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Age-related cardiovascular diseases continue to be important issues that contribute to the societal burden. Unveiling the molecular mechanisms underlying age-related cardiovascular diseases provides novel opportunities to delay aging and facilitate early disease diagnosis and treatment. This study utilized knockout mice lacking melatonin receptors type 1A (MT1) and 1B (MT2). Ultrasonography, pathological staining, and transcriptomics were used to investigate the role of MT1/2 in the hearts of aging mice. Knockout of both receptors decreased ejection fraction and exacerbated fibrosis, inflammation, oxidative stress, and apoptosis levels in aging mice. Our findings indicated that the cardiac function of MT1 knockout mice was more severely affected than that of MT2 knockout mice. Additionally, we observed that intraperitoneal administration of melatonin (20 mg/kg/day for 90 days) ameliorated abnormal cardiac function in aging mice. However, the absence of MT1/2 resulted in the inability of melatonin to improve cardiac function. Our study, utilizing an aging polymerase chain reaction assay and cell experiments, revealed that melatonin receptors potentially influence cardiac function in aging mice through their effects on leukocyte differentiation antigen 14 (CD14) expression. Consequently, melatonin receptors, particularly MT1, are key contributors to cardiac aging, and therapeutic interventions targeting this receptor are promising for delaying the progression of cardiac aging.

Introduction: Leukocyte infiltration is an early event during cardiac remodeling frequently leading to heart failure (HF). Integrins mediate leukocyte infiltration during inflammation. However, the importance of specific integrins in hypertensive cardiac remodeling is still unclear. Objectives: To elucidate the significance of CD11b in hypertensive cardiac remodeling. Methods: Angiotensin (Ang II) or deoxycorticosterone acetate (DOCA)-salt was used to induce cardiac remodeling in mice of gene knockout (KO), bone marrow (BM) chimera, and the CD11b neutralizing antibody or agonist leukadherin-1 (LA1) treatment. Results: Our microarray data showed that integrin subunits Itgam (CD11b) and Itgb2 (CD18) were the most highly upregulated in Ang II-infused hearts. CD11b expression and CD11b/CD18+ myelomonocytes were also time-dependently increased. KO or pharmacological blockade of CD11b greatly attenuated cardiac remodeling and macrophage infiltration and M1 polarization induced by Ang II or DOCA-salt. This protection was verified in wild-type mice transplanted with CD11b-deficient BM cells. Conversely, administration of CD11b agonist LA1 showed the opposite effects. Further, CD11b KO reduced Ang II-induced macrophage adhesion and M1 polarization, leading to reduction of cardiomyocyte enlargement and fibroblast differentiation in vitro. The numbers of CD14+CD11b+CD18+ monocytes and CD15+CD11b+CD18+ granulocytes were obviously higher in HF patients than in normal controls. Conclusion: Our data demonstrate an important role of CD11b+ myeloid cells in hypertensive cardiac remodeling, and suggest that HF may benefit from targeting CD11b.

Cardiac remodeling is an important mechanism of heart failure, which frequently results from leukocyte infiltration. Vascular cellular adhesion molecule-1 (VCAM-1) plays a critical role in leukocyte adhesion and transmigration. However, the importance of VCAM-1 in the development of angiotensin II (Ang II)-induced cardiac remodeling remains unclear. Wild-type (WT) mice were infused with Ang II (1,000 ng/kg/min) for 14 days and simultaneously treated with VCAM-1 neutralizing antibody (0.1 or 0.2 mg) or IgG control. Systolic blood pressure (SBP) and cardiac function were detected by a tail-cuff and echocardiography. Cardiac remodeling was evaluated by histological staining. Adhesion and migration of bone marrow macrophages (BMMs) were evaluated in vitro. Our results indicated that VCAM-1 levels were increased in the serum of patients with heart failure (HF) and the hearts of Ang II-infused mice. Furthermore, Ang II-caused hypertension, cardiac dysfunction, hypertrophy, fibrosis, infiltration of VLA-4+ BMMs and oxidative stress were dose-dependently attenuated in mice administered VCAM-1 neutralizing antibody. In addition, blocking VCAM-1 markedly alleviated Ang II-induced BMMs adhesion and migration, therefore inhibited cardiomyocyte hypertrophy and fibroblast activation. In conclusion, the data reveal that blocking VCAM-1 ameliorates hypertensive cardiac remodeling by impeding VLA-4+ macrophage infiltration. Selective blockage of VCAM-1 may be a novel therapeutic strategy for hypertensive cardiac diseases.

