Biomedical subjects

Shoichi Ichimura

Publications and source records attributed to Shoichi Ichimura.

At least 19 recordsLinked to original sources

PubMed2005

Diagnostic efficacy of thin slice CT in osteoid osteoma of the thoracic spine: report of two cases.

We present a 24-year-old man and a 31-year-old woman who complained of persistent back pain with osteoid osteoma of the thoracic spine. Computed tomography (CT) revealed a round sclerotic lesion in the posterior element of the thoracic spine, although their plain radiographs showed no abnormalities except a slight scoliosis. The patients underwent total excision of the tumor via a posterior approach. They are currently asymptomatic with no recurrence of the lesion and have returned to full activity. The thin slice CT is one of the most important diagnostic tools for osteoid osteoma of the spine.

Adult↗

PubMed2005

Anterior lumbar interbody fusion: changes in area of the dural tube, disc height, and prevalence of cauda equina adhesion in magnetic resonance images.

OBJECTIVE: Many investigators have reported satisfactory outcome in anterior lumbar interbody fusion (ALIF) performed for lumbar disc herniation or "multiply operated back" (MOB), but without comparing preoperative and postoperative dural tube area and cauda equina adhesion in magnetic resonance imaging (MRI). We conducted this study to determine these data in ALIF performed for lumbar disc herniation and MOB. METHODS: Thirty-two patients who underwent ALIF, involving 38 discs, were studied. In MRI obtained before and after surgery (interval 9-48 months, mean 19.2 months), cross-sectional areas of the lumbar dural tube were measured from axial T2-weighted images using a computer-linked digitizer. At 30 disc levels operated on, the cauda was identified in images; cauda equina adhesions were classified according to Matsui et al (grade I-III). Clinical improvement was scored. RESULTS: Bony union was observed in radiographs of all patients. Preoperative and postoperative cross-sectional areas of the lumbar dural tube were 1.32 +/- 0.4 and 1.87 +/- 0.5 cm, respectively, and expansion ratio was 1.43 +/- 0.4. Recovery did not correlate with expansion ratio. Positive correlation was noted between expansion ratio and disc height ratio. At 30 disc levels where cauda equina was identified, 22 represented grade I and 8 represented grade II. At three of the latter, prior surgery had been performed via a posterior approach. CONCLUSIONS: No significant difference was noted in occurrence of grade II adhesions between primary ALIF and ALIF performed for MOB. Dural tube expansion was accomplished even without exposure of the tube, and cauda equina adhesion was uncommon in primary ALIF.

Adolescent↗

PubMed2005

Overexpression of the human interleukin 1a gene causes osteopenia in mice.

OBJECTIVE: Osteoporosis is a major complication of chronic inflammatory diseases such as rheumatoid arthritis (RA). We describe disordered bone metabolism in transgenic mice that overexpress human interleukin 1a (hIL-1a). METHODS: Bone mineral density (BMD), microcomputed tomography (microCT), histomorphometry, and blood biochemical data of hIL-1a transgenic mice and littermate wild-type mice were examined. RESULTS: The femoral BMD of transgenic mice was decreased by 27.7% compared with wild-type mice. microCT revealed a marked reduction in the trabecular bone, and cortical thinning with an enlarged cavity was observed in femora of transgenic mice. Histomorphometric analysis revealed inhibition of several measures of bone formation, while the serum alkaline phosphatase level was reduced in transgenic mice; however, their indices of bone resorption were not elevated. CONCLUSION: Overexpression of hIL-1a causes osteopenia in mice. It was suggested that the systemic osteopenia in these transgenic mice occurred primarily as a result of decreased bone formation, with a reduction of bone mineralization rather than increased osteoclastic bone resorption. This may be one aspect of bone metabolism in RA that results in disease complications.

Alkaline Phosphatase↗

PubMed2005

[Bisphosphontes].

