1
|
Reid DG, Duer MJ, Jackson GE, Murray RC, Rodgers AL, Shanahan CM. Citrate occurs widely in healthy and pathological apatitic biomineral: mineralized articular cartilage, and intimal atherosclerotic plaque and apatitic kidney stones. Calcif Tissue Int 2013; 93:253-60. [PMID: 23780351 DOI: 10.1007/s00223-013-9751-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 05/14/2013] [Indexed: 11/25/2022]
Abstract
There is continuing debate about whether abundant citrate plays an active role in biomineralization of bone. Using solid state NMR dipolar dephasing, we examined another normally mineralized hard tissue, mineralized articular cartilage, as well as biocalcifications arising in pathological conditions, mineralized intimal atherosclerotic vascular plaque, and apatitic uroliths (urinary stones). Residual nondephasing ¹³C NMR signal at 76 ppm in the spectra of mineralized cartilage and vascular plaque indicates that a quaternary carbon atom resonates at this frequency, consistent with the presence of citrate. The presence, and as yet unproven possible mechanistic involvement, of citrate in tissue mineralization extends the compositional, structural, biogenetic, and cytological similarities between these tissues and bone itself. Out of 10 apatitic kidney stones, five contained NMR-detectable citrate. Finding citrate in a high proportion of uroliths may be significant in view of the use of citrate in urolithiasis therapy and prophylaxis. Citrate may be essential for normal biomineralization (e.g., of cartilage), play a modulatory role in vascular calcification which could be a target for therapeutic intervention, and drive the formation of apatitic rather than other calcific uroliths, including more therapeutically intractable forms of calcium phosphate.
Collapse
Affiliation(s)
- David G Reid
- Department of Chemistry, University of Cambridge, UK
| | | | | | | | | | | |
Collapse
|
2
|
Xu H, Zisman AL, Coe FL, Worcester EM. Kidney stones: an update on current pharmacological management and future directions. Expert Opin Pharmacother 2013; 14:435-47. [PMID: 23438422 DOI: 10.1517/14656566.2013.775250] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Kidney stones are a common problem worldwide with substantial morbidities and economic costs. Medical therapy reduces stone recurrence significantly. Much progress has been made in the last several decades in improving therapy of stone disease. AREAS COVERED This review discusses i) the effect of medical expulsive therapy on spontaneous stone passage, ii) pharmacotherapy in the prevention of stone recurrence and iii) future directions in the treatment of kidney stone disease. EXPERT OPINION Fluid intake to promote urine volume of at least 2.5 L each day is essential to prevent stone formation. Dietary recommendations should be adjusted based on individual metabolic abnormalities. Properly dosed thiazide treatment is the standard therapy for calcium stone formers with idiopathic hypercalciuria. Potassium alkali therapy is considered for hypocitraturia, but caution should be taken to prevent potential risk of calcium phosphate stone formation. For absorptive hyperoxaluria, low oxalate diet and increased dietary calcium intake are recommended. Pyridoxine has been shown effective in some cases of primary hyperoxaluria type I. Allopurinol is used in calcium oxalate stone formers with hyperuricosuria. Treatment of cystine stones remains challenging. Tiopronin can be used if urinary alkalinization and adequate fluid intake are insufficient. For struvite stones, complete surgical removal coupled with appropriate antibiotic therapy is necessary.
Collapse
Affiliation(s)
- Hongshi Xu
- University of Chicago Medical Center, University of Chicago Pritzker School of Medicine, Chicago, IL, USA
| | | | | | | |
Collapse
|
3
|
Assimos DG. Re: Insurance Status, Stone Composition, and 24-Hour Urine Composition. J Urol 2013. [DOI: 10.1016/j.juro.2013.04.104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
4
|
Strohmaier WL, Seilnacht J, Schubert G. Urinary stone formers with hypocitraturia and 'normal' urinary pH are at high risk for recurrence. Urol Int 2012; 88:294-7. [PMID: 22398801 DOI: 10.1159/000335441] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 11/25/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND Citrate is one of the most important inhibitors in urolithiasis. Hypocitraturia is a common risk factor in stone formers. Citrate excretion is regulated - amongst others - by acidosis and protein intake. A considerable number of stone formers, however, show hypocitraturia in the presence of normal urine pH levels. This is potentially due to defects in the renal tubular citrate carriers (NaDC 1 and 3) which may be genetically determined. PATIENTS AND METHODS 350 consecutive stone formers were examined. Exclusion criteria were urinary tract infection, hypokalemia, and steatorrhea. The following parameters were measured: serum: creatinine, calcium, potassium, and uric acid; urine: pH profiles, citrate, calcium, uric acid, ammonia, urea, and creatinine. RESULTS 83/350 patients were hypocitraturic (48 males, 35 females). 14/83 had low urine pH (≤ 6), 69/83 showed normal levels (>6). In the latter group there was a significantly higher recurrence rate (23 vs. 9%). The two groups were not different in serum parameters apart from uric acid. In urine, only pH and calcium (males) were significantly lower in the first group. Citrate did not correlate with urine pH and creatinine in the hypocitraturia-normal pH group, only with calcium in both sexes and urea and ammonia in females. In the hypocitraturia-low pH patients, there was no significant correlation between citrate and any other parameter tested. CONCLUSIONS Hypocitraturia with normal urine pH is an entity indicating a high risk for recurrence. Since there was no correlation between citrate and pH, urea and ammonia, respectively, citrate excretion is not regulated in these patients as usual. There may be a link to calcium excretion. Potentially, these patients have defects in the renal tubular citrate carriers which may be genetically determined. Genetic examinations should be performed to elucidate a potential genetic disorder in hypocitraturia-normal pH stone formers.