Inflammation plays an important role in hypertensive retinal vascular injury and subsequent retinopathy. Monocyte chemotaxis via CXCL1-CXCR2 binding has been implicated in various cardiovascular diseases, but the function of CXCL1-CXCR2 signalling involved in retinopathy, which was investigated as angiotensin II (Ang II)-induced retinopathy, is unclear. In our study, we established a hypertensive retinopathy (HR) model by Ang II infusion (3000 ng/min/kg) for 3 weeks. To determine the involvement of CXCR2 signalling, we used CXCR2 knockout (KO) mice or C57BL/6J wild-type (WT) mice as experimental subjects. The mice were treated with a CXCL1 neutralizing antibody or SB225002 (the specific CXCR2 inhibitor). Our results showed that after Ang II treatment, the mRNA levels of CXCL1 and CXCR2 and the number of CXCR2+ inflammatory cells were significantly elevated. Conversely, unlike in the IgG control group, the CXCL1 neutralizing antibody greatly reduced the increase in central retinal thickness induced by Ang II infusion, arteriolar remodelling, superoxide production, and retinal dysfunction in WT mice. Furthermore, Ang II infusion induced arteriolar remodelling, infiltration of Iba1+ macrophages, the production of oxidative stress, and retinal dysfunction, but the symptoms were ameliorated in CXCR2 KO mice and SB225002-treated mice. These protective effects were related to the reduction in the number of CXCR2+ immune cells, particularly macrophages, and the decrease in proinflammatory cytokine (IL-1β, IL-6, TNF-ɑ, and MCP-1) expression in Ang II-treated retinas. Notably, serum CXCL1 levels and the number of CXCR2+ monocytes/neutrophils were higher in HR patients than in healthy controls. In conclusion, this study provides new evidence that the CXCL1-CXCR2 axis plays a vital role in the pathogenesis of hypertensive retinopathy, and selective blockade of CXCL1-CXCR2 activation may be a potential treatment for HR.

Adhesion of monocytes to the vascular endothelium frequently leads to an inflammatory response, which contributes to hypertension and vascular remodeling. Vascular cellular adhesion molecule-1 (VCAM-1) plays an important role in leukocyte adhesion and migration during inflammatory diseases. However, its role in angiotensin (Ang) II -induced hypertension and vascular dysfunction remains largely unknown. Wild-type (WT) mice were administered a VCAM-1 neutralizing antibody (0.1 or 0.2 mg/mouse/day) or IgG control and then infused with Ang II (490 ng kg−1 min−1) or saline continuously for 14 days. Systolic blood pressure (SBP) was measured with a tail-cuff system, pathological changes in the aorta were assessed by histological staining, and vascular relaxation was analyzed an aortic ring assay. Our results indicated that compared with saline infusion, Ang II infusion significantly upregulated VCAM-1 expression in the mouse aorta and serum. Moreover, Ang II infusion markedly increased arterial hypertension, wall thickness, fibrosis, infiltration of Mac-2+ macrophages, reactive oxygen species (ROS) production and vascular relaxation dysfunction. Conversely, blockade of VCAM-1 with a neutralizing antibody substantially alleviated these effects. In vitro experiments further confirmed that the VCAM-1 neutralizing antibody inhibited Ang II-induced macrophage adhesion and migration and DNA damage and oxidative stress in endothelial cells (ECs). In conclusion, these results indicate that blockade of VCAM-1 exerts a protective effect against Ang II-induced arterial hypertension and dysfunction by regulating monocytes adhesion and infiltration into the endothelium and represents a novel therapeutic approach for hypertension.

