Fructosamine and glycated hemoglobin in the assessment of glycaemic control in dogs

Fructosamine and glycated hemoglobin (HbA1c) concentrations were measured simultaneously in 222 dogs (96 healthy and 126 sick dogs). The dogs were divided into 3 groups according to the glucose concentration: hypo, hyper and euglycaemic dogs. Serum fructosamine concentrations were measured by the reduction test with nitroblue tetrazolium. A turbidimetric inhibition immunoassay and specific polyclonal antibodies were used to evaluate glycated hemoglobin concentrations. A significant correlation was found between glucose concentration and either fructosamine (r = 0.63, p < 0.0001) or glycated hemoglobin (r = 0.82, p < 0.0001). The correlation was higher in hyperglycaemic dogs for fructosamine (r = 0.80, p < 0.0001) and in hypoglycaemic dogs for glycated hemoglobin (r = 0.91, p < 0.005). We found a significant correlation between serum fructosamine and glycated hemoglobin (r = 0.65, p < 0.0001 ) when all the dogs were studied. A significant correlation was observed between serum fructosamine and glycated hemoglobin only in hyperglycaemic dogs (r = 0.82, p < 0.0003). Thus, fructosamine and HbA1c may be considered for use in screening tests for diabetes mellitus in dogs and clinical tests for monitoring control and evaluation of the diabetic animal's response to treatment. The choice of the analytical assay depends on the characteristic and analytical opportunities of the laboratory, as well as the number of serum samples to be analysed.     

Reliability of history and physical examination findings for assessing control of glycemia in dogs with diabetes mellitus: 53 cases (1995-1998)

OBJECTIVE: To evaluate the reliability of history and physical examination findings for assessing control of glycemia in insulin-treated diabetic dogs. DESIGN: Retrospective study. ANIMALS: 53 insulin-treated dogs with diabetes mellitus. PROCEDURE: Medical records of insulin-treated diabetic dogs from June 1995 to June 1998 were reviewed, and information on owner perception of their dog's response to insulin treatment, physical examination findings, body weight, insulin dosage, and concentrations of food-withheld (i.e., fasting) blood glucose (FBG), mean blood glucose (MBG) during an 8-hour period, blood glycosylated hemoglobin (GHb), and serum fructosamine was obtained. Owner's perception of their dog's response to insulin treatment, physical examination findings, and changes in body weight were used to classify control of glycemia as good or poor for each dog. The FBG, MBG/8 h, blood GHb, and serum fructosamine concentrations were compared between well-controlled and poorly controlled insulin-treated diabetic dogs. RESULTS: Presence or absence of polyuria, polydipsia, polyphagia, lethargy, and weakness were most helpful in classifying control of glycemia. Mean FBG and MBG/8 h concentrations, blood GHb concentrations, and serum fructosamine concentrations were significantly decreased in 25 well-controlled diabetic dogs, compared with 28 poorly controlled diabetic dogs. Most well-controlled diabetic dogs had concentrations of FBG between 100 and 300 mg/dl, MBG/8 h < or = 250 mg/dl, blood GHb < or = 7.5%, and serum fructosamine < or = 525 mumol/L, whereas most poorly controlled diabetic dogs had results that were greater than these values. CONCLUSIONS AND CLINICAL RELEVANCE: Reliance on history, physical examination findings, and changes in body weight are effective for initially assessing control of glycemia in insulin-treated diabetic dogs.     

Evaluation of a disposable device for the measurement of haemoglobin A1c in dogs

A disposable device designed for measuring glycated haemoglobin (hba1c) in human blood was evaluated for use in dogs. edta blood samples were collected from 50 normoglycaemic dogs, 10 dogs suffering from anaemia and 112 diabetic dogs. hba1c was measured in all the dogs except for five of the diabetic animals, in which the concentrations were above the range of the device, that is, more than 13 per cent, and two of the anaemic dogs, in which they were below its limit of detection, that is less than 3 per cent. The diabetic dogs had higher hba1c values (range 4.9 to >13 per cent, median 9.3 per cent) than the normoglycaemic dogs (range 3.7 to 5.6 per cent, median 4.7 per cent). In the anaemic dogs the values were significantly lower (range <3.0 per cent to 5.2 per cent, median 3.5 per cent) than in the normoglycaemic dogs. There was a good correlation (R(2)=0.48) between the measurements obtained with the device and the measurements obtained with a system already validated for use in dogs.     