Collapse
Affiliation(s)
- Walter Ludwig Strohmaier
- Department of Urology and Pediatric Urology, Klinikum Coburg, Coburg, Germany. walter.strohmaier @ klinikum-coburg.de
| | | | | |
Collapse
|
5
|
SU WS, LEKAS P, CARLISLE EJ, COWIN R, BELLAMY J, MARGETTS PJ, BRIMBLE KS, CLASE CM, GANGJI AS. Management of hypophosphatemia in nocturnal hemodialysis with phosphate-containing enema: A technical study. Hemodial Int 2011; 15:219-25. [DOI: 10.1111/j.1542-4758.2011.00533.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
6
|
Parks JH, Coe FL, Evan AP, Worcester EM. Urine pH in renal calcium stone formers who do and do not increase stone phosphate content with time. Nephrol Dial Transplant 2008; 24:130-6. [PMID: 18662977 DOI: 10.1093/ndt/gfn420] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Calcium phosphate (CaP) renal stones appear to be increasing in prevalence, and are caused by high urine CaP supersaturation, which arises from genetic hypercalciuria and high urine pH. Renal damage from stones or procedures, or treatments for stone could raise urine pH; alternatively pH may be intrinsically high in some people who are thereby predisposed to CaP stones. METHODS To distinguish these alternatives we sequenced changes in urine pH and stone CaP content asking which occurs first in patients whose stones showed progressive increase in CaP over time. From 4767 patients we found 62 in whom we could document transformation from calcium oxalate (CaOx) to CaP stones, and 134 CaOx controls who did not transform. Laboratory and clinical finding were contrasted between these groups. RESULTS Even when patients were forming relatively pure CaOx stones, those destined to increase stone CaP had higher urine pH than controls who never did so. Their higher pH was present before and during treatments to prevent new stone formation. Shock wave lithotripsy was strongly associated with increasing stone CaP but urine pH bore no relationship to number of procedures. CONCLUSION We conclude that high pH may not be acquired as a result of stones or their treatments but may precede transformation from CaOx to CaP stones and arise from diet or possibly heredity.
Collapse
Affiliation(s)
- Joan H Parks
- Department of Medicine, Nephrology Section, University of Chicago, Chicago, IL 60637, USA
| | | | | | | |
Collapse
|
7
|
Vega D, Maalouf NM, Sakhaee K. Increased propensity for calcium phosphate kidney stones with topiramate use. Expert Opin Drug Saf 2007; 6:547-57. [PMID: 17877442 DOI: 10.1517/14740338.6.5.547] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Topiramate (TPM) is a neuromodulatory agent that was initially approved as an antiepileptic drug and is increasingly used in the treatment of a number of neurological and metabolic disorders. Among its various pharmacological actions, TPM has been shown to inhibit the activity of specific carbonic anhydrase enzymes in the kidney. This action is associated with the development of metabolic acidosis, hypocitraturia, hypercalciuria and elevated urine pH, leading to an increased risk of kidney stone disease. Despite the cautionary note in the package insert of TPM, the extent of these complications has not been fully explored. Few prescribing physicians are aware of these complications, underscoring the need for improved surveillance. Because the drug is among the most frequently prescribed agents in the US, more controlled studies are required to determine the prevalence of kidney stone disease among TPM users, and the optimal approach to prevent and treat nephrolithiasis in these individuals.