The profitable effects of bisphosphontes on treatment of osteoporosis have been consistently reported in Japan as in the United States and European countries. Alendronate and risedronate increased bone mineral density and reduced the risk of vertebral fracture. Histomorphomeric analysis and microCT have confirmed that normal bone microarchitecture and mineralization are preserved after 3 or 5 years of treatment. Long-term (7 or 10 years) treatment with bisphosphonates seemed to have a sustained effect on BMD and bone turnover, however, the optimal duration of bisphosphonate treatment is unresolved.

Bone Density↗

PubMed2004

Differential effect of vitamin K and vitamin D supplementation on bone mass in young rats fed normal or low calcium diet.

The purpose of this study was to clarify the differential effect of vitamin K and vitamin D supplementation on bone mass in young rats fed a normal or low calcium diet. Ninety female Sprague-Dawley rats, 6 weeks of age, were randomized by stratified weight method into nine groups with 10 rats in each group: baseline control, and 0.5% (normal) or 0.1% (low) calcium diet, either alone, or with vitamin K (30 mg/100g, food intake), vitamin D (25 micro g/100 g, food intake), or vitamin K + vitamin D. After 10 weeks of feeding, bone histomorphometric analyses were performed on cortical bone of the tibial shaft and cancellous bone of the proximal tibia. Vitamin K supplementation increased the maturation-related cancellous bone gain and retarded the reduction in the maturation-related cortical bone gain in rats fed a low calcium diet, and increased the maturation-related cortical bone gain in rats fed a normal calcium diet. Vitamin D supplementation reduced the maturation-related cancellous bone gain, prevented the reduction in periosteal bone gain, and enhanced the enlargement of the marrow cavity, with no significant effect on the reduction in the maturation-related cortical bone gain in rats fed a low calcium diet, and increased the maturation- related cancellous and cortical bone gains with increased periosteal bone gain in rats fed a normal calcium diet. An additive effect of vitamin K and vitamin D on the maturation- related cortical bone gain was found in rats fed a normal calcium diet. This study shows the differential effects of vitamin K and vitamin D supplementation on cancellous and cortical bone mass in young rats fed a normal or low calcium diet, as well as the additive effect on cortical bone under calcium sufficient condition.

Age Factors↗

PubMed2004

Effects of treadmill exercise on bone mass, bone metabolism, and calciotropic hormones in young growing rats.

The aim of the present study was to examine the effects of exercise on bone mass, bone metabolism, and calciotropic hormones in young growing rats. Twenty 6-week-old female Wistar rats were randomized into the following four groups with 5 animals each: 7 weeks of exercise, 7 weeks of sedentary control, 11 weeks of exercise, and 11 weeks of sedentary control. The exercise regimen consisted of running on a treadmill at 25 m/min for 1 h each day on 5 days a week. After each period of exercise, the bone mineral content (BMC) of the tibia and fifth lumbar spine was measured by dual-energy X-ray absorptiometry, using a Lunar DPX-L instrument. The femoral length and levels of bone markers and calciotropic hormones were also assessed. Seven and 11 weeks of exercise increased the serum osteocalcin and 1,25-dihydroxyvitamin D(3) levels, and decreased the serum parathyroid level. Seven weeks of exercise decreased the urinary deoxypyridinoline level, and 11 weeks of exercise increased the serum alkaline phosphatase level and decreased the serum tartrate-resistant acid phosphatase level. As a result, 7 and 11 weeks of exercise increased the femoral length and tibial BMC, but did not alter the lumbar BMC. The present study demonstrates that treadmill exercise stimulates bone formation and suppresses bone resorption, increases the serum 1,25-dihydroxyvitamin D(3) level, and decreases the serum parathyroid hormone level, resulting in an increase in bone mass with stimulation of longitudinal bone growth, especially at weight-bearing sites, in young growing rats. Further studies with long-term exercise may be needed to obtain a positive effect on the lumbar BMC.

