Correlation of clinical changes with regard to thyroxine replacement therapy in hypothyroid patients: focusing on the change of renal function

Levothyroxine sodium tablets reversed Hashimoto thyroiditis-induced kidney injury, muscle injury, and lipid metabolism disorder: A case report and literature review

RATIONALE

Hashimoto thyroiditis (HT), a common cause of hypothyroidism, has shown an increasing incidence in recent years, particularly among women. In addition to the common complications such as lipid metabolism disorders, patients with HT may also experience some serious complications, acute kidney injury and severe muscle damage for instance. This article explored the effectiveness of levothyroxine sodium tablets (L-T4) replacement therapy in severe complications of hypothyroidism, including treatment dosage, duration of complication recovery, and whether additional treatment is needed.

PATIENT CONCERNS, DIAGNOSES, AND INTERVENTIONS

We described a case of a 52-year-old woman with HT who exhibited kidney injury, muscle injury, and lipid metabolism disorders. The increased levels of serum creatinine, creatine kinase, cholesterol, triglyceride, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and the decreased levels of estimated glomerular filtration rate were obviously observed. This patient was started on L-T4 (75 and 100 µg, alternate).

OUTCOMES AND LESSONS

Following a two-month treatment, the serum creatine kinase level decreased to within normal range. The estimated glomerular filtration rate level was restored, and the serum creatinine level was down-regulated, although slightly higher than the normal range. L-T4 partially reversed HT-induced the disorders of muscle, renal function, and lipid profile of this patient and remarkably alleviated her HT-related symptoms.

Analysis of metabolomics profile in hypothyroid patients before and after thyroid hormone replacement

PURPOSE

The serum metabolic changes occurring during the transition from hypothyroidism to euthyroidism are not known. This study aimed to determine the metabolomic profile in hypothyroid patients before (HypoT₀) and after (HypoT₁) euthyroidism achieved through levothyroxine (L-T4) treatment.

METHODS

Eighteen patients with overt primary hypothyroidism were recruited for the study. All patients were treated with L-T4 to achieve euthyroidism. Thyrotropin (TSH), free thyroxine (FT4), free triiodothyronine (FT3) and metabolomics profiles were measured before and after 3 months of treatment. The euthyroid control group consisted of 28 healthy volunteers. Metabolomics analysis was performed using Nuclear Magnetic Resonance (NMR) spectroscopy.

RESULTS

¹H NMR-based metabolomics profiling of patients with newly diagnosed hypothyroidism (HypoT₀) showed significantly higher levels of citrate, creatinine, glycerol, myo-inositol and serine, and lower levels of proline and taurine compared to controls. Interestingly, some metabolic changes were persistent three months after pharmacological treatments, despite normal serum TSH and thyroid hormone concentrations (HypoT₁). When an Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) model was built to evaluate possible differences in the metabolic profile between HypoT₀ and HypoT₁, the data obtained were not significantly different.

CONCLUSION

These results suggest that metabolic changes in the patients with hypothyroidism may persist after normalization of serum levels of FT3, FT4, and TSH, which currently represent the gold standard in laboratory testing for diagnosis and evaluation of thyroid pathology. So, the metabolomics approach may contribute to integrate classical hormone assays and to determine the euthyroid status achievement with greater efficacy.

Proteinuria in Severe Hypothyroidism: A Prospective Study

CONTEXT

Hypothyroidism is associated with reversible decline in kidney function as measured by estimated glomerular filtration rate (eGFR). eGFR and proteinuria are the most important markers for clinical assessment of kidney function. Though hypothyroidism is associated with proteinuria in cross-sectional data, the impact of treatment on proteinuria is unknown.

OBJECTIVE

This study explores the effect of thyroid hormone replacement therapy on eGFR and 24-hour urine protein excretion in patients with severe primary hypothyroidism.