Collapse
Affiliation(s)
- Damaris Vega
- University of Texas Southwestern Medical Center, Department of Internal Medicine and Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, 5323 Harry Hines Boulevard, Dallas, TX 75390-8885, USA
| | | | | |
Collapse
|
8
|
Tang R, Nancollas GH, Giocondi JL, Hoyer JR, Orme CA. Dual roles of brushite crystals in calcium oxalate crystallization provide physicochemical mechanisms underlying renal stone formation. Kidney Int 2006; 70:71-8. [PMID: 16641926 DOI: 10.1038/sj.ki.5000424] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Calcium oxalate monohydrate (COM) crystals are the major mineral component of most kidney stones, and thus have an important role in chronic human disease. However, the physicochemical mechanisms leading to calcium oxalate (CaOx) stone disease are only partially defined. As spontaneous precipitation of CaOx is rare under renal conditions, an alternative pathway for CaOx crystallization seems necessary to resolve this central issue. We performed kinetic studies using the dual constant composition method to simultaneously analyze the crystallization of COM and brushite, the form of calcium phosphate that is most readily formed in the typical slightly acidic urinary milieu. These studies were supported by parallel analysis by scanning electron and atomic force microscopy. In these studies, mineralization of a thermodynamically stable phase (COM) was induced by the presence of brushite, a more readily precipitated inorganic phase. Furthermore, once formed, the COM crystals grew at the expense of brushite crystals causing the dissolution of the brushite crystals. These studies show that brushite may play crucial roles in the formation of COM crystals. The definition of these two roles for brushite thereby provides physicochemical explanations for the initiation of COM crystallization and also for the relative paucity of calcium phosphate detected in the majority of CaOx renal stones.
Collapse
Affiliation(s)
- R Tang
- Department of Chemistry, The State University of New York at Buffalo, Buffalo, New York 14260, USA
| | | | | | | | | |
Collapse
|
9
|
Parks JH, Worcester EM, Coe FL, Evan AP, Lingeman JE. Clinical implications of abundant calcium phosphate in routinely analyzed kidney stones. Kidney Int 2004; 66:777-85. [PMID: 15253733 DOI: 10.1111/j.1523-1755.2004.00803.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND To better portray the clinical phenotype of kidney stone patients with high calcium phosphate (CaP) stone abundance, we present here clinical and laboratory findings of large numbers of stone formers (SF) with stone CaP ranging from 0% to 100%. Our purpose was to inform clinicians and highlight areas that seem to deserve further research. METHODS We calculated average percent CaP (CaP%) in all stones of 1201 patients, and classified them into CaOx (N= 1011) or CaP (N= 190). Sex differences, stone formation rates, urine stone risk factors, extracorporeal shock wave lithotripsy (ESWL) treatments, and relapse during treatment were quantified in relation to stone CaP content. RESULTS CaP% has risen for three decades, especially among women. ESWL rates adjusted for numbers of stones and duration of stone disease were higher in CaP SF (0.6 vs. 1.86 and 0.73 vs. 1.82, CaOx vs. CaP, men and women, respectively, P < 0.001), and especially when stones contained brushite (2.90 vs. 1.02 and 3.11 vs. 1.35, brushite vs. not, males and females, respectively, P < 0.001). Urine pH and CaP supersaturation rose in proportion to CaP% in a dose response manner. Relapse rates of CaP and CaOx SF did not differ, and both did well with medical prevention. CONCLUSION Stone CaP% has risen for three decades. CaP SF, particularly with brushite stones, receive more ESWL treatments than CaOx SF, not explained by stone number or duration of stone disease. Urine supersaturations explain the high CaP%. High CaP% does not hamper medical stone prevention.
Collapse
Affiliation(s)
- Joan H Parks
- Nephrology Section, Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
| | | | | | | | | |
Collapse
|
10
|
Zamboni WC, Jung LL, Egorin MJ, Potter DM, Friedland DM, Belani CP, Agarwala SS, Wong MMW, Fakih M, Trump DL, Jin R, Strychor S, Vozniak M, Troetschel M, Ramanathan RK. Phase I and Pharmacologic Study of Intermittently Administered 9-Nitrocamptothecin in Patients with Advanced Solid Tumors. Clin Cancer Res 2004; 10:5058-64. [PMID: 15297407 DOI: 10.1158/1078-0432.ccr-03-0288] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE 9-Nitrocamptothecin (9NC) is an oral camptothecin analogue currently administered at 1.5 mg/m(2)/day x 5 days/week in Phase III studies for pancreatic carcinoma. In an effort to increase the dose administered per day and determine whether the daily dose or number of days of treatment influence toxicity, we performed a Phase I study of 9NC using intermittent schedules of administration. EXPERIMENTAL DESIGN On schedule A, 9NC was administered orally daily x 5 days for 2 weeks every 4 weeks (one cycle). On schedule B, 9NC was administered orally daily x 14 days every 4 weeks (one cycle). Dose levels were determined by adaptive dose finding. Serial blood samples were obtained on day 1 of each schedule for pharmacokinetic studies of 9NC and its 9-aminocamptothecin (9AC) metabolite, and lactone forms were measured by high-performance liquid chromatography. RESULTS The recommended Phase II doses for schedules A and B were 2.43 and 1.70 mg/m(2)/day, respectively, each providing the same dose intensity (i.e., 24 mg/m(2)/cycle). The primary toxicities on schedules A and B were neutropenia, thrombocytopenia, and diarrhea. On schedule A, two patients with gastric cancer and two patients with pancreatic cancer had stable disease for more than six cycles. On schedule B, one patient with pancreatic cancer had stable disease for more than six cycles, and a patient with pancreatic cancer had a partial response. There was significant interpatient variability in the disposition of 9NC and 9AC. Most of the drug remained in the 9NC form with a ratio of 9NC to 9AC of approximately 4 to 1. CONCLUSIONS These studies suggest that 9NC administered on an intermittent schedule is tolerable and may be an active regimen in patients with gastric or pancreatic cancers. Dosing 9NC on a mg/m(2) basis does not reduce pharmacokinetic variability.
