calcitonin and Disease-Models--Animal

Osteoporosis is a systemic skeletal condition characterized by decreased bone strength with consequent increased susceptibility to bone fracture. Fragility fractures in osteoporosis are often painful and result in loss of quality of life and disability. Salmon calcitonin (SCT) is a natural hormone that may assist in the management of osteoporotic patients following fracture by reducing fracture risk and decreasing pain. SCT is an antiresorptive agent which has been shown to reduce the risk of vertebral fractures (by 36%) in postmenopausal women with osteoporosis and previous fractures, with a safety profile comparable to placebo over long-term use. Clinical evidence suggests that SCT (with either subcutaneous and intranasal delivery) is an analgesic for the acute pain following osteoporotic fracture. Pain relief with SCT occurs after 1 week or less of treatment. Associated with this pain relief, vertebral fracture patients receiving SCT have been observed to have earlier mobilization compared with those receiving a placebo. Both preclinical and clinical data suggest a central analgesic effect for SCT. The mechanism(s) by which SCT induces pain relief has (have) not been conclusively shown. Neither a direct receptor-mediated action nor an indirect endorphin-mediated effect can be ruled out.

Topics: Analgesics; Animals; Calcitonin; Controlled Clinical Trials as Topic; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Fractures, Bone; Humans; Osteoporosis, Postmenopausal; Pain

Topics: Animals; Bone and Bones; Bone Density; Calcitonin; Disease Models, Animal; Female; Fractures, Spontaneous; Humans; Male; Osteoblasts; Osteoporosis; Spinal Fractures

Epilepsy is a chronic neurological disease that is thought to affect up to 1% of the world's population. Evidence suggests that salmon calcitonin (sCT) has positive effects on epileptic seizures and epileptogenesis. However, it remains unknown that whether nitric oxide (NO) pathway contributed to this antiepileptic effect of sCT. We have used the pentylenetetrazole (PTZ)-induced seizure rat model to identify the effect of sCT on seizure score, seizure-induced cognitive deficit, and the NO pathway in the brain. We found that sCT increases the first myoclonic jerk (FMJ), decreased Racine's convulsion scale (RCS), and abates seizure-induced cognitive impairment. We further demonstrated that sCT attenuated the abnormal increase of NO in the brain. These results revealed that sCT exerts an antiepileptic effect by modulating the NO pathway in the brain.

Topics: Animals; Anticonvulsants; Calcitonin; Disease Models, Animal; Electroencephalography; Nitric Oxide; Pentylenetetrazole; Rats; Rats, Sprague-Dawley

Recent findings have identified salmon calcitonin (sCT), an amylin receptor agonist and analogue of endogenous amylin, as a potential regulator of alcohol-induced activation of the mesolimbic dopamine system and alcohol consumption. Providing that the role of amylin signalling in alcohol-related behaviours remains unknown, the present experiments investigate the effect of sCT on these behaviours and the mechanisms involved. We showed that repeated sCT administration decreased alcohol and food intake in outbred rats. Moreover, single administration of the potent amylin receptor antagonist, AC187, increased short-term alcohol intake in outbred alcohol-consuming rats, but did not affect food intake. Acute administration of sCT prevented relapse-like drinking in the "alcohol deprivation effect" model in outbred alcohol-experienced rats. Additionally, acute sCT administration reduced operant oral alcohol self-administration (under the fixed ratio 4 schedule of reinforcement) in selectively bred Sardinian alcohol-preferring rats, while it did not alter operant self-administration (under the progressive ratio schedule of reinforcement) of a highly palatable chocolate-flavoured beverage in outbred rats. Lastly, we identified differential amylin receptor expression in high compared to low alcohol-consuming rats, as reflected by decreased calcitonin receptor and increased receptor activity modifying protein 1 expression in the nucleus accumbens (NAc) of high consumers. Collectively, our data suggest that amylin signalling, especially in the NAc, may contribute to reduction of various alcohol-related behaviours.

Topics: Alcohol Drinking; Alcoholism; Amylin Receptor Agonists; Animals; Behavior, Animal; Calcitonin; Disease Models, Animal; Drinking Behavior; Eating; Male; Nucleus Accumbens; Peptide Fragments; Rats; Rats, Wistar; Receptors, Islet Amyloid Polypeptide; Self Administration

