RUNX2 Regulates Osteoblast Differentiation via the BMP4 Signaling Pathway.

RUNX2 is a master osteogenic transcription factor, and mutations in RUNX2 cause the inherited skeletal disorder cleidocranial dysplasia (CCD). Studies have revealed that RUNX2 is not only a downstream target of the bone morphogenetic protein (BMP) pathway but can also regulate the expression of BMPs. However, the underlying mechanism of the regulation of BMPs by RUNX2 remains unknown. In this project, we diagnosed a CCD patient with a 7.86-Mb heterozygous deletion on chromosome 6 containing all exons of RUNX2 by multiplex ligation-dependent probe amplification (MLPA) and whole-genome sequencing (WGS). Bone marrow mesenchymal stem cells (BMSCs) were further extracted from patient alveolar bone fragments (CCD-BMSCs), an excellent natural model to explore the possible mechanism. The osteogenic differentiation ability of CCD-BMSCs was severely affected by RUNX2 heterozygous deletion. Also, BMP4 decreased most in BMP ligands, and CHRDL1, a BMP antagonist, was abnormally elevated in CCD-BMSCs. Furthermore, BMP4 treatment essentially rescued the osteogenic capacity of CCD-BMSCs, and RUNX2 overexpression reversed the abnormal expression of BMP4 and CHRDL1. Notably, we constructed CRISPR/Cas9 Runx2+/m MC3T3-E1 cells, which simulated a variant in CCD-BMSCs, to exclude the interference of other gene deletions and the heterogeneity of the genetic background of primary cells, and verified all findings from the CCD-BMSCs. Moreover, the luciferase reporter experiment showed that RUNX2 could inhibit the transcription of CHRDL1. Through immunofluorescence, the inhibitory effect of CHRDL1 on BMP4/Smad signaling was confirmed in MC3T3-E1 cells. These results revealed that RUNX2 regulated the BMP4 pathway by inhibiting CHRDL1 transcription. We collectively identified a novel RUNX2/CHRDL1/BMP4 axis to regulate osteogenic differentiation and noted that BMP4 might be a valuable therapeutic option for treating bone diseases.

[Eltrombopag for thrombocytopenia in 24 children after hematopoietic stem cell transplantation].

Objective: To evaluate the efficacy and safety of eltrombopag for children with thrombocytopenia after hematopoietic stem cell transplantation (HSCT). Methods: Clinical data of 24 patients with thrombocytopenia after HSCT,who were treated with eltrombopag in the Department of Pediatrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University from August 1, 2018 to April 1, 2019 were analyzed retrospectively. The response rate and adverse reactions of eltrombopag were evaluated. Patients were divided into groups by source of hematopoietic stem cells (umbilical cord blood group and peripheral stem cell group) and type of disease (malignant and non-malignant disease group) and the clinical outcomes between groups were compared. Rank Sum test was used for comparisons between groups. Results: Among 24 cases, 15 were males and 9 females, the age of starting eltrombopag was 7.7 (2.6-13.7) years, the time of eltrombopag treatment after HSCT was 27.5 (8.0-125.0) days, the time from treatment to complete response (CR) was 23.5 (6.0-83.0) days, with the treatment course 36.5 (8.0-90.0) days. The total dose of eltrombopag was 1 400(200-5 900) mg. Complete response rate was 92% (22/24),without eltrombopag related adverse reactions. Comparing with peripheral stem cell group (n=8), the course and total dose of eltrombopag in umbilical cord blood group (n=16) were significantly reduced(24.5 (8.0-81.0) vs. 65.5 (35.0-90.0) d, Z=-3.004, P=0.002; 900.0 (200.0-3 850.0) vs. 2 862.5 (1 175.0-5 900.0) mg, Z=-2.604, P=0.007), but no significant differences were found in the time from treatment to complete response, platelet count after 2 weeks of eltrombopag withdrawal or platelet count at the end point of follow-up (all P>0.05). Comparing malignant patients (n=12) and non-malignant patients (n=12), no significant differences were found in the time from treatment to complete response, course, total dose, platelet count after 2 weeks of eltrombopag withdrawal, and platelet count at the end point of follow-up in non-malignant patients (all P>0.05). Conclusion: Eltrombopag is safe and maybe effective for thrombocytopenia after HSCT, especially for umbilical cord blood transplantation.

