Pre-implantation teriparatide administration improves initial implant stability and accelerates the osseointegration process in osteoporotic rats.

PURPOSE: Osteoporotic individuals who have dental implants usually require a prolonged healing time for osseointegration due to the shortage of bone mass and the lack of initial stability. Although studies have shown that intermittent teriparatide administration can promote osseointegration, there is little data to support the idea that pre-implantation administration is necessary and beneficial. METHODS: Sixty-four titanium implants were placed in the bilateral proximal tibial metaphysis in 32 female SD rats. Bilateral ovariectomy (OVX) was used to induce osteoporosis. Four major groups (n = 8) were created: PRE (OVX + pre-implantation teriparatide administration), POST (OVX + post-implantation administration), OP (OVX + normal saline (NS)) and SHAM (sham rats + NS). Half of rats (n = 4) in each group were euthanized respectively at 4 weeks or 8 weeks after implantation surgery, and four major groups were divided into eight subgroups (PRE4 to SHAM8). Tibiae were collected for micro-CT morphometry, biomechanical test and undecalcified sections analysis. RESULTS: Compared to OP group, rats in PRE and SHAM groups had a higher value of insertion torque (p < 0.05). The micro-CT analysis, biomechanical test, and histological data showed that peri-implant trabecular growth, implants fixation and bone-implant contact (BIC) were increased after 4 or 8 weeks of teriparatide treatment (p < 0.05). There was no statistically difference in those parameters between PRE4 and POST8 subgroups (p > 0.05). CONCLUSIONS: In osteoporotic rats, post-implantation administration of teriparatide enhanced peri-implant bone formation and this effect was stronger as the medicine was taken longer. Pre-implantation teriparatide treatment improved primary implant stability and accelerated the osseointegration process.

Abaloparatide is more potent than teriparatide in restoring bone mass and strength in type 1 diabetic male mice.

This study investigated the efficacy of the two FDA-approved bone anabolic ligands of the parathyroid hormone receptor 1 (PTH1R), teriparatide or human parathyroid hormone 1-34 (PTH) and abaloparatide (ABL), to restoring skeletal health using a preclinical murine model of streptozotocin-induced T1-DM. Intermittent daily subcutaneous injections of equal molar doses (12 pmoles/g/day) of PTH (50 ng/g/day), ABL (47.5 ng/g/day), or vehicle, were administered for 28 days to 5-month-old C57Bl/6 J male mice with established T1-DM or control (C) mice. ABL was superior to PTH in increasing or restoring bone mass in control or T1-MD mice, respectively, which was associated with superior stimulation of trabecular and periosteal bone formation, upregulation of osteoclastic/osteoblastic gene expression, and increased circulating bone remodeling markers. Only ABL corrected the reduction in ultimate load, which is a measure of bone strength, induced by T1-DM, and it also increased energy to ultimate load. In addition, bones from T1-DM mice treated with PTH or ABL exhibited increased ultimate stress, a material index, compared to T1-DM mice administered with vehicle. And both PTH and ABL prevented the increased expression of the Wnt antagonist Sost/sclerostin displayed by T1-DM mice. Further, PTH and ABL increased to a similar extent the circulating bone resorption marker CTX and the bone formation marker P1NP in T1-DM after 2 weeks of treatment; however, only ABL sustained these increases after 4 weeks of treatment. We conclude that at equal molar doses, ABL is more effective than PTH in increasing bone mass and restoring the cortical and trabecular bone lost with T1-DM, due to higher and longer-lasting increases in bone remodeling.

Analyzing the factors associated with efficacy among teriparatide treatment in postmenopausal women with osteoporosis.

