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Biomedical subjects

Kiyoshi Kurokawa

Publications and source records attributed to Kiyoshi Kurokawa.

At least 19 recordsLinked to original sources
PubMed2006

Tagging of avidin immobilized beads with biotinylated YAG:Ce3+ nanocrystal phosphor.

YAG:Ce3+ nanoparticles 9.5+/-1.2 nm in diameter have been synthesized from aluminium isopropoxide and acetates of yttrium and cerium in 1,4-butanediol (1,4-BD) by autoclave treatment at 300 degrees C for 2 h. After replacing 1,4-BD by ultrapure water, NH2 groups were introduced on the surface of YAG:Ce3+ nanoparticles by addition of 3-aminopropyltrimethoxysilane then biotinylation with sulfo-NHS-LC-biotin. We demonstrated that avidin immobilized beads are tagged by biotinylated YAG:Ce3+ nanoparticles by the selective avidin-biotin interaction, furnishing a green fluorescent image on excitation with blue light. This result indicates that YAG:Ce3+ nanoparticle phosphors have much potential in biological applications.

Avidin↗
PubMed2006

Renin angiotensin aldosterone system blockade and renal disease in patients with type 2 diabetes: a subanalysis of Japanese patients from the RENAAL study.

BACKGROUND: The Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study has previously shown losartan to confer significant benefits to patients with type 2 diabetes and nephropathy. The original study of 1513 patients included 96 Japanese patients; the present study is a post-hoc analysis of the effects of losartan in this Japanese subpopulation. METHODS: This double-blind, randomized study compared losartan (50 to 100 mg once daily) with placebo. The study medication was taken in addition to conventional antihypertensive treatment, and the mean follow-up period for the Japanese patients was 2.8 years. The primary endpoint was the composite of doubling of serum creatinine, endstage renal disease, or death. Secondary endpoints included changes in proteinuria levels. Safety was also evaluated. RESULTS: The primary composite endpoint was reached in fewer Japanese patients receiving losartan than placebo (50.0% versus 65.4%, respectively). The treatment effects of losartan were more robust when data were corrected for differences in proteinuria at baseline--a significant relative risk reduction of 45% with losartan (P=0.0397) was apparent. Treatment benefit exceeded that attributable to blood pressure changes alone. Levels of proteinuria were reduced with losartan compared with placebo, with an overall losartan treatment effect of 37.8% (P<0.001). Overall, losartan was similarly well tolerated in both the Japanese patients and the total population. CONCLUSIONS: In Japanese patients with type 2 diabetes and nephropathy, losartan offers renal protection and is generally well tolerated.

Adult↗
PubMed2006

Prognostic factors for a composite end-point of renal outcomes in patients with chronic kidney disease.

We aimed to investigate prognostic factors for a composite end-point of end-stage renal disease (ESRD) and the progression of renal disease in Japanese patients with chronic renal disease. Using a composite end-point comprising a doubling of serum creatinine (sCr), an increase in sCr level to 6.0 mg/dL, or initiation of dialysis and renal transplantation caused by ESRD, we examined data obtained in a prospective cohort study. The present study consisted of 641 patients who were 20 years of age or older with chronic renal disease caused by diabetic nephropathy, glomerulonephritis, or nephrosclerosis, and who had baseline sCr levels of 5.0 mg/dL or less. The following criteria were examined as prognostic factors: sex; age; elapsed time from initial diagnosis; disease underlying the nephropathy (diabetic or non-diabetic); complications with hypertension, hyperlipidemia, or anemia; baseline sCr level; therapeutic regimen, including use of ACE inhibitors or Ca2+ -channel blockers; and diet. A log-rank test was used for univariate analysis, and Cox regression analysis was used for multivariate analysis. Underlying disease (diabetic or non-diabetic), baseline sCr level, and Ca2+ -channel blocker therapy were significantly related to event incidence. In the present study, we identified underlying disease and baseline sCr level as important prognostic factors for a composite end-point in a predialysis patient population in both the early and middle stages of renal disease. These factors should be considered as balancing variables for randomization in future clinical studies.

Aged↗
PubMed2006

A severe diabetic nephropathy model with early development of nodule-like lesions induced by megsin overexpression in RAGE/iNOS transgenic mice.

