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Tetsuhiko Sato

Publications and source records attributed to Tetsuhiko Sato.

18 recordsLinked to original sources
PubMed2007

Recurrent renal hyperparathyroidism caused by parathyromatosis.

BACKGROUND: Parathyromatosis is defined as multiple foci of benign hyperfunctioning parathyroid tissue in the neck or mediastinum. Parathyromatosis is a problematic cause of recurrent hyperparathyroidism (HPT). In renal HPT, the stimuli of the parathyroid cells persist after parathyroidectomy (PTx), and for this reason, parathyromatosis might be important in renal HPT. METHODS: Between July 1973 and December 2005, 1,932 patients underwent PTx for advanced renal HPT in our department. We evaluated the frequency, clinical findings and the prognosis of this kind of parathyroid disorder. RESULTS: After total PTx with forearm autograft for renal HPT, which was performed initially in our department, the risk for developing parathyromatosis was 0.11% (2/1837); after sub-total PTx, it was 5% (1/20). The risk for developing parathyromatosis was lower after total PTx with forearm autograft than after sub-total PTx (P < 0.05). In patients who developed persistent or recurrent HPT and were referred to our department for neck re-operation, parathyromatosis occurred in 12.1% (7/58); in those originally operated on at our hospital, the corresponding figure was 7.1% (3/42). This difference was not significant (P = 0.42). Only in 4 of 10 patients was parathyromatosis suggested before re-operation. However, in spite of several re-operations, high parathyroid hormone (PTH) levels persisted in 6 of 10 patients with parathyromatosis. CONCLUSION: Parathyromatosis is a non-negligible cause of recurrent renal HPT in patients who require neck re-exploration. Parathyromatosis is difficult to diagnose pre-operatively and completely controlled by re-operation. Parathyromatosis should be kept in mind when performing neck re-exploration for recurrent renal HPT.

Adult↗
PubMed2006

Surgical significance of undescended parathyroid gland in renal hyperparathyroidism.

BACKGROUND: In renal hyperparathyroidism, in which basically all parathyroid glands are hyperplastic, overlooking one undescended parathyroid gland becomes important. METHODS: Between July 1973 and December 2004, 1750 patients in our department underwent parathyroidectomy for severely advanced renal hyperparathyroidism. We evaluated the frequency and location of undescended parathyroid glands and the clinical findings and the prognosis of patients with such glands. RESULTS: Undescended parathyroid glands in our series of renal hyperparathyroidism numbered 16 of 1750 cases (0.91%). In 9 patients, the glands were removed at the initial parathyroidectomy in our hospital. Two of these glands were detected by preoperative imaging; 6 glands were removed with an undescended thymus. The mean weight of the undescended parathyroid glands that were removed at initial operations was 470 mg (30 to 1392 mg). In 7 other patients, unrecognized undescended glands were responsible for persistent hyperparathyroidism in 6 patients and recurrent disease in 1 patient. In 4 of these 7 patients, the initial parathyroidectomy was performed at our hospital; in the other 3 patients, the initial parathyroidectomy had been done at another hospital, and the glands were removed on reoperation. The mean weight of these glands was 1295 mg (range, 444-2396 mg). In 12 of a total of 16 patients with undescended glands, there appeared to be an inferior parathyroid gland, and the other 4 glands appeared to be a superior gland. No glands were detected by sestamibi scans. CONCLUSION: In operations for renal hyperparathyroidism, an undescended parathyroid gland can be readily overlooked, which leads to persistent or recurrent hyperparathyroidism. Because an undescended parathyroid gland is not always an inferior gland, in surgery for persistent and/or recurrent renal hyperparathyroidism, it is very important to examine carefully the submandibular portion to detect such an undescended gland.

Adult↗
PubMed2005

A critical role for enhanced TGF-alpha and EGFR expression in the initiation of parathyroid hyperplasia in experimental kidney disease.