Study of the effect of total serum protein and albumin concentrations on canine fructosamine concentration.

The relationship among serum fructosamine concentration and total serum protein and albumin concentrations were evaluated in healthy and sick dogs (diabetics and dogs with insulinoma were not included). Fructosamine was determined using a commercial colorimetric nitroblue tetrazolium method applied to the Technicon RA-500 (Bayer). Serum fructosamine concentration was not correlated to total protein in normoproteinemic (r = 0.03) and hyperproteinemic dogs (r = 0.29), but there was a high correlation (r = 0.73) in hypoproteinemic dogs. Similar comparison between serum fructosamine and albumin concentrations showed middle correlation (r = 0.49) in normoalbuminemic dogs and high degree of correlation (r = 0.67) in hypoalbuminemic dogs. These results showed the importance of recognizing serum glucose concentration as well as total serum protein and albumin concentrations in the assay of canine serum fructosamine concentration.     

Glycosylated haemoglobin assay of canine blood samples

A method for assaying canine glycosylated haemoglobin was evaluated. The method is a turbidimetric inhibition immunoassay and the final reaction is bichromatically measured using a multichannel automatic analyser. Within-run coefficients of variation (2.07 to 4.46 per cent) were permissible, but between-run coefficients of variation (2.10 to 8.25 per cent) were slightly more elevated. The detection limit of this assay is 0.052 per cent. A sample dilution of 10 microliters of sample and 500 microliters of haemolysing reagent is recommended for routine analysis of canine blood samples. A normal reference interval of 1.39 +/- 0.70 per cent was obtained from the glycosylated haemoglobin analysis in 82 healthy dogs and no statistically significant differences in relation to age or gender were observed. Some changes in glycosylated haemoglobin concentrations were noted throughout the ovarian cycle, although differences between dogs were evident. Since this assay specifically measures the glycosylated haemoglobin content in canine blood samples, it could be very useful for monitoring diabetic dogs.     

Comparison of serum fructosamine and blood glycosylated hemoglobin concentrations for assessment of glycemic control in cats with diabetes mellitus.

OBJECTIVE: To correlate serum fructosamine concentrations with established measures of glycemic control and to compare serum fructosamine and blood glycosylated hemoglobin (GHb) concentrations as a means for assessing glycemic control in diabetic cats. DESIGN: Longitudinal cohort study. ANIMALS: 26 healthy cats, 5 cats with stress-induced hyperglycemia, 15 untreated diabetic cats, and 36 treated diabetic cats. PROCEDURE: Control of glycemia was classified and monitored and serum fructosamine and blood GHb concentrations were measured for 12 poorly controlled diabetic cats before and after improving glycemic control, 8 well-controlled treated diabetic cats before and after glycemic control deteriorated, and 5 cats with diabetes mellitus before and after onset of stress-induced hyperglycemia. RESULTS: Mean serum fructosamine and blood GHb concentrations were significantly higher in untreated diabetic cats, compared with healthy cats, and in 24 poorly controlled diabetic cats, compared with 12 well-controlled diabetic cats. Mean serum fructosamine and blood GHb concentrations decreased significantly in 12 poorly controlled diabetic cats after improving glycemic control and increased significantly in 8 well-controlled diabetic cats after glycemic control deteriorated. A significant stress-induced increase in mean blood glucose concentration was evident 12 hours after insulin administration, but not in 5 docile diabetic cats that became fractious. CLINICAL IMPLICATIONS: Serum fructosamine and blood GHb concentrations are clinically useful tools for monitoring control of glycemia in cats with diabetes mellitus.     