Many factors are involved in the pathogenesis of diabetic nephropathy. A single gene abnormality may be prerequisite but insufficient to the disease to manifest. It is therefore only when a second or sometimes a third damage is associated that the consequences of pathogenic phenotypes become evident. We generated the triple transgenic mice overexpressing megsin (a novel glomerular-specific serpin), a receptor for advanced glycation end products (RAGE), and inducible nitric oxide synthase (iNOS). Compared with the single- or two-gene transgenic mice, the triple transgenic mice developed, at an early age (16 weeks), severe albuminuria and renal damage with all of the characteristics of human diabetic nephropathy (i.e., glomerular hypertrophy, diffuse mesangial expansion, inflammatory cell infiltration, and interstitial fibrosis). Interestingly, 30-40% of glomeruli exhibit nodule-like lesions. Oxidative and carbonyl stress makers (pentosidine, N(epsilon)-carboxymethyllysine, and 8-hydroxy-deoxyguanosine) were significantly higher in the triple transgenic mice. The iNOS transgenic mice have a diabetes phenotype, the renal consequences of which are moot, and the superimposition of RAGE leads to more conspicuous manifestations. By additional overexpression of megsin, a gene known to be involved in mesangial proliferation and expansion, these local consequences become dramatically manifest and approximate those observed in human pathology. This multiple hit approach is of interest in consideration of the sequential events during development of diabetic nephropathy.

Animals↗
PubMed2005

Renoprotective properties of angiotensin receptor blockers beyond blood pressure lowering.

Clinical studies have demonstrated that some antihypertensive agents provide renoprotection independent of BP lowering. Recent in vitro and in vivo studies evaluated the mechanisms involved in this protection. First, the in vitro effects of several angiotensin II type 1 receptor blockers (ARB), calcium channel blockers (CCB), and beta blockers (BB) on various mediators were compared: Formation of pentosidine (an advanced glycation end product), hydroxyl radical-induced formation of o-tyrosine, and transition metals-induced oxidation of ascorbic acid (the Fenton reaction). All of the six tested ARB but neither the six CCB nor the nine BB inhibited pentosidine formation. ARB, as well as BB but not CCB, inhibited hydroxyl radicals-mediated o-tyrosine formation. ARB but neither BB nor CCB inhibited efficiently transition metals-catalyzed oxidation of ascorbic acid. Second, the in vivo consequences for the kidney of these various in vitro effects were evaluated. Hypertensive, type 2 diabetic rats with nephropathy, SHR/NDmcr-cp, were given for 20 wk either olmesartan (ARB) or nifedipine (CCB), or atenolol (BB). Despite similar BP reduction, only ARB significantly reduced proteinuria and prevented glomerular and tubulointerstitial damage (mesangial activation, podocyte injury, tubulointerstitial injury, and inflammatory cell infiltration). It is interesting that only ARB prevented abnormal iron deposition in the interstitium, corrected chronic hypoxia, reduced expressions of heme oxygenase and p47phox (a subunit of NADPHoxidase), and inhibited pentosidine formation (which correlates well with proteinuria). These observations confirm unique renoprotective properties of ARB, independent of BP lowering but related to decreased oxidative stress (hydroxyl radicals scavenging and inhibition of the Fenton reaction), correction of chronic hypoxia, and inhibition of advanced glycation end product formation and of abnormal iron deposition. These benefits of ARB may contribute to the renoprotection observed beyond BP lowering.

Analysis of Variance↗
PubMed2005

In a type 2 diabetic nephropathy rat model, the improvement of obesity by a low calorie diet reduces oxidative/carbonyl stress and prevents diabetic nephropathy.

BACKGROUND: The present study has been undertaken to unravel the critical factors involved in the progression of diabetic nephropathy (DN). METHODS: A unique type 2 diabetic rat model with a wide range of metabolic derangements and hypertension has been utilized, the spontaneously hypertensive/NIH-corpulent rat SHR/NDmcr-cp(cp/cp). It develops histologically evident glomerular injury and tubulointerstitial damage, including mesangial activation, podocyte injury, and inflammatory cell infiltration in the tubulointerstitium. RESULTS: A low calorie diet for 22 weeks significantly improves obesity, proteinuria and renal morphological alterations. The correction of renal injury is independent of blood pressure control. Obesity correction, although partial, normalizes the renal content of pentosidine taken as a marker of oxidative stress and advanced glycation end products (AGEs). This occurs despite the fact that, in this model, improvement of glucose control and hyperlipidaemia is limited. Proteinuria and body weight are highly correlated with renal pentosidine content, while proteinuria and body weight are also correlated with each other. Diabetic renal injury is thus inhibited by a low calorie diet with an attendant reduction of oxidative stress and AGE formation, despite sustained hypertension. CONCLUSION: The present findings suggest a direct role of obesity in the generation of a localized oxidative stress and AGE formation, directly responsible for DN.