Pain is a debilitating symptom of rheumatoid arthritis (RA), caused by joint inflammation and cartilage and bone destruction. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to treat pain and inflammation in RA, but are not disease-modifying and do not prevent joint destruction when administered alone. KBPs (Key Bioscience peptides) are synthetic peptides based on salmon calcitonin and are expected to inhibit bone resorption and to be chondroprotective. In this study, we investigated if combining a standard of care NSAID (naproxen) with a KBP resulted in improvement in pain scores, as well as disease activity and structural damage in a rat model of RA.. Collagen-induced arthritis (CIA) was induced in 40 female Lewis rats by immunization with porcine type II collagen; 10 rats were given sham injections. CIA rats were treated with KBP and/or naproxen. Health scores and joint scores were evaluated daily. Mechanical and cold allodynia tests and burrowing tests were used to assess pain-like behaviors. Blood samples were collected for biomarker testing, and paws were collected for histology and microcomputed tomography.. Naproxen monotherapy increased the time until humane endpoints was reached, and improved health score, pain assessments, and trabecular thickness, while KBP monotherapy did not result in improvements. Combination therapy had improved efficacy over naproxen monotherapy; combination therapy resulted in improved health scores, and importantly reduced mechanical and cold allodynia assessment. Furthermore, protection of articular cartilage structure and preservation of bone structure and bone volume were also observed.. This study demonstrates that combining KBP and naproxen may be a relevant therapeutic strategy for RA, resulting in improvements to the overall health, pain, inflammation, and joint structure.

Topics: Amylin Receptor Agonists; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Density Conservation Agents; Calcitonin; Collagen Type II; Disease Models, Animal; Female; Humans; Islet Amyloid Polypeptide; Naproxen; Pain; Pain Measurement; Rats, Inbred Lew; Receptors, Calcitonin; Swine

BACKGROUND Facet joint degeneration (FJD) is one of the common causes of low back pain (LBP), and estrogen deficiency is one of the triggers for FJD. Calcitonin may possess the potential for treating osteoarthritis, but to date the hormone has not been studied in the treatment of FJD. Therefore, the aim of this study was to investigate the effects of salmon calcitonin (sCT) on FJD induced by estrogen deficiency after ovariectomy (OVX). MATERIAL AND METHODS Thirty female Sprague-Dawley rats were randomly assigned to 3 groups: the OVX group received bilateral OVX, the OVX + sCT group received subcutaneous administration of sCT (16 IU/kg/2 days) following bilateral OVX, and the Sham group received sham surgery. All rats were euthanized at 12 weeks post-OVX. Serum COMP level, cartilage degradation, and subchondral bone micro-architecture were evaluated. RESULTS sCT relieved cartilage surface lesions, reduced histological score, and significantly increased cartilage thickness. The OVX + sCT group exhibited significantly increased expression of aggrecan, as well as significantly decreased levels of ADAMTS-4, MMP-13, and caspase-3. The results of micro-computed tomography analysis revealed that the OVX + sCT group exhibited higher BMD, BV/TV, and Tb.Th values but a lower Tb.Sp value than that of the OVX group. Serum COMP concentrations were significantly correlated with histological score and cartilage thickness. CONCLUSIONS sCT can inhibit the progression of FJD in OVX rats, which is attributed to its inhibitory effects on cartilage metabolism imbalance, chondrocyte apoptosis, and subchondral bone remodeling. Serum COMP has diagnostic potential for FJD.

Topics: Animals; Biomarkers; Bone and Bones; Calcitonin; Cartilage; Cartilage Oligomeric Matrix Protein; Disease Models, Animal; Female; Lumbar Vertebrae; Ovariectomy; Rats, Sprague-Dawley; X-Ray Microtomography; Zygapophyseal Joint

Polyelectrolyte nanoparticle constructs (NPs) comprising salmon calcitonin (sCT), chitosan (CS), and hyaluronic acid (HA) were previously established as having anti-inflammatory potential when injected via the intra-articular (i.a.) route to a mouse model. We attempted to translate the formulation to a large animal model, the lipopolysaccharide (LPS)-stimulated equine model of joint inflammation. The aim was to manufacture under aseptic conditions to produce sterile pyrogen-free NPs, to confirm physicochemical characteristics, and to test toxicity and efficacy in a pilot study. NP dispersions were successfully formulated using pharmaceutical-grade source materials and were aseptically manufactured under GMP-simulated conditions in a grade A modular aseptic processing workstation. The NP formulation had no detectable pathogen or endotoxin contamination. NPs were then tested versus a lactated Ringer's solution control following single i.a. injections to the radiocarpal joints of two groups of four horses pre-treated with LPS, followed by arthrocentesis at set intervals over 1 week. There was no evidence of treatment-related toxicity over the period. While there were no differences between clinical read-outs of the NP and the control, two synovial fluid-derived biomarkers associated with cartilage turnover revealed a beneficial effect of NPs. In conclusion, NPs comprising well-known materials were manufactured for an equine i.a.-injectable pilot study and yielded no NP-attributable toxicity. Evidence of NP-associated benefit at the level of secondary endpoints was detected as a result of decreases in synovial fluid inflammatory biomarkers.

