Expression of 5HT-1A and 5HT-1B Receptor Genes in Brains of Wistar-Zagreb 5HT Rats

By selective breeding, two sublines of rats with high or low activity of platelet serotonin (5HT) transporter (5HTt) have been developed (Wistar-Zagreb 5HT rats). Previous studies demonstrated significant differences between the sublines in the expression of platelet 5HTt at the level of both, mRNA and protein. Pharmacological studies showed marked alterations in brain 5HTt function, indicating differences in central serotonin homeostasis, although analysis of regional brain 5HTt gene expression did not show analogous differences. In this study, we searched for possible changes in the expression of the two central 5HT receptor subtypes: 5HT-1A and 5HT-1B, both participating in the regulation of brain 5HT transmission. Semi-quantitative RT-PCR, with three different housekeeping genes as internal standards, showed no differences in the levels of 5HT-receptor expression between the sublines. Results suggest that constitutional alteration of 5HT homeostasis, induced by selective breeding for the extremes of platelet 5HTt activity, did not cause measurable changes in the expression of central 5HT-1A (hippocampus) and 5HT-1B (striatum) receptors in the mentioned rat sublines under physiological conditions

Functional promoter polymorphism of the neuronal isoform of tryptophan hydroxylase (Tph2) in suicide

The association between suicide and G-703T polymorphism of the tryptophan hydroxylase 2 (TPH2), the rate-limiting enzyme in the biosynthesis of the neurotransmitter serotonin, was studied in a sample of 291 suicide victims and 280 healthy subjects of Croatian origin. No significant differences were found between the groups. Obtained results do not support involvement of the investigated polymorphism in the susceptibility to suicide completion

Iron overload in aging Bmp6−/− mice induces exocrine pancreatic injury and fibrosis due to acinar cell loss

The relationship between hemochromatosis and diabetes has been well established, as excessive iron deposition has been reported to result in impaired function of the endocrine and exocrine pancreas. Therefore, the objective of the present study was to analyze the effects of iron accumulation on the pancreata and glucose homeostasis in a bone morphogenetic protein 6‑knockout (Bmp6‑/‑) mouse model of hemochromatosis. The sera and pancreatic tissues of wild‑type (WT) and Bmp6‑/‑ mice (age, 3 and 10 months) were subjected to biochemical and histological analyses. In addition, 18F‑fluorodeoxyglucose biodistribution was evaluated in the liver, muscle, heart, kidney and adipose tissue of both animal groups. The results demonstrated that 3‑month‑old Bmp6‑/‑ mice exhibited iron accumulation preferentially in the exocrine pancreas, with no signs of pancreatic injury or fibrosis. No changes were observed in the glucose metabolism, as pancreatic islet diameter, insulin and glucagon secretion, blood glucose levels and glucose uptake in the liver, muscle and adipose tissue remained comparable with those in the WT mice. Aging Bmp6‑/‑ mice presented with progressive iron deposits in the exocrine pancreas, leading to pancreatic degeneration and injury that was characterized by acinar atrophy, fibrosis and the infiltration of inflammatory cells. However, the aging mice exhibited unaltered blood glucose levels and islet structure, normal insulin secretion and moderately increased α‑cell mass compared with those in the age‑matched WT mice. Additionally, iron overload and pancreatic damage were not observed in the aging WT mice. These results supported a pathogenic role of iron overload in aging Bmp6‑/‑ mice leading to iron‑induced exocrine pancreatic deficiency, whereas the endocrine pancreas retained normal function

Constitutively elevated blood serotonin is associated with bone loss and type 2 diabetes in rats

Reduced peripheral serotonin (5HT) in mice lacking tryptophan hydroxylase (TPH1), the rate limiting enzyme for 5HT synthesis, was reported to be anabolic to the skeleton. However, in other studies TPH1 deletion either had no bone effect or an age dependent inhibition of osteoclastic bone resorption. The role of 5HT in bone therefore remains poorly understood. To address this issue, we used selective breeding to create rat sublines with constitutively high (high-5HT) and low (low-5HT) platelet 5HT level (PSL) and platelet 5HT uptake (PSU). High-5HT rats had decreased bone volume due to increased bone turnover characterized by increased bone formation and mineral apposition rate, increased osteoclast number and serum C-telopeptide level. Daily oral administration of the TPH1 inhibitor (LX1032) for 6 weeks reduced PSL and increased the trabecular bone volume and trabecular number of the spine and femur in high-5HT rats. High-5HT animals also developed a type 2 diabetes (T2D) phenotype with increased: plasma insulin, glucose, hemoglobin A1c, body weight, visceral fat, β-cell pancreatic islets size, serum cholesterol, and decreased muscle strength. Serum calcium accretion mediated by parathyroid hormone slightly increased, whereas treatment with 1,25(OH)2D3 decreased PSL. Insulin reduction was paralleled by a drop in PSL in high-5HT rats. In vitro, insulin and 5HT synergistically up-regulated osteoblast differentiation isolated from high-5HT rats, whereas TPH1 inhibition decreased the number of bone marrow-derived osteoclasts. These results suggest that constitutively elevated PSL is associated with bone loss and T2D via a homeostatic interplay between the peripheral 5HT, bone and insulin