The parathyroid hyperplasia secondary to kidney disease is associated with enhanced expression of the growth promoter transforming growth factor-alpha (TGF-alpha). TGF-alpha stimulates growth through activation of its receptor, the epidermal growth factor receptor (EGFR), normally expressed in the parathyroid glands. Because enhanced coexpression of TGF-alpha and EGFR causes aggressive cellular growth, these studies utilized highly specific inhibitors of EGFR tyrosine kinase, a step mandatory for TGF-alpha-induced EGFR activation, to assess the contribution of growth signals from enhanced expression of TGF-alpha exclusively or both TGF-alpha and EGFR to the rapid parathyroid growth induced by kidney disease and exacerbated by high-phosphorus (P) and low-calcium (Ca) diets in rats. The enhancement in parathyroid gland weight and proliferating activity (proliferating cell nuclear antigen/Ki67) induced by kidney disease and aggravated by either high P or low Ca intake, within the first week after 5/6 nephrectomy, in rats, coincided with simultaneous increases (2- to 3-fold) in TGF-alpha and EGFR content. Conversely, prevention of the increases in both TGF-alpha and EGFR paralleled the efficacy of either P restriction or high-Ca intake in ameliorating uremia-induced parathyroid hyperplasia. More importantly, suppression of TGF-alpha/EGFR signaling, through prophylactic administration of potent and highly selective inhibitors of ligand-induced EGFR activation, completely prevented both high-P- and low-Ca-induced parathyroid hyperplasia as well as TGF-alpha self-upregulation. Thus enhanced parathyroid TGF-alpha/EGFR expression, self-upregulation, and growth signals occur early in kidney disease, are aggravated by low-Ca and high-P intake, and constitute the main pathogenic mechanism of the severity of parathyroid hyperplasia.

Animals↗
PubMed2005

Calciphylaxis: a rare complication of patients who required parathyroidectomy for advanced renal hyperparathyroidism.

Calciphylaxis is a relatively rare but life-threatening complication in uremic patients. Clinical findings and prognosis were evaluated in six patients who developed calciphylaxis from a group of 1499 patients who underwent parathyroidectomy (PTx) for advanced renal hyperparathyroidism (HPT) in our department from July 1972 to July 2003. The frequency of calciphylaxis was 0.40% (6/1499). Two patients were women and four were men. The mean age was 50.5 years, and the mean duration of hemodialysis (HD) treatment was 14.0 years. In five of six patients, calciphylaxis was classified as distal type; in one case, as proximal type. In three patients, calciphylaxis was diagnosed at the time for PTx. In two patients, calciphylaxis was identified after PTx, although the serum parathyroid hormone (PTH) level was within the appropriate range for dialysis patients. In two patients, calciphylaxis improved after PTx, but two patients required leg and toe amputations after PTx. In one patient with the proximal type of calciphylaxis, the condition occurred when a high PTH level recurred after the initial PTx. The patient died as a result of a serious infection due to uncontrollable skin ulcers. Calciphylaxis is a rare complication in patients who require PTx for renal HPT. Especially the proximal type has a poor prognosis. High levels of the Ca x P product and/or PTH are risk factors. Therefore, this syndrome should be kept in mind and attention should be paid to reduce risk factors. It is important that PTx being performed at the right time in patients with advanced renal HPT refractory to medical treatment.

Adult↗
PubMed2005

Cardiovascular complications caused by advanced secondary hyperparathyroidism in chronic dialysis patients; special focus on dilated cardiomyopathy.

BACKGROUND: The frequency and prognosis of dilated cardiomyopathy (DCM) caused by secondary hyperparathyroidism (2 degrees HPT) is not known. The purpose of this study was to determine the morbidity of DCM caused by 2 degrees HPT and the efficacy of parathyroidectomy (PTx) in chronic dialysis patients with advanced 2 degrees HPT was analyzed prospectively. METHODS: Between November 2000 and January 2003, 237 dialysis patients who underwent total PTx with forearm autograft at our department were enrolled in this study. Cardiac complications that existed before PTx were examined. Ten patients (4%) had DCM without valvular disease (VD) or ischemic heart disease (IHD). In these 10 patients with DCM before operation, we estimated left ventricular (LV) function at 6 months after PTx, according to echocardiography findings and clinical symptoms. RESULTS: Six months after PTx, left ventricular ejection fraction (LVEF) in these 10 patients was significantly improved, from 31.0 +/- 9.8% before PTx, to 56.8 +/- 13.5% (P = 0.0003), and left ventricular end-diastolic dimension (LVDd) was reduced, from 59.8 +/- 9.7 mm to 46.3 +/- 7.0 mm (P = 0.0014). The symptoms due to DCM and the fall of blood pressure that had occurred during dialysis were clearly improved after PTx. CONCLUSIONS: Advanced 2 degrees HPT can influence LV function, and in patients who suffered from DCM, LV function was dramatically improved by PTx. PTx should be performed immediately in patients with DCM caused by 2 degrees HPT.

Aged↗
PubMed2005

Surgical indications and procedures of parathyroidectomy in patients with chronic kidney disease.

