Joseph R. Tucci

Mutations in Kelch-like 3 and Cullin 3 cause hypertension and electrolyte abnormalities

Hypertension affects one billion people and is a principal reversible risk factor for cardiovascular disease. Pseudohypoaldosteronism type II (PHAII), a rare Mendelian syndrome featuring hypertension, hyperkalaemia and metabolic acidosis, has revealed previously unrecognized physiology orchestrating the balance between renal salt reabsorption and K+ and H+ excretion. Here we used exome sequencing to identify mutations in kelch-like 3 (KLHL3) or cullin 3 (CUL3) in PHAII patients from 41 unrelated families. KLHL3 mutations are either recessive or dominant, whereas CUL3 mutations are dominant and predominantly de novo. CUL3 and BTB-domain-containing kelch proteins such as KLHL3 are components of cullin–RING E3 ligase complexes that ubiquitinate substrates bound to kelch propeller domains. Dominant KLHL3 mutations are clustered in short segments within the kelch propeller and BTB domains implicated in substrate and cullin binding, respectively. Diverse CUL3 mutations all result in skipping of exon 9, producing an in-frame deletion. Because dominant KLHL3 and CUL3 mutations both phenocopy recessive loss-of-function KLHL3 mutations, they may abrogate ubiquitination of KLHL3 substrates. Disease features are reversed by thiazide diuretics, which inhibit the Na–Cl cotransporter in the distal nephron of the kidney; KLHL3 and CUL3 are expressed in this location, suggesting a mechanistic link between KLHL3 and CUL3 mutations, increased Na–Cl reabsorption, and disease pathogenesis. These findings demonstrate the utility of exome sequencing in disease gene identification despite the combined complexities of locus heterogeneity, mixed models of transmission and frequent de novo mutation, and establish a fundamental role for KLHL3 and CUL3 in blood pressure, K+ and pH homeostasis.

Effect of Three Years of Oral Alendronate Treatment in Postmenopausal Women with Osteoporosis

OBJECTIVE Oral alendronate sodium is a potent, specific inhibitor of osteoclast-mediated bone resorption. To assess its efficacy and safety, a 3-year, randomized, double-blind, multicenter study of 478 postmenopausal women with osteoporosis was conducted. PATIENTS AND METHODS Subjects received either placebo, alendronate 5 or 10 mg/day for 3 years, or 20 mg/day for 2 years followed by 5 mg/day for 1 year (20/5 mg). All subjects received 500 mg/day of supplemental calcium. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry (DXA). RESULTS After 3 years, alendronate 10 mg induced marked increases in BMD of the lumbar spine (9.6 +/- 0.4%), femoral neck (4.7 +/- 0.7%) and trochanter (7.4 +/- 0.6%) (mean +/- SE; each P < or = 0.001) versus decreases of 0.8 to 1.6% with placebo. Progressive increases at these sites in the alendoronate 10 mg group were significant during both the second and third years. Alendronate 10 mg increased total body BMD (1.6 +/- 0.3%, P < or = 0.001), and prevented loss but did not increase BMD at the 1/3 forearm site. Alendronate 20/5 mg was no more effective, whereas alendronate 5 mg was significantly less effective than 10 mg at all sites. Bone turnover decreased to a stable nadir over 3 months for resorption markers (urine deoxypyridinoline) and over 6 months for formation markers (alkaline phosphatase and osteocalcin). Mean loss of stature was reduced by 41% in alendronate treated subjects (P = 0.01). CONCLUSION The safety profile of alendronate was similar to that of placebo. At 10 mg, there were no trends toward increased frequency of any adverse experience except for abdominal pain, which was usually mild, transient, and resolved with continued treatment. Thus, alendronate appears to be an important advance in the treatment of osteoporosis in postmenopausal women.

Risedronate in the Treatment of Paget's Disease of Bone: An Open Label, Multicenter Study

An open‐label, multicenter study was conducted to determine the efficacy and safety of oral risedronate (a pyridinyl bisphosphonate) in 162 patients (102 men, 60 postmenopausal women; mean age, 68 years) with moderate to severe Pagets disease of bone (mean serum alkaline phosphatase [ALP] approximately seven times the upper limit of normal). Patients were treated with oral risedronate, 30 mg/day for 84 days, followed by 112 days without treatment. This 196‐day cycle was repeated once if serum ALP did not normalize or increased from the nadir value by ≥25%. At the end of the first and second cycles, the mean percentage decreases for serum ALP were 65.7% and 69.1%, and for urinary hydroxyproline/creatinine 50.4% and 66.9%, respectively. The decreases from baseline in ALP and urinary hydroxyproline/creatinine were significant (p < 0.001). Normalization of serum ALP was observed in 86 patients (53.8%): 53 during the first treatment cycle and 33 during the second. There was a significant proportion of patients reporting a decrease in the pagetic bone pain at days 84 and 196 (p < 0.001). Overall, risedronate was well tolerated. Five patients withdrew due to adverse events, none of which were considered to be drug related. In conclusion, 30 mg of oral risedronate administered daily for 84 days significantly reduced the biochemical indices of disease activity and was associated with pain reduction in patients with moderate to severe Pagets disease of bone. Normalization of ALP was observed in the majority of patients. Repeated administration of risedronate was shown to be beneficial. In general, risedronate was well tolerated and demonstrated a good safety profile.