BACKGROUND: Teriparatide (TPTD) is a widely used anabolic agent for the treatment of osteoporosis. Several factors have been identified to be related to bone mineral density (BMD) increase in anti-osteoporosis treatment with other agents; however, there has been no systematic analysis to summarize the associated determinants of BMD reaction to daily teriparatide treatment. METHODS: In this retrospective study, we performed a comprehensive investigation involving not only clinical data but also several relevant lifestyle factors to be examined for their potential contribution to BMD response. This post-hoc analysis included 258 post-menopaused patients with osteoporosis who received TPTD at 20 µg/day for 12 months. Univariate and multivariate analyses were conducted to distinguish the response variables of lumbar spine (LS) BMD transformation, the principal outcome measure of efficacy, from the baseline at 12 months. RESULTS: Twelve months of TPTD treatment resulted in an absolute 0.39 ± 0.37 increase in T-score of LS BMD. Gastrointestinal disease, prior bisphosphonate or glucocorticoid treatment, no vitamin K2 supplementation, low levels of serum 25(OH)D and PINP, weak increment of PINP and ß-CTX at 3 months, unhealthy lifestyle (excessive smoking, tea, coffee, and drinking), vegetarian diet pattern, low ALT level, and high BMD at baseline were determined by univariate analyses to be related to the weak reaction of TPTD treatment (P < 0.10). In the multiple regression model, postmenopausal women with vitamin K2 supplementation, higher baseline serum 25(OH)D level, and higher PINP concentration at 3 months indicated a good reaction of LS BMD at 12 months (P < 0.05). Patients with gastrointestinal disease, prior bisphosphonate and glucocorticoid treatment, vegetarian diet pattern, and higher baseline BMD were significantly more likely to have a lower absolute LS BMD response compared to patients without these characteristics (P < 0.05). Further analysis confirmed the negative effect of unhealthy lifestyle on TPTD treatment. CONCLUSION: Our results emphasize the significance of a comprehensive assessment of clinical or lifestyle-related characteristics of postmenopausal women with osteoporosis in the management of TPTD therapy in routine care.

Design, Synthesis, and Anti-Osteoporotic Characterization of Arginine N-Glycosylated Teriparatide Analogs via the Silver-catalyzed Solid-Phase Glycosylation Strategy.

In spite of effective antiosteoporosis potency, teriparatide, a bone-building agent approved by the FDA (Food and Drug Administration), was proven to exhibit various side effects. In our previous work, we developed a universal strategy for synthesizing arginine N-glycosylated peptides termed silver-promoted solid-phase glycosylation (SSG) strategy. However, it is unknown whether the SSG strategy can be applied in the peptide drug design. Herein, we first reported the optimization of teriparatide via SSG strategy. Using Arg20 and/or Arg25 as the modifying positions, three series of arginine N-glycosylated teriparatide analogs were successfully synthesized, of which the introduced sugar groups included glucose, galactose, mannose, rhamnose, ribose, 2-acetamino-2-deoxy-glucose, xylose, lactose, and maltose. Among the 27 arginine N-glycosylated derivatives, Arg20-xylose and Arg25-maltose teriparatide analogs, termed PTH-1g and PTH-2i, respectively, indicated enhanced serum stability and significantly improved antiosteoporotic activities in vitro and in vivo compared with the native counterpart. They may serve as effective therapeutic candidates for treating osteoporosis.

Comparative study in estrogen-depleted mice identifies skeletal and osteocyte transcriptomic responses to abaloparatide and teriparatide.

Osteocytes express parathyroid hormone (PTH)/PTH-related protein (PTHrP) receptors and respond to the PTHrP analog abaloparatide (ABL) and to the PTH 1-34 fragment teriparatide (TPTD), which are used to treat osteoporosis. Several studies indicate overlapping but distinct skeletal responses to ABL or TPTD, but their effects on cortical bone may differ. Little is known about their differential effects on osteocytes. We compared cortical osteocyte and skeletal responses to ABL and TPTD in sham-operated and ovariectomized mice. Administered 7 weeks after ovariectomy for 4 weeks at a dose of 40 µg/kg/d, TPTD and ABL had similar effects on trabecular bone, but ABL showed stronger effects in cortical bone. In cortical osteocytes, both treatments decreased lacunar area, reflecting altered peri-lacunar remodeling favoring matrix accumulation. Osteocyte RNA-Seq revealed that several genes and pathways were altered by ovariectomy and affected similarly by TPTD and ABL. Notwithstanding, several signaling pathways were uniquely regulated by ABL. Thus, in mice, TPTD and ABL induced a positive osteocyte peri-lacunar remodeling balance, but ABL induced stronger cortical responses and affected the osteocyte transcriptome differently. We concluded that ABL affected the cortical osteocyte transcriptome in a manner subtly different from TPTD, resulting in more beneficial remodeling/modeling changes and homeostasis of the cortex.

