Impact of vaginal estriol on serum hormone levels: a systematic review

The genitourinary syndrome of menopause (GSM) affects up to 84% of postmenopausal women and may significantly reduce the quality of life in some. For symptom relief, there are several non-hormonal and hormonal vaginal products available. In Europe, vaginal estriol (E3) is the most frequently chosen estrogen for GSM treatment. The aim of this systematic review was to assess the impact of vaginal E3 on serum sex hormone levels, an outcome that has been previously used to assess safety in similar products. In our review, we did not find any alterations in serum estrone, estradiol, testosterone, progesterone and sex hormone binding globulin levels after vaginal E3 application. In contrast, some studies showed a minimal and transient decrease in serum gonadotropin levels, which however remained within the postmenopausal range. Similarly, only a few studies reported a minimal and transient increase of serum E3 levels, with the rest reporting no changes. The lack of clinically relevant long-term changes in serum sex hormone levels supports the current literature providing evidence about the safety of vaginal E3 products.

Discovery of the TLR7/8 Antagonist MHV370 for Treatment of Systemic Autoimmune Diseases

Toll-like receptor (TLR) 7 and TLR8 are endosomal sensors of the innate immune system that are activated by GU-rich single stranded RNA (ssRNA). Multiple genetic and functional lines of evidence link chronic activation of TLR7/8 to the pathogenesis of systemic autoimmune diseases (sAID) such as Sjögren's syndrome (SjS) and systemic lupus erythematosus (SLE). This makes targeting TLR7/8-induced inflammation with small-molecule inhibitors an attractive approach for the treatment of patients suffering from systemic autoimmune diseases. Here, we describe how structure-based optimization of compound 2 resulted in the discovery of 34 (MHV370, (S)-N-(4-((5-(1,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-4-yl)-3-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridin-1-yl)methyl)bicyclo[2.2.2]octan-1-yl)morpholine-3-carboxamide). Its in vivo activity allows for further profiling toward clinical trials in patients with autoimmune disorders, and a Phase 2 proof of concept study of MHV370 has been initiated, testing its safety and efficacy in patients with Sjögren's syndrome and mixed connective tissue disease.

Preclinical characterization of the Toll-like receptor 7/8 antagonist MHV370 for lupus therapy

Genetic and in vivo evidence suggests that aberrant recognition of RNA-containing autoantigens by Toll-like receptors (TLRs) 7 and 8 drives autoimmune diseases. Here we report on the preclinical characterization of MHV370, a selective oral TLR7/8 inhibitor. In vitro, MHV370 inhibits TLR7/8-dependent production of cytokines in human and mouse cells, notably interferon-α, a clinically validated driver of autoimmune diseases. Moreover, MHV370 abrogates B cell, plasmacytoid dendritic cell, monocyte, and neutrophil responses downstream of TLR7/8. In vivo, prophylactic or therapeutic administration of MHV370 blocks secretion of TLR7 responses, including cytokine secretion, B cell activation, and gene expression of, e.g., interferon-stimulated genes. In the NZB/W F1 mouse model of lupus, MHV370 halts disease. Unlike hydroxychloroquine, MHV370 potently blocks interferon responses triggered by specific immune complexes from systemic lupus erythematosus patient sera, suggesting differentiation from clinical standard of care. These data support advancement of MHV370 to an ongoing phase 2 clinical trial.

Structure-Based Optimization of a Fragment-like TLR8 Binding Screening Hit to an In Vivo Efficacious TLR7/8 Antagonist

Inappropriate activation of TLR7 and TLR8 is linked to several autoimmune diseases, such as lupus erythematosus. Here we report on the efficient structure-based optimization of the inhibition of TLR8, starting from a co-crystal structure of a small screening hit. Further optimization of the physicochemical properties for cellular potency and expansion of the structure-activity relationship for dual potency finally resulted in a highly potent TLR7/8 antagonist with demonstrated in vivo efficacy after oral dosing.

Target-Based Identification and Optimization of 5-Indazol-5-yl Pyridones as Toll-like Receptor 7 and 8 Antagonists Using a Biochemical TLR8 Antagonist Competition Assay

Inappropriate activation of endosomal TLR7 and TLR8 occurs in several autoimmune diseases, in particular systemic lupus erythematosus (SLE). Herein, the development of a TLR8 antagonist competition assay and its application for hit generation of dual TLR7/8 antagonists are reported. The structure-guided optimization of the pyridone hit 3 using this biochemical assay in combination with cellular and TLR8 cocrystal structural data resulted in the identification of a highly potent and selective TLR7/8 antagonist (27) with in vivo efficacy. The two key steps for optimization were (i) a core morph guided by a TLR7 sequence alignment to achieve a dual TLR7/8 antagonism profile and (ii) introduction of a fluorine in the piperidine ring to reduce its basicity, resulting in attractive oral pharmacokinetic (PK) properties and improved TLR8 binding affinity.