Circ-DONSON promotes malignant progression of glioma through modulating FOXO3.

OBJECTIVE: The aim of this study was to investigate the expression level of circ-DONSON in glioma and to explore its effect on glioma metastasis and the underlying mechanism. PATIENTS AND METHODS: Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine circ-DONSON expression in 40 paired glioma tumor tissues and adjacent tissues. Meanwhile, the relation between circ-DONSON level and clinical parameters of glioma and the prognosis of patients was analyzed. The expression of circ-DONSON in glioma cell lines was analyzed by qRT-PCR as well. In addition, circs-DONSON silencing model was constructed in glioma cell lines. Cell counting kit-8 (CCK-8), cell scratch, and transwell migration assays were performed to investigate the effect of circ-DONSON on biological functions of glioma cells. Finally, the interplay between FOXO3 and circ-DONSON was explored. RESULTS: QRT-PCR results revealed that the expression level of circ-DONSON in glioma tumor tissues was remarkably higher than that of adjacent tissues, and the difference was statistically significant (p<0.05). Compared with patients with low expression of circ-DONSON, significantly higher prevalence of lymph node or distant metastasis and worse prognosis were observed in patients with high expression of circ-DONSON (p<0.05). The proliferation and migration abilities of glioma cells in circ-DONSON silenced group were remarkably suppressed when compared with NC group (p<0.05). Additionally, FOXO3 expression was remarkably down-regulated in glioma cell lines and tissues. FOXO3 expression was negatively correlated with circ-DONSON expression. In addition, cell reverse experiment demonstrated that circ-DONSON and FOXO3 can regulate each other, thereby together affecting the malignant progression of glioma. CONCLUSIONS: Circ-DONSON was remarkably associated with lymph node or distant metastasis, as well as poor prognosis of patients with glioma. Furthermore, it promoted the metastasis of glioma cells via regulating FOXO3.

[Effect of comprehensive AIDS intervention among men aged 50 or over who had non-marital sexual behavior].

Objective: To evaluate the effectiveness of AIDS intervention programs on men aged 50 or over and having had non-marital sexual behavior. Methods: A community-based intervention/experimental and based on individual level study was adopted. Stratified sampling method was used. 12 townships/streets in Fuyang district of Hangzhou were identified as intervention or control group (six research sites each). All of the subjects in the township (street) were included. The inclusion criteria of study objects would include men aged 50 or older who reported having unmarried sex in the last year. Estimated sample size was 290, with each 145 in the intervention group and the control group. All the intervention group participants were provided with a total of 4 intervention-related items (knowledge and education on AIDS prevention, information radiation and behavioral change, broadcast expert lectures), every 3 months, for 12 month, the main evaluation indicators would include: incidence of non-marital sex and commercial sex in the last year, condom use when having non-marital sex in the last episode. Results: A total of 312 subjects were recruited. 300 of them completed the baseline study while 284 of them completed the follow-up survey. Among the subjects who had undergone the baseline study, the average age was (65.58±7.89), 71.33% were married or cohabiting with someone, 52.00% having had primary school education. After the implementation of intervention programs, the incidence of non-marital sex dropped to 59.42% (82/138) and the incidence of commercial sex dropped from 79.73% (118/148) to 55.07% (76/138). Condom use rate in the last non-marital sexual contact increased from 19.59% (29/148) to 51.22% (42/82). In the control group, the incidence of non-marital sex in the year before dropped to 74.66% (109/146) and the incidence of commercial sex dropped from 91.45% (139/152) to 72.60% (106/146). Rates of condom use during the last non-marital sexual contact dropped from 32.89% (50/152) to 31.19% (34/109). Statistically, there were significant differences appeared between the two groups on the incidence of non-marital sex in the past year (χ(2)=7.48, P=0.008), the incidence of commercial sex in the last year (χ(2)=9.47, P=0.003) and the rate of condom use in the last sex experience (χ(2)=7.83, P=0.007). Conclusions: Results from this intervention study showed that: in the intervention group, both the incidence rates of non-marital or commercial sex had reduced, together with the increase of condom use in non-marital sex in the last sexual experience. Intervention strategies that involving knowledge and education on AIDS prevention, information radiation and behavioral change, broadcasting lectures by experts etc. were all proved effective.