Parathyroid hormone therapy improves MRSA-infected fracture healing in a murine diabetic model.

Introduction: Diabetes mellitus (DM) impairs fracture healing and is associated with susceptibility to infection, which further inhibits fracture healing. While intermittent parathyroid hormone (1-34) (iPTH) effectively improves fracture healing, it is unknown whether infection-associated impaired fracture healing can be rescued with PTH (teriparatide). Methods: A chronic diet-induced type 2 diabetic mouse model was used to yield mice with decreased glucose tolerance and increased blood glucose levels compared to lean-fed controls. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated in a surgical tibia fracture model to simulate infected fracture, after which mice were treated with a combination of antibiotics and adjunctive teriparatide treatment. Fracture healing was assessed by Radiographic Union Scale in Tibial Fractures (RUST), micro-computed tomography (µCT), biomechanical testing, and histology. Results: RUST score was significantly poorer in diabetic mice compared to their lean nondiabetic counterparts. There were concomitant reductions in micro-computed tomography (µCT) parameters of callus architecture including bone volume/total volume, trabecular thickness, and total mineral density in type 2 diabetes mellitus (T2DM) mice. Biomechanicaltesting of fractured femora demonstrated diminished torsional rigidity, stiffness, and toughness to max torque. Adjuvant teriparatide treatment with systemic antibiotic therapy improved numerous parameters of bone microarchitecture bone volume, increased connectivity density, and increased trabecular number in both the lean and T2DM group. Despite the observation that poor fracture healing in T2DM mice was further impaired by MRSA infection, adjuvant iPTH treatment significantly improved fracture healing compared to antibiotic treatment alone in infected T2DM fractures. Discussion: Our results suggest that teriparatide may constitute a viable adjuvant therapeutic agent to improve bony union and bone microarchitecture to prevent the development of septic nonunion under diabetic conditions.

Preventive effect of teriparatide on medication-related osteonecrosis of the jaw in rats.

This study aimed to investigate the preventive effect of teriparatide (TPD) administration on medication-related osteonecrosis of the jaw (MRONJ) before tooth extraction due to periodontal lesions in bilaterally ovariectomized female rats treated with zoledronic acid. Thirty skeletally mature Sprague-Dawley rats were randomly divided into three groups: control (CONT, n = 10), zoledronic acid (ZA, n = 10), and zoledronic acid and teriparatide (ZA-TPD, n = 10). The rats were sacrificed 8 weeks after tooth extraction. Micro-computed tomography analysis of the tibia showed that bone mineral density was highest in the CONT, followed by that in the ZA and ZA-TPD groups (CONT/ZA, p = 0.009; CONT/ZA-TPD, p < 0.001; ZA/ZA-TPD, p < 0.001). In the trabecular bone analysis of the extraction site, significant differences in specific bone surface (CONT/ZA, p = 0.010; CONT/ZA-TPD, p = 0.007; ZA/ZA-TPD, p = 0.002) and trabecular thickness (CONT/ZA-TPD, p = 0.002; ZA/ZA-TPD, p = 0.002) were observed. Histological analyses of the extraction sites revealed characteristic MRONJ lesions in the ZA group. Osteonecrosis, inflammatory cells, and sequestrum were less frequently observed in the ZA-TPD group than in the ZA group. In conclusion, TPD administration before tooth extraction helped reduce the occurrence of MRONJ in rats treated with zoledronic acid, confirming its preventative effects.

The effect of pharmacological treatment in combination with vitamin K on healing in an experimental rat model of osteoporosis.

