was aimed to compare blood glucose variability with insulin glargine vs. neutral protamine Hagedorn (NPH) in patients with type 2 diabetes mellitus using a continuous glucose-monitoring system (CGMS), in patients treated with basal insulin using stable dose of oral antidiabetic agents and HbA1c in the range of 4.5-8.0 % International Federation of Clinical Chemistry (IFCC) units. [6.2-9.4 % Diabetes Control and Complications Trial (DCCT) units]. METHODS: This was a multicenter, prospective, open-label, single-arm study in patients (N = 116) treated for ≥ 2 months with NPH and metformin combined with sulfonylurea or glinide. Glucose variability was measured after a 4-week NPH treatment phase and after a subsequent 12-week glargine treatment phase using CGMS. Based on 72-hour CGMS, glucose variability was assessed by area under the curve [AUC (mmol/L · h)]. Differences (glargine-NPH) in AUC within 24 h in the glucose ranges of ≤ 3.3, ≤ 3.9, 7.5-3.9 (margins excluding), ≥ 7.5, ≥ 10, and ≥ 15 mmol/L were evaluated. Circadian fluctuation of glucose was assessed by M-value (log-transformation of the deviation from an arbitrary standard). RESULTS: AUCs of glucose in the lowest ranges (≤ 3.3 and ≤ 3.9 mmol/L) did not change significantly after treatment with glargine. Those in the higher ranges (≥ 7.5, ≥ 10, and ≥ 15 mmol/L) were significantly lower (p < 0.001 for all ranges), whereas AUC of glucose in the normal range (3.9-7.5 mmol/L) was significantly higher (p < 0.001) at the end of glargine treatment phase. Circadian fluctuation of glucose assessed by M-value showed a significant decrease after glargine treatment (p < 0.003). No significant differences in hypoglycemia confirmed by glucose value ≤ 3.3 mmol/L were found between treatment phases. This trial is registered at ClinicalTrials.gov, NCT00659477. CONCLUSIONS: As monitored by CGMS, switching from NPH to glargine with active titration shifted glucose from abnormally high to normal levels with reduced fluctuation and without increased risk of hypoglycemia.

• MeSH
• diabetes mellitus 2. typu krev   diagnóza   farmakoterapie   MeSH
• dlouhodobě působící inzulin aplikace a dávkování   MeSH
• dospělí MeSH
• hypoglykemika aplikace a dávkování   MeSH
• inzulin glargin MeSH
• krevní glukóza analýza   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• monitorování léčiv metody   MeSH
• náhrada léků MeSH
• NPH inzulin aplikace a dávkování   MeSH
• reprodukovatelnost výsledků MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• senzitivita a specificita MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky kontrolované MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• dlouhodobě působící inzulin MeSH
• hypoglykemika MeSH
• inzulin glargin MeSH
• krevní glukóza MeSH
• NPH inzulin MeSH

BACKGROUND: The MTNR1B gene encodes a receptor for melatonin, a hormone regulating biorhythms. Disruptions in biorhythms contribute to the development of type 2 diabetes mellitus (T2DM). Genetic studies suggest that variability in the MTNR1B gene affects T2DM development. Our aim was to compare the distribution of the genetic variant rs10830963 between persons differing in glucose tolerance in a sample of the Czech population (N=1206). We also evaluated possible associations of the polymorphism with insulin sensitivity, beta cell function, with the shape of glucose, insulin and C-peptide trajectories measured 7 times during a 3-hour oral glucose tolerance test (OGTT) and with glucagon response. In a subgroup of 268 volunteers we also evaluated sleep patterns and biorhythm. RESULTS: 13 persons were diagnosed with T2DM, 119 had impaired fasting blood glucose (IFG) and/or impaired glucose tolerance (IGT). 1074 participants showed normal results and formed a control group. A higher frequency of minor allele G was found in the IFG/IGT group in comparison with controls. The GG constellation was present in 23% of diabetics, in 17% of IFG/IGT probands and in 11% of controls. Compared to CC and CG genotypes, GG homozygotes showed higher stimulated glycemia levels during the OGTT. Homozygous as well as heterozygous carriers of the G allele showed lower very early phase of insulin and C-peptide secretion with unchanged insulin sensitivity. These differences remained significant after excluding diabetics and the IFG/IGT group from the analysis. No associations of the genotype with the shape of OGTT-based trajectories, with glucagon or with chronobiological patterns were observed. However, the shape of the trajectories differed significantly between men and women. CONCLUSION: In a representative sample of the Czech population, the G allele of the rs10830963 polymorphism is associated with impaired early phase of beta cell function, and this is evident even in healthy individuals.

• Klíčová slova
• MTNR1B gene, OGTT trajectories, beta cell function, glucose tolerance, insulin sensitivity, rs10830963, type 2 daibetes mellitus,
• MeSH
• C-peptid MeSH
• diabetes mellitus 2. typu * epidemiologie   genetika   MeSH
• glukagon MeSH
• glukosa MeSH
• inzulin MeSH
• inzulinová rezistence * genetika   MeSH
• kinetika MeSH
• krevní glukóza MeSH
• lidé MeSH
• porucha glukózové tolerance * epidemiologie   genetika   MeSH
• prediabetes * MeSH
• receptor melatoninový MT2 * genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• C-peptid MeSH
• glukagon MeSH
• glukosa MeSH
• inzulin MeSH
• krevní glukóza MeSH
• MTNR1B protein, human MeSH Prohlížeč
• receptor melatoninový MT2 * MeSH

The pancreas, liver and hypothalamus have a regulatory function in the glucose homeostasis. As the blood glucose level changes, these compartments react and the level changes again. Subsequently to this reaction, the interstitial glucose level changes with some delay. In this paper, I propose a hypothesis that the change of the blood glucose level includes information about the estimated rate with which the hypothalamus expects the blood glucose level to return to normal range, by means of regulatory mechanisms of glucose homeostasis. As the interstitial glucose level change reflects the blood glucose level change, I propose a method to estimate the blood-to-interstitial glucose level delay. It is an important factor for glucose level prediction. Once the delay was calculated, it was possible to relate the present blood glucose level and future interstitial glucose level with such coefficients, which do not seem to change over the time of the experiment to a significant extent. Perhaps, it is a parameterization of regulatory processes of glucose homeostasis, which could be possibly encoded within hypothalamus set-points. The delays were constant per subject and ranged from 7 min up to 34 min for hereditary hypertriglyceridemic rats of 230-480 g weight, in experiments with a variable glucose infusion rate.

• MeSH
• biologické modely * MeSH
• extracelulární tekutina metabolismus   MeSH
• homeostáza fyziologie   MeSH
• hypertriglyceridemie krev   MeSH
• hypothalamus metabolismus   MeSH
• játra metabolismus   MeSH
• krevní glukóza metabolismus   fyziologie   MeSH
• krysa rodu Rattus MeSH
• monitorování fyziologických funkcí MeSH
• pankreas metabolismus   MeSH
• reakční čas MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• krevní glukóza MeSH