Animals↗
PubMed2005

Downregulation of parathyroid hormone receptor gene expression and osteoblastic dysfunction associated with skeletal resistance to parathyroid hormone in a rat model of renal failure with low turnover bone.

BACKGROUND: Adynamic bone disease (ABD), which is characterized by reduced bone formation and resorption, has become an increasingly common manifestation of bone abnormalities in patients with end-stage renal failure. It has been recognized that skeletal resistance to parathyroid hormone (PTH) underlies the pathogenesis of ABD; however, the mechanisms of such resistance remain unclear. METHODS: We established a rat model simulating ABD under chronic renal failure conditions by thyroparathyroidectomy and partial nephrectomy (TPTx-Nx). TPTx-Nx rats were infused subcutaneously with a physiological dose of PTH. We analysed bone histomorphometric parameters and demonstrated gene expression using semi-quantitative reverse transcription-polymerase chain reaction. RESULTS: Reduced bone formation was observed in this model, simulating ABD. The reduction was dependent on the degree of renal dysfunction. Bone formation rate was 6.4+/-2.7 microm3/m2/year in TPTx-5/6Nx rats and 22.7+/-7.2 microm3/m2/year in TPTx rats (P<0.05). Osteoblast surface was also significantly depressed (P<0.05) in TPTx-5/6Nx (3.8+/-2.7%) compared with TPTx rats (15.9+/-8.6). The expression of PTH/parathyroid hormone-related peptide (PTHrP) receptor and alkaline phosphatase genes was reduced significantly in TPTx-Nx compared with TPTx rats (P<0.05). Reduced bone formation in TPTx-Nx rats was ameliorated by intermittent injection of pharmacological doses of PTH. CONCLUSIONS: Renal dysfunction without secondary hyperparathyroidism induces osteoblast dysfunction and reduces bone formation. Skeletal resistance to PTH develops in renal failure even at low or normal PTH levels, possibly through downregulation of PTH/PTHrP receptor and dysfunction of osteoblasts.

Actins↗
PubMed2005

Novel serpinopathy in rat kidney and pancreas induced by overexpression of megsin.

The intracellular polymerization of abnormal serine protease inhibitors (serpins) results in liver or neuronal cell abnormalities recently identified as "serpinopathies." It was demonstrated in transgenic rats that overexpression of megsin, a recently discovered serpin located in the kidney, produces renal and pancreatic lesions characteristic of serpinopathies. Megsin expression is elevated in a variety of organs, including kidney and pancreas. Periodic acid-Schiff-positive, diastase-resistant intracellular inclusions develop only in the kidney and the pancreas. They correspond to electron-dense deposits, shown to contain megsin by immunohistochemistry and immunoelectron microscopy. In the kidney, inclusions are located mainly in the endoplasmic reticulum of glomerular epithelial, distal, and collecting duct cells, and are associated with massive proteinuria and an impaired renal function. In the pancreas, similar inclusions are found in the exocrine and Langerhans islet cells, where islet beta cells are reduced as a result of apoptosis. They are associated with diabetes with low insulin levels. The animals have an impaired growth and die within 10 wk. Rats that overexpress a mutant megsin, characterized by a deficient conformational transition activity, do not develop the serpinopathy, suggesting that some conformational flexibility of the serpin is required for the development of serpinopathy. This model of serpinopathy is the first to involve the kidney and the pancreas.

Animals↗
PubMed2005

A mammalian dpy-19 homologue is expressed in GABAergic neurons.