State-of-the-art of the Bone Morphogenetic Protein research field: 13th International BMP Conference, Dubrovnik 2022

The 13th International BMP Conference was held in October 2022 in Dubrovnik. The conference was attended by more than 240 participants from North America, Europe, Asia, and Australia who got an insight into the latest achievements in basic, translational, and clinical research of BMP mol- ecules through 75 lectures categorized into several scientific sections. This review paper provides the most important novel findings on the structure, function, and signaling of BMPs, the role of BMPs in patterning and organoids as well as the role of BMP in metabolism. Moreover, we discussed the role of BMPs in various diseases including cancer pathogenesis, pulmonary arterial hyperten- sion, and fibrodysplasia ossificans progressiva (FOP). Finally, we provided an overview of the new BMP-based therapies in regenerative medicine that are currently in different stages of preclinical and clinical trials

Autologous blood coagulum containing rhBMP6 induces new bone formation to promote anterior lumbar interbody fusion (ALIF) and posterolateral lumbar fusion (PLF) of spine in sheep

resent study, we evaluated an autologous bone graft substitute (ABGS) composed of recombinant human BMP6 (rhBMP6) dispersed within autologous blood coagulum (ABC) used as a physiological carrier for new bone formation in spine fusion sheep models. The application of ABGS included cervical cage for use in the anterior lumbar interbody fusion (ALIF), while for the posterolateral lumbar fusion (PLF) sheep model allograft devitalized bone particles (ALLO) were applied with and without use of instrumentation. In the ALIF model, ABGS (rhBMP6/ABC/cage) implants fused significantly when placed in between the denuded L4- L5 vertebrae as compared to control (ABC/cage) which appears to have a fibrocartilaginous gap, as examined by histology and micro CT analysis at 16 weeks following surgery. In the PLF model, ABGS implants with or without ALLO showed a complete fusion when placed ectopically in the gutter bilaterally between two decorticated L4-L5 transverse processes at a success rate of 88% without instrumentation and at 80% with instrumentation ; however the bone volume was 50% lower in the instrumentation group than without, as examined by histology, radiographs, micro CT analyses and biomechanical testing at 27 weeks following surgery. The newly formed bone was uniform within ABGS implants resulting in a biomechanically competent and histologically qualified fusion with an optimum dose in the range of 100 g rhBMP6 per mL ABC, while in the implants that contained ALLO, the mineralized bone particles were substituted by the newly formed remodeling bone via creeping substitution. These findings demonstrate for the first time that ABGS (rhBMP6/ABC) without and with ALLO particles induced a robust bone formation with a successful fusion in sheep models of ALIF and PLF, and that autologous blood coagulum (ABC) serves as a preferred physiological native carrier to induce new bone at low doses of rhBMP6 and to achieve a successful spinal fusion

Koštani morfogenetski proteini (BMP): Od otkrića do razvoja nove autologne koštane naprave koja se sastoji od rekombinantnog humanog BMP6 u autolognom krvnom ugrušku kao nosaču

Bone Morphogenetic Proteins (BMPs) are growth and differentiation factors within the TGFβ superfam- ily of proteins. They induce ectopic and orthotopic endochondral bone formation and are involved in the regulation of cell proliferation, differentiation, apoptosis and mesenchymal-epithelial interactions in critical morphogenetic processes of tissues beyond bone. BMP2 and BMP7 osteogenic devices have been approved for enhancing healing in patients with long bone defects and anterior spinal fusion proce- dures. However, due to a high price and various serious adverse events including heterotopic ossifica- tion, retrograde ejaculation and pain their clinical use have been limited. In this review we discuss the BMP discovery, biology and their use in clinical studies with particular reference to the newly developed BMP6 based autologous bone graft substitute (ABGS). A novel ABGS consisting of an autologous bone coagulum (ABC) carrier with dispersed BMP6 to initiate the differentiation of mesenchymal cells into endochondral bone. The ABC met the conditions for an optimal delivery system for BMP6 due to han- dling simplicity, without an immunogenic and inflammatory response at the implantation site. Addition of allograft or synthetic ceramics to ABGS demonstrated in animal models significantly increased volume and better microarchitecture of the newly formed bone. The first clinical study was conducted in patients with distal radial fractures (Phase I study) and the second in patients undergoing high tibial osteotomy (Phase I/II study) and no serious adverse events have been observed. Finally, in the ongoing OSTEO- proSPINE study ABGS enforced with allograft bone is evaluated in patients with chronic back pain due to degenerative disc diseases. The novel ABGS bone mimetic is a major breakthrough and contribution to bone biology and regenerative medicine of skeletal repair.Koštani morfogenetski proteini (BMP) čine grupu čimbenika rasta i diferencijacije unutar TGFβ nado- bitelji. Oni induciraju stvaranje ektopične i ortotopične endohondralne kosti te su uključeni u regulaciju stanične proliferacije, diferencijacije, apoptoze i mezenhimalno-epitelne interakcije u važnim tkivnim morfogenetskim procesima izvan koštanog sustava. Koštane naprave koje sadrže BMP2 i BMP7 pro- tein odobrene su za poboljšanje koštanog cijeljenja kod pacijenata s defektima dugih cjevastih kostiju i kod prednje spinalne fuzije kralježnice. Međutim, zbog visoke cijene i mnogobrojnih nuspojava koje su uključivale pojavu heterotopičnih osifikacija, retrogradnu ejakulaciju i bol, njihova je klinička prim- jena ograničena. U ovom smo preglednom radu raspravili otkriće BMP molekula, njihovu biologiju i primjenu u kliničkim studijama s posebnim osvrtom na nedavno otkrivenu novu autolognu koštanu napravu (ABGS) koja sadrži BMP6. Novi ABGS sastoji se od nosača autolognog koaguluma (ABC) s otopljenim BMP6 koji je ključan za pokretanje diferencijacije mezenhimalnih stanica u smjeru stvaranja endohondralne kosti. ABC je ispunio sve potrebne uvjete za formulaciju optimalnog nosača za BMP6 isključivo zbog jednostavnosti priprave i primjene te odsustva imunogenog i upalnog odgovora na mjestu implantacije. Uz dodatak alografta ili sintetičke keramike što je potvrđeno na životinjskim modelima došlo je do značajnog povećanja volumena te poboljšanja mikroarhitekture novonastale kosti. Prvo kliničko ispitivanje provedeno je na pacijentima s distalnim prijelomima radijusa (faza I studije), a drugo na pacijentima koji su podvrgnuti visokoj osteotomiji tibije (faza I/II studije) bez uočenih ozbiljnih nuspojava. Trenutno je u tijeku studija OSTEOproSPINE u kojoj se testira učinkovitost ABGS u kom- binaciji s koštanim alograftom u bolesnika s kroničnim bolovima u leđima uzrokovanim degenerativnim promjenama intervertebralnog diska. Nova ABGS koštana naprava značajna je prekretnica i napredak u području koštane biologije te regenerativne medicine koštanog sustava