Inhibition of porcine detrusor contractility by the flavonoid fraction of Bryophyllum pinnatum--a potential phytotherapeutic drug for the treatment of the overactive bladder syndrome

AIMS

To determine if the phytotherapeutic agent, Bryophyllum pinnatum, could serve as an alternative drug for the overactive bladder syndrome, and to characterise the fraction responsible for the inhibition of detrusor contractility.

METHODS

Fractions were prepared from the MeOH extract of B. pinnatum and further analysed by HPLC-PDA-MS. Detrusor muscle strips were prepared from porcine bladders and the electrically induced muscle contractility measured by organ bath. The effect of B. pinnatum leaf press juice (2.5-10%), a flavonoid fraction (0.1-1 mg/ml), and a bufadienolide fraction (0.1-40 μg/ml) on detrusor contractility was assessed and compared with controls (polar fraction (0.5-5 mg/ml) and oxybutynin (10(-8)-10(-6) M)).

RESULTS

The press juice, at a concentration of 10% led to a reduction of detrusor contractility. Bladder strips treated with the flavonoid fraction showed a significant reduction of the contractility to 21.3 ± 5.2% (1 mg/ml) while the bufadienolide fraction had no inhibitory effect in the investigated concentrations. The polar fraction showed a reduction of the contractility in a pH-dependent fashion. At 10(-6) M concentration oxybutynin reduced the detrusor contractility to 21.9 ± 4.7%.

CONCLUSIONS

The flavonoid fraction of Bryophyllum pinnatum reduces the porcine detrusor contractility in a dose- and time-dependent manner. Fractions from B. pinnatum may be a new pharmacological approach for the treatment of OAB.

Distinct effects of IPSU and suvorexant on mouse sleep architecture

Dual orexin receptor (OXR) antagonists (DORAs) such as almorexant, SB-649868, suvorexant (MK-4305), and filorexant (MK-6096), have shown promise for the treatment of insomnias and sleep disorders. Whether antagonism of both OX₁R and OX₂R is necessary for sleep induction has been a matter of some debate. Experiments using knockout mice suggest that it may be sufficient to antagonize only OX₂R. The recent identification of an orally bioavailable, brain penetrant OX₂R preferring antagonist 2-((1H-Indol-3-yl)methyl)-9-(4-methoxypyrimidin-2-yl)-2,9-diazaspiro[5.5]undecan-1-one (IPSU) has allowed us to test whether selective antagonism of OX₂R may also be a viable strategy for induction of sleep. We previously demonstrated that IPSU and suvorexant increase sleep when dosed during the mouse active phase (lights off); IPSU inducing sleep primarily by increasing NREM sleep, suvorexant primarily by increasing REM sleep. Here, our goal was to determine whether suvorexant and IPSU affect sleep architecture independently of overall sleep induction. We therefore tested suvorexant (25 mg/kg) and IPSU (50 mg/kg) in mice during the inactive phase (lights on) when sleep is naturally more prevalent and when orexin levels are normally low. Whereas IPSU was devoid of effects on the time spent in NREM or REM, suvorexant substantially disturbed the sleep architecture by selectively increasing REM during the first 4 h after dosing. At the doses tested, suvorexant significantly decreased wake only during the first hour and IPSU did not affect wake time. These data suggest that OX₂R preferring antagonists may have a reduced tendency for perturbing NREM/REM architecture in comparison with DORAs. Whether this effect will prove to be a general feature of OX₂R antagonists vs. DORAs remains to be seen.