Relationship between the change in pacing threshold and the myocardial injury.

OBJECTIVE: To investigate the effects of general conditions and past medical history of patients on the short-term pacing threshold after the implantation of active electrodes of a cardiac pacemaker, and to understand whether the application of active electrodes will cause muscle injury and the severity of the injury. PATIENTS AND METHODS: A total of 156 patients who were treated with a cardiac pacemaker and implanted with single or double active electrodes in Cardiovascular Department of Central Hospital of Jiangjin District were enrolled, including 96 patients treated with a single active electrode and 60 patients treated with double active electrodes. Their clinical data were collected. During operation, the short-term atrial and ventricular pacing thresholds were monitored and recorded after the implantation of the active fixed electrode lead. RESULTS: Multivariate Logistic regression analysis showed that female sex, age, smoking, drinking, coronary heart disease, diabetes mellitus and hyperlipidemia had effects on pacing thresholds in a short-term to some extent after the implantation of active fixed electrode lead of cardiac pacemaker. The levels of myocardial enzymes, myoglobin (MYO), creatine kinase (CK), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and cardiac troponin I (cTNI), in patients were gradually increased after the implantation of active fixed electrode lead and reached the peak at 24 h, which were higher than those before operation (p < 0.05). The levels were decreased at 72 h with statistically significant differences. CONCLUSIONS: Female sex, age, smoking, drinking, coronary heart disease, diabetes mellitus and hyperlipidemia are independent influencing factors of pacing thresholds in a short term after the implantation of active fixed electrode lead of cardiac pacemaker. The implantation of active electrodes can raise the myocardial enzyme indexes compared with those before operation, but will fall to the preoperative levels or normal, near normal levels at 72 h after operation. The implantation of active electrodes is safe and feasible for myocardial tissues.

[Expression of E-cadherin, N-cadherin, ß-catenin and their clinical significance in laryngeal carcinoma].

OBJECTIVE: To investigate the expression of E-cadherin(E-cad), N-cadherin(N-cad), ß-catenin(ß-cat), which are the markers of Epithelial-mesenchymal transition and analyze their relationships with the clinicopathological features and the prognosis of the laryngeal squamous cell carcinoma. METHODS: The expression levels of E-cad, N-cad, ß-cat in 76 tumor tissues and their corresponding adjacent normal laryngeal tissues were determined by immunohistochemistry method. Relationships between the proteins' expression and clinicopathological features were analyzed. Survival curves were calculated using the Kaplan-Meier method. Differences in the survival rates were analyzed by the log-rank test among different expression groups. Cox's regression model was used to examine the independent predictor of the prognosis of the laryngeal cancer. RESULTS: The expression levels of E-cad, N-cad, ß-cat in tumor tissues and adjacent normal tissues were statistically significant(P<0.001). The expression level of E-cad and ß-cat in the laryngeal carcinoma was related to lymph node metastasis, clinical pathological stage and differentiation degree (P<0.05), while N-cad expression level was associated with clinical stage and differentiation degree (P<0.05). The expression of E-cad was correlated with the expression of ß-cat (P=0.001), and the expression of N-cad was correlated with ß-cat (P=0.02), but the expression of E-cad was not correlated with N-cad. There were four subgroups of patterns of E-cad and N-cad expression: E-cad (+ )/N-cad (-), E-cad (+ ) /N-cad (+ ), E-cad (-) /N-cad (-), E-cad (-) /N-cad (+ ). The expression level of each group was related to the clinical pathological stage and differentiation degree (P<0.05). The expression level of E-cad/ß-cat was associated with lymph node metastasis, clinical pathological stage and differentiation degree (P<0.01). Log-rank analysis showed that the prognosis of negative and positive groups was statistically different (P<0.05), and the combined analysis showed that the prognosis of E-cad/N-cad or E-cad/ß-cat group was significantly different (P<0.01). Cox's regression model analysis showed that the clinical stage and ß-cat were independent predictors of the prognosis of laryngeal carcinoma. CONCLUSIONS: The low expression of E-cad, high abnormal expression of N-cad and ß-cat played an important role in the occurrence and development of laryngeal carcinoma. It can provide a reference for evaluating clinical prognosis. The clinical pathological stage and ß-cat can be used as independent predictors for the prognosis of laryngeal carcinoma.