Effect of Acute Hyperglycaemia on the Serum Fructosamine and Blood Glycated Haemoglobin Concentrations in Canine Samples

The effect was studied of an acute and non-persistent hyperglycaemia on the serum fructosamine and blood glycated haemoglobin concentrations in canine samples. Five dogs were given glucose solution intravenously and blood samples were taken from each dog before and at 5, 15, 30, 60 and 120 min and 24 h after the infusion. There was an intense hyperglycaemia 5 min after the injection was given, but no statistically significant differences in the serum fructosamine and glycated haemoglobin were observed. It was concluded that an acute and transient hyperglycaemia does not cause significant changes in the glycated haemoglobin and fructosamine concentrations in healthy dogs.     

Relation of fructosamine to serum protein, albumin, and glucose concentrations in healthy and diabetic dogs.

The relation of the glycated serum protein, fructosamine, to serum protein, albumin, and glucose concentrations was examined in healthy dogs, dogs with hypo- or hyperproteinemia, and diabetic dogs. Fructosamine was determined by use of an adaptation of an automated kit method. The reference range for fructosamine in a composite group of control dogs was found to be 1.7 to 3.38 mmol/L (mean +/- SD, 2.54 +/- 0.42 mmol/L). Fructosamine was not correlated to serum total protein, but was highly correlated to albumin in dogs with hypoalbuminemia. To normalize the data with respect to albumin, it is suggested that the lower limit of the reference range for albumin concentration (2.5 g/dl) be used for adjustment of fructosamine concentration and only in hypoalbuminemic dogs. In 6 hyperglycemic diabetic dogs, fructosamine concentration was well above the reference range. It is concluded that although fructosamine may be a potentially useful guide to assess the average blood glucose concentration over the preceding few days in dogs, further study is required to establish its value as a guide to glucose control in diabetic dogs.     

Keratoconjunctival effects of diabetes mellitus in dogs

OBJECTIVES: To compare Schirmer tear test (STT) values, corneal sensitivity, tear film break up times (TFBUTs), and tear glucose concentrations in relation to conjunctival microflora, and conjunctival cytologic and histologic findings among diabetic cataractous, nondiabetic cataractous, and nondiabetic noncataractous dogs. Procedures Fifteen dogs in each category underwent neuro-ophthalmic examination; aerobic, anaerobic and fungal conjunctival cultures; assessment of corneal touch threshold (CTT), STT, tear glucose, TFBUT; and conjunctival cytology and histology (in certain cases only). Degree of cataract and uveitis were critically graded. Glycemic control was estimated using serum fructosamine and glycosylated hemoglobin. RESULTS: STT values were significantly lower in diabetic cataractous than nondiabetic noncataractous dogs. CTT of diabetic cataractous dogs was significantly lower than that of nondiabetic noncataractous dogs. Mean TFBUTs were significantly less in diabetic cataractous dogs than nondiabetic cataractous and nondiabetic noncataractous dogs. Tear glucose concentrations were significantly higher in diabetic cataractous dogs than nondiabetic cataractous and nondiabetic noncataractous dogs. Conjunctival microbial isolates did not differ among groups. There were no significant differences in degree of cataract or uveitis between diabetic cataractous and nondiabetic cataractous groups. There was mild submucosal inflammatory infiltrate in conjunctival specimens from diabetic dogs. Conjunctival epithelial dysplasia and/or squamous metaplasia was/were detected in conjunctival biopsies of 5/7 diabetic dogs. Reductions in conjunctival goblet cell (GC) densities were noted in 4/7 diabetic dogs; there were no significant differences in mean GC densities among the three groups. CONCLUSIONS: Diabetic cataractous dogs have significantly altered keratoconjunctival characteristics compared to nondiabetic cataractous and nondiabetic noncataractous dogs.     