Kinetic properties of "dual" orexin receptor antagonists at OX1R and OX2R orexin receptors

Orexin receptor antagonists represent attractive targets for the development of drugs for the treatment of insomnia. Both efficacy and safety are crucial in clinical settings and thorough investigations of pharmacokinetics and pharmacodynamics can predict contributing factors such as duration of action and undesirable effects. To this end, we studied the interactions between various “dual” orexin receptor antagonists and the orexin receptors, OX₁R and OX₂R, over time using saturation and competition radioligand binding with [³H]-BBAC ((S)-N-([1,1′-biphenyl]-2-yl)-1-(2-((1-methyl-1H-benzo[d]imidazol-2-yl)thio)acetyl)pyrrolidine-2-carboxamide). In addition, the kinetics of these compounds were investigated in cells expressing human, mouse and rat OX₁R and OX₂R using FLIPR® assays for calcium accumulation. We demonstrate that almorexant reaches equilibrium very slowly at OX₂R, whereas SB-649868, suvorexant, and filorexant may take hours to reach steady state at both orexin receptors. By contrast, compounds such as BBAC or the selective OX₂R antagonist IPSU ((2-((1H-Indol-3-yl)methyl)-9-(4-methoxypyrimidin-2-yl)-2,9-diazaspiro[5.5]undecan-1-one) bind rapidly and reach equilibrium very quickly in binding and/or functional assays. Overall, the “dual” antagonists tested here tend to be rather unselective under non-equilibrium conditions and reach equilibrium very slowly. Once equilibrium is reached, each ligand demonstrates a selectivity profile that is however, distinct from the non-equilibrium condition. The slow kinetics of the “dual” antagonists tested suggest that in vitro receptor occupancy may be longer lasting than would be predicted. This raises questions as to whether pharmacokinetic studies measuring plasma or brain levels of these antagonists are accurate reflections of receptor occupancy in vivo.

Identification of a novel series of orexin receptor antagonists with a distinct effect on sleep architecture for the treatment of insomnia

Dual orexin receptor (OXR) antagonists (DORAs) such as almorexant, 1 (SB-649868), or suvorexant have shown promise for the treatment of insomnias and sleep disorders in several recent clinical trials in volunteers and primary insomnia patients. The relative contribution of antagonism of OX1R and OX2R for sleep induction is still a matter of debate. We therefore initiated a drug discovery project with the aim of creating both OX2R selective antagonists and DORAs. Here we report that the OX2R selective antagonist 26 induced sleep in mice primarily by increasing NREM sleep, whereas the DORA suvorexant induced sleep largely by increasing REM sleep. Thus, OX2R selective antagonists may also be beneficial for the treatment of insomnia.

Bryophyllum pinnatum inhibits detrusor contractility in porcine bladder strips--a pharmacological study towards a new treatment option of overactive bladder

AIMS

A broad spectrum of synthetic agents is available for the treatment of overactive bladder. Anti-cholinergic drugs show a poor compliance due to side effects. There is an increasing use of plant extracts in medicine. We have therefore investigated the inhibitory effects of leaf press juice from Bryophyllum pinnatum (Lam.) Oken (Kalanchoe pinnata L.) on bladder strips and compared the effects to that of oxybutynin.

METHODS

Strips of porcine detrusor were prepared in Krebs solution and contractility was measured in a myograph system chamber aired with O₂/CO₂ at 37 °C. To induce contractions, electrical field stimulation (32 Hz, 40 V) was used for the inhibitory effect measurements, and carbachol (50 μM) for the relaxant effect measurements. Recordings were obtained in the absence and presence of increasing concentrations of Bryophyllum pinnatum leaf press juice (BPJ, 0.1-10%), and oxybutynin (10⁻⁷-10⁻³ M) as a reference substance.

RESULTS

In inhibition experiments, BPJ as well as oxybutynin inhibited electrically induced contractions of porcine detrusor. BPJ at concentrations of 5% inhibited the contraction compared to a time matched control significantly by 74.6±10.2% (p<0.001). BPJ as well as oxybutynin relaxed carbachol pre-contracted porcine detrusor strips. The maximum relaxant effect of BPJ compared to a time matched control was 18.7±3.7 (p<0.05) at a concentration of 10% BPJ.

CONCLUSIONS

Our investigations show that BPJ inhibits contractions induced by electrical field stimulation and relaxes carbachol-induced contractions. However, the effect was lower than that of the reference substance oxybutynin. It is important to continue in vitro experiments as well as clinical studies with BPJ that might offer a new treatment option for patients with OAB.

[Gynecology: urinary incontinence - mini-review and case reports]

Although urinary incontinence affects one in three women, it is still a taboo topic. Today, effective conservative and surgical treatment options are available. When conservative therapies fail, minimally invasive surgical methods can be offered. The tension-free vaginal tape TVT is gold standard in the treatment of female stress urinary incontinence. In case of immobile urethra or in multi-morbid patients, the minimally invasive technique of periurethral injection of bulking agents may be useful. In patients with refractory overactive bladder, the intravesical injection of botulinum neurotoxin is available.