Gsh2 homeobox transcription factors play a crucial role in the development of GABAergic neurons. Caenorhabditis elegans's mab-5 gene is homologous to Gsh2; its expression is controlled by dpy-19. This study produced the polyclonal anti-mammalian DPY-19 (MDPY-19) antibody and showed the distribution of anti-MDPY-19 immunopositive cells. In addition, the mammalian dpy-19 (Mdpy-19) 5'-flanking region was analyzed by in vivo transient transfection assays. Mdpy-19 is expressed in ependymal cells in the adult rat brain, embryonic neuroepithelial cells, and cultured neural stem cells. In the adult rat ventricular zone, immunoreactivity with MDPY-19 of the dorsal area is stronger than that of the ventral area. Embryonic neuroepithelial cells and radial glial cells show strong anti-MDPY-19 immunoreactivity. We created the Mdpy-19 green fluorescent protein (GFP) reporter gene. Our results show that Mdpy-19 is expressed in neural stem cells and progenitor cells, especially radial glial cells. Only ependymal cells among differentiated cells express Mdpy-19 gene. However, the possibility exists that the Mdpy-19 gene is able to transcript in GABAergic neurons. It is suggested that a factor existing in mature neurons withdraws the expression of Mdpy-19.

Animals↗
PubMed2005

Study design and methods for a clinical trial of an oral carbonaceous adsorbent used to prevent the progression of chronic kidney disease (CAP-KD).

BACKGROUND: The number of patients with chronic kidney disease (CKD) in Japan is currently rising. Therefore, measures to control the progression of CKD from a predialysis condition to endstage renal failure are urgently required. We are conducting a clinical trial to investigate the efficacy of an oral carbonaceous adsorbent (Kremezin) in patients at the predialysis stage of progressive chronic kidney disease (the Carbonaceous oral Adsorbent's effectiveness on Progression of chronic Kidney Disease [CAP-KD] trial). METHODS: A multidisciplinary treatment regimen, consisting of antihypertensive therapy (using an angiotensin-converting-enzyme inhibitor and/or an angiotensin II receptor blocker) and a low-protein diet is conventionally used to treat patients with kidney disease. To assess the efficacy of Kremezin in preventing the progression of CKD, we compare two groups of patients, receiving either conventional treatment alone or such treatment paired with Kremezin. The CAP-KD trial is a prospective, multicenter, randomized, open-label, two-arm, parallel-group comparison clinical trial and will be conducted as a researcher-directed study. The primary endpoint of this study is the time to the first event of a composite endpoint, comprising the following: (1) a doubling of serum creatinine (sCr); (2) an increase in sCr level to 6.0 mg/dl or more; (3) endstage renal disease (defined as that requiring dialysis or renal transplantation); and (4) death. Secondary endpoints are as follows: (1) variation in urinary protein; (2) changes in creatinine clearance rate; (3) changes in health-related quality of life; and (4) adverse events. The total number of patients (putative) in this trial will be 450, with 225 patients in each group. Enrollment will take place over 2 years, with a 1-year follow-up period. RESULTS: As this is an ongoing trial, results are not yet available. CONCLUSIONS: We believe that the CAP-KD trial is a well-designed study that will provide internationally relevant evidence concerning the outcomes of treatment in Japanese patients with CKD.

Adult↗
PubMed2005

Glutamate receptor antagonists and benzodiazepine inhibit the progression of granule cell dispersion in a mouse model of mesial temporal lobe epilepsy.

PURPOSE: Unilateral intrahippocampal injection of kainic acid (KA) in adult mice induces the progressive dispersion of dentate granule cells, one of the characteristic pathologic changes of mesial temporal lobe epilepsy. However, little is known about the mechanisms that trigger this dispersion. In this study, the possible involvement of glutamatergic and gamma-aminobutyric acid (GABA)ergic neurotransmissions in the development of granule cell dispersion (GCD) was examined in this model. METHODS: Antagonists of N-methyl-d-aspartate (NMDA) receptor (MK-801) and non-NMDA receptor (GYKI52466), and an agonist of benzodiazepine-GABA(A) receptor (midazolam) were injected before and after KA in various ways, and the morphologic changes of the hippocampus, especially GCD, were examined. RESULTS: MK-801 (5 mg/kg, i.p.) did not reduce GCD when injected 2 h before KA injection but inhibited GCD almost completely for <or=14 days, when injected 4 h after KA. However, mild to moderate dispersion was observed at 28 days, indicating that MK-801 may delay the progression of GCD. Similarly, daily treatment with MK-801 (2 x 1 mg/kg i.p./day) for the first 26 days after KA significantly reduced GCD. In contrast, GYKI52466 (30 mg/kg, s.c.) was effective only when it was injected before KA. A significant reduction of GCD was also observed after continuous administration of midazolam (10 mg/kg/h) after KA. CONCLUSIONS: These data show that GCD in this mouse model is triggered by either the stimulation of the NMDA receptor or reduction of GABA(A)-mediated inhibition after intrahippocampal injection of KA. It is suggested that the increased excitation or the reduced inhibition or both could be one of the factors triggering or maintaining or both the process of GCD.