The Kidney Foundation of the USA proposed clinical practice guidelines for bone metabolism and disease in chronic kidney disease including parathyroidectomy (PTx). We performed PTx in a total of 1725 patients with advanced secondary hyperparathyroidism (2HPT) and evaluated the K/DOQI guideline concerning PTx, comparing it with our surgical strategy. The guidelines emphasize the avoidance of ectopic calcification and cardiovascular complications which may be induced by hypercalcemia, hyperphosphatemia, and persistent high parathyroid hormone level. We agree with the attitude of the K/DOQI guideline. To decide surgical indications, we emphasize that the size of parathyroid gland is one of the important factors. The guideline recommends subtotal PTx and total PTx with autotransplantation. We prefer total PTx with forearm autograft, mainly because it is easier and safer to remove the residual parathyroid tissue from the forearm at recurrence compared to neck re-exploration. In Japan, almost all patients require long-term hemodialysis after PTx because of the very small opportunity of kidney transplantation. The risk of recurrence is not negligible. Based on our huge experience we believe our strategy for advanced secondary hyperparathyroidism can be accepted at least in Japan.

Calcium↗
PubMed2005

[Usefulness of power Doppler ultrasonography for the diagnosis of autoinfarction of parathyroid gland in secondary hyperparathyroidism].

Spontaneous remission due to parathyroid infarction of secondary hyperparathyroidism is rare compared with that of primary hyperparathyroidism, probably because several glands are enlarged in secondary hyperparathyroidism. Lately, neck ultrasound examination has become a more beneficial and specific method for the diagnosis of enlarged parathyroid glands in contrast to classic diagnostic techniques such as computed tomography (CT), magnetic resonance imaging (MRI) and scintigraphy. However, the diagnosis of parathyroid infarction reported in previous studies was often based on CT, MRI and scintigraphy findings and there are few studies that reported such diagnosis by urgent power Doppler ultrasonography of the neck. Here we present a hemodialysis patient with autoinfarction of the left parathyroid gland diagnosed by urgent power Doppler ultrasonography of the neck.

Adult↗
PubMed2005

[Two patients with hyperparathyroidism which was progressive for more than ten years after successful kidney transplantation].

It is well known that in some patients advanced renal hyperparathyroidism (HPT) persists after successful kidney transplantation (RTx) and in those patients parathyroidectomy is required usually within one year after RTx. We experienced two patients with advanced renal HPT which released after successful RTx and parathyroidectomy was performed in more than 10 years after RTx, even their kidney function was well-preserved. Hypercalcemia was gradually progressive for ten years after RTx and enlarged parathyroid glands were detected by image diagnosis. We performed parathyroidectomy and HPT was dramatically improved. It is possible that primary HPT occurred de novo after RTx or renal HPT was progressive. We evaluated those possibility based on histopathological findings dramatically improved of removed parathyroid glands.

Disease Progression↗
PubMed2004

1,25-Dihydroxyvitamin D downregulation of TGFalpha/EGFR expression and growth signaling: a mechanism for the antiproliferative actions of the sterol in parathyroid hyperplasia of renal failure.

Elevated serum levels of parathyroid hormone (PTH) contribute to the increased morbidity and mortality in renal failure patients. Parathyroid gland hyperplasia is a major cause of high serum PTH. The present studies used the rat model of renal failure to address the mechanisms underlying uremia-induced parathyroid hyperplasia and the antiproliferative properties of vitamin D therapy (1,25-dihydroxyvitamin D (1,25(OH)(2)D(3)) or its less calcemic analogs). Enhanced TGFalpha/EGFR co-expression is the major mitogenic signal in uremic parathyroid glands. At early stages of renal failure, vitamin D therapy efficiently counteracts uremia- and high phosphorus-induced hyperplasia by inhibiting the increases in parathyroid-TGFalpha/EGFR co-expression. In established hyperparathyroidism, characterized by highly enhanced-TGFalpha/EGFR co-expression, vitamin D therapy arrests growth by suppressing EGFR-growth signals from the plasma membrane and nuclear EGFR actions as a transactivator of the cyclin D1 gene, an important contributor to parathyroid hyperplasia in humans. In advanced renal failure, reduced-parathyroid vitamin D receptor levels limits the antiproliferative efficacy of vitamin D therapy. However, non-antiproliferative doses of 1,25-dihydroxyvitamin D enhance the anti-EGFR actions of EGFR-tyrosine kinase inhibitors (TKI). In fact, combined 1,25-dihydroxyvitamin D/TKI therapy inhibits parathyroid hyperplasia more efficiently than phosphorus restriction, the most powerful promoter of parathyroid growth arrest available at present.