Huntingtin cleavage product A forms in neurons and is reduced by gamma-secretase inhibitors

Background

The mutation in Huntington's disease is a polyglutamine expansion near the N-terminus of huntingtin. Huntingtin expressed in immortalized neurons is cleaved near the N-terminus to form N-terminal polypeptides known as cleavage products A and B (cpA and cpB). CpA and cpB with polyglutamine expansion form inclusions in the nucleus and cytoplasm, respectively. The formation of cpA and cpB in primary neurons has not been established and the proteases involved in the formation of these fragments are unknown.

Results

Delivery of htt cDNA into the mouse striatum using adeno-associated virus or into primary cortical neurons using lentivirus generated cpA and cpB, indicating that neurons in brain and in vitro can form these fragments. A screen of small molecule protease inhibitors introduced to clonal striatal X57 cells and HeLa cells identified compounds that reduced levels of cpA and are inhibitors of the aspartyl proteases cathepsin D and cathepsin E. The most effective compound, P1-N031, is a transition state mimetic for aspartyl proteases. By western blot analysis, cathepsin D was easily detected in clonal striatal X57 cells, mouse brain and primary neurons, whereas cathepsin E was only detectible in clonal striatal X57 cells. In primary neurons, levels of cleavage product A were not changed by the same compounds that were effective in clonal striatal cells or by mRNA silencing to partially reduce levels of cathepsin D. Instead, treating primary neurons with compounds that are known to inhibit gamma secretase activity either indirectly (Imatinib mesylate, Gleevec) or selectively (LY-411,575 or DAPT) reduced levels of cpA. LY-411,575 or DAPT also increased survival of primary neurons expressing endogenous full-length mutant huntingtin.

Conclusion

We show that cpA and cpB are produced from a larger huntingtin fragment in vivo in mouse brain and in primary neuron cultures. The aspartyl protease involved in forming cpA has cathepsin-D like properties in immortalized neurons and gamma secretase-like properties in primary neurons, suggesting that cell type may be a critical factor that specifies the aspartyl protease responsible for cpA. Since gamma secretase inhibitors were also protective in primary neurons, further study of the role of gamma-secretase activity in HD neurons is justified.

The mTOR kinase inhibitor Everolimus decreases S6 kinase phosphorylation but fails to reduce mutant huntingtin levels in brain and is not neuroprotective in the R6/2 mouse model of Huntington's disease

Background

Huntington's disease (HD) is a progressive neurodegenerative disorder caused by a CAG repeat expansion within the huntingtin gene. Mutant huntingtin protein misfolds and accumulates within neurons where it mediates its toxic effects. Promoting mutant huntingtin clearance by activating macroautophagy is one approach for treating Huntington's disease (HD). In this study, we evaluated the mTOR kinase inhibitor and macroautophagy promoting drug everolimus in the R6/2 mouse model of HD.

Results

Everolimus decreased phosphorylation of the mTOR target protein S6 kinase indicating brain penetration. However, everolimus did not activate brain macroautophagy as measured by LC3B Western blot analysis. Everolimus protected against early declines in motor performance; however, we found no evidence for neuroprotection as determined by brain pathology. In muscle but not brain, everolimus significantly decreased soluble mutant huntingtin levels.

Conclusions

Our data suggests that beneficial behavioral effects of everolimus in R6/2 mice result primarily from effects on muscle. Even though everolimus significantly modulated its target brain S6 kinase, this did not decrease mutant huntingtin levels or provide neuroprotection.

Novel scaffold for cathepsin K inhibitors

Pyrrolopyrimidine, a novel scaffold, allows to adjust interactions within the S3 subsite of cathepsin K. The core intermediate 10 facilitated the P3 optimization and identified highly potent and selective cathepsin K inhibitors 11-20.

[Primary malignant melanoma of the vagina--case report and review of the literature]

The primary malignant melanoma of the vagina is a very rare tumor with less than 300 cases reported worldwide. Metastatic melanomas of the vagina are even rarer and only 5 cases have been reported so far. We describe the case of patient with a melanoma of the left side of the vagina with a tumor size of 6 cm and a tumor invasion of 2.5 cm. At the time of diagnosis there were no signs of nodal metastases in the positron emission tomography. In the literature, wide local excision with adjuvant radiotherapy is recommended, and radical surgery with adjuvant radiotherapy as second-line therapy. Both procedures show similar 5-year survival rates. To reduce the risk of metastases, we had planned an immunotherapy with interferon-alpha, which has been shown to improve relapse-free and overall survival in patients with high-risk cutaneous melanoma. Unfortunately, the cancer was found to have heavily metastasized 6 months later; the patient therefore received a palliative chemotherapy with dacarbazine and thalidomide.