Effects of inhibiting PI3K-Akt-mTOR pathway on lipid metabolism homeostasis in goose primary hepatocytes.

UNLABELLED: Phosphatidylinositol-3 kinases (PI3K)-Protein kinase B (Akt)-mammalian target of rapamycin (mTOR) pathway plays an important role in the synthesis and secretion of triacylglycerol. However, the mechanism of PI3K-Akt-mTOR pathway in regulating lipid metabolism of goose liver was poorly understood. The purpose of this study was to determine how PI3K-Akt-mTOR pathway regulating lipid metabolic homeostasis in goose hepatocytes. Goose primary hepatocytes were treated with different PI3K-Akt-mTOR signal inhibitors (LY294002, rapamycin and NVP-BEZ235) for 24 h. The results showed that these inhibitors evidently inhibited PI3K-Akt-mTOR downstream signaling. Meanwhile, these PI3K-Akt-mTOR inhibitors reduced intracellular lipid accumulation, decreased the mRNA expression and protein content of genes involved in the de novo fatty acid synthesis, while increased the transcriptional and protein level of key factors involved in fatty acid oxidation and very low density lipoprotein (VLDL) assembly and secretion. CONCLUSION: These findings suggested that the reduction of lipids accumulation induced-by inhibiting PI3K-Akt-mTOR pathway was closely linked to the decrease of lipogenesis, the increase of fatty acids oxidation, and the increase of VLDL assembly and secretion in goose hepatocytes.

Long-term treatment efficacy in primary inflammatory breast cancer by hormonal receptor- and HER2-defined subtypes.

BACKGROUND: Subtypes defined by hormonal receptor (HR) and HER2 status have not been well studied in inflammatory breast cancer (IBC). We characterized clinical parameters and long-term outcomes, and compared pathological complete response (pCR) rates by HR/HER2 subtype in a large IBC patient population. We also compared disease-free survival (DFS) and overall survival (OS) between IBC patients who received targeted therapies (anti-hormonal, anti-HER2) and those who did not. PATIENTS AND METHODS: We retrospectively reviewed the records of patients diagnosed with IBC and treated at MD Anderson Cancer Center from January 1989 to January 2011. Of those, 527 patients had received neoadjuvant chemotherapy and had available information on estrogen receptor (ER), progesterone receptor (PR), and HER2 status. HR status was considered positive if either ER or PR status was positive. Using the Kaplan-Meier method, we estimated median DFS and OS durations from the time of definitive surgery. Using the Cox proportional hazards regression model, we determined the effect of prognostic factors on DFS and OS. Results were compared by subtype. RESULTS: The overall pCR rate in stage III IBC was 15.2%, with the HR-positive/HER2-negative subtype showing the lowest rate (7.5%) and the HR-negative/HER2-positive subtype, the highest (30.6%). The HR-negative, HER2-negative subtype (triple-negative breast cancer, TNBC) had the worst survival rate. HR-positive disease, irrespective of HER2 status, had poor prognosis that did not differ from that of the HR-negative/HER2-positive subtype with regard to OS or DFS. Achieving pCR, no evidence of vascular invasion, non-TNBC, adjuvant hormonal therapy, and radiotherapy were associated with longer DFS and OS. CONCLUSIONS: Hormone receptor and HER2 molecular subtypes had limited predictive and prognostic power in our IBC population. All molecular subtypes of IBC had a poor prognosis. HR-positive status did not necessarily confer a good prognosis. For all IBC subtypes, novel, specific treatment strategies are needed in the neoadjuvant and adjuvant settings.

