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Biomedical subjects

V Jorgetti

Publications and source records attributed to V Jorgetti.

At least 19 recordsLinked to original sources
PubMed2007

Decreased in vitro osteoblast proliferation and low turnover bone disease in nonuremic proteinuric patients.

Patients with proteinuria, even those with normal glomerular filtration rate, often present abnormal bone histology. We evaluated bone histology and the in vitro proliferation of osteoblasts in samples obtained from 17 proteinuric patients with primary glomerulopathies. Histomorphometric analysis of bone biopsies was performed, and bone fragments were obtained for osteoblast culture, in which we evaluated cell proliferation. In comparison to controls, patients presented lower trabecular bone volume (20.9+/-14.5% vs 26.8+/-5.9%; P=0.0008); lower trabecular number (1.7+/-0.2/mm vs 2.0+/-0.3/mm; P=0.004); and greater trabecular separation (475.5+/-96.4 microm vs 368.3+/-86.2 microm, P=0.0002). We also found alterations in bone formation and resorption: lower osteoid volume (0.9+/-0.7% vs 2.0+/-1.4%; P=0.0022); lower osteoid thickness (6.4+/-2.8 microm vs 11.5+/-3.2 microm; P<0.0001); less mineralizing surface (4.6+/-3.1% vs 13.5+/-6.0%; P<0.0001); lower bone formation rate (0.03+/-0.04 microm(3)/microm(2)/day vs 0.09+/-0.05 microm(3)/microm(2)/day; P<0.0001); and greater osteoclast surface (0.35+/-0.6 vs 0.05+/-0.1%, P=0.0016). Mean in vitro osteoblast proliferation was lower in patients than in controls (910.2+/-437.1 vs 2261.0+/-1121.0 d.p.m./well, P=0.0016). Serum concentrations of 25-hydroxyvitamin-D(3) correlated negatively with proteinuria and positively with in vitro osteoblast proliferation. Our results demonstrate that nonuremic proteinuric glomerulonephritic patients present bone structure disorder, low bone formation and high bone resorption, as well as low osteoblast proliferation.

Adult↗
PubMed2006

Comparative study of axial and femoral bone mineral density and parameters of mandibular bone quality in patients receiving dental implants.

INTRODUCTION: In view of the increase in the life expectancy of humans and in edentulism of the population above 50 years of age, in which the prevalence of osteoporosis is also higher, it is fundamental to better understand the effects of systemic bone mass loss on the healing process of dental implants and to determine the quality of the bone that surrounds them. The objective of the present study was to compare systemic osteoporosis (axial and femoral) and parameters of mandibular bone quality, and to evaluate osseointegration in postmenopausal women receiving dental implants. METHODS: The sample consisted of 39 women aged 48-70 years, 19 with a densitometric diagnosis of osteoporosis in the lumbar spine and femoral neck and 20 controls with a normal densitometric diagnosis. Bone mineral density was measured in the patients and controls by dual-energy X-ray absorptiometry. Eighty-two osseointegrated dental implants were placed in the mandible, 39 of them in the osteoporosis group and 43 in the control group. Mandibular bone quality was evaluated by classifying mandibular inferior cortical and trabecular bone on panoramic radiographs and by histomorphometric analysis of a mandibular bone biopsy. Osseointegration was analyzed after 9 months. RESULTS: No significant difference was observed between patients with osteoporosis and controls when comparing individuals with a normal cortex and those with a severely or moderately eroded cortex determined on panoramic radiographs. Histomorphometric analysis also revealed no difference in the parameters of bone formation or resorption between the two groups. Implant failure was observed in only one case. CONCLUSION: We conclude that there is no association between systemic osteoporosis (axial and femur) and parameters of poor mandibular bone quality. The loss of one implant (1.2%) is compatible with the literature and cannot be attributed to systemic osteoporosis.

Aged↗
PubMed2006

Osteoporosis in hemodialysis patients revisited by bone histomorphometry: a new insight into an old problem.