Absorptiometry, Photon↗

PubMed2004

Effect of walking exercise on bone metabolism in postmenopausal women with osteopenia/osteoporosis.

The purpose of this prospective study was to determine whether moderate walking exercise in postmenopausal women with osteopenia/osteoporosis would affect bone metabolism. Fifty postmenopausal women, aged 49-75 years, with osteopenia/osteoporosis were recruited: 32 women entered the exercise program (the exercise group) and 18 served as controls (the control group). The exercise consisted of daily outdoor walking, the intensity of which was 50% of maximum oxygen consumption, with a duration of at least 1 h with more than 8000 steps, at a frequency of 4 days a week, over a 12-month period. Lumbar (L2-L4) bone mineral density (BMD) was measured at the baseline and every 6 months with dual-energy X-ray absorptiometry (DXA) in both groups. Serum bone-specific alkaline phosphatase (BAP) and urinary cross-linked N-terminal telopeptides of type I collagen (NTX) levels were measured at baseline and at months 1, 3, 6, 9, and 12 by EIA and ELISA, respectively, in the exercise group, and urinary NTX level was measured at the baseline and every 6 months in the control group. There were no significant differences in baseline characteristics including age, height, body weight, bone mass index, years since menopause, lumbar BMD, and urinary NTX level between the two groups. Although no significant changes were observed in lumbar BMD and the urinary NTX level in the control group, lumbar BMD in the exercise group was increased as compared with the control group, but was sustained from the baseline. In the exercise group, the urinary NTX level rapidly responded to walking exercise from month 3, and this reduction was sustained until month 12, followed by reduction in the serum BAP level. A moderately negative correlation was found between the percent change in the urinary NTX level at month 3 and that in lumbar BMD at month 12 in the exercise group. This study clearly demonstrates that the mechanism for the positive response of lumbar BMD to moderate walking exercise in postmenopausal women with osteopenia/osteoporosis appears to be the suppression of bone turnover, and that an early change in the urinary NTX level may be useful to predict the long-term response of increasing lumbar BMD to exercise, although its efficacy for lumbar BMD may be quite modest.

Aged↗

PubMed2004

Distribution of type VI collagen in chondrocyte microenvironment: study of chondrons isolated from human normal and degenerative articular cartilage and cultured chondrocytes.

The chondron is the microanatomical unit composed of a chondrocyte and its pericellular microenvironment (PCME), including the pericellular matrix and capsule. In the present study, we extracted chondrons from human articular cartilages and investigated the relationship between the distribution of the matrix molecules, including type VI collagen, and the degeneration of articular cartilage. We also investigated the effects of interleukin-1beta (IL-1beta) and transforming growth factor beta-1 (TGF-beta1) on the distribution of type VI collagen in cultured chondrocytes. Chondrons were extracted by low-speed homogenization from cartilage pieces obtained from forensic autopsies and from patients with knee osteoarthritis (OA) undergoing total knee arthroplasty. Cartilage sections were classified into three groups (normal, slight degeneration, and moderate degeneration) based on the degree of degeneration according to Mankin's score. Extracted chondrons were immunostained, and the distribution of the matrix molecules, including type VI collagen, was investigated using a confocal laser scanning microscope (CLSM). The chondrocytes isolated by enzymic treatment were subjected to three-dimensional culture in agarose gel and then treated with IL-1beta or TGF-beta1. The distribution of newly synthesized type VI collagen in agarose gel was also investigated using the CLSM. Type VI collagen was localized specifically within the PCME of chondrons. The volume ratio of PCME to chondrocyte (P/C ratio) was significantly higher in the moderate degeneration group than in the other two groups. The accumulation of type VI collagen around a chondrocyte was obviously increased by the addition of TGF-beta1. The P/C ratio significantly increased as the severity of the OA progressed, suggesting that type VI collagen distributed specifically in the PCME was playing a protective role for chondrocytes by maintaining the pericellular microenvironment in OA.