Statin use in primary inflammatory breast cancer: a cohort study.

BACKGROUND: Some studies have suggested that statins, which have cholesterol-lowering and anti-inflammatory properties, may have antitumor effects. Effects of statins on inflammatory breast cancer (IBC) have never been studied. METHODS: We reviewed 723 patients diagnosed with primary IBC in 1995-2011 and treated at The University of Texas MD Anderson Cancer Center. Statin users were defined as being on statins at the initial evaluation. Based on Ahern et al's statin classification (JNCI, 2011), clinical outcomes were compared by statin use and type (weakly lipophilic to hydrophilic (H-statin) vs lipophilic statins (L-statin)). We used the Kaplan-Meier method to estimate the median progression-free survival (PFS), overall survival (OS) and disease-specific survival (DSS), and a Cox proportional hazards regression model to test the statistical significance of potential prognostic factors. RESULTS: In the multivariable Cox model, H-statins were associated with significantly improved PFS compared with no statin (hazard ratio=0.49; 95% confidence interval=0.28-0.84; P<0.01); OS and DSS P-values were 0.80 and 0.85, respectively. For L-statins vs no statin, P-values for PFS, DSS, and OS were 0.81, 0.4, and 0.74, respectively. CONCLUSION: H-statins were associated with significantly improved PFS. A prospective randomised study evaluating the survival benefits of statins in primary IBC is warranted.

The impact of phosphorylated AMP-activated protein kinase expression on lung cancer survival.

BACKGROUND: The aim of this study is to investigate the prognostic role of phosphorylated AMP-activated protein kinase (pAMPK) in surgically resected non-small-cell lung cancer (NSCLC). METHODS: Immunohistochemical staining of pAMPK was carried out on tissue microarrays containing 463 samples obtained from patients with NSCLC and correlated with clinicopathological characteristics and survival. RESULTS: pAMPK expression levels were significantly higher in never smokers versus former smokers versus current smokers (P=0.045). A positive pAMPK expression was associated with increased overall survival (OS) and recurrence-free survival (RFS) (P=0.0009 and P=0.0007, respectively). OS and RFS were statistically superior in pAMPK-positive than in pAMPK-negative patients with adenocarcinoma (ADC; median OS: 5.6 and 4.2 years, respectively, P=0.0001; median RFS: 5.0 and 2.4 years, respectively, P=0.001), whereas they were similar in those patients with squamous cell carcinoma. Multivariate analysis confirmed that pAMPK positivity was associated with OS [hazard ratio (HR)=0.574, 95% confidence interval (CI) 0.418-0.789, P=0.0006) and RFS (HR=0.608, 95% CI 0.459-0.807, and P=0.0006), independent of clinical covariates. CONCLUSIONS: High pAMPK expression levels are associated with increased survival in patients with NSCLC, especially those with ADC. Our results support further evaluation of AMP-activated protein kinase as a potential prognostic and therapeutic target for lung cancer.

Histopathological and biochemical changes following fat embolism with administration of corn oil micelles: a new animal model for fat embolism syndrome.

Several experimental models have been used to produce intravascular fat embolism. We have developed a simple technique to induce fat embolism using corn oil emulsified with distilled water to form fatty micelles. Fat embolism was produced by intravenous administration of these fatty micelles in anaesthetised rats, causing alveolar oedema, haemorrhage and increased lung weight. Histopathological examination revealed fatty droplets and fibrin thrombi in the lung, kidney and brain. The arteriolar lumen was filled with fatty deposits. Following fat embolism, hypoxia and hypercapnia occurred. The plasma phospholipase A(2), nitrate/nitrite, methylguidanidine and proinflammatory cytokines were significantly increased. Mass spectrometry showed that the main ingredient of corn oil was oleic acid. This simple technique may be applied as a new animal model for the investigation of the mechanisms involved in the fat embolism syndrome.

Nicotinamide abrogates acute lung injury caused by ischaemia/reperfusion.