Osteoporosis in hemodialysis patients is associated with high morbidity and mortality and, although extensively studied by noninvasive methods, has never been assessed through bone biopsy. The aim of this study was to use histomorphometry to evaluate osteoporosis and identify factors related to its development in hemodialysis patients. We conducted a cross-sectional study involving 98 patients (35 women and 63 men; mean age: 48.4 +/- 13 years) on hemodialysis for 36.9 +/- 24.7 months. Patients were submitted to transiliac bone biopsy with double tetracycline labeling. The bone metabolism factors ionized calcium, phosphorus, bone alkaline phosphatase, deoxypyridinoline, intact parathyroid hormone, and 25(OH) vitamin D were evaluated, as were the bone remodeling cytokines osteoprotegerin (OPG), soluble receptor-activator of NF-kappabeta ligand (sRANKL) and tumor necrosis factor-alpha (TNF)alpha. Osteoporosis was defined as trabecular bone volume (BV/TV) greater than 1 s.d. below normal (men <17.4%; women <14.7%). Forty-five patients (46%) presented osteoporosis, which was correlated with white race. We found BV/TV to correlate with age, OPG/sRANKL ratio, TNFalpha levels, and length of amenorrhea. In multiple regression analysis adjusted for sex and age, length of amenorrhea, white race, and OPG/sRANKL ratio were independent determinants of BV/TV. Histomorphometric analysis demonstrated that osteoporotic patients presented normal eroded surface and low bone formation rate (BFR/BS). Osteoporosis is prevalent in hemodialysis patients. Low BFR/BS could be involved in its development, even when bone resorption is normal. Cytokines may also play a role as may traditional risk factors such as advanced age, hypogonadism, and white race.

Adult↗
PubMed2006

Body composition changes in haemodialysis patients with secondary hyperparathyroidism after parathyroidectomy measured by conventional and vector bioimpedance analysis.

Considering the negative effects of secondary hyperparathyroidism (SHPT) in patients with chronic renal failure (CRF), the objective of the present study was to evaluate body composition changes using conventional and vector bioimpedance analysis in patients before and after parathyroidectomy (PTX). Twelve adult patients, mean age 43.4 (sd 12.7) years, were evaluated prior to and 6 months after PTX. Diets were assessed with 3 d dietary records, and mean energy, protein, calcium and phosphorus intake were estimated from these inventories. Weight, height, BMI and bioelectrical impedance were measured; and biochemical markers of nutritional status (albumin and total protein) and bone metabolism (calcium, phosphorus and intact parathyroid hormone) were determined. No significant differences were observed in mean energy, protein and phosphorus after surgery. There was a significant increase in calcium intake after PTX (382.3 (sd 209.6) mg to 656.6 (sd 313.8) mg; P<0.05). Mean weight, BMI, conventional bioelectrical impedance measurements, total body fat, lean body mass and total body water were unaffected by surgery. However, the phase angle and reactance significantly increased after PTX (5.0 degrees (sd 1.4) to 5.6 degrees (sd 1.3); 44.1 (sd 15.6) Omega to 57.1 (sd 14.4) Omega, respectively). The high levels of intact parathyroid hormone before surgery had a negative effect on total body fat (r -0.69, P<0.05). After PTX, the mean albumin significantly increased (3.9 (sd 0.4) g/dl to 4.2 (sd 0.6) g/dl; P<0.05). PTX for SHPT is associated with certain changes in laboratory values, dietary intake and body composition. The latter is best seen with bioimpedance vector analysis.

Adipose Tissue↗
PubMed2005

Improvement of adynamic bone disease after renal transplantation.