Adolescent↗

PubMed2004

Posterior spinal fusion for lumbar degenerative diseases using the Crock-Yamagishi (C-Y) spinal fixation system.

Although many transpedicular screw systems have been developed and have undergone wide clinical use, experience with semirigid transpedicular systems has rarely been reported. We evaluated the efficacy and safety of the Crock-Yamagishi (C-Y) system for posterior spinal fusion in lumbar degenerative diseases. The outcomes for 26 patients (14 men, 12 women) with lumbar degenerative diseases who underwent posterior spinal fusion using the C-Y system were analyzed (posterior lumbar interbody fusion (PLIF), 11 patients; posterolateral fusion (PLF), 14; and facet fusion (FF), 1. Symptoms were evaluated using the Japanese Orthopaedic Association Assessment of Treatment for Low Back Pain (JOA score). Preoperative scores ranged from -1 to 23 points (mean, 12.8), while postoperative scores ranged from 19 to 29 points (mean, 26.4). Degree of recovery ranged from 23.1% to 100% (mean, 83.2%). Overall fusion rate was 96.2% (25/26). Neither breakage nor loosening of implants was observed radiographically. Intra- and postoperative complications included one case of transient L5 nerve root palsy attributable to surgical technique, and one deep postoperative infection. The C-Y system, categorized as semirigid, is effective when used with one- or two-level PLIF or PLF for lumbar degenerative disorders, grade I to II spondylolisthesis, and failed back syndrome.

Adult↗

PubMed2004

Differential effect of short-term etidronate treatment on three cancellous bone sites in orchidectomized adult rats.

The aim of the present study was to analyze the effects of short-term treatment with the antiresorptive agent, etidronate, on orchidectomized adult rats, via comparison of three cancellous bone sites, the lumbar vertebral body (LVB), proximal tibial metaphysis (PTM), and distal tibial metaphysis (DTM). Thirty-five male Wistar rats, aged 10 months, were randomly divided into four groups: baseline control (BLC, nF10), age-matched sham-operated control (AMC, nF9), orchidectomy (ORX, nF9), and ORXBetidronate treatment (nF7). Etidronate treatment (10 mg/kg, daily subcutaneous injection) was initiated 2 weeks after surgery and was continued for 2 weeks. Four weeks after surgery, the 5th LVB, PTM, and DTM were processed for histomorphometric analysis of cancellous bone (secondary spongiosa). ORX resulted in a decrease in body weight. No significant difference in cancellous bone volume (BV/TV) was found between the BLC and AMC groups at any skeletal site. The cancellous BV/TV loss was attributable to increased eroded surface (ES/BS) with no significant alteration in the mineral apposition rate (MAR), at all skeletal sites and etidronate treatment in ORX rats significantly decreased ES/BS to a level not significantly different from that in the AMC group, resulting in complete prevention of ORX-induced cancellous BV/TV loss. The MAR was markedly decreased in the PTM and LVB, but maintained in the DTM by etidronate treatment. The present study showed that etidronate treatment could completely prevent ORX-induced cancellous bone loss regardless skeletal sites by suppressing bone resorption. In particular, suppression of bone formation in terms of osteoblastic activity by etidronate treatment was not evident only in the DTM

Animals↗

PubMed2003

Combined treatment with vitamin k2 and bisphosphonate in postmenopausal women with osteoporosis.