Vitamin D therapy in patients with primary hyperparathyroidism and hypovitaminosis D

OBJECTIVE To determine whether vitamin D repletion of patients with primary hyperparathyroidism (PHPT) and vitamin D deficiency or insufficiency (hypovitaminosis D) has deleterious clinical and/or biochemical effects. DESIGN Prospective audit of the effect of vitamin D repletion on biochemical data in 56 patients with PHPT. Patients were treated with 50,000 units of vitamin D2 weekly for 8 weeks with biochemical measurements at 5 and 10 weeks, and subsequently after 12 weeks on 800 units of vitamin D3 daily, and in those with hypovitaminosis D after 12 weeks of up to 100 000 units of vitamin D(2) monthly. METHODS Serum calcium, albumin, phosphorus, 25-OHD, intact parathyroid hormone (PTH) and urine calcium/creatinine (Ca/Cr) ratios were measured before and during vitamin D therapy. RESULTS Patients treated with 50,000 units of vitamin D2 weekly for 8 weeks resulted in a significant increase in serum 25-OHD levels from 36.4 to 89.4 nmol/l at 5 weeks (P<0.0001) and 88.6 nmol/l at 10 weeks (P<0.0001). There were no significant changes in serum calcium. At 10 weeks, there was a non-significant decrease in serum PTH and in urine Ca/Cr ratios. None of the patients developed any calcium-related adverse events. Subsequently, patients with subnormal 25-OHD levels on 800 units of vitamin D daily were treated for the next 12 weeks with up to 100,000 units of vitamin D2 monthly with normalization of serum 25-OHD in all but 4 patients. CONCLUSION These data fail to demonstrate any adverse effects of vitamin D repletion in PHPT.

Endocrine Studies in an Arrhenoblastoma Responsive to Dexamethasone, ACTH and Human Chorionic Gonadotropin

Abstract Urinary and plasma steroid studies were performed in a 19 year old girl before and after removal of a virilizing arrhenoblastoma. Prior to surgery, base line urinary 17-ketosteroid (17-KS) excretion levels were slightly elevated whereas the plasma testosterone level was markedly elevated and in the normal male range. Individual 17-KS levels were within the normal range, but there was an abnormal androsterone to etiocholanolone ratio. Dexamethasone administration resulted in a fall in plasma testosterone levels and a decrease in urinary 17-KS excretion. The administration of both human chorionic gonadotrophin (HCG) and ACTH was associated with impressive increments in plasma testosterone and/or urinary 17-KS excretion, whereas the administration of HCG alone resulted in increments in only the 11-deoxy 17-KS fractions; ACTH alone raised both the 11-deoxy and 11-oxy 17-KS fractions, with the most notable changes occurring in the former. Within 1 week of surgery, the plasma testosterone level had fallen to normal and urinary 17-KS excretion to subnormal levels. The pre- and postoperative peripheral blood and urinary studies, and the finding of an elevated ovarian vein testosterone level on the side draining the tumor at the time of surgery, demonstrate testosterone secretion by the tumor and, for the first time, an arrhenoblastoma unique in its hormonal responsiveness to dexamethasone, HCG and ACTH.

Excretion of sweat and urine pyridinoline crosslinks in healthy controls and subjects with established metabolic bone disease.

Abstract Convenient techniques for measuring rates of bone turnover have been developed in recent years with the advent of biochemical markers of bone metabolism. One recent of these techniques is a collection method and quantitative enzyme immunoassay for free pyridinoline crosslinks in human sweat. The concentrations of pyridinoline crosslinks in 5-day sweat collections and first morning void and 24-hour urine collections from healthy subjects and subjects with established metabolic bone disorders were determined. T-scores were higher in the sweat system than in the urine system by up to 10-fold in postmenopausal subjects, women with hyperparathyroidism, and subjects with postmenopausal osteoporosis. For subjects with postmenopausal osteoporosis, receiver-operating characteristic curve analysis yielded areas under the curve of 0.699, 0.629, and 0.520 for sweat pyridinoline, first morning void urine pyridinoline, and 24 hour urine pyridinoline respectively. The areas under the curve of the sweat and first morning void urine measurements were significantly greater (p﹤0.05) than the 24-hour pyridinoline measurements. Healthy postmenopausal subjects and subjects with postmenopausal osteoporosis were monitored before and during estrogen replacement therapy or alendronate therapy. Sweat pyridinoline values declined by 49.0 ±12.4％ and 19.4 ±19.9％ for estrogen and alendronate subjects respectively. We conclude that this non-invasive technique is a sensitive and specific measure of bone resorption and is appropriate as an adjunct to techniques such as bone density and may also be useful in monitoring of response to anti-resorptive therapies.