Low bone remodeling and relatively low serum parathyroid hormone (PTH) levels characterize adynamic bone disease (ABD). The impact of renal transplantation (RT) on the course of ABD is unknown. We studied prospectively 13 patients with biopsy-proven ABD after RT. Bone histomorphometry and bone mineral density (BMD) measurements were performed in the 1st and 12th months after RT. Serum PTH, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and osteocalcin were measured regularly throughout the study. Serum PTH levels were slightly elevated at transplantation, normalized at the end of the third month and remained stable thereafter. Bone biopsies performed in the first month after RT revealed low bone turnover in all patients, with positive bone aluminum staining in 5. In the 12th month, second biopsies were performed on 12 patients. Bone histomorphometric dynamic parameters improved in 9 and were completely normalized in 6, whereas no bone mineralization was detected in 3 of these 12 patients. At 12 months post-RT, no bone aluminum was detected in any patient. We also found a decrease in lumbar BMD and an increase in femoral BMD. Patients suffering from ABD, even those with a reduction in PTH levels, may present partial or complete recovery of bone turnover after successful renal transplantation. However, it is not possible to positively identify the mechanisms responsible for the improvement. Identifying these mechanisms should lead to a better understanding of the physiopathology of ABD and to the development of more effective treatments.

Absorptiometry, Photon↗
PubMed2004

High prevalence of low bone mineral density in pre-dialysis chronic kidney disease patients: bone histomorphometric analysis.

UNLABELLED: Chronic kidney disease (CKD) leads to reduced bone mineral density (BMD) in pre-dialysis and dialysis patients. A few studies have used dual-energy x-ray absorptiometry (DEXA) to assess BMD in pre-dialysis CKD patients and have shown low BMD to be highly prevalent. Until now there have been no studies reporting the histological features of low BMD in pre-dialysis CKD patients. AIM: To determine the prevalence and histological features of low BMD in pre-dialysis CKD patients. METHOD: Pre-dialysis CKD patients (n = 103, 46 females/57 males), median creatinine clearance of 29 (10 - 78) ml/min/ 1.73 m2, were evaluated using biochemical analysis and DEXA. Bone biopsies were obtained from those with low BMD. RESULTS: Fifty (48.5%) out of the 103 patients had low BMD (LBD group) and 53 (51.5%) had normal BMD (NBD group). The risk for low BMD was increased in those patients with alkaline phosphatase levels above 190 U/l and intact-PTH (iPTH) below 70 pg/ml (p < 0.05). Demographic and biochemical parameters from both groups were comparable, except for lower body mass index (BMI) in LBD subjects (p = 0.04). Women who had been post-menopausal for at least 1 year comprised 65% (13/20) and 50% (13/26) of the LBD and NBD groups, respectively (p = NS). In 40 LBD patients, bone histomorphometry revealed adynamic bone disease (ABD, 52.5%), osteomalacia (OM, 42.5%) and mixed bone disease (MBD, 5%). Trabecular bone volume (BV/TV) was lower in ABD and OM patients. A nearly significant association was found between ABD and iPTH < or = 150 pg/ml (p = 0.056), whereas higher values of iPTH were associated with OM. Total alkaline phosphatase < or = 190 U/l was significantly associated with ABD, whereas higher values were associated with OM. No correlation was observed between BV/TV and BMD. CONCLUSION: Low BMD is frequent in pre-dialysis CKD patients, and low turnover bone disease, manifesting as ABD and OM, was the hallmark of this bone loss.

Absorptiometry, Photon↗
PubMed2003

Skeletal overexpression of noggin results in osteopenia and reduced bone formation.