Vitamin K2, as well as bisphosphonates, such as etidronate, alendronate, and risedronate, is widely used in the treatment with osteoporosis in Japan. Etidronate increases the lumbar bone mineral density (BMD), and prevents new vertebral fractures, in patients with osteoporosis, while alendronate and risedronate increase the lumbar and femoral neck BMDs, and prevent new vertebral and femoral neck fractures. Vitamin K2 enhances gamma-carboxylation of bone glutamic acid residues and the secretion of osteocalcin, sustains the lumbar BMD, and prevents osteoporotic fractures in patients with osteoporosis. Bisphosphonates, such as alendronate and risedronate, rather than vitamin K2, should be initially chosen for the treatment of osteoporosis, because they are more efficacious than vitamin K2. Available evidence suggest that risedronate prevents deterioration of the connectivity of the trabeculae in ovariectomized rats, whereas vitamin K2 increase the trabecular thickness, and that a combination of risedronate and vitamin K2 has a synergistic effect on preventing the deterioration of trabecular bone architecture induced by estrogen deficiency. Some studies have shown that combined treatment with etidronate and vitamin K2 appears to be more effective than etidronate alone in the prevention of new osteoporotic vertebral fractures. Based on these findings, combined treatment with vitamin K2 and bisphosphonates may be more efficacious in the prevention new vertebral fractures than a single treatment with bisphosphonate in postmenopausal women with osteoporosis. Thus, this combined treatment should be recommended for the treatment of postmenopausal osteoporosis. It is proposed that the role of vitamin K2 should be emphasized, when used in combination with bisphosphonates, especially in patients with vitamin K deficiency.

Aged↗

PubMed2003

An atelocollagen honeycomb-shaped scaffold with a membrane seal (ACHMS-scaffold) for the culture of annulus fibrosus cells from an intervertebral disc.

The aim of this study was to investigate the possibility of using the atelocollagen honeycomb-shaped scaffold with a membrane seal (ACHMS-scaffold) for the culture of annulus fibrosus (AF) cells in tissue engineering procedures of intervertebral disc repair. AF cells from the intervertebral discs of Japanese white rabbits were cultured for up to 3 weeks in the ACHMS-scaffold to allow a high density, three-dimensional culture. Although the DNA content in the scaffold increased at a lower rate than in the monolayer culture, scanning electron microscopy data showed that the scaffold was filled with the grown AF cells and produced extracellular matrix on day 21. The amount of type II collagen and its mRNA expression by the scaffold cultured cells were determined using Western blotting and Northern blotting analyses, respectively, and remained at a higher level than in the monolayer cultured cells. Furthermore, glycosaminoglycan (GAG) accumulation in the scaffold culture was at a higher level than in the monolayer culture. Western blot analysis for extracted proteoglycans from the scaffold culture also exhibited a much higher proteoglycan accumulation than the monolayer culture. These results indicate that the AF cells are able to grow and remain phenotypically stable in the scaffold.

Animals↗

PubMed2003

Effect of vitamin K2 on cortical and cancellous bones in orchidectomized young rats.

OBJECTIVES: The purpose of the present study was to compare the effect of vitamin K(2) on cortical and cancellous bones in orchidectomized young rats. METHODS: Forty male Sprague-Dawley rats, 6 weeks of age, were randomized by stratified weight method into four groups with 10 rats in each group: baseline controls (BLC), age-matched controls (AMC), orchidectomy (ORX), and ORX+vitamin K(2) administration (K). Vitamin K(2) (menatetrenone) was administered subcutaneously twice a week at dose of 30 mg/kg each. The experimental period was 8 weeks, and cortical and cancellous bone histomorphometry was performed on the tibial shaft and the proximal tibia, respectively. RESULTS: Cortical area (Ct Ar) and cancellous bone volume (BV/TV) were significantly greater in the AMC group than in the BLC group. Ct Ar was significantly lower in the ORX group than in the AMC group, and cancellous BV/TV was also significantly lower in the ORX group than in the AMC group as a result of significantly increased eroded surface (ES/BS). Although Ct Ar in the ORX+K group did not differ significantly from that in the ORX group, cancellous BV/TV was significantly greater in the ORX+K group than in the ORX group, but still significantly lower than in the AMC group. This protective effect of vitamin K(2) on cancellous bone was attributable to normalizing increased ES/BS. CONCLUSIONS: Vitamin K(2) appears to act more strongly on cancellous bone than on cortical bone in ORX young rats. High dose vitamin K(2) could partially prevent the reduction of cancellous bone gain by normalizing raised bone resorption in ORX young rats.