Effect of the alpha-glucosidase inhibitor acarbose on control of glycemia in dogs with naturally acquired diabetes mellitus

OBJECTIVE: To evaluate effect of acarbose on control of glycemia in dogs with diabetes mellitus. DESIGN: Prospective randomized crossover controlled trial. ANIMALS: 5 dogs with naturally acquired diabetes mellitus. PROCEDURE: Dogs were treated with acarbose and placebo for 2 months each: in 1 of 2 randomly assigned treatment sequences. Dogs that weighed < or = 10 kg (22 lb; n = 3) or > 10 kg (2) were given 25 or 50 mg of acarbose, respectively, at each meal for 2 weeks, then 50 or 100 mg of acarbose, respectively, at each meal for 6 weeks, with a 1-month interval between treatments. Caloric intake, type of insulin, and frequency of insulin administration were kept constant, and insulin dosage was adjusted as needed to maintain control of glycemia. Serum glucose concentrations, blood glycosylated hemoglobin concentration, and serum fructosamine concentration were determined. RESULTS: Significant differences in mean body weight and daily insulin dosage among dogs treated with acarbose and placebo were not found. Mean preprandial serum glucose concentration, 8-hour mean serum glucose concentration, and blood glycosylated hemoglobin concentration were significantly lower in dogs treated with insulin and acarbose, compared with insulin and placebo. Semisoft to watery feces developed in 3 dogs treated with acarbose. CONCLUSIONS AND CLINICAL RELEVANCE: Acarbose may be useful as an adjunctive treatment in diabetic dogs in which cause for poor glycemic control cannot be identified, and insulin treatment alone is ineffective.     

Fructosamine

Fructosamines are glycated serum proteins that, depending on their life span, reflect glycemic control over the previous 2 to 3 weeks. The nitroblue tetrazolium reduction method adapted to autoanalysis appeared to be a practical means to assay fructosamine quickly, economically, and accurately. The upper limit of the reference range is 374 μmol/L in dogs (95% percentile) and 340 μmol/L in cats (95% percentile). Newly diagnosed diabetic dogs and cats that had not undergone previous insulin therapy had significantly higher fructosamine concentrations than nondiabetic animals. In diabetic dogs that were receiving insulin therapy, the fructosamine test reflected the glycemic state far more accurately than did individual blood glucose measurements. Animals with satisfactory metabolic control revealed fructosamine concentrations within the reference range, whereas fructosamine concentrations above 400 μmol/L indicated insufficient metabolic control. On the basis of fructosamine concentrations, cats with a transitory hyperglycemia and cats with diabetes mellitus were differentiated. The fructosamine test is a valuable parameter for the diagnosis and metabolic control of diabetes mellitus in dogs and cats.     

Glycated hemoglobin fractions in normal and diabetic dogs measured by high performance liquid chromatography.

We established a new analytical condition to measure the canine glycated hemoglobin by high performance liquid chromatography (HPLC) using cation exchange column. The canine hemoglobin gave five peaks consisting of 2 major and 3 minor hemoglobin fractions such as HbA1a, HbA1b and HbA1c. Measurement was done in 38 clinically normal dogs and 10 diabetic dogs. Mean HbA1c values (% of total Hb) in normal and diabetic dogs were 2.60 and 6.41%, respectively. And mean HbA1 values were 3.58 and 7.41%, respectively. The mean values of the canine HbA1c and HbA1 in diabetic dogs was higher than those in normal dogs, significantly (p less than 0.01). Advantages of the HPLC method and applicability for monitoring effectiveness of insulin therapy in the canine diabetes mellitus are discussed.     

Glycosylated haemoglobin in dogs: study of critical difference value

Measurement of glycated proteins can be of use in diagnosis and monitoring of diabetic dogs. Its use in monitoring can be facilitated by comparison of results with a reference interval derived from levels in normal dogs. In this study, a commercial immunoturbidometric assay was used to measure glycosylated haemoglobin in 15 normal dogs over a 5-week period. Following statistical analysis of the results a critical difference value of 0.38 per cent was obtained.     