2-Cyano-pyrimidines: A New Chemotype for Inhibitors of the Cysteine Protease Cathepsin K

Starting from the purine lead structure 1, a new series of cathepsin K inhibitors based on a pyrimidine scaffold have been explored. Investigations of P3 and P2 substituents based on molecular modeling suggestions resulted in potent cathepsin K inhibitors with an improved selectivity profile over other cathepsins.

Structure-Based Design and Synthesis of Macroheterocyclic Peptidomimetic Inhibitors of the Aspartic Protease β-Site Amyloid Precursor Protein Cleaving Enzyme (BACE)

Based on the X-ray cocrystal structure of the Tang-Ghosh heptapeptide inhibitor 1 (OM00-3), a series of macroheterocyclic analogues were designed and synthesized. Analogues containing dithia, dioxa, oxathia, and carbathia macrocycles were synthesized by methods relying on ring-closing olefin metathesis for the dioxa analogues and by alkylation of thiolates or bisthiolates for the others. Molecular modeling suggested that the incorporation of piperidine units appended to the macrocycles improved interactions through additional H-bonds and introduced further rigidity. These were synthesized in enantiomerically pure form using enzyme-catalyzed desymmetrization and diastereomer separation. Inhibitory activity on beta-site amyloid precursor protein cleaving enzyme (BACE) was observed with several macroheterocyclic inhibitors and structure-activity relationship (SAR) correlations were deduced. Cocrystal structures of two synthetic analogues revealed interesting and unexpected binding interactions.

Dipeptide nitrile inhibitors of cathepsin K

A series of dipeptidyl nitriles as inhibitors of cathepsin K have been explored starting from lead structure 1 (Cbz-Leu-NH-CH2-CN, IC50 = 39 nM). Attachment of non-natural amino acid side chains in P1 and modification of the P3 subunit led to inhibitors with higher potency and improved pharmacokinetic properties.

Structure-based design, synthesis, and memapsin 2 (BACE) inhibitory activity of carbocyclic and heterocyclic peptidomimetics

Molecular modeling based on the X-ray crystal structure of the Tang-Ghosh heptapeptide inhibitor 1 (OM99-2) of BACE led to the design and synthesis of a series of constrained P(1)' analogues. A cyclopentane ring was incorporated in 1 spanning the P(1)' Ala methyl group and the adjacent methylene carbon atom of the chain. Progressive truncation at the P(2)'-P(4)' sites led to a potent truncated analogue 5 with good selectivity over Cathepsin D. Using the same backbone replacement concept, a series of cyclopentane, cyclopentanone, tetrahydrofuran, pyrrolidine, and pyrrolidinone analogues were synthesized with considerable variation at the P and P' sites. The cyclopentanone and 2-pyrrolidinone analogues 45 and 57 showed low nM BACE inhibition. X-ray cocrystal structures of two analogues 5 and 45 revealed excellent convergence with the original inhibitor 1 structure while providing new insights into other interactions which could be exploited for future modifications.

Structure-Based Design, Synthesis, and Memapsin 2 (BACE) Inhibitory Activity of Carbocyclic and Heterocyclic Peptidomimetics

Molecular modeling based on the X-ray crystal structure of the Tang-Ghosh heptapeptide inhibitor 1 (OM99-2) of BACE led to the design and synthesis of a series of constrained P(1)' analogues. A cyclopentane ring was incorporated in 1 spanning the P(1)' Ala methyl group and the adjacent methylene carbon atom of the chain. Progressive truncation at the P(2)'-P(4)' sites led to a potent truncated analogue 5 with good selectivity over Cathepsin D. Using the same backbone replacement concept, a series of cyclopentane, cyclopentanone, tetrahydrofuran, pyrrolidine, and pyrrolidinone analogues were synthesized with considerable variation at the P and P' sites. The cyclopentanone and 2-pyrrolidinone analogues 45 and 57 showed low nM BACE inhibition. X-ray cocrystal structures of two analogues 5 and 45 revealed excellent convergence with the original inhibitor 1 structure while providing new insights into other interactions which could be exploited for future modifications.