Topics: Animals; Arthrocentesis; Biomarkers; Calcitonin; Chitosan; Disease Models, Animal; Drug Carriers; Horses; Hyaluronic Acid; Injections, Intra-Articular; Lipopolysaccharides; Nanoconjugates; Pilot Projects; Synovial Fluid; Synovitis

Traumatic osteoarthritis (OA) is possibly augmented by effects from loss of sex hormones. Salmon calcitonin is shown to reduce OA pathogenesis and bone resorption. We investigated the effects of oral salmon calcitonin treatment and ovariectomy on cartilage and bone pathology in a traumatic OA model.. Six groups with 10 7-month-old female Sprague Dawley rats each were subjected to bilateral meniscectomy (MNX), ovariectomy (OVX) or Sham surgery and treated for 8 weeks with oral salmon calcitonin (CT) or vehicle (V) in the following way: (1) Sham+V; (2) MNX+V; (3) MNX+CT; (4) OVX+V; (5) MNX/OVX+V; (6) MNX/OVX+CT. Weights were recorded weekly and CTX-II was measured in serum. At termination 56 days post-surgery, the right tibia was analyzed for changes in articular cartilage thickness, extent of cartilage damage and subchondral bone changes in predefined zones, as recommended in the novel OARSI histopathology score.. The combined MNX/OVX model produced a significantly reduced cartilage thickness (P=0.033) in the outer zone (Z1) of the tibial plateau and increased calcified cartilage damage (P=0.0004) and serum CTX-II (P=0.003). Addition of OVX to MNX significantly increased the width of matrix damage at the surface (P=0.025) and 50% cartilage depth (P=0.004). Treatment with oral salmon calcitonin counteracted the loss of cartilage thickness (P=0.055), significantly reduced subchondral bone damage score (P=0.019) and reduced the type II collagen degradation (P=0.009).. Addition of ovariectomy augmented site-specific traumatic OA pathology, which was reduced by oral salmon calcitonin treatment. Treatments for OA might ideally affect both bone and cartilage.

Topics: Administration, Oral; Animals; Bone Density Conservation Agents; Calcitonin; Cartilage, Articular; Disease Models, Animal; Female; Osteoarthritis; Ovariectomy; Rats; Rats, Sprague-Dawley; Tibia

On a model of autoimmune arthritis in rabbits, reduction of inflammatory-destructive process manifestation was observed in all joint tissues under the influence of the intraarticular introduction of calcitonin. Improving metabolic processes in the matrix of tissue-connecting elements of a joint, this specimen inhibits the inflammatory destruction of the subchondral bone and hyaline cartilage in conditions of experimental rheumatoid inflammation.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone and Bones; Calcitonin; Cartilage, Articular; Disease Models, Animal; Injections, Intra-Articular; Joints; Rabbits

To investigate whether oral calcitonin treatment influences the increases in type II collagen (CII) degradation and related surface erosions of articular cartilage in ovariectomized rats.. Fifty rats were randomly allocated into 1 of the 5 following intervention groups: sham-operated, ovariectomy, ovariectomy plus subcutaneously implanted 17beta-estradiol pellet, ovariectomy plus 2 mg/kg salmon calcitonin plus 50 mg/kg 5CNAC (carrier), or ovariectomy plus 50 mg/kg 5CNAC. Each treatment was administered for 9 weeks after the ovariectomy. Blood samples for biochemical marker analysis were collected from fasting animals at baseline, on day 3, and after 1, 2, 4, 6, and 9 weeks. CII degradation was quantified by specific immunoassay, and the changes in severity scores of articular cartilage erosions were visualized and scored in histologic sections of the knees.. Ovariectomy resulted in a marked increase in serum levels of C-telopeptide of type II collagen (CTX-II) (P < 0.001), which could be effectively reversed by 17beta-estradiol supplementation. Oral administration of calcitonin elicited similar decreases in serum levels of CTX-II (P < 0.001). Histologic scoring of cartilage erosion showed significantly less cartilage erosion in calcitonin-treated ovariectomized rats versus control ovariectomized rats that were untreated or treated with 5CNAC alone. (P < 0.01).. The in vivo effects of calcitonin in rats suggest that calcitonin is able to counteract CII degradation and the accompanying structural disintegration of articular cartilage promoted by estrogen deficiency. Clinical assessment of the chondroprotective potential of calcitonin in postmenopausal women seems warranted.

Topics: Administration, Oral; Animals; Bone Density Conservation Agents; Calcitonin; Cartilage, Articular; Collagen Type I; Collagen Type II; Disease Models, Animal; Estradiol; Female; Ovariectomy; Peptides; Rats; Rats, Sprague-Dawley; Stifle