Animals↗
PubMed2005

Predictors and consequences of altered mineral metabolism: the Dialysis Outcomes and Practice Patterns Study.

BACKGROUND: Altered mineral metabolism contributes to bone disease, cardiovascular disease, and other clinical problems in patients with end-stage renal disease. METHODS: This study describes the recent status, significant predictors, and potential consequences of abnormal mineral metabolism in representative groups of hemodialysis facilities (N= 307) and patients (N= 17,236) participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS) in the United States, Europe, and Japan from 1996 to 2001. RESULTS: Many patients fell out of the recommended guideline range for serum concentrations of phosphorus (8% of patients below lower target range, 52% of patients above upper target range), albumin-corrected calcium (9% below, 50% above), calcium-phosphorus product (44% above), and intact PTH (51% below, 27% above). All-cause mortality was significantly and independently associated with serum concentrations of phosphorus (RR 1.04 per 1 mg/dL, P= 0.0003), calcium (RR 1.10 per 1 mg/dL, P < 0.0001), calcium-phosphorus product (RR 1.02 per 5 mg(2)/dL(2), P= 0.0001), PTH (1.01 per 100 pg/dL, P= 0.04), and dialysate calcium (RR 1.13 per 1 mEq/L, P= 0.01). Cardiovascular mortality was significantly associated with the serum concentrations of phosphorus (RR 1.09, P < 0.0001), calcium (RR 1.14, P < 0.0001), calcium-phosphorus product (RR 1.05, P < 0.0001), and PTH (RR 1.02, P= 0.03). The adjusted rate of parathyroidectomy varied 4-fold across the DOPPS countries, and was significantly associated with baseline concentrations of phosphorus (RR 1.17, P < 0.0001), calcium (RR 1.58, P < 0.0001), calcium-phosphorus product (RR 1.11, P < 0.0001), PTH (RR 1.07, P < 0.0001), and dialysate calcium concentration (RR 0.57, P= 0.03). Overall, 52% of patients received some form of vitamin D therapy, with parenteral forms almost exclusively restricted to the United States. Vitamin D was potentially underused in up to 34% of patients with high PTH, and overused in up to 46% of patients with low PTH. Phosphorus binders (mostly calcium salts during the study period) were used by 81% of patients, with potential overuse in up to 77% patients with low serum phosphorus concentration, and potential underuse in up to 18% of patients with a high serum phosphorus concentration. CONCLUSION: This study expands our understanding of the relationship between altered mineral metabolism and outcomes and identifies several potential opportunities for improved practice in this area.

Calcium↗
PubMed2005

Kidney transplantation and wait-listing rates from the international Dialysis Outcomes and Practice Patterns Study (DOPPS).

BACKGROUND: The international Dialysis Outcomes and Practice Patterns Study (DOPPS I and II) allows description of variations in kidney transplantation and wait-listing from nationally representative samples of 18- to 65-year-old hemodialysis patients. The present study examines the health status and socioeconomic characteristics of United States patients, the role of for-profit versus not-for-profit status of dialysis facilities, and the likelihood of transplant wait-listing and transplantation rates. METHODS: Analyses of transplantation rates were based on 5267 randomly selected DOPPS I patients in dialysis units in the United States, Europe, and Japan who received chronic hemodialysis therapy for at least 90 days in 2000. Left-truncated Cox regression was used to assess time to kidney transplantation. Logistic regression determined the odds of being transplant wait-listed for a cross-section of 1323 hemodialysis patients in the United States in 2000. Furthermore, kidney transplant wait-listing was determined in 12 countries from cross-sectional samples of DOPPS II hemodialysis patients in 2002 to 2003 (N= 4274). RESULTS: Transplantation rates varied widely, from very low in Japan to 25-fold higher in the United States and 75-fold higher in Spain (both P values <0.0001). Factors associated with higher rates of transplantation included younger age, nonblack race, less comorbidity, fewer years on dialysis, higher income, and higher education levels. The likelihood of being wait-listed showed wide variation internationally and by United States region but not by for-profit dialysis unit status within the United States. CONCLUSION: DOPPS I and II confirmed large variations in kidney transplantation rates by country, even after adjusting for differences in case mix. Facility size and, in the United States, profit status, were not associated with varying transplantation rates. International results consistently showed higher transplantation rates for younger, healthier, better-educated, and higher income patients.