Cell Division↗
PubMed2004

Total parathyroidectomy reduces elevated circulating fibroblast growth factor 23 in advanced secondary hyperparathyroidism.

BACKGROUND: Secondary hyperparathyroidism is a common complication in patients with stage 5 chronic kidney disease (CKD), accelerated by hyperphosphatemia. Fibroblast growth factor 23 (FGF-23), a phosphorus-regulating protein, has key roles in several phosphate-wasting disorders. The aim of this study is to examine the association of advanced secondary hyperparathyroidism with circulating FGF-23 levels. METHODS: Fifteen patients with marked secondary hyperparathyroidism (parathyroid hormone [PTH], 990 +/- 118 pg/mL [ng/L]) were enrolled. All underwent parathyroidectomy with forearm autotransplantation (PTX), and their FGF-23 levels were measured before and after PTX (days 1, 3, 7, and 10) by means of sandwich enzyme-linked immunosorbent assay. RESULTS: Preoperative FGF-23 levels correlated positively with phosphorus (P < 0.05), calcium-phosphorus product (Ca x P; P < 0.0005), and PTH values (P < 0.05). Serum FGF-23 levels decreased time dependently after PTX (P < 0.0005). Both serum phosphorus and Ca x P values decreased similarly after PTX ( P = 0.0001). Furthermore, FGF-23 levels days 1 and 3 correlated linearly with serum phosphorus (P < 0.05; P < 0.005, respectively) and Ca x P values (P < 0.01; P < 0.0001, respectively). CONCLUSION: FGF-23 levels correlate positively with serum phosphorus, Ca x P, and PTH values in patients with advanced secondary hyperparathyroidism. Complete ablation of progressive parathyroid glands reduces circulating FGF-23 levels, simultaneously decreasing serum phosphorus and Ca x P values. These findings suggest that hyperplastic parathyroid glands, together with hyperphosphatemia, affect abnormal FGF-23 metabolism in patients with stage 5 CKD with advanced secondary hyperparathyroidism.

Chronic Disease↗
PubMed2004

Infarction of mediastinal parathyroid gland causing spontaneous remission of secondary hyperparathyroidism.

Secondary hyperparathyroidism is a serious complication in long-term hemodialysis patients. The authors report on 2 patients on long-term hemodialysis who suffered from persistent secondary hyperparathyroidism due to missed mediastinal parathyroid gland after total parathyroidectomy with forearm autograft. Reoperation was planned. In both cases, severe hypocalcemia suddenly developed; serum parathyroid hormone (PTH) level decreased markedly after this episode. The serum calcium level increased gradually in response to administration of vitamin D and calcium carbonate, but serum PTH level remained low. A follow-up computed tomography scan showed that the formerly enlarged mediastinal parathyroid gland was markedly reduced in size. Moreover, a hot spot formerly detected by technetium 99m-MIBI (methoxy-isobutyl-isonitrile) scintigraphy in the mediastinum disappeared after this episode. The authors considered that necrosis of the enlarged ectopic parathyroid gland, probably due to infarction, resulted in hypocalcemia. To the authors' knowledge, this is the first case report of spontaneous mediastinal parathyroid autoinfarction after parathyroidectomy in hemodialysis patients.

Choristoma↗
PubMed2003

Diabetes mellitus after transplant: relationship to pretransplant glucose metabolism and tacrolimus or cyclosporine A-based therapy.

OBJECTIVE: The purpose of this study was to identify pretransplantation and posttransplantation indicators for the development of diabetes mellitus in the first 2 months after renal transplantation and to examine the influence of a cyclosporine A (CsA)-based versus a tacrolimus-based immunosuppressive regimen on these risk factors. METHODS: Key variables associated with the development of posttransplant diabetes mellitus (PTDM) in the first 2 months after transplantation were assessed in 48 patients who underwent living-related renal transplantation and who were treated with a CsA-based or a tacrolimus-based immunosuppressive regimen. The insulinogenic index (I Index) and glucose infusion rate (GIR) were measures of insulin secretion and insulin sensitivity, respectively. RESULTS: Eight patients developed PTDM. I Index (odds ratio, 0.000384) and GIR (odds ratio, 0.349) were significant risk factors for PTDM development. The cumulative steroid dose had a borderline association. PTDM developed in 4 of 28 CsA-treated patients and in 4 of 20 tacrolimus-treated patients. CsA therapy increased the mean I Index from 0.713+/-0.071 preoperatively to 1.130+/-0.140 postoperatively (P<0.01), whereas in tacrolimus-treated patients, I Index remained unchanged (1.09+/-0.264 preoperatively and 0.949+/-0.296 postoperatively; P=not significant). Age, duration of pretransplant dialysis, and body mass index did not predict PTDM development. All eight patients with PTDM had hypertension. CONCLUSIONS: Pre- and posttransplant abnormalities of insulin secretion and sensitivity are significant predictors of PTDM. Corticosteroid cumulative dose may affect the incidence of PTDM during the first 2 months after transplantation. CsA treatment increases insulin secretion in patients with a high pretransplant risk of PTDM.