Ovariectomy induces deterioration of the trabecular structure in the femoral neck of ewes, as depicted by MR microscopic imaging. This structural deterioration is prevented by salmon calcitonin treatment.. This study evaluated the trabecular (Tb) microarchitecture of an ovariectomy (OVX)-induced osteoporotic model in ewes and determined the effects of salmon calcitonin (sCT), an osteoclast inhibitor, on the Tb structure. This is the first report of OVX-induced changes in the Tb structure in the femoral neck in the ewes and effect of sCT on the microarchitecture.. Ewes (5-8 years old, n = 28) were equally allocated into sham (Sham), OVX injected with vehicle, or OVX injected with sCT at 50 or 100 IU, three injections per week. They were killed 6 months after OVX. The femoral neck was examined with an MR imager at 9.4 T in axial, coronal, and sagittal planes. An internal calibration procedure as a means of standardizing image analysis was used to adjust the segmentation threshold. Data from all three planes were averaged.. Compared with Sham, OVX induced significant changes (p < 0.0125) in the MRI-derived femoral neck Tb structure: Tb bone volume fraction (BV/TV), -18%; Tb number, -20%; Tb separation, +23%; number of free ends, +28%; number of nodes, -39%; number of Tb branches, -23%; mean length of Tb branches, -19%. Compared with OVX, treatment of sCT at 100 IU significantly improved all the Tb structural parameters to the Sham level (p < 0.0001 approximately p = 0.0281), whereas 50 IU significantly increased the Tb number and the mean length of the Tb branches. BV/TV explained 74% of the variation of compressive stress of the trabecular cylinder cores of the femoral neck. Combining all structural parameters in a multivariate regression analysis significantly improved the explanation to 84%, and adding BMD further improved the predictive ability of the model to 92%. We conclude that OVX induces deterioration of the MRI-derived Tb microstructure in the femoral neck of ewes. sCT treatment prevents OVX-induced changes. The femoral neck microarchitecture significantly correlates with its biomechanical properties. Combining microstructural parameters with BMD further improves the prediction of bone biomechanical properties. The effects of sCT on OVX ewes may help explain reduced fracture risk in postmenopausal osteoporotic women treated with sCT.

Topics: Animals; Calcitonin; Compressive Strength; Disease Models, Animal; Female; Femur Neck; Magnetic Resonance Imaging; Osteoporosis; Ovariectomy; Sheep

The effect of salmon calcitonin on the maturation of the regenerate bone was assessed in an experimental model in rabbits. Twenty-six New Zealand White male rabbits, approximately 5 months old and weighing 3 to 3.5 kg, were subjected to a mid-diaphyseal tibial osteotomy. After 5 days, the right tibia was lengthened gradually at a rate of 0.375 mm every 12 hours, for 10 days. Ten international units of salmon calcitonin were administered daily subcutaneously to the study group (14 animals), whereas the animals of the control group (12 animals) were injected with a placebo, for the duration of the experiment. The bone mineral density of the regenerate bone was assessed on Days 20, 35, 45, and 55 of the experiment, in both groups, using dual energy xray absorptiometry. No statistical significant difference was found in the dual energy xray absorptiometry measurements between the study and control groups regarding the change of the bone mineral density of the new bone relative to a preoperative baseline measurement. Characteristic time-related changes were observed in the bone mineral density of the regenerate bone during its maturation, which proved to be identical in both groups. It seems that the administration of calcitonin does not enhance regenerate bone mineralization rate and tendency during bone lengthening.

Topics: Absorptiometry, Photon; Analysis of Variance; Animals; Bone Density; Bone Regeneration; Calcitonin; Disease Models, Animal; Drug Administration Schedule; Drug Evaluation, Preclinical; Injections, Subcutaneous; Leg Length Inequality; Male; Osteogenesis, Distraction; Rabbits; Tibia; Time Factors

The effects of salmon calcitonin and clodronate were compared in ovariectomised rats. Sixty female Wistar rats ( 260 g in weight) were fed the same diet and had the same living conditions. The rats were divided into the following groups: 15 rats with sham ovariectomy and no drug treatment (Sham-OVX); 45 rats with bilateral ovariectomy subdivided into 15 rats not receiving drug treatment (OVX group), 15 rats treated with subcutaneous salmon calcitonin, 2 U/kg/day every 2 days (OVX + CT group) and 15 rats treated with subcutaneous clodronate, 5 mg/kg/day every 2 days (OVX + Cl group). Sixty days after surgery, the rats were sacrificed and their femurs and fifth lumbar vertebrae were dissected and cleaned of soft tissue. Femur length, vertebral height, and bone mineral content and bone mineral density of the femur and fifth lumbar vertebra by dual-energy X-ray absorptiometry were measured. Calcitonin had a significant and stronger effect in preventing ovariectomy-induced osteopenia in the femur (OVX + CT vs OVX groups, p < 0.0001); both calcitonin and clodronate had a significant effect on the fifth lumbar vertebra, which was greater in the calcitonin group (OVX + CT vs OVX + Cl groups, p<0.005). These findings indicate that calcitonin has a protective effect on both the axial (trabecular bone) and peripheral (cortical bone) skeletons, but clodronate only has a protective effect on the axial skeleton.