OBJECTIVES: This study aims to compare the effects of teriparatide, zoledronic acid, and their combination therapy with vitamin K on osteoporotic rats. MATERIALS AND METHODS: We divided a total of 50 female Sprague-Dawley rats into five groups: A (the control group), B and D (the teriparatide group), and C and E (the zoledronic acid group). Following ovariectomy and subcutaneous heparin administration at a dose of 2 IU/kg for four weeks, osteoporosis was created. Groups A, B, and C were fed with standard feed, while Groups D and E were fed with vitamin K-rich feed. After four weeks of treatment, sacrification was performed. The right and left femurs were separated for histopathological and biomechanical evaluation, respectively. For histopathological evaluation, the femurs were decalcified, and the sections were stained with hematoxylin-eosin and evaluated under a light microscope. Fracture healing was evaluated using the classification system as described previously. For biomechanical evaluation, the 3-point stress test and torsion stress test were applied to 10 femurs from each group. RESULTS: Groups B-E were histopathologically and biomechanically superior to Group A in fracture healing of osteoporotic rats; however, it was not statistically significant (p>0.05). The group that received additional vitamin K was histopathologically and biomechanically superior to the group which was fed with standard feed, although it was not statistically significant (p>0.05). CONCLUSION: Our study results indicated that both teriparatide and zoledronic acid had beneficial effects on osteoporotic fractures with comparable histological and biochemical results. Vitamin K promoted teriparatide and zoledronic acid treatment on osteoporotic fracture healing. Based on these findings, combination therapies may yield the most optimal results in biomechanical and histological examinations.

Clinical efficacy of denosumab, teriparatide, and oral bisphosphonates in the prevention of glucocorticoid-induced osteoporosis: a systematic review and meta-analysis.

BACKGROUND: Continuous use of glucocorticoids (GCs) has become the primary cause of secondary osteoporosis. Bisphosphonate drugs were given priority over denosumab and teriparatide in the 2017 American College of Rheumatology (ACR) guidelines but have a series of shortcomings. This study aims to explore the efficacy and safety of teriparatide and denosumab compared with those of oral bisphosphonate drugs. METHODS: We systematically searched studies included in the PubMed, Web of Science, Embase, and Cochrane library databases and included randomized controlled trials that compared denosumab or teriparatide with oral bisphosphonates. Risk estimates were pooled using both fixed and random effects models. RESULTS: We included 10 studies involving 2923 patients who received GCs for meta-analysis, including two drug base analyses and four sensitivity analyses. Teriparatide and denosumab were superior to bisphosphonates in increasing the bone mineral density (BMD) of the lumbar vertebrae [teriparatide: mean difference [MD] 3.98%, 95% confidence interval [CI] 3.61-4.175%, P = 0.00001; denosumab: MD 2.07%, 95% CI 0.97-3.17%, P = 0.0002]. Teriparatide was superior to bisphosphonates in preventing vertebral fractures and increasing hip BMD [MD 2.39%, 95% CI 1.47-3.32, P < 0.00001]. There was no statistically significant difference between serious adverse events, adverse events, and nonvertebral fracture prevention drugs. CONCLUSIONS: Teriparatide and denosumab exhibited similar or even superior characteristics to bisphosphonates in our study, and we believe that they have the potential to become first-line GC-induced osteoporosis treatments, especially for patients who have previously received other anti-osteoporotic drugs with poor efficacy.

An overview of the management of osteoporosis in the aging female population.

Osteoporosis is a systemic skeletal disease that is a cause of morbidity and mortality. It can affect all ages but most frequently postmenopausal women. It is a silent condition, however, osteoporotic fractures can lead to significant pain and disability. In this review article, we aim to review the clinical approach to the management of postmenopausal osteoporosis. We include risk assessment, investigations, and the various pharmacological and non-pharmacological options used in the treatment of osteoporosis. We have discussed the pharmacological options individually including their mechanism of action, safety profile, effects on bone mineral density and fracture risks, and duration of use. Potential new treatments are also discussed. The importance of sequence in the use of osteoporotic medicine is also highlighted in the article. An understanding of the different treatment options will hopefully help in the management of this very common and debilitating condition.