Poly (ADP-ribose) synthase or polymerase (PARS and PARP, respectively) is a cytotoxic enzyme which causes cellular damage. Nicotinamide, a compound of vitamin B complex, has been reported to exert an inhibitory effect on PARS or PARP. The present study tests the effects of nicotinamide on acute lung injury and associated alterations following ischaemia/reperfusion (I/R) of the isolated perfused rat's lung. I/R increased the lung weight (LW) to body weight ratio, LW gain, protein and dye tracer leakage, pulmonary arterial pressure and capillary permeability. The insult also increased nitrate/nitrite, methyl guanidine, tumour necrosis factor-alpha and interleukin-1beta in lung perfusate, while it decreased adenosine triphosphate content with an increase in PARP activity in lung tissue. Most of the I/R-induced changes were abrogated by post-treatment (30 min after I/R) with nicotinamide (100 mg.kg(-1) body weight). However, the increase in pulmonary arterial pressure was enhanced by nicotinamide post-treatment. Following I/R, the inducible nitric oxide synthase (iNOS) mRNA expression was enhanced. Nicotinamide reduced the iNOS expression. The results suggest that nicotinamide exerted a protective effect on the acute lung injury caused by ischaemia/reperfusion. The mechanisms may be mediated through the inhibition on the poly (adenosine diphosphate-ribose) polymerase activity, inducible nitric oxide synthase expression and the subsequent suppression of nitric oxide, free radicals and pro-inflammatory cytokines with restoration of adenosine triphosphate.

Stem cell therapy in stroke: strategies in basic study and clinical application.

Stem cell therapies are an important strategy for the treatment of stroke. Bone marrow-derived stem cells (BMSCs) may promote structural and functional repair in several organs via stem cell plasticity. The tissue damage could stimulate the stem cells migration, and they track into the site of damage and then undergo differentiation. The plasticity functions of BMSCs in an injuries tissue are dependent on the specific signals present in the local environment of the damaged tissue. Recent studies have also identified the specific molecular signals, such as SDF-1/CXCR4, required for the interaction of BMSCs and damaged host tissues. This review summarizes the current understanding of how BMSCs reach and function in cerebral ischemic tissues.

A retrospective analysis of the outcome of patients who have received two prior chemotherapy regimens including platinum and docetaxel for recurrent non-small-cell lung cancer.

With the availability of chemotherapy agents for first- and second-line treatment of advanced non-small-cell lung cancer (NSCLC), the patient population that requires subsequent chemotherapy is increasing. This retrospective analysis was performed to describe the clinical course after two standard or approved chemotherapy agents in patients with good overall performance status. Data were selected from patients with advanced NSCLC who had received third- or fourth-line chemotherapy after two prior chemotherapy regimens that included platinum and docetaxel given concurrently or sequentially. Prior regiments had failed due to discase progression within 90 days of chemotherapy, or unacceptable toxicity. Examination of over 700 patient records between January 1993 and January 2000 at one US and one European cancer centre revealed 43 patients that fulfilled the inclusion criteria. Response rates decreased with each line of treatment: first line, 20.9%; second line, 16.3%; third line, 2.3%; and fourth line, 0%. The disease control rate (response plus stable disease) also decreased dramatically from first- to fourth-line treatment, although it was higher for second-line treatment (74.4%) than for first-line treatment (62.8%). The median overall survival time from diagnosis was 16.4 months. The median overall survival time from the start of the last treatment (either third or fourth line) was 4 months. Patients with stage III disease at diagnosis had a longer overall survival from diagnosis than patients with stage IV disease (P=0.02). This review highlights the need for novel therapy approaches for patients with recurrent NSCLC who have failed second-line therapy and provides a baseline for the statistical design of such studies.

Loss of PTEN expression as a prognostic marker for tongue cancer.