Skeletal cells synthesize bone morphogenetic proteins (BMPs) and BMP antagonists. Noggin is a glycoprotein that binds BMPs selectively and antagonizes BMP actions. Noggin expression in osteoblasts is induced by BMPs and noggin opposes the effects of BMPs on osteoblastic differentiation and function in vitro. However, its effects in vivo are not known. We investigated the direct in vivo effects of noggin on bone remodeling in transgenic mice overexpressing noggin under the control of the osteocalcin promoter. Noggin transgenics suffered long bone fractures in the first month of life. Total, vertebral, and femoral bone mineral densities were reduced by 23-29%. Static and dynamic histomorphometry of the femur revealed that noggin transgenic mice had decreased trabecular bone volume, number of trabeculae, and bone formation rate. Osteoblast surface and number of osteoblasts/trabecular area were not significantly decreased, indicating impaired osteoblastic function. Osteoclast surface and number were normal/decreased, there was no increase in bone resorption, and the tissue had the appearance of woven bone. Vertebral microcomputed tomography scanning confirmed decreased trabecular bone volume and trabecular number. In conclusion, transgenic mice overexpressing noggin in the bone microenvironment have decreased trabecular bone volume and impaired osteoblastic function, leading to osteopenia and fractures.

Animals↗
PubMed2002

Transgenic mice overexpressing insulin-like growth factor binding protein-5 display transiently decreased osteoblastic function and osteopenia.

Skeletal cells synthesize IGFs and their six IGF binding proteins (IGFBP). IGFBP-5 was reported to stimulate bone cell growth in vitro and selected parameters of osteoblastic function in vivo, but its actual effects on bone formation are not established. We investigated the direct effects of IGFBP-5 on bone remodeling in two lines of transgenic mice overexpressing IGFBP-5 under the control of the osteocalcin promoter. Static and dynamic histomorphometry revealed that IGFBP-5 transgenic mice had a transient decrease in trabecular bone volume secondary to reduced trabecular number and thickness and a transient decrease in bone mineral apposition rate. Osteoblast number was normal, indicating impaired osteoblastic function. Osteoclast number and bone resorption were normal. Total, vertebral, and femoral bone mineral densities were reduced in IGFBP-5 transgenics by 14-27% at 4 wk of age, but not in older animals. Stromal cells expressing the IGFBP-5 transgene displayed decreased expression of alkaline phosphatase, osteocalcin, core binding factor 1, and type I collagen transcripts when compared with cells from wild-type animals. In conclusion, transgenic mice overexpressing IGFBP-5 in the bone microenvironment have a transient decrease in trabecular bone volume, impaired osteoblastic function, and osteopenia.

Alkaline Phosphatase↗
PubMed2002

Bone involvement in idiopathic hypercalciuria.

BACKGROUND: To evaluate bone involvement in idiopathic hypercalciuria, 40 lithiasic patients and 10 controls were studied. METHODS: According to urinary calcium excretion, patients were first classified as hypercalciuric (Hca, n = 22) and normocalciuric (Nca, n = 18). The Hca patients were then subclassified according to bone densitometry (BMD) as osteopenic (HcaO, n = 10) and non-osteopenic (HCaNO, n = 12). Routine biochemistry, dietary records, bone histomorphometry. and cytokines (IL-1beta, IL-6, and TNF) production by peripheral blood mononuclear cell cultures were studied. RESULTS: There were no differences in routine biochemistry between Hca and Nca groups, except for urinary calcium. Inadequate nutrition was observed in Hca group, showing high protein (80.9% of the patients), carbohydrate (76.2%) and sodium (90%) intake. Calcium intake was low in Hca (57%) and Nca (83%) groups. IL-6 and TNF were not different between the Hca and Nca groups. IL-1beta levels were significantly high in both groups when compared to controls. IL-6 and TNF were higher in HcaO than Nca. BMD in femoral neck in HcaO was lower than in HcaNO and Nca groups. Eroded surface (ES/BS) increased in 91% of the Hca group and 36% had a mineralization defect. In the HcaO group serum PTH correlated negatively with trabecular bone volume (BV/TV) and positively with ES/BS. 1,25(OH),D3 levels correlated positively with osteoblastic surface. Calcium intake correlated positively with BV/TV and inversely with ES/BS. A negative correlation was observed between IL-6 levels and Z score of the femoral neck. CONCLUSION: Bone involvement was detected in a young population with nephrolithiasis demonstrating that a strict follow-up is necessary in order to control hypercalciuria.