Effects of Perioperative Teriparatide Treatment on the Hounsfield Unit Values at the Upper Instrumented Vertebra in Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective single-center study. OBJECTIVE: This study aimed to assess the effects of pre and postoperative teriparatide (TPTD) treatment on Hounsfield units (HU) after surgery for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: The most commonly used method for assessing bone mineral density is dual-energy x-ray absorptiometry. HU values at the upper instrumented vertebra (UIV) have been proposed as a surrogate method for assessing bone quality, particularly in patients with ASD. However, the effect of TPTD treatment on vertebral HU values remains unclear. MATERIALS AND METHODS: We identified 57 consecutive patients with ASD who underwent long-instrumented fusion surgery (>5 vertebrae) between 2014 and 2020. Patients were retrospectively divided into a non-TPTD group (n = 31) and a TPTD group (n = 26). HU measurements were obtained at a level above the UIV (UIV + 1). Changes in the HU value at 1-year postoperatively were compared between the TPTD and non-TPTD groups. The duration of preoperative TPTD was compared between the proximal junctional proximal junctional failure (PJF) and non-PJF groups. RESULTS: Preoperative HU values were significantly lower in the TPTD group than in the non-TPTD group, despite no significant difference in preoperative bone mineral density of the proximal femur between the two groups. Changes in HU values were significantly higher in the TPTD group than in the non-TPTD group (20.8 ± 15.7% vs -2 ± 10.2%, P < 0.001). In the subanalysis of the TPTD group, the duration of preoperative TPTD treatment was significantly shorter in the PJF group than in the non-PJF group (34.7 ± 16.8 days vs 86.9 ± 34.7 days, P = 0.004). CONCLUSIONS: Pre and post-operative TPTD treatment increased the average HU value at UIV + 1 by 20.8%. Therefore, more prolonged preoperative TPTD treatment improves bone quality and may help prevent osteoporosis-related complications.

Potential effects of teriparatide (PTH (1-34)) on osteoarthritis: a systematic review.

Osteoarthritis (OA) is a common and prevalent degenerative joint disease characterized by degradation of the articular cartilage. However, none of disease-modifying OA drugs is approved currently. Teriparatide (PTH (1-34)) might stimulate chondrocyte proliferation and cartilage regeneration via some uncertain mechanisms. Relevant therapies of PTH (1-34) on OA with such effects have recently gained increasing interest, but have not become widespread practice. Thus, we launch this systematic review (SR) to update the latest evidence accordingly. A comprehensive literature search was conducted in PubMed, Web of Science, MEDLINE, the Cochrane Library, and Embase from their inception to February 2022. Studies investigating the effects of the PTH (1-34) on OA were obtained. The quality assessment and descriptive summary were made of all included studies. Overall, 307 records were identified, and 33 studies were included. In vivo studies (n = 22) concluded that PTH (1-34) slowed progression of OA by alleviating cartilage degeneration and aberrant remodeling of subchondral bone (SCB). Moreover, PTH (1-34) exhibited repair of cartilage and SCB, analgesic, and anti-inflammatory effects. In vitro studies (n = 11) concluded that PTH (1-34) was important for chondrocytes via increasing the proliferation and matrix synthesis but preventing apoptosis or hypertrophy. All included studies were assessed with low or unclear risk of bias in methodological quality. The SR demonstrated that PTH (1-34) could alleviate the progression of OA. Moreover, PTH (1-34) had beneficial effects on osteoporotic OA (OPOA) models, which might be a therapeutic option for OA and OPOA treatment.

Approach to the Patient: Pharmacological Therapies for Fracture Risk Reduction in Adults With Osteogenesis Imperfecta.

CONTEXT: Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility largely caused by defects in structure, synthesis, or post-translational processing of type I collagen. The effectiveness of medications used for fracture reduction in adults with OI is understudied and practice recommendations are not well established. Drugs currently used to improve skeletal health in OI were initially developed to treat osteoporosis. Oral and intravenous bisphosphonates have been shown to improve bone mineral density (BMD) in adults with OI and are commonly used; however, conclusive data confirming fracture protection are lacking. Similarly, teriparatide appears to increase BMD, an effect that seems to be limited to individuals with type I OI. The role of denosumab, abaloparatide, romosozumab, and estradiol/testosterone in adult OI have not been systematically studied. Anti-sclerostin agents and transforming growth factor-beta antagonists are under investigation in clinical trials. OBJECTIVE: This review summarizes current knowledge on pharmacologic treatment options for reducing fracture risk in adults with OI. METHODS: A PubMed online database search of all study types published in the English language using the terms "osteogenesis imperfecta," "OI," and "brittle bone disease" was performed in June 2022. Articles screened were restricted to adults. Additional sources were identified through manual searches of reference lists. CONCLUSION: Fracture rates are elevated in adults with OI. Although clinical trial data are limited, bisphosphonates and teriparatide may be useful in improving BMD. Further research is needed to develop medications for adults with OI that will lead to definite fracture rate reduction.