BACKGROUND: Abnormalities of PTEN, a candidate tumor suppressor gene located at 10q23.3, play an important role in the tumorigenesis of multiple tumor types. OBJECTIVES: To investigate the expression of PTEN and its clinical implication in squamous cell carcinoma of the tongue. DESIGN: Retrospective analysis of PTEN protein expression in archived primary oral tongue tumor samples. SETTING: Academic center. PATIENTS AND METHODS: PTEN expression was determined by immunohistochemical analysis in tissue samples from 41 patients with stage II, III, and IV squamous cell carcinoma of the tongue. All the patients underwent curative surgical treatment with a median follow-up of 81 months. The Kaplan-Meier method was used for survival analysis. Multivariate analysis was performed according to the Cox proportional hazards model. RESULTS: Lack of staining for PTEN was demonstrated in 12 (29%) of the 41 tumors. Patients whose tumors lacked PTEN expression had a significantly shorter overall survival time (P = .03) and event-free survival time (P = .01) than those patients with positive PTEN expression. Multivariate regression analysis demonstrated that PTEN expression is an independent predictor of poor outcome when compared with tumor stage and nodal status. CONCLUSIONS: Although genetic alterations of the PTEN gene are rare in head and neck squamous cell carcinoma, loss of PTEN is not an uncommon event in squamous cell carcinoma of the tongue. Lack of PTEN expression may be an independent prognostic indicator for clinical outcome in patients with this tumor type.

The pharmacology of bimatoprost (Lumigan).

Bimatoprost (Lumigan) is a pharmacologically unique and highly efficacious ocular hypotensive agent. It appears to mimic the activity of a newly discovered family of fatty acid amides, termed prostamides. One biosynthetic route to the prostamides involves anandamide as the precursor. Bimatoprost pharmacology has been extensively characterized by binding and functional studies at more than 100 drug targets, which comprise a diverse variety of receptors, ion channels, and transporters. Bimatoprost exhibited no meaningful activity at receptors known to include antiglaucoma drug targets as follows: adenosine (A(1-3)), adrenergic (alpha(1), alpha(2), beta(1), beta(2)), cannabinoid (CB(1), CB(2)), dopamine (D(1-5)), muscarinic (M(1-5)), prostanoid (DP, EP(1-4), FP, IP, TP), and serotonin (5HT(1-7)). Bimatoprost does, however, exhibit potent inherent pharmacological activity in the feline iris sphincter preparation, which is prostamide-sensitive. Bimatoprost also resembles the prostamides in that it is a potent and highly efficacious ocular hypotensive agent. A single dose of bimatoprost markedly reduces intraocular pressure in dogs and laser-induced ocular hypertensive monkeys. Decreases in intraocular pressure are well maintained for at least 24 hr post-dose. Human studies have demonstrated that systemic exposure to bimatoprost is low and that accumulation does not occur. The sclera is the preferred route of accession to the eye. The high scleral permeability coefficient Papp is a likely contributing factor to the rapid onset and long-acting ocular hypotensive profile of bimatoprost.

Preclinical safety profile of brimonidine.

Brimonidine is a selective alpha 2-adrenergic agonist developed for lowering intraocular pressure in glaucoma patients. Since brimonidine will be used in long-term theraphy, the safety of this drug is an important feature for its clinical success. Brimonidine has been evaluated in a number of safety studies using doses much greater than those in humans. In this paper chronic and carcinogenicity studies are presented. The results of the 6-month ocular/systemic study in rabbits and the 1-year ocular/systemic study in monkeys with 0.2, 0.5, and 0.8% brimonidine ophthalmic formulations showed no ocular or organ toxicity. The highest concentration of 0.8% used in rabbits and monkeys resulted in plasma drug concentrations of 95 (Cmax) and 10 (C2hr) times, respectively, higher than those seen in humans following topical dosing. Dose-related transient exaggerated pharmacologic effects of sedation were observed in the 1-year oral study in monkeys without any organ toxicity. The dose that elicited an apparent pharmacologic effect produced a plasma drug concentration that was approximately 115 times higher than that in humans. In 2-year carcinogenicity studies in mice and rats using doses that produced plasma concentrations 77 and 118 times, respectively, higher than those seen in humans, no oncogenic effect was observed. Based on the extensive safety research on brimonidine, it was concluded that this drug has an excellent safety profile.