Systemically available bone morphogenetic protein two and seven affect bone metabolism

PURPOSE: Bone morphogenetic protein (BMP)-2 and -7 are used in patients with long-bone fractures, nonunions and spinal fusions. It is unknown whether their potential systemic bioavailability following local bone administration might affect skeletal metabolism. To answer this question, we examined effects of systemically administered BMP-2 and -7 on bone in a newly developed rat model with a low level of calciotropic hormones. ----- METHODS: Removal of thyroid and parathyroid glands (TPTx) in rats resulted in a decreased level of calciotropic hormones and subsequent bone loss assessed by micro computed tomography (micro-CT) and measurement of serum bone formation and resorption markers, including osteocalcin, C-telopeptide, osteoprotegerin and receptor activator of nuclear factor kappa-B ligand. Results were complemented with in vitro studies on osteoblast and osteoclast activity by both BMP-2 and -7. The doses used were calculated from published pharmacodynamic studies and bioavailability results from preclinical BMP-2 and -7 studies. ----- RESULTS: TPTx resulted in bone loss, which was restored by systemic administration of 10-70 μg/kg of BMP-2 and 10-250 μg/kg of BMP-7. BMP-2 showed a higher capacity for enhancing trabecular microarchitecture, whereas BMP-7 augmented trabecular thickness. In vitro experiments revealed that BMP-2 and -7 when uncoupled increased the number and activity of both osteoblasts and osteoclasts. ----- CONCLUSIONS: Surprisingly, both BMP-2 and -7 showed an increased bone volume in an in vivo environment of low calciotropic hormones. Locally administered BMP-2 and -7 from bone devices might become partially available in circulation but will not mediate systemic bone loss

Autologous blood coagulum is a physiological carrier for BMP6 to induce new bone formation and promote posterolateral lumbar spine fusion in rabbits

In the present study, we describe autologous blood coagulum (ABC) as a physiological carrier for BMP6 to induce new bone formation. Recombinant human BMP6 (rhBMP6), dispersed within ABC and formed as an autologous bone graft substitute (ABGS), was evaluated either with or without allograft bone particles (ALLO) in rat subcutaneous implants and in a posterolateral lumbar fusion (PLF) model in rabbits. ABGS induced endochondral bone differentiation in rat subcutaneous implants. Coating ALLO by ABC significantly decreased the formation of multinucleated foreign body giant cells (FBGCs) in implants, as compared with ALLO alone. However, addition of rhBMP6 to ABC/ALLO induced a robust endochondral bone formation with little or no FBGCs in the implant. In rabbit PLF model, ABGS induced new bone formation uniformly within the implant resulting in a complete fusion when placed between two lumbar transverse processes in the posterolateral gutter with an optimum dose of 100-μg rhBMP6 per ml of ABC. ABGS containing ALLO also resulted in a fusion where the ALLO was replaced by the newly formed bone via creeping substitution. Our findings demonstrate for the first time that rhBMP6, with ABC as a carrier, induced a robust bone formation with a complete spinal fusion in a rabbit PLF model. RhBMP6 was effective at low doses with ABC serving as a physiological substratum providing a permissive environment by protecting against foreign body reaction elicited by ALLO