Corneal sensitivity in dogs with diabetes mellitus

OBJECTIVE: To compare aesthesiometer-determined corneal sensitivity between diabetic and nondiabetic dogs and to investigate the correlation between corneal sensitivity and duration of diabetes or status of glycemic control, as estimated by use of glycated blood protein concentrations. ANIMALS: 23 diabetic and 29 nondiabetic normoglycemic dogs. PROCEDURE: A Cochet-Bonnet aesthesiometer was used to measure corneal touch threshold (CTT) in 5 corneal regions of each dog. At the time of ocular examination, duration of diabetes mellitus was estimated from the history, and blood was drawn for assessment of blood glycosylated hemoglobin and serum fructosamine concentrations. RESULTS: Median CTT for central, nasal, dorsal, temporal, and ventral corneal regions in nondiabetic dogs (1.6, 2.3, 2.8, 2.8, and 5.1 g/mm2, respectively) was significantly lower than in diabetic dogs (2.8, 4.0, 5.1, 5.1, and 6.6 g/mm2, respectively). Median regional CTT in diabetic dogs was not significantly correlated with estimated duration of diabetes mellitus or blood glycated protein concentrations. No significant difference was found in regional CTT between eyes of normoglycemic dogs with unilateral cataracts. CONCLUSIONS AND CLINICAL RELEVANCE: Diabetic dogs have significantly reduced corneal sensitivity in all regions, compared with nondiabetic normoglycemic dogs. Regional variation in corneal sensitivity is similar in diabetic and normoglycemic dogs. Neither glycemic control nor duration of diabetes, as estimated, is significantly correlated with corneal hyposensitivity. Corneal nerve dysfunction may be associated with recurrent or nonhealing ulcers in diabetic dogs for which no other underlying cause can be found.     

Glycosylated hemoglobin measurement in dogs and cats: implications for its utility in diabetic monitoring

The measurement of glycosylated hemoglobin (HbA₁) levels in humans is used to indicate the degree of long-term diabetic control. Using a commercially available kit for human HbA₁, values were obtained for normal and diabetic dogs and cats. The normal range established in dogs was broad and overlapped considerably with the range in diabetics. Under the assay conditions and with a limited number of diabetic animals, the test was not found to be of value for dogs or cats.     

Efficacy and safety of allogenic canine adipose tissue-derived mesenchymal stem cell therapy for insulin-dependent diabetes mellitus in four dogs: A pilot study

Mesenchymal stem cells (MSCs) possess regenerative and immunomodulatory properties and can control the immune dysregulation that leads to β-cell destruction. Stem-cell transplantation could thus manage insulin-dependent diabetes mellitus (IDDM) in dogs. In this pilot study, we aimed to assess canine adipose tissue-derived MSCs (cAT-MSCs) transplantation as a treatment for canine diabetes mellitus. This study included four dogs with over a year of insulin treatment for IDDM, following diagnosis at the Veterinary Medicine Teaching Hospital of Seoul National University. Allogenic cAT-MSCs were infused intravenously three or five times monthly to dogs with IDDM. Blood and urine samples were obtained monthly. General clinical symptoms, including changes in body weight, vitality, appetite, and water intake were assessed. Three of the four owners observed improvement of vitality after stem cell treatment. Two of the four dogs showed improvement in appetite and body weight, polyuria, and polydipsia. C-peptide has increased by about 5–15% in three of the cases, and fructosamine and HbA1c levels have improved in two of the cases. Hyperlipidemia was resolved in two of the dogs, and there was no concurrent bacterial cystitis in any of the dogs. C-peptide secretion and lipid metabolism are associated with diabetic complications. Improvement in these parameters following the treatment suggests that cAT-MSC transplantation in dogs with IDDM might help to improve their insulin secretory capacity and prevent diabetic complications.     

Glycosylated hemoglobin in dogs: precision, stability, and diagnostic utility

The precision and stability of the ion exchange chromatography assay for canine glycosylated hemoglobin (HbA(1)) were examined. The coefficient of variation (CV) of within-run replicate assays was 1.3 to 2.6%; the CV of between-run duplicate assays was 3.1%. The mean HbA(1) content in 44 healthy dogs was 7.1% (SD = 1.1%, range = 5.1-9.7%). Paired aliquots of 12 blood samples were stored at 4 degrees C and 25 degrees C, and HbA(1) was measured on the day of collection and at 3, 5, and 7 days after collection. In the blood stored at 4 degrees C, no significant increase in the HbA(1) content was seen. No significant increase in HbA(1) content was found in the blood stored at 25 degrees C after 3 days, but dramatic increases were observed after 5 and 7 days of storage. No significant difference was observed in the HbA1 content in heart blood collected 18 hours after death from 9 dogs kept at 25 degrees C. The HbA(1) content was measured in 10 hospitalized diabetic dogs. Five of the dogs had received no insulin and all 5 had elevated HbA(1) values. The other 5 dogs had received insulin for 1 to 9 months; 2 of the 5 had increased HbA(1) content. The HbA(1) content was determined periodically for 9 months in one diabetic dog and it declined from 14% to 8.2%.     