Topics: Absorptiometry, Photon; Animals; Bone Density; Bone Diseases, Metabolic; Calcitonin; Clodronic Acid; Disease Models, Animal; Female; Femur; Injections, Subcutaneous; Ovariectomy; Rats; Rats, Wistar; Spine; Treatment Outcome

In the present study, two ulcer models--central thyrotropin-releasing hormone (TRH) injection and cold-restraint stress (CRS) application--were compared. Animals were treated either with salmon calcitonin (sCT) or saline intracerebroventricularly (ICV) before CRS exposure or ICV TRH injection. In both models, besides ultrastructural properties, ulcer indexes and lipid peroxidation (LP) and glutathione (GSH) levels of liver and stomach were determined. While TRH treatment did not affect GSH and LP levels of the stomach and led to a slight decrease in hepatic GSH levels, CRS induced a marked reduction in gastric and hepatic GSH and an increase in LP levels of both tissues. sCT pretreatment prevented the reduction of gastric and hepatic GSH levels and morphological damage of both tissues in the CRS group. However, the same treatment did not prevent the TRH-induced reduction of hepatic GSH levels and, interestingly, it worsened the ultrastructural disturbances in the liver. Although sCT prevented macroscopic ulcer formation in both models, it did not totally reverse the microscopic effects of TRH.

Topics: Animals; Calcitonin; Cold Temperature; Disease Models, Animal; Female; Gastric Mucosa; Glutathione; Injections, Intraventricular; Lipid Peroxidation; Liver; Male; Rats; Rats, Wistar; Restraint, Physical; Stomach; Stomach Ulcer; Thyrotropin-Releasing Hormone

The study was designed to compare the skeletal effects of intermittent and continuous administration of calcitonin (CT) in ovariectomized (OVX) rats. Female rats were sham operated or OVX at 3 months of age and treated for 6 weeks with vehicle or salmon CT. Sham-operated control rats were injected subcutaneously with vehicle on alternate days. One group of OVX rats was treated with vehicle intermittently by subcutaneous injection or continuously via Alzet osmotic minipumps. The remaining OVX rats were treated with CT by either subcutaneous injections (16 U/kg) on alternate days or by continuous infusion via minipumps at a daily dose of 8 U/kg. OVX rats treated with CT continuously were mildly hypocalcemic compared with all other groups. The proximal tibial metaphyses of vehicle-treated OVX rats were osteopenic with a cancellous bone volume at only 28% of the vehicle-treated control level. This bone loss was associated with increased indices of bone turnover such as osteoclast surface, osteoblast surface, and bone formation rate. Cancellous bone volume in OVX rats treated with CT either intermittently or continuously was significantly higher than that of vehicle-treated OVX rats, but lower than that of vehicle-treated control rats. Treatment of OVX rats with intermittent or continuous CT significantly decreased all indices of bone turnover compared with vehicle-treated OVX rats. However, osteoclast and osteoblast surfaces of OVX rats treated with CT continuously were still significantly higher than those of vehicle-treated control rats. These results indicate that intermittent and continuous administration of CT had similar skeletal effects in OVX rats. Both treatment regimens depressed bone turnover and partially prevented cancellous bone loss in the estrogen-deplete skeleton.

Topics: Analysis of Variance; Animals; Bone Density; Bone Development; Bone Diseases, Metabolic; Calcitonin; Calcium; Disease Models, Animal; Female; Humans; Infusion Pumps, Implantable; Injections, Subcutaneous; Osteoclasts; Osteoporosis, Postmenopausal; Ovariectomy; Random Allocation; Rats; Rats, Sprague-Dawley; Tibia

Previous studies have shown that parathyroid hormone (PTH) stimulates bone formation and completely restores lost cancellous bone at skeletal sites with moderate osteopenia in relatively young ovariectomized (OVX) rats. The current study was designed to determine whether PTH has similar bone anabolic effects in aged OVX rats and to compare the bone restorative response to PTH at skeletal sites with moderate and severe osteopenia. Female Sprague-Dawley rats were subjected to sham surgery or bilateral ovariectomy at 3 months of age and maintained untreated for the first year after surgery to allow for the development of moderate vertebral osteopenia and severe tibial osteopenia in OVX rats. Groups of baseline control and OVX rats were sacrificed at the end of this pretreatment period. The remaining OVX rats were then treated for 10 weeks with vehicle, antiresorptive agents alone (estrogen, the bisphosphonate risedronate, or calcitonin) or PTH alone. Other groups of OVX rats were treated concurrently with PTH and each of the antiresorptive agents. As expected, the proximal tibia of baseline OVX rats exhibited severe cancellous osteopenia, whereas the first lumbar vertebral body was moderately osteopenic. Treatment of OVX rats with antiresorptive agents alone failed to restore cancellous bone at both skeletal sites, whereas treatment with PTH alone markedly stimulated bone formation and completely restored lost cancellous bone in the lumbar vertebra. PTH also stimulated bone formation and in the severely osteopenic proximal tibia of OVX rats but only marginally restored lost cancellous bone, possibly due to an inadequate number of bone spicules to serve as a foundation for new bone formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aging; Animals; Biomarkers; Bone Development; Bone Diseases, Metabolic; Bone Remodeling; Calcitonin; Disease Models, Animal; Drug Therapy, Combination; Estradiol; Etidronic Acid; Female; Lumbar Vertebrae; Ovariectomy; Parathyroid Hormone; Rats; Rats, Sprague-Dawley; Tibia