Abaloparatide outperforms teriparatide in protecting against alveolar bone loss in experimental periodontitis.

BACKGROUND: The aim of this study was to compare the effects of two osteoanabolic drugs, abaloparatide (ABL) and teriparatide (TPTD), on protecting alveolar bone in experimental periodontitis. METHODS: Twenty-four 9-week-old, male, Sprague-Dawley rats were placed with silk suture around the right maxillary second molar, and then were randomly divided into three groups, that is, the ABL, TPTD, and saline group, receiving intermittent subcutaneous injections of ABL (80 µg/kg), TPTD (80 µg/kg) or saline respectively every other day for 4 weeks. Samples on both sides were assessed through micro-computerized tomography, histological, and immunohistochemical analysis. Mouse pre-osteoblast MC3T3 cell was cultured with lipopolysaccharide (LPS) and treated with ABL or TPTD, before assays of cell proliferation, alkaline phosphatase (ALP) activity and real-time polymerase chain reaction. RESULTS: On the ligature side, both ABL and TPTD significantly reduced alveolar bone loss, and ABL had significantly better effects with higher expression of runt-related transcription factor 2 (RUNX2) and Bglap (formerly called osteocalcin); meanwhile, the ligature induced osteoclastogenesis and down-regulation of osteoprotegerin (OPG) was affected by neither drug. On the non-ligature side, ABL also showed better osteoanabolic effects. In vitro studies revealed that, in the presence of LPS, ABL, and TPTD similarly promoted MC3T3 proliferation, whereas ABL induced higher ALP activity and osteoblastic gene expression compared to TPTD. CONCLUSION: Both ABL and TPTD protect and regenerate alveolar bone in experimental periodontitis, and ABL behaves even better than TPTD at the same dose, attributed to its stronger osteoanabolic effects in this context.

Teriparatide prevented synovial inflammation and cartilage destruction in mice with DMM.

AIM: Emerging data have demonstrated that low-grade inflammation in osteoarthritis, a long-held degenerative disease. The inflamed synovium produces various cytokines that induce cartilage destruction and joint pain. A previous study showed that teriparatide, an FDA approved anti-osteoporotic drug, may enhance cartilage repair. Our study focuses on its role in OA synovitis. MATERIALS AND METHODS: Primary mouse articular chondrocytes were used to determine the most potent cytokines involved in OA inflammation and cartilage destruction. A destabilization of the medial meniscus mouse model was established to investigate the effect of teriparatide in OA, particularly, on synovial inflammation and cartilage degradation. RESULTS: In vitro experiments showed that TNF-α was the most potent inducer of cartilage matrix-degrading enzymes, and that teriparatide antagonized the TNF-α of effect. Consistently, articular cartilage samples from TNF-α transgenic mice contained more MMP-13 positive chondrocytes than those from wild type mice. In addition, more type II collagen was cleaved in human OA cartilage than in normal cartilage samples. CONCLUSIONS: Teriparatide can prevent synovitis and cartilage degradation by suppressing TNF-α mediated MMP-13 overexpression. Together with its chondroregenerative capability, teriparatide may be the first effective disease modifying osteoarthritis drug.

Abaloparatide and teriparatide enhance mandibular growth in adolescent rats with site-specific and mechano-related effects.

OBJECTIVE: Teriparatide (TPTD) and abaloparatide (ABL) are two osteoanabolic drugs targeting parathyroid hormone (PTH)1R signalling. This study aimed to investigate the effects of TPTD and ABL on the adolescent mandibular growth. METHOD: In total, 70 4-week-old male Sprague-Dawley rats were randomly divided into 14 groups, treated with intermittent TPDT or ABL at various doses, accompanied by mandibular advancement (MA) or not. 3D printing was used to fabricate an innovative splint for MA. After a 4-week treatment, morphological measurement, histological and immunohistochemical analysis were performed. Mandibular condylar chondrocytes (MCCs) were treated with TPTD or ABL, followed by CCK-8 assay, alcian blue staining, real time-PCR and immunofluorescent staining. RESULT: In vivo, TPTD or ABL alone increased the condylar length and cartilage thickness, with up-regulated SOX9 and COL II, whilst down-regulated COL X; however, when combined with MA, the promotive effects were attenuated. TPTD or ABL alone increased the mandibular body height and mandibular angle width, whilst increased the mandibular body length and alveolar bone width when combined with MA. In vitro, TPTD or ABL enhanced the MCC proliferation, glycosaminoglycan synthesis, COL II and SOX9 expression, whilst down-regulated COL X, Ihh and PTH1R expression. CONCLUSION: Both ABL and TPTD enhance mandibular growth in adolescent rats with site-specific and mechano-related effects, including propelling chondrogenesis at the condylar cartilage and promoting bone apposition at other mechano-responsive sites. They behave as promising drugs for mandibular growth modification, and in general ABL seems more potent than TPTD in this context.