DESIGN AND PARTICIPANTS

This study was a prospective, observational cohort study in adults with severe primary hypothyroidism (serum thyrotropin [TSH] > 50 µIU/mL). Individuals with preexisting or past kidney disease, kidney or urinary tract abnormalities, calculi or surgery, diabetes mellitus, or hypertension were excluded. The participants received thyroid hormone replacement therapy. Thyroid functions, eGFR, 24-hour urine protein excretion, and biochemical parameters were measured at baseline and 3 months.

SETTING

This study took place at a single center, a tertiary care referral and teaching hospital.

RESULTS

Of 44 enrolled participants, 43 completed 3 months of follow-up. At 3 months, serum TSH levels decreased and thyroxine levels increased (P < .001 for both). Significant increases in eGFR (mean difference, 18.25 ± 19.49 mL/min/1.73 m2; 95% CI, 12.25 to 24.25, P < .001) and declines in 24-hour urine protein excretion (mean difference, -68.39 ± 125.89 mg/day; 95% CI, -107.14 to -29.65, P = .001) were observed. Serum cholesterol and low-density lipoprotein levels also significantly decreased (P < .001).

CONCLUSIONS

Thyroid hormone replacement therapy in patients with severe primary hypothyroidism improves eGFR and decreases 24-hour urine protein excretion, thereby suggesting reversible alterations.

PDZ domain containing protein 1 (PDZK1), a modulator of membrane proteins, is regulated by the nuclear receptor THRβ

Genome wide association studies revealed single nucleotide polymorphisms (SNP) located within the promoter of PDZ domain containing protein 1 (PDZK1) to be associated with serum uric acid levels. Since modulation of transporters and particularly of membrane proteins involved in uric acid handling by PDZK1 has previously been reported, the aim of this study was to analyze the impact of the polymorphisms rs1967017, rs1471633, and rs12129861 on promoter activity and thereby transcription of PDZK1. Cell-based reporter gene assays showed transactivation of the PDZK1-promoter by triiodothyronine mediated by thyroid hormone receptors (THR) α and β. In silico analysis verified localization of the polymorphism rs1967017 within the most likely THR binding site whose deletion reduced THR-mediated transactivation. Furthermore, our study shows regulation of PDZK1 by thyroid hormones, thereby providing a mechanistic basis for the previously reported associations between thyroid hormone status and uric acid homeostasis.

Renal function improves with the treatment of hypothyroidism

BACKGROUND

It has been known that thyroid hormones may affect renal function. In this study, we aimed to investigate the effect of levothyroxine replacement on renal function in hypothyroid patients before and after treatment.

METHODS

We retrospectively investigated free T3 (fT3), free T4 (fT4), TSH, creatinine, and eGFR measurements during both hypothyroid and euthyroid states of hypothyroid patients. The eGFR was calculated using the simplified Modification of Diet in Renal Disease formula.

RESULTS

fT3, fT4, and eGFR measurements increased, meanwhile creatinine and TSH levels decreased significantly after euthyroidism was achieved with levothyroxine treatment (p < 0.0001 for all). The correlation analyses revealed that ∆creatinine and ∆TSH levels were significantly correlated before and after levothyroxine treatment (r: 0.288, p < 0.0001). ∆eGFR and ∆TSH levels were significantly correlated before and after LT4 treatment (r: -0.272, p < 0.0001).

CONCLUSION

In this study, we evaluated creatinine and eGFR levels in patients with hypothyroidism and found out that renal function improved in most patients after euthyroidism was achieved. In some patients, above-normal creatinine levels completely returned to normal once the patients became euthyroid.

Effects of Thyroid Hormone Withdrawal and Recombinant Human Thyrotropin on Glomerular Filtration Rate During Radioiodine Therapy for Well-Differentiated Thyroid Cancer

BACKGROUND

Renal function is related to thyroid hormonal status, and glomerular filtration rate (GFR) seems to be impaired in patients with hypothyroidism. The aim of this work was to evaluate quantitatively the effect of hypothyroidism on GFR using a (51)Cr-EDTA radioisotope assay.