Collapse
Affiliation(s)
- William C Zamboni
- Program of Molecular Therapeutics and Drug Discovery, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Schwille PO, Schmiedl A, Manoharan M. Is calcium oxalate nucleation in postprandial urine of males with idiopathic recurrent calcium urolithiasis related to calcium phosphate nucleation and the intensity of stone formation? Studies allowing insight into a possible role of urinary free citrate and protein. ACTA ACUST UNITED AC 2004; 42:283-93. [PMID: 15080561 DOI: 10.1515/cclm.2004.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractIn idiopathic recurrent urolithiasis (IRCU) calcium oxalate and calcium phosphate are components of stones. It is not sufficiently known whether in urine the nucleation (liquid-solid transition) of each salt requires a different environment, if so which environment, and whether there is an impact on stone formation. Nucleation was induced by in vitro addition of oxalate or calcium to post-test meal load whole urine of male stone patients (n=48), showing normal daily and baseline fasting oxaluria. The maximally tolerated (until visible precipitates occur) concentration of oxalate (T-Ox) or calcium (T-Ca) was determined; additionally evaluated were other variables in urine, including total, complexed and free citrate (F-Cit), protein (albumin, non-albumin protein) and the clinical intensity (synonymous metabolic activity; MA) of IRCU. In the first of three trials the accumulation of substances in stone-forming urine was verified (trial-V); in the second (clinical trial 1) two strata of T-Ox (Low, High) were compared; in the third (clinical trial 2) IRCU patients (n=27) and a control group (n=13) were included to clarify whether in stone-forming urine the first crystal formed was calcium oxalate or calcium phosphate, and to identify the state of F-Cit. T-Ox was studied at the original pH (average<6.0), T-Ca at prefixed pH 6.0; the precipitates were subjected to electron microscopy and element analysis. Trial-V: Among the urinary substances accumulating at the indicated pHs were calcium, oxalate and phosphate, and the crystal-urine ratios were compatible with the nucleation of calcium oxalate, calcium-poor and calcium-rich calcium phosphate; citrate, protein and potassium also accumulated. Clinical trial 1: the two strata exhibited an inverse change of T-Ox and T-Ca, the ratio T-Ox/T-Ca and MA. The initial (before induction of Ox or Ca excess) supersaturation of calcium oxalate and brushite were unchanged, with the difference of proteinuria being borderline. Several correlations were significant (p≤0.05): urine pH with citrate and volume, protein with volume and MA, T-Ox with T-Ca and MA. Clinical trial 2: in patients with reduced urine volume and moderate urine calcium excess, the first precipitate appeared to be calcium oxalate, followed by amorphous calcium phosphate. Conversely, when the calcium excess was extreme, calcium-rich hydroxyapatite developed, followed by calcium oxalate; F-Cit, not total and complexed citrate, was decreased in IRCU vs. male controls; F-Cit rose pH-dependently, and the ratio F-Cit at original pH vs. F-Cit at pH 6.0 correlated inversely with the nucleation index T-Ox/T-Ca; MA correlated inversely with the ratio F-Cit at pH 6.0, respectively, original pH, but directly with the urinary albumin/non-albumin protein ratio. In summary 1) to study calcium oxalate and calcium phosphate nucleation in whole urine of IRCU patients is feasible; 2) at this crystallization stage the two substances, dominant in calcium stones, appear intimately linked, 3) in stone-forming urine, calcium phosphate may be ubiquitously present, likely as particles <0.22 μm; 4) together with co-precipitation of calcium oxalate and calcium phosphate, low F-Cit and alteration of proteinuria may act in concert and accelerate stones.
Collapse
Affiliation(s)
- Paul O Schwille
- Mineral Metabolism and Endocrine Research Laboratory, Department of Surgery, University of Erlangen, Erlangen, Germany
| | | | | |
Collapse
|
12
|
Uletilović S, Davidović B, Saničanin Ž. Relation of oxalate and citrate concentration in urine of the examinees with kidney stones. SCRIPTA MEDICA 2004. [DOI: 10.5937/scrimed0402075u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
|