Genetic causes of hypomagnesemia, a clinical overview

Determinants of hypomagnesemia in patients with type 2 diabetes mellitus

BACKGROUND

Hypomagnesemia (plasma magnesium (Mg²⁺) concentration <0.7 mmol/L) has been described in patients with type 2 diabetes. Polypharmacy is inevitable when treating a complex disease such as type 2 diabetes and could explain disturbances in the plasma Mg²⁺ concentration. In this study, we aimed to establish the extent of hypomagnesemia in a cohort of type 2 diabetes patients and to identify the determinants of plasma Mg²⁺ levels.

METHODS

Patient data and samples of 395 type 2 diabetes patients were investigated. Plasma Mg²⁺ concentrations were measured using a spectrophotometric assay. Using Pearson correlation analyses, variables were correlated to plasma Mg²⁺ levels. After excluding confounding variables, all parameters correlating (P < 0.1) with plasma Mg²⁺ were included in a stepwise backward regression model.

RESULTS

The mean plasma Mg²⁺ concentration in this cohort was 0.74 ± 0.10 mmol/L. In total, 121 patients (30.6%) suffered from hypomagnesemia. Both plasma triglyceride (r = -0.273, P < 0.001) and actual glucose levels (r = -0.231, P < 0.001) negatively correlated with the plasma Mg²⁺ concentration. Patients using metformin (n = 251, 62%), proton pump inhibitors (n = 179, 45%) or β-adrenergic receptor agonists (n = 31, 8%) displayed reduced plasma Mg²⁺ levels. Insulin use (n = 299, 76%) positively correlated with plasma Mg²⁺ levels. The model predicted (R²) 20% of all variance in the plasma Mg²⁺ concentration.

CONCLUSIONS

Hypomagnesemia is highly prevalent in type 2 diabetes patients. Plasma triglycerides and glucose levels are major determinants of the plasma Mg²⁺ concentration, whereas only a minor part (<10%) of hypomagnesemia can be explained by drug intake, excluding polypharmacy as a major cause for hypomagnesemia in type 2 diabetes.

Ion transport in the zebrafish kidney from a human disease angle: possibilities, considerations, and future perspectives

Unique experimental advantages, such as its embryonic/larval transparency, high-throughput nature, and ease of genetic modification, underpin the rapid emergence of the zebrafish ( Danio rerio) as a preeminent model in biomedical research. Particularly in the field of nephrology, the zebrafish provides a promising model for studying the physiological implications of human solute transport processes along consecutive nephron segments. However, although the zebrafish might be considered a valuable model for numerous renal ion transport diseases and functional studies of many channels and transporters, not all human renal electrolyte transport mechanisms and human diseases can be modeled in the zebrafish. With this review, we explore the ontogeny of zebrafish renal ion transport, its nephron structure and function, and thereby demonstrate the clinical translational value of this model. By critical assessment of genomic and amino acid conservation of human proteins involved in renal ion handling (channels, transporters, and claudins), kidney and nephron segment conservation, and renal electrolyte transport physiology in the zebrafish, we provide researchers and nephrologists with an indication of the possibilities and considerations of the zebrafish as a model for human renal ion transport. Combined with advanced techniques envisioned for the future, implementation of the zebrafish might expand beyond unraveling pathophysiological mechanisms that underlie distinct genetic or environmentally, i.e., pharmacological and lifestyle, induced renal transport deficits. Specifically, the ease of drug administration and the exploitation of improved genetic approaches might argue for the adoption of the zebrafish as a model for preclinical personalized medicine for distinct renal diseases and renal electrolyte transport proteins.