Absorptiometry, Photon↗
PubMed2001

Effect of 17beta-estradiol or alendronate on the bone densitometry, bone histomorphometry and bone metabolism of ovariectomized rats.

The objective of the present study was to evaluate the effect of 17beta-estradiol or alendronate in preventing bone loss in 3-month-old ovariectomized Wistar rats. One group underwent sham ovariectomy (control, N = 10), and the remaining three underwent double ovariectomy. One ovariectomized group did not receive any treatment (OVX, N = 12). A second received subcutaneous 17beta-estradiol at a dose of 30 microg/kg for 6 weeks (OVX-E, N = 11) and a third, subcutaneous alendronate at a dose of 0.1 mg/kg for 6 weeks (OVX-A, N = 8). Histomorphometry, densitometry, osteocalcin and deoxypyridinoline measurements were applied to all groups. After 6 weeks there was a significant decrease in bone mineral density (BMD) at the trabecular site (distal femur) in OVX rats. Both alendronate and 17beta-estradiol increased the BMD of ovariectomized rats, with the BMD of the OVX-A group being higher than that of the OVX-E group. Histomorphometry of the distal femur showed a decrease in trabecular volume in the untreated group (OVX), and an increase in the two treated groups, principally in the alendronate group. In OVX-A there was a greater increase in trabecular number. An increase in trabecular thickness, however, was seen only in the OVX-E group. There was also a decrease in bone turnover in both OVX-E and OVX-A. The osteocalcin and deoxypyridinoline levels were decreased in both treated groups, mainly in OVX-A. Although both drugs were effective in inhibiting bone loss, alendronate proved to be more effective than estradiol at the doses used in increasing bone mass.

Alendronate↗
PubMed2000

Different patterns of renal osteodystrophy in Iberoamerica.

The various forms of renal osteodystrophy are predominant hyperparathyroid bone disease, mixed uremic osteodystrophy, low turnover osteomalacia, and adynamic bone disease. The present study analyses a total number of 1,209 bone biopsies from 5 different countries (Brazil, Uruguay, Argentina, Portugal, and Spain). Low turnover osteomalacia and mixed uremic osteodystrophy were more common in Brazil, Uruguay, and Argentina than in Portugal and Spain whereas predominant hyperparathyroid bone disease was seen more often in Portugal and Spain. In all centers, independent of the aluminum staining technique used, the extent of aluminum deposited in bone was greater in patients presenting with low bone turnover, whether from low turnover osteomalacia or adynamic bone disease, than in the predominant hyperparathyroid bone disease. In summary, even though recent reports have indicated that, over the last decade, the incidence of aluminum-induced toxicity was reduced, aluminum still seems to be implicated in a great percentage of symptomatic low bone remodelling lesions in Iberoamerica.

Aluminum↗
PubMed2000

Histomorphometric evaluation of titanium implants in osteoporotic rabbits.

In this study, the osteointegration of two kinds of titanium implants were analyzed (cylindrical and screw-type) inserted in the tibiae of control (n = 8) and osteoporotic (n = 12) female rabbits. Osteoporosis was induced by the surgical removal of the ovaries (oophorectomy). Bone mass density of all animals was evaluated by densitometry of the tibiae and vertebrae. Densitometry was carried out at the beginning of the study and 4 months after oophorectomy. Mass loss in the tibia was not observed, however, in the vertebrae there was an 11% loss compared with the initial value. The implants remained for 8 weeks, after which the animals were then sacrificed and bone segments were analyzed by histomorphometry. The trabecular volume and mineral apposition rate was significantly greater in control animals than in osteoporotic animals, independent of which type of implant was used. In the osteoporotic animals, the area and osteoid perimeter were greater than in the control animals. By measuring the thickness of the compact layer in the tibia, it was observed that in the control animals, it was 28% thicker than in the osteoporotic animals. This study leads to the conclusion that bone formation was greater in the control animals than in the osteoporotic animals. The screw-type implants yielded the greatest formation of bone both in the control and in the osteoporotic animals.