METHODS

Twenty-eight patients without known renal disease or dysfunction who had been referred for radioiodine therapy (RIT) after total thyroidectomy were enrolled in this study and divided into two groups. Group A underwent thyroid hormone withdrawal (THW) resulting in hypothyroidism, while group B underwent recombinant human thyrotropin (rhTSH) stimulation and hence remained euthyroid. GFR was assessed by (51)Cr-EDTA before and after THW or rhTSH.

RESULTS

No clinical differences were observed between the two groups. The mean ± SD GFRs were 94 ± 19 mL/min/1.73 m(2) before THW and 76 ± 16 mL/min/1.73 m(2) after THW for group A (p = 0.009), and 91 ± 18 mL/min/1.73 m(2) before rhTSH and 93 ± 15 mL/min/1.73 m(2) after rhTSH for group B (p = 0.613). The percent decrease in GFR during hypothyroidism is approximately 18-22%.

CONCLUSION

GFR decreases in patients with normal kidney function during THW for RIT, and rhTSH preserves GFR in these patients. This GFR impairment following thyroidectomy is related to hypothyroidism due to a significant reduction in thyroid hormone levels and is not due to a rise in the TSH level.

Thyroid status and renal function in older persons in the general population

BACKGROUND

Prevalence estimates of thyroid dysfunction and chronic kidney disease both increase with age. The aim of this study was to investigate the cross-sectional association between low thyroid function and renal function in subjects aged 85 years and to assess whether a low thyroid function at age 85 years is associated with an accelerated decline in renal function during follow-up.

METHODS

We included 558 participants from the Leiden 85-plus Study. At baseline (age 85 y), TSH, free T4 (fT4), and free T3 levels were measured. Thyroid function groups were created using clinical cutoff values of TSH and fT4. Serum creatinine concentrations were determined at baseline and annually during a 5-year follow-up period. Estimated glomerular filtration rates (eGFRs) were calculated by means of the Modification of Diet in Renal Disease Study equation.

RESULTS

At baseline, subjects with higher levels of TSH and lower levels of fT4 and free T3 had lower renal function. Participants with hypothyroidism [mean 53.7 (2.0) mL/min per 1.73 m(2))] and subclinical hypothyroidism [55.7 (2.1) mL/min per 1.73 m(2)] had lower mean eGFRs (SE) than participants with normal thyroid function [59.5 (0.7) mL/min per 1.73 m(2)]; the highest eGFR was observed in participants with hyperthyroidism [eGFR 61.5 (3.1) mL/min per 1.73 m(2)] (P for trend = .004). There was no association between thyroid hormone levels at baseline and the change in renal function during follow-up.

CONCLUSIONS

Although low thyroid function was associated with lower renal function at age 85 years, an association between a low thyroid function and change in renal function over time was absent. Our findings question the causal relevance of the thyroid status for the deterioration of renal function in the oldest old.

Nonthyroidal illness and the cardiorenal syndrome

The cardiorenal syndrome represents a final common pathway for renal and congestive heart failure and heralds a poor prognosis. Factors that link the failing heart and the failing kidneys--the so-called cardiorenal connectors--are, therefore, of clinical and therapeutic interest. Alterations in the levels and function of thyroid hormones that fit the spectrum of nonthyroidal illnesses could be considered to be cardiorenal connectors as both renal failure and heart failure progress with the development of nonthyroidal illness. In addition, circumstantial evidence suggests that nonthyroidal illness can induce deterioration in the function of the heart and the kidneys via multiple pathways. As a consequence, these reciprocal associations could result in a vicious cycle of deterioration that likely contributes to increased mortality. In this Review, we describe the evidence for a pathophysiological role of nonthyroidal illness in the cardiorenal syndrome. We also discuss the available data from studies that have investigated the efficacy of thyroid hormone replacement therapy in patients with renal failure and the rationale for interventional trials to examine the effects of normalization of the thyroid hormone profile in patients with renal failure and congestive heart failure.