The activity of a novel calcitonin SB 205614 was compared with salmon calcitonin (sCT) and (Asu1,7)-eel calcitonin (ELC) in six different models of osteoclastic bone resorption in vitro and in vivo. SB 205614 is an ELC analogue that has an acetylenic bridge instead of the natural disulphide bridge, rendering the molecule more stable biologically than sCT and equally stable to ELC. Our aim was to determine whether this structural change compromised biologic activity, and if not, whether the increased stability could be used to exploit novel modes of administration. In the in vitro assays of pit formation by disaggregated rat osteoclasts on cortical bone slices (DROcA) and PTH stimulation of 45Ca-release from prelabeled fetal rat bone, no significant differences in activity were observed between the three calcitonins. In the DROcA, IC50s of 0.003, 0.015 and 0.064 pg/ml for sCT, ELC, and SB 205614, respectively, were determined, with total or near complete inhibition observed at 1 pg/ml (0.3 pM). In the assay of PTH-stimulation of 45Ca release, IC50s were measured of 5.5, 4.8, and 12.9 pM for sCT, ELC, and SB 205614, respectively; in every case maximal inhibition (ca. 80%) was observed at 30 and 100 pM. The internationally approved U.S. Pharmacopoeia bioassay of hypocalcemia in the rat following intravenous (IV) administration indicated that SB 205614 had a greater potency than ELC or sCT. More important, a full dose-hypocalcemic response curve demonstrated significantly increased potency compared to sCT or ELC, as the doses causing 15% lowering of serum calcium (approximately 50% of the maximum effect) were 33.9, 25.2, and 12.9 mg/kg for sCT, ELC, and SB 205614, respectively. As a preliminary means of investigating alternative delivery forms of calcitonin, the time course of the hypocalcemic effect was investigated in the rat and rabbit following IV administration, and was compared with that following intranasal (IN) administration (rat and rabbit), and following intracolonic administration (rat only). Maximal effects were similar, whereas in general the hypocalcemic effect of SB 205614 was of a longer duration than the other two calcitonins; this was reflected in a larger area over the curve (AOC). However, following IN administration in the rabbit, where an aerosol delivery device similar to that used in the clinic was used to administer the calcitonins, SB 205614 (100 IU/kg) induced a highly significant two-fold increase in the AOC compared to ELC or sCT

Topics: Amino Acid Sequence; Animals; Bone Resorption; Calcitonin; Disease Models, Animal; Drug Administration Routes; Evaluation Studies as Topic; Hypocalcemia; In Vitro Techniques; Male; Molecular Sequence Data; Osteoclasts; Osteoporosis; Rabbits; Rats; Rats, Sprague-Dawley; Rats, Wistar

The benzyl ester of hyaluronic acid (Hyaff 11) is a highly mucoadhesive polymer and can be processed into microspheres that can effectively deliver incorporated drugs by closely adhering to the mucosal surface and by protecting the drug from enzymatic inactivation. In this study, Hyaff 11 microspheres have been investigated as novel delivery system for the vaginal administration of salmon calcitonin (sCT) to ovariectomized rats. Moreover, this particular animal model has been used to evaluate the biological activity of the polypeptide after vaginal and I.M. administration by measuring the skeletal effect of sCT. A total of 66 female rats were used: 6 rats served as the basal group; 12 were subjected to sham operation and left without pharmacological treatment; 48 underwent bilateral ovariectomy and these were divided at random into four groups of 12 animals. One group was not submitted to pharmacological treatment; another was treated daily with sCT I.M.; in the other two groups, the hormone was incorporated into Hyaff 11 microspheres and was daily administered by vaginal route as dry powder or dispersed in pessaries. Sixty days after surgery, rats were sacrificed and the proximal third of the right tibia was removed and prepared for histomorphometry. Treatment with sCT, independent of the administration route, largely prevented the bone volume loss of the nontreated ovariectomized group. Prevention mainly depended on the maintenance of the trabecular number and on the increase of the trabecular thickness. Independent of the administration procedure, sCT greatly reduced the increase of tartrate-resistant acid phosphatase-positive poly- and, particularly, mononucleated osteoclasts found in the nontreated ovariectomized group.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Intravaginal; Animals; Bone Diseases, Metabolic; Bone Resorption; Calcitonin; Disease Models, Animal; Female; Hyaluronic Acid; Injections, Intramuscular; Microspheres; Ovariectomy; Rats