Absorptiometry, Photon↗
PubMed2000

Restoration of impaired T-cell proliferation after parathyroidectomy in hemodialysis patients.

BACKGROUND/AIMS: Severe secondary hyperparathyroidism is not infrequent in hemodialysis patients and recent studies suggest that parathyroid hormone (PTH) may play a role in the genesis of cell immunity abnormalities in uremia. The aim of the present study is to describe the effect of parathyroidectomy on T- and B-cell functions in hemodialysis patients. METHODS: The study was performed on 6 patients with severe secondary hyperparathyroidism. iPTH, B, CD4(+), CD8(+), total number of lymphocytes, lymphoproliferative response to PHA, PWM and Candidin, and IgG, IgM, IL-2 production in vitro were determined 1 day before and 4 months after parathyroidectomy. RESULTS: The lymphoproliferative response to PHA increased significantly after parathyroidectomy. We also observed a trend to an increase in production of IgG and IgM after PWM stimulation before therapy. CONCLUSION: The present study suggests that patients with extremely high levels of PTH show a complete restoration of impaired T-cell proliferation after parathyroidectomy.

Adult↗
PubMed2000

Immune response in hemodialysis patients: is there any difference when low and high iPTH levels are compared?

BACKGROUND: Chronic renal failure is frequently associated with secondary hyperparathyroidism and immunological disorders. Recent studies support the hypothesis that high levels of parathyroid hormone (PTH) may contribute to the impairment of the cellular and humoral immune response by an immunosuppressive effect on T- and B-cell functions. However, many studies indicate that excess PTH exerts a stimulatory effect on T lymphocytes. Since reports about the immunomodulatory effect of PTH are controversial, our aim was to compare the effect of low and high levels of intact PTH (iPTH) in hemodialysis patients. METHODS: The study was performed on 14 hemodialysis patients with high levels of iPTH (GI), 12 patients with low levels of iPTH (GII) and 13 volunteers (GIII), for whom time of dialysis, iPTH, total number of lymphocytes, B, CD4+, CD8+, lymphoproliferative response to phytohemagglutin (PHA), pokeweed mitogen (PWM) and candidin, IgG and IgM production in vitro in response to PWM, and interleukin (IL)-2 and IL-6 production in vitro in response to PHA were determined. RESULTS: Patients with high iPTH levels had significantly higher responses to PHA than patients with low iPTH. Lymphocyte transformation by PWM and candidin antigen was similar in both groups of patients, but significantly decreased when compared to controls. CD4+ cell counts were significantly increased in GI, and there was a positive correlation between the lymphoproliferative response to PHA and iPTH levels and CD4+ number. CONCLUSION: The present study suggests that high levels of iPTH in hemodialysis patients affect T-cell function, increasing the lympho-proliferative response to PHA and the CD4+ number.

Adult↗
PubMed1999

Dynamic tests of parathyroid hormone secretion using hemodialysis and calcium infusion cannot be compared.