Adult↗
PubMed2003

Re-operation is frequently required when parathyroid glands remain after initial parathyroidectomy for advanced secondary hyperparathyroidism in uraemic patients.

BACKGROUND: Parathyroidectomy (PTx) is the most successful treatment for advanced secondary hyperparathyroidism (2HPT) not responsive to medical treatment. However, persistent HPT remains problematic after PTx if some glands remain. The clinical course in patients with persistent 2HPT was evaluated to clarify the risk for re-operation after PTx. METHODS: Between March 1981 and December 2001, initial total PTx with forearm autograft were performed in 1156 uraemic patients. Persistent HPT cases were defined as those in which the lowest post-operative intact parathyroid hormone (i-PTH) concentration was >60 pg/ml, and patients were classified into groups A, B and C, with i-PTH concentrations of >or=500, 300-500 and 60-300 pg/ml, respectively. These patients were followed for 7-234 months after PTx. RESULTS: Persistent HPT was identified in 49/1156 patients (4.2%), with nine cases in group A, 10 in group B and 30 in group C. Re-operation was required in 21/49 (42.8%) cases, and in seven of these the last i-PTH concentration was >or=500 pg/ml. All cases in group A required re-operation. In group C, 11/30 (36.7%) patients required re-operation. The missed glands removed at re-operation were supernumerary in 14 cases, and located in the mediastinum in 13 cases. The frequency of advanced HPT and re-operation was not negligible. CONCLUSIONS: To prevent persistent 2HPT, all parathyroid glands must be found and resected during the initial operation. Even if small parathyroid glands remain, there is a risk of progression. Complete PTx is the first treatment choice for advanced 2HPT.

Female↗
PubMed2002

Reoperation for renal hyperparathyroidism.

Reoperation for secondary hyperparathyroidism (HPT) due to uremia (2HPT) may be required among patients with persistent renal failure if not all parathyroid glands are removed at the initial operation. Between March 1981 and July 2001, altogether 1,110 patients underwent total parathyroidectomy with forearm autograft for advanced 2HPT in our department. In this study, we evaluated the clinical features of patients who required reoperation and classified them into persistent HPT [the lowest intact parathyroid (PTH) level after initial operation remained higher than 60 pg/ml] and recurrent HPT (the lowest intact PTH level was normalized after surgery but reelevated became high enough to require reoperation). Removal of residual glands was indicated in 30 (2.7%) cases for persistent or recurrent HPT. All remaining glands were detected by preoperative imaging diagnoses. In 44 (4.0%) patients persistent HPT was recognized and in 15 of them (1.4% of all cases) reoperation was required. In 11 cases, the responsible glands were supernumerary ones removed from the mediastinum. In 4 cases, the glands were resected from the neck. In 15 cases (1.4%), reoperation was performed for recurrent HPT when residual glands were left either in the neck or in the thymic tongue. In all but one case, the missed glands were supernumerary. This study reveals that it is often difficult to avoid persistent HPT induced by mediastinal supernumerary glands and recurrent HPT caused by small glands left in the neck. Our findings indicate that patients with uremia should be closely followed considering the possibility that persistent or recurrent HPT may occur after parathyroidectomy.

Adult↗
PubMed2002

[PTH and non-classical target organs--ligand-receptor interaction in end stage renal disease (ESRD)].

Secondary hyperparathyrodism and uremic symptoms have long been discussed for more than 2 decades. Its relevance may indicate PTH-receptor interaction in ESRD. Two human PTH receptors (PTH1R, PTH2R) are now identified and distributed in extrarenal and extraskeletal organs, such as nerve system, cardiovascular system and lung. These organ-related symptoms and complications may be related to elevated PTH levels in ESRD. PTH should be well-controlled within optimized levels to prevent irreversible serious complications.

English Abstract↗