Nephrotic Syndrome as a Cause of Transient Clinical Hypothyroidism

Nephrotic syndrome may trigger the onset of hypothyroidism, promoting massive urinary protein losses including thyroxine (T4) and triiodothyronine (T3) along with their binding proteins. At an early stage, a clinical and biochemical euthyroid state is expected. However, in patients with prolonged and severe proteinuria, especially with concomitant low thyroid reserve, urinary losses of free and protein-bound thyroid hormones are sufficiently pronounced to induce a subclinical or overt hypothyroidism. Despite its high prevalence in clinical practice, the literature lacks case reports of newly diagnosed clinical hypothyroidism due to NS in adults, making this condition under-recognized. We report a case of a 23-year-old man with previous normal thyroid function who developed overt hypothyroidism due to a severe nephrotic syndrome, requiring supplementation with levothyroxine (LT). After the patient had undergone bilateral nephrectomy, treatment with LT was discontinued and thyroid function normalized.

The Effect of Bilateral Nephrectomy on Renalase and Catecholamines in Hemodialysis Patients

Background/Aims: Renalase is an enzyme with monoamine oxidase activity that metabolizes catecholamines; therefore, it has a significant influence on arterial blood pressure regulation and the development of cardiovascular diseases. Renalase is mainly produced in the kidneys. Nephrectomy and hemodialysis (HD) may alter the production and metabolism of renalase. The aim of this study was to examine the effect of bilateral nephrectomy on renalase levels in the serum and erythrocytes of hemodialysis patients. Methods: This study included 27 hemodialysis patients post-bilateral nephrectomy, 46 hemodialysis patients without nephrectomy but with chronic kidney disease and anuria and 30 healthy subjects with normal kidney function. Renalase levels in the serum and erythrocytes were measured using an ELISA kit. Results: Serum concentrations of renalase were significantly higher in post-bilateral nephrectomy patients when compared with those of control subjects (101.1 ± 65.5 vs. 19.6 ± 5.0; p < 0.01). Additionally, renalase concentrations, calculated per gram of hemoglobin, were significantly higher in patients after bilateral nephrectomy in comparison with those of healthy subjects (994.9 ± 345.5 vs. 697.6 ± 273.4, p = 0.015). There were no statistically significant differences in plasma concentrations of noradrenaline or adrenaline. In contrast, the concentration of dopamine was significantly lower in post-nephrectomy patients when compared with those of healthy subjects (116.8 ± 147.7 vs. 440.9 ± 343.2, p < 0.01). Conclusions: Increased serum levels of renalase in post-bilateral nephrectomy hemodialysis patients are likely related to production in extra-renal organs as a result of changes in the cardiovascular system and hypertension.

Increased Circulatory Extrarenal 1α,25-Dihydroxyvitamin D3 in Bilaterally Nephrectomized Rats

Background: Extrarenal 1α,25-dihydroxyvitamin D3 (1,25-D) locally produced by immune cells plays crucial roles in the regulation of the immune system. However, in vivo status of extrarenal 1,25-D and 25-hydroxyvitamin D (25-D) in acute inflammatory conditions are unknown. Objective: The aim of this study was to determine the extrarenal 1,25-D level in circulation in bilaterally nephrectomized rats, induced by low-dose lipopolysaccharide (LPS). Methods: Renal 1,25-D synthesis was terminated through bilateral nephrectomy in rats. The rats received intraperitoneal LPS (50 μg/kg BW) three times and the experiment was ended 24 hours after nephrectomy. Serum 1,25-D, 25-D, calcium, phosphorus, intact parathyroid hormone, and calcitonin levels were measured and immunohistochemistry was applied to detect the sources of extrarenal 1,25- D synthesis. Results: Circulatory 1,25-D concentration remarkably increased in both LPS-treated and non-treated bilaterally nephrectomized rats. Elevated circulatory 1,25-D did not have hypercalcemic endocrinal effects. The increased 1,25-D level also resulted in a concurrent rapid and dramatic depletion of circulatory 25-D. Conclusions: Extrarenal 1,25-D could enter into the systemic circulation and, therefore, might have systemic effects besides its autocrine and paracrine functions.