We have previously established an uremic rat model which is suitable for investigating the effect of various treatment modalities on the progression of renal osteodystrophy [1]. Four months subsequent to 5/6 nephrectomy, animals were treated three times a week for 3 months with either vehicle, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], 1,25(OH)2D3 + 24,25-dihydroxyvitamin D3 [24,25(OH)2D3], 1,25(OH)2D3 + calcitonin (CT), or 1,25(OH)2D3 + 24,25(OH)2D3 + CT. At termination of the study, clinical chemistry, chemical composition, and mechanical properties of femurs, calvarial parathyroid hormone (PTH)-elicited adenylate cyclase (AC), and phospholipase C (PL-C) activities, femoral cross-sectional area, and bone histomorphometry were analyzed. The main findings were that 1,25(OH)2D3 +/- 24,25(OH)2D3 treatment enhanced elasticity as well as time to fracture at the femoral metaphysis. CT potentiated the increase in elasticity obtained by 1,25(OH)2D3 +/- 24,25(OH)2D3 treatment. Only 24,25(OH)2D3 administration rectified the supernormal PTH-stimulated uremic bone AC, and only 1,25(OH)2D3 medication normalized the diminished CT-elicited AC. The obliterated uremic bone PTH-sensitive PL-C was fully normalized by all drug regimens. Femoral shaft inner zone diameter was enhanced by uremia, however, all drug treatments normalized it. Ditto effect was registered with either drug treatment on the subnormal outer and inner zone widths. Histomorphometrical analyses showed that 1,25(OH)2D3 administration reduced both eroded and osteoid surfaces. Most prominently, adjuvant 24,25(OH)2D3 or CT administration potentiated the beneficial effect of 1,25(OH)2D3 on fibrosis and osteomalacia. We assert that vitamin D3 treatment markedly reverses the development of renal osteodystrophy, and CT potentiates the effect of vitamin D3.

Topics: 24,25-Dihydroxyvitamin D 3; Adenylyl Cyclases; Animals; Bone and Bones; Bone Density; Calcitonin; Calcitriol; Calcium; Chronic Kidney Disease-Mineral and Bone Disorder; Creatinine; Disease Models, Animal; Drug Administration Schedule; Female; Femur; Rats; Rats, Wistar; Type C Phospholipases; Uremia

Local immobilization is a good model for studying disuse-induced bone loss and to appreciate the effects of drugs, especially preventive action of antiresorptive therapy. In fact, increased osteoclastic activity is the main point of such a bone loss. The effect of salmon calcitonin was investigated on immobilization-induced osteoporosis in the sheep. Twenty-four nonovariectomized, adult, female, Welsh mountain sheep were submitted, by an external fixator procedure, to hock joint immobilization from the tibia to the the metatarsus for 12 weeks. The sheep were randomized into two groups receiving either an injection of placebo or salmon calcitonin (100 IU) three times per week, for 12 weeks. Histomorphometric analysis was performed on pre- and posttherapeutic transiliac bone biopsies, and on immobilized (left) and nonimmobilized calcanei removed after sacrifice. Results showed a 29% significant decrease of cancellous bone volume in the placebo group due to a significant reduced trabecular thickness when we compared immobilized versus nonimmobilized calcaneus. This structural adaptation appeared to be the consequence of an overall increased bone turnover. In the calcitonin group, same changes were observed, with a 23% reduction of bone mass in the immobilized calcaneus. By comparing calcitonin with placebo groups in both left and right calcanei, no difference was found. On the other hand, a significant increase of mineralization parameters in the iliac crest was only observed in the calcitonin group. In conclusion, salmon calcitonin, at a dose of 100 IU/day three times a week, was ineffective in preventing local disuse osteoporosis in this sheep model.

Topics: Animals; Calcaneus; Calcitonin; Cattle; Disease Models, Animal; Female; Immobilization; Osteoporosis; Sheep

Male young adult Wistar rats were treated parenterally with cortisol and cortisol combined with salmon calcitonin for 28 and 56 days and the stomach was investigated histologically as well as the G cells using immunohistochemistry. After 28 days of cortisol administration desquamation of the superficial layers of gastric mucosa was found and after 56 days ulcer-like changes developed and increased gastrin immunoreactivity was observed. Administration of high doses of salmon calcitonin together with cortisol resulted in a significant hypoplasia of G cells and prevented the pathological changes in the gastric mucosa.

Topics: Animals; Calcitonin; Disease Models, Animal; Drug Interactions; Gastric Mucosa; Gastrins; Hydrocortisone; Immunohistochemistry; Injections, Intraperitoneal; Male; Rats; Rats, Wistar; Stomach Ulcer

A screening method for anti-osteoporotics using ovariectomized rats was designed using a compact method to monitor the bone density. It was found that ovariectomy (OVX) of Wistar female rats (11 weeks old) induced acute and focal osteopenia within 2 weeks, which responded well to intermittent salmon calcitonin (SCT: 5 and 20 U/kg, s.c., every other day) employed as the standard anti-osteoporotic and injected up to 4 weeks with or without a delay of 2 weeks after OVX.