Animals↗

PubMed2003

Comparative effects of orchidectomy and sciatic neurectomy on cortical and cancellous bone in young growing rats.

The purpose of the present study was to compare the effects of orchidectomy and sciatic neurectomy on cortical and cancellous bone in male rats. Fifty male Sprague-Dawley rats, 6 weeks of age, were randomized into five groups, with ten rats in each group: baseline control, age-matched intact control, orchidectomy (ORX), unilateral sciatic neurectomy (NX), and ORX + NX. After 8 weeks of feeding, the tibial shaft and proximal tibia were processed for cortical and cancellous bone histomorphometric analyses, respectively. ORX-induced reductions in maturation-related cortical and cancellous bone gains were attributable to decreased periosteal bone gain and increased trabecular bone resorption, respectively. NX- and ORX + NX-induced reductions in maturation-related cortical bone gain were attributable to decreased periosteal bone formation and increased endocortical bone turnover, while NX- and ORX + NX -induced reductions in maturation-related cancellous bone gain were attributable to increased bone resorption and decreased bone formation. NX more markedly reduced maturation-related cortical and cancellous bone gains than did ORX, and the ORX-induced reductions in maturation-related cortical and cancellous bone gains were more pronounced when combined with NX. The present study demonstrated differences in changes in cortical and cancellous bone following ORX and NX in young rats. The importance of mechanical loading, with or without testosterone deficiency, is emphasized in cortical and cancellous bone growth.

Animals↗

PubMed2003

Effects of cyclical etidronate with alfacalcidol on lumbar bone mineral density, bone resorption, and back pain in postmenopausal women with osteoporosis.

The purpose of the present open-labeled, randomized, prospective study was to compare the effects of cyclical etidronate combined with alfacalcidol with those of cyclical etidronate alone on lumbar bone mineral density (BMD), bone resorption, and back pain in postmenopausal women with osteoporosis. Forty postmenopausal women with osteoporosis, 60-86 years of age, without any vertebral fractures in the lumbar spine, were randomly divided into two groups with 20 patients in each group. One group was treated with cyclical etidronate (oral etidronate 200 mg daily for 2 weeks every 3 months) and the other was given cyclical etidronate combined with alfacalcidol (cyclical etidronate plus alfacalcidol 1 Ig daily continuously). The BMD of the lumbar spine (L1-L4) measured by dual-energy X-ray absorptiometry, urinary crosslinked N-terminal telopeptides of type I collagen (NTX) measured by an enzyme-linked immunosorbent assay, and back pain evaluated by the face scale score were assessed at baseline, 6 months, and 12 months. There were no significant differences in baseline characteristics including age, body mass index, years since menopause, lumbar BMD, urinary NTX level, and face scale score between the two treatment groups. Both treatments significantly reduced the urinary NTX level and back pain. Cyclical etidronate combined with alfacalcidol significantly increased the lumbar BMD with a more significant reduction in the urinary NTX level than cyclical etidronate alone, but cyclical etidronate alone did not significantly increase the lumbar BMD. Alleviation of back pain was similar in the two groups. These results suggest that cyclical etidronate combined with alfacalcidol appears to be more useful than cyclical etidronate alone for increasing the lumbar BMD by more markedly suppressing bone resorption in postmenopausal women with osteoporosis.

Aged↗

PubMed2003

Effects of treatment with etidronate and alfacalcidol for osteogenesis imperfecta type I: a case report.