Ten Years’ Experience With Alendronate for Osteoporosis in Postmenopausal Women

BACKGROUND Antiresorptive agents are widely used to treat osteoporosis. We report the results of a multinational randomized, double-blind study, in which postmenopausal women with osteoporosis were treated with alendronate for up to 10 years. METHODS The initial three-year phase of the study compared three daily doses of alendronate with placebo. Women in the original placebo group received alendronate in years 4 and 5 and then were discharged. Women in the original active-treatment groups continued to receive alendronate during the initial extension (years 4 and 5). In two further extensions (years 6 and 7, and 8 through 10), women who had received 5 mg or 10 mg of alendronate daily continued on the same treatment. Women in the discontinuation group received 20 mg of alendronate daily for two years and 5 mg daily in years 3, 4, and 5, followed by five years of placebo. Randomized group assignments and blinding were maintained throughout the 10 years. We report results for the 247 women who participated in all four phases of the study. RESULTS Treatment with 10 mg of alendronate daily for 10 years produced mean increases in bone mineral density of 13.7 percent at the lumbar spine (95 percent confidence interval, 12.0 to 15.5 percent), 10.3 percent at the trochanter (95 percent confidence interval, 8.1 to 12.4 percent), 5.4 percent at the femoral neck (95 percent confidence interval, 3.5 to 7.4 percent), and 6.7 percent at the total proximal femur (95 percent confidence interval, 4.4 to 9.1 percent) as compared with base-line values; smaller gains occurred in the group given 5 mg daily. The discontinuation of alendronate resulted in a gradual loss of effect, as measured by bone density and biochemical markers of bone remodeling. Safety data, including fractures and stature, did not suggest that prolonged treatment resulted in any loss of benefit. CONCLUSIONS The therapeutic effects of alendronate were sustained, and the drug was well tolerated over a 10-year period. The discontinuation of alendronate resulted in the gradual loss of its effects.

Normocalcemic primary hyperparathyroidism associated with progressive cortical bone loss – A case report

The existence of normocalcemic primary hyperparathyroidism (NPHP) was acknowledged at the Third and Fourth International Proceedings on primary hyperparathyroidism PHPT but data relating to its clinical presentation, natural history, and skeletal status were limited and there was no information nor guidelines as to definitive therapy. Herein are reported biochemical, hormonal, and densitometry data in a postmenopausal woman seen initially for osteoporosis who was found to have increased serum PTH levels and normal serum total and ionized calcium levels without evidence of secondary hyperparathyroidism. Over a seven year period, the patient exhibited continuing preferential cortical bone loss at the one-third site of the radius in the face of relatively stable readings at the lumbar spine and hip that led to a subtotal parathyroidectomy for parathyroid hyperplasia with resultant normalization of serum PTH.

Effect of zoledronic acid on serum calcium in Paget's disease patients after educational strategies to improve calcium and vitamin D supplementation.

Objective: Bisphosphonates are the most effective therapeutic agents in patients with Paget’s disease of bone. As a result of their inhibition of osteoclastic activity, hypocalcemia of variable frequency and severity following intravenous bisphosphonate therapy has been reported. The present study assessed the effect of physician and patient education on adequate supplementation of calcium and vitamin D to reduce the potential risk of developing hypocalcemia following infusion of 5 mg zoledronic acid. Methods: This was an open-label, multicenter, controlled registry trial in which patients with Paget’s disease were treated with a single intravenous infusion of zoledronic acid. Physicians were provided with educational materials focusing on optimization of calcium and vitamin D supplementation following zoledronic infusion that they used to educate their patients. The primary safety variable was the percentage of patients with serum calcium level <2.07mmol/l 9–11 days after zoledronic acid infusion. Results: A total of 75 patients were evaluable in the post dose hypocalcemia safety analysis. Of these, only 1 patient had treatment-emergent hypocalcemia, with a serum calcium level of 1.92 mmol/l 4 days following therapy. Hypocalcemia-related symptoms were not reported in this patient and the serum calcium returned to normal range at 2.17 mmol/l within 1 week on oral calcium supplementation. Conclusions: These results suggest that, with optimization of calcium and vitamin D supplementation by physician and patient education, hypocalcemia is an infrequent occurrence following zoledronic acid infusion.

Preoperative Management of Paget’s Disease

Orthopedic surgery may be necessary for the management of complications due to Paget’s disease such as treatment refractory hip pain due to secondary osteoarthritis, pathologic or impending fracture of the femur, and progressive femoral deformity and malalignment. Potential complications during and following surgery on pagetic bone include pathologic fracture, excessive bleeding peri- and postoperatively due to increased vascularity of pagetic bone, delayed union or nonunion, and heterotopic ossification. A thorough preoperative medical evaluation in patients with Paget’s disease particularly in those with polyostotic disease is necessary prior to an orthopedic procedure on pagetic bone. Prior to antipagetic therapy, vitamin D and calcium status should be assessed and managed to prevent bisphosphonate induced hypocalcemia and to optimize the response to orthopedic surgery. Antipagetic therapy with a bisphosphonate and/or calcitonin will decrease pagetic activity, prevent or diminish excess peri- and postoperative blood loss, and post-immobilization hypercalcemia.