Topics: Analgesics; Animals; Bone Density; Bone Diseases, Metabolic; Calcitonin; Disease Models, Animal; Estrogens; Female; Ovariectomy; Rats; Rats, Wistar; Tibia

Experimental and clinical evidence testifies to an antinociceptive action of salmon calcitonin (sCT), administered in different ways, on the central nervous system. These studies were performed almost exclusively in acute pain models. The purpose of the present study was to investigate the effects of sCT, injected directly into the lateral cerebral ventriculi, on the firing of single nociceptive thalamic neurons, detected by electrophysiological techniques in an experimental model of prolonged or chronic pain, such as rats rendered arthritic by injection of Freund's adjuvant into the left hindfoot. The noxious test stimuli used were either extension or flexion of the ankle or mild lateral pressure on the heel. With increasing doses of sCT (5, 10, 20, 40 micrograms, 5 microliters/i.c.v.) it was possible to observe correspondingly increasing inhibitory and long-lasting effects on the evoked firing, with a significant dose-effect relationship. In agreement with electrophysiological findings, preliminary data, obtained with a patch clamp technique, on depression of calcium fluxes through neuronal membrane, induced by sCT, oriented the attention to a direct action of sCT on CNS.

Topics: Analgesics; Animals; Arthritis, Experimental; Calcitonin; Chronic Disease; Disease Models, Animal; Electrophysiology; Injections, Intraventricular; Male; Movement; Nociceptors; Pain; Physical Stimulation; Pressure; Rats; Rats, Sprague-Dawley; Thalamus

To assess whether calcitonin exerts an influence on cartilage, three models of arthropathies in rabbits--representing three different modes of cartilage destruction--were used: (1) corticosteroid administration (endocrinological disturbances model); (2) meniscectomy (mechanical stress model); and (3) immobilization of the hind leg (nutritional disorder model). After 12 weeks of methylprednisolone (MP) administration, the rabbit femur heads displayed cartilage erosions, marked decrease of glycosaminoglycans (GAG) content, and narrowing of joint spaces. Elevation of serum uronic acid, activity of alkaline phosphatase, and calmodulin content was evident. All these changes were minimal--close to normal--in the group treated for 12 weeks with MP + salmon calcitonin (sCT). Partial meniscectomy and hind leg immobilization caused statistically significant loss of GAG from the cartilage and narrowing of the knee joint space during the same experimental period, 12 weeks. In both these models the groups of rabbits treated simultaneously with sCT showed only insignificantly smaller joint spaces and GAG content. These results support our hypothesis of a chondroprotective property of calcitonin. However, the mechanism through which calcitonin influences joint cartilage remains unknown. A direct effect of calcitonin on cultivated chondrocytes, as well as the role of calmodulin, beta-endorphins, calcium, and interleukin-1 in the process are discussed.

Topics: Alkaline Phosphatase; Animals; Calcitonin; Calmodulin; Cartilage, Articular; Disease Models, Animal; Glycosaminoglycans; Immobilization; Joint Diseases; Methylprednisolone; Rabbits; Stress, Mechanical; Uronic Acids

Many different experimental models for the induction of gastric ulcers have been reported in rats. Most of these experimental designs are often not reproducible and the interpretation of the results obtained is sometimes difficult. In the present study, three different models were found to give reliable and reproducible results, which could be repeated at any time of the year with different experimenters performing the procedure. To date, these methods are in our opinion, the best in designing gastric ulcer experiments and assessing the effect of pharmacological active substances. Two pharmacological active substances were investigated in the present study, pindolol, a beta-blocking agent with intrinsic sympathomimetic activity and salmon calcitonin, a hormone influencing calcium homeostasis in blood. Using all three different models no effect was seen after pindolol administration, while a strong inhibitory effect on the formation of gastric ulcers was observed after salmon calcitonin. Following ligation of the pylorus, the ulcer formation rate was significantly decreased from 80 to 33% with a significant fall in ulcer index from 2 to 0.42 and reduction of the ulcer areas from 6.6 to 0.58 mm2 (p less than 0.05). In addition, following phenylbutazone administration the appearance of gastric ulcers was diminished after salmon calcitonin from 1.4 to 0.43 and in ulcer area from 4.5 to 0.95 mm2 (p less than 0.01). These three ulcer models used in the present study were found to be very reliable as compared with other models reported in the literature and tested in our laboratory.

Topics: Animals; Calcitonin; Disease Models, Animal; Ligation; Male; Phenylbutazone; Pindolol; Pylorus; Rats; Stomach Ulcer; Stress, Physiological