Medical optimization of osteoporosis for adult spinal deformity surgery: a state-of-the-art evidence-based review of current pharmacotherapy.

PURPOSE: Osteoporosis is a common, but challenging phenomenon to overcome in adult spinal deformity (ASD) surgery. Several pharmacological agents are at the surgeon's disposal to optimize the osteoporotic patient prior to undergoing extensive reconstruction. Familiarity with these medications will allow the surgeon to make informed decisions on selecting the most appropriate adjuncts for each individual patient. METHODS: A comprehensive literature review was conducted in PubMed from September 2021 to April 2022. Studies were selected that contained combinations of various terms including osteoporosis, specific medications, spine surgery, fusion, cage subsidence, screw loosening, pull-out, junctional kyphosis/failure. RESULTS: Bisphosphonates, denosumab, selective estrogen receptor modulators, teriparatide, abaloparatide and romosozumab are all pharmacological agents currently available for adjunctive use. While these medications have been shown to have beneficial effects on improving bone mineral density in the osteoporotic patient, varying evidence is available on their specific effects in the context of extensive spine surgery. There is still a lack of human studies with use of the newer agents. CONCLUSION: Bisphosphonates are first-line agents due to their low cost and robust evidence behind their utility. However, in the absence of contraindications, optimizing bone quality with anabolic medications should be strongly considered in preparation for spinal deformity surgeries due to their beneficial and favorable effects on fusion and hardware compared to the anti-resorptive medications.

Protective effect of teriparatide against vancomycin-induced cytotoxicity in osteoblasts.

BACKGROUND: Intrawound vancomycin powder is effective in preventing surgical site infection after spine surgery. In a previous study, vancomycin-induced cytotoxicity in osteoblasts was investigated in vitro, and vitamin D3 was verified to be a candidate drug aiding recovery from vancomycin-induced cytotoxicity. The treatment practices involving osteogenesis-promoting drugs vary widely. Teriparatide, an anabolic agent, highly promotes bone formation by inducing osteoblast activation, increasing bone formation and mineral density, and preventing vertebral fractures. Hence, teriparatide may be administered in combination with vancomycin. METHODS: MC3T3-E1 cells were cultured in minimum essential medium supplemented with 10% fetal bovine serum at 37 °C in a humidified incubator containing 5% CO2. The experimental concentrations of vancomycin (2500, 5000, and 7500 µg/mL) were determined based on previous reports and our preliminary experiments. Teriparatide (100 ng/mL) was administered concomitantly to prevent cytotoxicity in osteoblasts, using pulsed vancomycin for 24 h (measured at 1, 3, and 7 days). Cell numbers and morphological changes in cells treated with vancomycin or vancomycin plus 100 ng/mL teriparatide were measured. Osteoblast differentiation was assessed using alkaline phosphatase staining, alkaline phosphatase activity, and alizarin red S staining. RESULTS: Teriparatide showed a recovery effect when vancomycin (7500 µg/mL) was administered only for 24 h. Microscopic examination revealed that teriparatide had a protective effect on osteoblasts exposed to 7500 µg/mL vancomycin. Addition of teriparatide led to the recovery of alkaline phosphatase staining and alizarin red staining. CONCLUSION: Vancomycin-induced cytotoxicity in osteoblasts could be inhibited by administering teriparatide concomitantly with vancomycin.

Factors affecting healing and progression of conservatively treated incomplete atypical femoral fractures: retrospective observational study.