Study of 253 dogs in the United Kingdom with diabetes mellitus

Clinical information and blood samples were collected from 253 dogs with naturally occurring diabetes mellitus. Over half of them were labrador retrievers, collies, Yorkshire terriers or crossbred dogs, and approximately 80 per cent of them were diagnosed between the ages of five and 12 years. The majority of the dogs were receiving insulin therapy once a day, but in the dogs receiving insulin injections twice a day there was a trend for lower serum fructosamine concentrations, suggesting better glycaemic control. The proportion of female dogs with diabetes was lower than in previous surveys. The disease was diagnosed more commonly in the winter months, a seasonal pattern also observed in human beings with diabetes, suggesting that similar environmental factors might be involved in the disease.     

Serum fructosamine concentration in nondiabetic and diabetic cats

Differentiating transient hyperglycemia from diabetic hyperglycemia can be difficult in cats since single blood glucose measurements reflect only momentary glucose concentrations, and values may be elevated because of stress-induced hyperglycemia. Glycated protein measurements serve as monitors of longer-term glycemic control in human diabetics. Using an automated nitroblue tetrazolium assay, fructosamine concentration was measured in serum from 24 healthy control cats and 3 groups of hospitalized cats: 32 euglycemic, 19 transiently hyperglycemic, and 12 diabetic cats. Fructosamine concentrations ranged from 2.1 - 3.8 mmol/L in clinically healthy cats; 1.1 - 3.5 mmol/L in euglycemic cats; 2.0 - 4.1 mmol/L in transiently hyperglycemic cats; and 3.4 to >6.0 mmol/L in diabetic cats. Values for with-in-run precision at 2 fructosamine concentrations (2.64 mmol/L and 6.13 mmol/L) were 1.5% and 1.3%, respectively. Between-run coefficient of variation was 3.8% at a fructosamine concentration of 1.85 mmol/L. The mean fructosamine concentration for the diabetic group differed significantly (P=0.0001) from the mean concentrations of the other 3 groups. Poorly regulated or newly diagnosed diabetic cats tended to have the highest fructosamine values, whereas well-regulated or over-regulated diabetic cats had values approaching the reference range. As a single test for differentiating nondiabetic cats from diabetic cats, fructosamine was very sensitive (92%) and specific (96%), with a positive predictive value of 85% and a negative predictive value of 98%. Serum fructosamine concentration shows promise as an inexpensive, adjunct diagnostic tool for differentiating transiently hyperglycemic cats from poorly controlled diabetic cats.     

Diagnostic significance of serum glycated albumin in diabetic dogs

Measurements of serum fructosamine, glycated hemoglobin, and glycated albumin (GA) are increasingly used to complement serum glucose concentration for better management of diabetes mellitus. Fructosamine tests are currently not performed in veterinary medicine in Japan. As such, the measurement of GA may serve as a replacement test. Therefore, in the current study, serum GA and fructosamine were evaluated for a positive correlation in dogs, and, depending on the correlation, a reference range of GA percentage would also be determined from healthy control dogs. The degree of glycemic control in diabetic dogs was determined by fructosamine concentration. A positive correlation between GA and fructosamine was observed with both normal and diabetic animals. In addition, the reference interval of serum GA percentage in control dogs was determined to be 11.4-11.9% (95% confidence interval). Interestingly, no significant difference in serum GA percentages was observed between samples from diabetic dogs with excellent glycemic control and control dogs. However, good, fair, and poor glycemic control diabetic dogs resulted in a significant increase in serum GA percentages in comparison with control dogs. These results suggest that serum GA may be a useful diagnostic indicator, substituting for fructosamine, to monitor glycemic control in diabetic dogs.