Adolescent↗
PubMed2005

Involvement of endoplasmic reticulum (ER) stress in podocyte injury induced by excessive protein accumulation.

BACKGROUND: An imbalance between protein load and folding capacity is referred to as endoplasmic reticulum (ER) stress. As a defense mechanism, cells express ER stress inducible chaperons, such as oxygen-regulated proteins 150 (ORP150) and glucose-regulated proteins (GRPs). While ER stress is important in various diseases, a pathophysiologic role for ER stress in kidney disease remains elusive. Here we investigate expression of ER stress proteins in cultured rat podocytes as well as in our recently developed animal model of abnormal protein retention within the ER of podocytes (i.e., megsin transgenic rat). METHODS: The expression of ER stress inducible proteins (ORP150, GRP78, or GRP94) in cultured podocytes treated with tunicamycin, A23187, SNAP, hypoxia, or hyperglycemia, and the renal tissues or isolated glomeruli from megsin transgenic rats was analyzed by Western blotting analysis, immunohistochemistry, or confocal microscopy. RESULTS: Cultured podocytes demonstrated that treatment with tunicamycin, A23187, and SNAP, but not hypoxia or hyperglycemia, up-regulate expression of ER stress proteins. Extracts of isolated glomeruli from megsin transgenic rats reveal marked up-regulation of ER stress chaperones in podocytes, which was supported by immunohistochemical analysis. Confocal microscopy revealed that ER stress in podocytes was associated with cellular injury. Podocytes of transgenic rats overexpressing a mutant megsin, without the capacity for polymerization within the ER, do not exhibit ER stress or podocyte damage, suggesting a pathogenic role of ER retention of polymerized megsin. CONCLUSION: This paper implicates a crucial role for the accumulation of excessive proteins in the podocyte ER in the induction of ER stress and associated podocyte injury.

Animals↗
PubMed2005

From molecular footprints of disease to new therapeutic interventions in diabetic nephropathy: a detective story.

Oxidative tissue damage in vivo is a complex phenomenon involving many factors and pathways. Proteins are particularly attractive targets for oxidative products analysis in order to understand better the physiopathology of human diseases. Protein modifications serve as footprints of biochemical processes. They also help ascertain the mechanism of anti-oxidative action of medical drugs and further search for novel agents that inhibit efficiently oxidative protein damage. Several drugs already used clinically interfere with oxidative protein damage through different mechanisms characteristic of their chemical structure. This review delineates the oxidative protein modifications existing in diabetic nephropathy and their regression in association with renoprotective anti-hypertensive agents. Our hypothetical approach will require further testing. Nevertheless, the insights gained on the biochemistry of protein modifications open new avenues towards the development of new classes of renoprotective agents for diabetic nephropathy.

Animals↗
PubMed2004

Menatetrenone rescues bone loss by improving osteoblast dysfunction in rats immobilized by sciatic neurectomy.

Menatetrenone (MK-4) is a vitamin K2 homologue that has been used as a therapeutic agent for osteoporosis in Japan. However, there is no far any reported evidence that MK-4 ameliorates a pre-existing condition of reduced bone mineral density (BMD) in vivo. In this study, we evaluated the effect of MK-4 in a rat model of established bone loss through immobilization caused by sciatic neurectomy. Unilateral sciatic neurectomy (SNx) was performed in rats, and 10 or 30 mg/kg of MK-4 or vehicle was administered to the rats three weeks after operation. Seven weeks after operation, the rats were sacrificed and BMD and bone histomorphometric parameters were measured to assess the effects of MK-4. While BMD of the distal femoral metaphysis was significantly decreased after SNx, MK-4 administration increased BMD in the neurectomized rats. Bone formation was decreased continuously and bone resorption was initially increased in SNx rats. Four weeks treatment of MK-4 increased bone formation and suppressed bone resorption. In addition, increased carboxylated osteocalcin and decreased undercarboxylated osteocalcin in serum were observed in MK-4-administered rats. These results indicated that MK-4 rescued bone volume by improving osteoblast dysfunction and accelerating gamma carboxylation of osteocalcin. MK-4 may be useful for treating disuse osteopenia.

Animals↗