INTRODUCTION: Incomplete atypical femoral fractures (iAFF) may occur with prolonged bisphosphonate usage. Factors influencing iAFF healing and progression are not well understood. This study of conservatively managed iAFF assessed factors influencing iAFF healing and progression including the effects of bisphosphonates and teriparatide use. MATERIALS AND METHODS: Single-center retrospective observational study of 69 consecutive patients with 78 radiographically confirmed iAFF from 2002 to 2017. Serial radiographs assessed for focal cortical thickening, dreaded black line (DBL) and complete fracture. Chief outcome measures were DBL healing and complete fracture. RESULTS: DBL had a significant association (p < 0.05) with fracture progression by multivariable logistic regression (55.8% versus 25.7%, odds ratio [OR] 26.57 (95% CI 1.40-504.78)) and shorter fracture-free survival (mean 3.21 versus 6.27 years). Presence of symptoms was associated with shorter fracture-free survival (mean 2.68 versus 5.98 years). Discontinuing bisphosphonates had significant associations (p < 0.001) by multivariable logistic regression with decreased fracture rate (11.6% versus 92.0%; OR 0.00, 95% CI 0.00-0.08) and longer fracture-free survival (mean 7.52 versus 1.99 years). DBL healing occurred in 36.4%, only when bisphosphonates were discontinued. Age, sex, race, fracture site, glucocorticoid use, teriparatide supplementation and duration of bisphosphonate use showed no statistically significant effect although teriparatide use appeared to improve DBL healing (50% versus 17.9%, p = 0.188). CONCLUSIONS: In conservatively managed iAFF, DBL healing occurred in 36.4% if bisphosphonates were discontinued. Bisphosphonates and DBL were significantly associated with fracture progression and together with symptoms with fracture survival.

Teriparatide Followed by Denosumab in Premenopausal Idiopathic Osteoporosis: Bone Microstructure and Strength by HR-pQCT.

Premenopausal women with idiopathic osteoporosis (PreMenIOP) have marked deficits in skeletal microstructure. We have reported that sequential treatment with teriparatide and denosumab improves central skeletal bone mineral density (BMD) by dual-energy X-ray absorptiometry and central QCT in PreMenIOP. We conducted preplanned analyses of high-resolution peripheral quantitative computed tomography (HR-pQCT) scans from teriparatide and denosumab extension studies to measure effects on volumetric BMD (vBMD), microarchitecture, and estimated strength at the distal radius and tibia. Of 41 women enrolled in the parent teriparatide study (20 mcg daily), 34 enrolled in the HR-pQCT study. HR-pQCT participants initially received teriparatide (N = 24) or placebo (N = 10) for 6 months; all then received teriparatide for 24 months. After teriparatide, 26 enrolled in the phase 2B denosumab extension (60 mg q6M) for 24 months. Primary outcomes were percentage change in vBMD, microstructure, and stiffness after teriparatide and after denosumab. Changes after sequential teriparatide and denosumab were secondary outcomes. After teriparatide, significant improvements were seen in tibial trabecular number (3.3%, p = 0.01), cortical area and thickness (both 2.7%, p < 0.001), and radial trabecular microarchitecture (number: 6.8%, thickness: 2.2%, separation: -5.1%, all p < 0.02). Despite increases in cortical porosity and decreases in cortical density, whole-bone stiffness and failure load increased at both sites. After denosumab, increases in total (3.5%, p < 0.001 and 3.3%, p = 0.02) and cortical vBMD (1.7% and 3.2%; both p < 0.01), and failure load (1.1% and 3.6%; both p < 0.05) were seen at tibia and radius, respectively. Trabecular density (3.5%, p < 0.001) and number (2.4%, p = 0.03) increased at the tibia, while thickness (3.0%, p = 0.02) increased at the radius. After 48 months of sequential treatment, significant increases in total vBMD (tibia: p < 0.001; radius: p = 0.01), trabecular microstructure (p < 0.05), cortical thickness (tibia: p < 0.001; radius: p = 0.02), and whole bone strength (p < 0.02) were seen at both sites. Significant increases in total vBMD and bone strength parameters after sequential treatment with teriparatide followed by denosumab support the use of this regimen in PreMenIOP. © 2022 American Society for Bone and Mineral Research (ASBMR).