A case of osteogenesis imperfecta (OI) that was successfully treated with oral etidronate and alfacalcidol is reported. A 36-year-old man with OI type I who had frequently been experiencing fragile fractures in the long bones of the upper and lower extremities presented to our hospital with back pain caused by fragile thoracic vertebral fractures. He was treated with intermittent cyclical etidronate (200 mg/day for 2 weeks per 3 months) and alfacalcidol (1 microgram/day, daily) over 18 months. The bone mineral density of the lumbar spine (L1-L4) measured by dual-energy X-ray absorptiometry (Hologic QDR 1500 W) increased over 18 months, and back pain due to thoracic vertebral fractures markedly decreased. No new fragile vertebral or nonvertebral fractures were observed during the 18 months of treatment. This report provides evidence indicating that treatment with intermittent cyclical oral etidronate and alfacalcidol has potential use in adult patients with OI type I.

Adult↗

PubMed2003

Early response to alendronate after treatment with etidronate in postmenopausal women with osteoporosis.

The purpose of the present study was to examine the early response of lumbar bone mineral density (BMD), bone resorption, and back pain to alendronate after treatment with cyclical etidronate in postmenopausal women with osteoporosis. Forty postmenopausal women with osteoporosis, 60-83 years of age, without any vertebral fractures in the lumbar spine, were randomly divided into two groups with 20 patients in each group: 18 months of cyclical etidronate (200 mg daily for 2 weeks every 3 months) group and 12 months of cyclical etidronate followed by 6 months of alendronate (5 mg daily) group. BMD of the lumbar spine (L1-L4) measured by DXA, urinary cross-linked N-terminal telopeptides of type I collagen (NTX) level measured by enzyme-linked immunosorbent assay, and back pain evaluated by face scale score were assessed at baseline and every 6 months. There were no significant differences in baseline characteristics including age, body mass index, years since menopause, lumbar BMD, urinary NTX level, and face scale score between the two groups. Cyclical etidronate significantly reduced urinary NTx level and face scale score over 12 months, but did not significantly increase lumbar BMD. After 12 months of treatment, the switch to alendronate significantly reduced urinary NTX level and face scale score, and significantly increased lumbar BMD, while continued cyclical etidronate did not significantly alter these parameters. These results suggest that switching to alendronate after treatment with cyclical etidronate produces a greater response of lumbar BMD, bone resorption, and back pain than continued cyclical etidronate in postmenopausal women with osteoporosis.

Aged↗

PubMed2003

Treatment with vitamin D3 and/or vitamin K2 for postmenopausal osteoporosis.

It is established in Japan that treatment with 1alpha-hydroxyvitamin D3 (alfacalcidol) slightly reduces bone turnover, sustains lumbar bone mineral density (BMD), and prevents osteoporotic vertebral fractures in postmenopausal women with osteoporosis, while vitamin K2 (menatetrenone) enhances gamma-carboxylation of bone glutamic acid residues and secretion of osteocalcin, sustains lumbar BMD, and prevents osteoporotic fractures in patients with osteoporosis. Available evidence suggests that the effect of vitamin K2 on mineralization by human periosteal osteoblasts is enhanced in the presence of 1,25 dihydroxyvitamin D3 in vitro. The effect of vitamin K2 on BMD in ovariectomized rats is affected by the plasma 25-hydroxyvitamin D3 level in vivo, and is significant only when rats are fed a diet containing vitamin D3. Based on this line of evidence, combined treatment with alfacalcidol and menatetrenone for osteoporosis is surmised to be more effective than treatment with menatetrenone alone, and may have anabolic effects on osteoporotic bone. This combined treatment may increase bone formation as well as bone resorption over the mild anti-resorptive effect of alfacalcidol itself, and shows the greatest effect on lumbar BMD or the incidence of vertebral fractures in studies in which the mean age and years since menopause of subjects were low and the degree of osteoporosis was mild. It may be effective for mild postmenopausal osteoporosis in which age-related deterioration of trabecular bone properties remains below the threshold for vertebral fractures, even if bone resorption is increased and trabecular bone has deteriorated.

Animals↗