BACKGROUND: Extracellular Ca++ concentration [Ca++] and parathormone (PTH) are related by a sigmoidal function. The set point of the control system is the [Ca++] that produces a half-maximal inhibition of PTH secretion. Whether or not this set point is abnormal in patients with chronic renal failure (CRF) and secondary hyperparathyroidism (SHP) is controversial. METHODS: We investigated whether the way [Ca++] is varied [hemodialysis (HD) or calcium gluconate/sodium citrate infusions (INF)] and the way the curve is constructed (four-parameter model or adapted four-parameter, created by Felsenfeld) could influence this set point. We performed dynamic tests of PTH secretion in 12 patients with CRF and SHP during either HD or INF. Both the four-parameter model or adapted four-parameter methods were used, creating four combinations: (a) hypocalcemia and hypercalcemia induced during HD, calculated by Brown's formula (HDB); (b) hypocalcemia and hypercalcemia induced during HD, calculated by Felsenfeld's formula (HDF); (c) hypocalcemia and hypercalcemia induced during infusion, calculated by Brown's formula (INFB); and (d) hypocalcemia and hypercalcemia induced during infusion, calculated by Felsenfeld's formula (INFF). RESULTS: The set points obtained with HDB correlated perfectly with those obtained with HDF (R2 = 0.999). A similar relationship was found between INFB and INFF (R2 = 0.9997). In contrast, there was no correlation between either HDB and INFB (R2 = 0.0157) or HDF and INFF (R2 = 0.0204). CONCLUSIONS: These findings indicate that the calculated [Ca++] set point in patients with CRF and SHP is determined by the way [Ca++] is varied, rather than by the mathematical model used to generate the curves. Further studies are needed to determine the differing physiological mechanisms triggered by HD and INF and the way they influence [Ca++] homeostasis in this setting.

Adolescent↗
PubMed1999

Triiodothyronine induces collagenase-3 and gelatinase B expression in murine osteoblasts.

Triiodothyronine (T3) increases bone resorption, but its effects on matrix metalloprotease (MMP) expression in bone are unknown. We tested the effects of T3 on collagenase-3 and gelatinase A and B expression in MC3T3 osteoblastic cells. T3 at 1 nM to 1 microM for 24-72 h increased collagenase-3 and gelatinase B mRNA levels, but it did not increase gelatinase A transcripts. In addition, T3 increased immunoreactive collagenase and gelatinase activity. Cycloheximide prevented the stimulatory effect of T3 on collagenase-3 but not on gelatinase B transcripts. Indomethacin did not prevent the effect of T3 on either MMP. T3 did not alter the decay of collagenase-3 or gelatinase B mRNA in transcriptionally arrested MC3T3 cells, and it increased the rate of collagenase-3 and gelatinase B gene transcription. Although T3 enhanced the expression of the tissue inhibitor of metalloproteinase-1 in MC3T3 cells, it increased collagen degradation in cultured intact rat calvariae. In conclusion, T3 increases collagenase-3 and gelatinase B synthesis in osteoblasts by transcriptional mechanisms. This effect may contribute to the actions of T3 on bone matrix remodeling.

3T3 Cells↗
PubMed1998

Are there any differences in the parathyroid response in the different types of renal osteodystrophy?

With the purpose of studying the curve of parathyroid response to variations of serum calcium during dialysis, we studied 20 patients on haemodialysis: 10 women and 10 men, with different forms of bone disease diagnosed by bone biopsy (adynamic bone disease, mild hyperparathyroidism, severe hyperparathyroidism). In all patients, we performed parathyroid stimulation by 4 h dialysis with 1 mEq/l of Ca2+ in the dialysate, and an inhibition test in another dialysis session with 4 mEq/l of Ca2+, with a 48 h interval. Ca2+ and intact parathyroid hormone (iPTH) were measured prior to dialysis and every hour subsequently, to obtain a Ca2+-iPTH for each patient. The analysis of the curves was made using Brown's four-parameter model. Stimulation and inhibition levels were similar in all groups, but basal iPTH and the response profiles obtained varied in the different histological groups. Basal, maximal and minimal iPTH were lower in adynamic forms than in the other two groups (P<0.04), and basal calcium was higher than basal calcium of severe hyperparathyroidism, expressing a basal inhibition status. In severe hyperparathyroidism, basal calcium was lower than the set-point, showing a permanent stimulation, and the slope was higher than in other groups, showing more sensitivity to serum calcium variations. The set-point of severe hyperparathyroidism was significantly higher than the set-point of mild and adynamic forms. In conclusion, the functional parathyroid study showed a different response in the different forms of renal osteodystrophy.

Adult↗