Basal glucosuria in cats

Silver-based bimetallic nanozyme fabrics with peroxidase-mimic activity for urinary glucose detection

The enhanced catalytic properties of bimetallic nanoparticles have been extensively investigated. In this study, bimetallic Ag-M (M = Au, Pt, or Pd) cotton fabrics were fabricated using a combination of electroless deposition and galvanic replacement reactions, and improvement in their peroxidase-mimicking catalytic activity compared to that of the parent Ag fabric was studied. The Ag-Pt bimetallic nanozyme fabric, which showed the highest catalytic activity and ability to simultaneously generate hydroxyl (•OH) and superoxide (O2•-) radicals, was assessed as a urine glucose sensor. This nanozyme fabric sensor could directly detect urinary glucose in the pathophysiologically relevant high millimolar range without requiring sample predilution. The sensor could achieve performance on par with that of the current clinical gold standard assay. These features of the Ag-Pt nanozyme sensor, particularly its ability to avoid interference effects from complex urinary matrices, position it as a viable candidate for point-of-care urinary glucose monitoring.

Refined protocol for newly onset identification in non-obese diabetic mice: an animal-friendly, cost-effective, and efficient alternative

BACKGROUND

Therapeutic interventions for diabetes are most effective when administered in the newly onset phase, yet determining the exact onset moment can be elusive in practice. Spontaneous autoimmune diabetes among NOD mice appears randomly between 12 and 32 weeks of age with an incidence range from 60 to 90%. Furthermore, the disease often progresses rapidly to severe diabetes within days, resulting in a very short window of newly onset phase, that poses significant challenge in early diagnosis. Conventionally, extensive blood glucose (BG) testing is typically required on large cohorts throughout several months to conduct prospective survey. We incorporated ultrasensitive urine glucose (UG) testing into an ordinary BG survey process, initially aiming to elucidate the lag period required for excessive glucose leaking from blood to urine during diabetes progression in the mouse model.

RESULTS

The observations unexpectedly revealed that small amounts of glucose detected in the urine often coincide with, sometimes even a couple days prior than elevated BG is diagnosed. Accordingly, we conducted the UG-based survey protocol in another cohort that was validated to accurately identified every individual near onset, who could then be confirmed by following few BG tests to fulfill the consecutive BG + criteria. This approach required fewer than 95 BG tests, compared to over 700 tests with traditional BG survey, to diagnose all the 37-38 diabetic mice out of total 60. The average BG level at diagnosis was slightly below 350 mg/dl, lower than the approximately 400 mg/dl observed with conventional BG monitoring.

CONCLUSIONS

We demonstrated a near perfect correlation between BG + and ultrasensitive UG + results in prospective survey with no lag period detected under twice weekly of testing frequency. This led to the refined protocol based on surveying with noninvasive UG testing, allowing for the early identification of newly onset diabetic mice with only a few BG tests required per mouse. This protocol significantly reduces the need for extensive blood sampling, lancet usage, labor, and animal distress, aligning with the 3Rs principle. It presents a convenient, accurate, and animal-friendly alternative for early diabetes diagnosis, facilitating research on diagnosis, pathogenesis, prevention, and treatment.

Basal glucose excretion in dogs: The impact of feeding, obesity, sex, and age

Background

The urine glucose (UG) measurements are an integral part of urinalyses, especially in dogs with polyuria and polydipsia. A positive dipstick result is considered pathologic for disease. This paradigm has been challenged by new ultrasensitive tests, where the manufacturers recommend tolerating slightly positive results. It implies that, as in other species, basal urine glucose losses can exceed the lower limits of detection using ultrasensitive glucose dipsticks in healthy dogs.

Objectives

We aimed to determine whether glucose is routinely detectable using a sensitive quantitative wet chemistry method in the urine of nondiabetic, nonazotemic dogs, and investigate the impact of food intake, obesity, sex, castration status, and age.

Methods

Serial UG measurements were performed in healthy clinic‐owned Beagle dogs that were randomly fasted or fed. Glucose was measured in morning urine samples from normal‐weight healthy and obese dogs, and the university's electronic database was searched for quantitative UG measurements (Gluco‐quant Enzyme Kit/Roche Diagnostics).

Results

Small amounts of glucose were detected in 555 (99.1%) of 560 urine samples analyzed. All urine samples from the clinic‐owned Beagle dogs, as well as from privately owned obese and normal‐weight healthy dogs that tested positive for glucose. The median (range) UG concentration obtained from the university's electronic database was 0.39 (0‐1.55) mmol/L, and 2.2% of the samples tested negative. Feeding, obesity, gender, castration status, and age did not affect UG concentrations.

Conclusions

Studies, including a larger number of healthy dogs, are warranted to define a cut‐off between physiologic and pathologic glucosuria.

Basal glucosuria in cats

Objective of this study was to demonstrate the ubiquitous presence of glucose in urine of euglycemic cats by a highly sensitive glucose assay. The local electronic database was searched for results of quantitative urine glucose measurements in cats. A total of 325 feline urine glucose measurements were identified, of which 303 (93%) had been submitted by one of the co-authors working in a near-by small animal practice. After the exclusion of patients with kidney disease (n = 60), hyperthyroidism (n = 15), diabetes mellitus (n = 11), multiple diseases (n = 9) or steroid treatment (n = 3), as well as serial measurements (n = 87) and outliers (n = 8), the final study population consisted of 132 cats. Urine creatinine concentration was unavailable in five patients. Whereas all but one cat had glucose concentrations above the detection limit of the assay (0.11 mmol/L, Gluco-quant Enzyme Kit/Roche Diagnostics), no positive glucose dipstick test result (Combur 9-Test, Roche Diagnostics) was observed. The median (range) of urinary glucose concentration and the glucose-to-creatinine ratio (UGCR) was 0.389 (<0.11-1.665) mmol/L and 0.0258 (0.007-0.517) respectively. The UGCR was not affected by age, gender, breed or leukocyturia, whereas cats with hematuria had slightly higher values. Data show that so-called "basal glucosuria" is present in the majority of cats and by no means diagnostic for diabetes mellitus or renal glucosuria. This has to be considered when using bio-analytical methods with a low limit of quantification.