Diets rich in polyphenols are known to be beneficial for cardiovascular health. Gallic acid (GA) is a plant-derived triphenolic chemical with multiple cardio-protective properties, such as antiobesity, anti-inflammation, and antioxidation. However, whether GA could protect against atherosclerotic cardiovascular diseases is still not defined. Here, we investigated the effects of low-dose GA administration on diet-induced metabolic disorders and atherosclerosis in the atherosclerosis-prone apolipoprotein E (Apoe) knockout mice fed on a high-fat Western-type diet (WTD) for 8 weeks. Our data showed that GA administration by oral gavage at a daily dosage of 20 mg/kg body weight did not significantly ameliorate WTD-induced hyperlipidemia, hepatosteatosis, adipogenesis, or insulin resistance; furthermore, GA administration did not significantly ameliorate WTD-induced atherosclerosis. In conclusion, our data demonstrate that low-dose GA administration does not elicit significant health effect on diet-induced metabolic disorders or atherosclerosis in the Apoe knockout mice. Whether GA could be beneficial for atherosclerotic cardiovascular diseases therefore needs further exploration.

Abstract Prolonged pressure overload triggers cardiac hypertrophy and frequently leads to heart failure (HF). Vascular endothelial growth factor‐C (VEGF‐C) and its receptor VEGFR‐3 are components of the central pathway for lymphatic vessel growth (also known as lymphangiogenesis), which has crucial functions in the maintenance of tissue fluid balance and myocardial function after ischemic injury. However, the roles of this pathway in the development of cardiac hypertrophy and dysfunction during pressure overload remain largely unknown. Eight‐ to 10‐week‐old male wild‐type (WT) mice, VEGFR‐3 knockdown (VEGFR‐3f/−) mice, and their WT littermates (VEGFR‐3f/f) were subjected to pressure overload induced by transverse aortic constriction (TAC) for 1–6 weeks. We found that cardiac lymphangiogenesis and the protein expression of VEGF‐C and VEGFR‐3 were upregulated in the early stage of cardiac hypertrophy but were markedly reduced in failing hearts. Moreover, TAC for 6 weeks significantly reduced cardiac lymphangiogenesis by inhibiting activation of VEGFR‐3‐mediated signals (AKT/ERK1/2, calcineurin A/NFATc1/FOXc2, and CX43), leading to increased cardiac edema, hypertrophy, fibrosis, apoptosis, inflammation, and dysfunction. These effects were further aggravated in VEGFR‐3f/− mice and were dose‐dependently attenuated by delivery of recombinant VEGF‐C156S in WT mice. VEGF‐C156s administration also reversed pre‐established cardiac dysfunction induced by sustained pressure overload. Thus, these results demonstrate, for the first time, that activation of the VEGF‐C‐VEGFR‐3 axis exerts a protective effect during the transition from cardiac hypertrophy to HF and highlight selective stimulation of cardiac lymphangiogenesis as a potential new therapeutic approach for hypertrophic heart diseases.

Pressure overload-induced hypertrophic remodeling is a critical pathological process leading to heart failure (HF). Suppressor of cytokine signaling-3 (SOCS3) has been demonstrated to protect against cardiac hypertrophy and dysfunction, but its mechanisms are largely unknown. Using primary cardiomyocytes and cardiac-specific SOCS3 knockout (SOCS3cko) or overexpression mice, we demonstrated that modulation of SOCS3 level influenced cardiomyocyte hypertrophy, apoptosis and cardiac dysfunction induced by hypertrophic stimuli. We found that glucose regulatory protein 78 (GRP78) was a direct target of SOCS3, and that overexpression of SOCS3 inhibited cardiomyocyte hypertrophy and apoptosis through promoting proteasomal degradation of GRP78, thereby inhibiting activation of endoplasmic reticulum (ER) stress and mitophagy in the heart. Thus, our results uncover SOCS3-GRP78-mediated ER stress as a novel mechanism in the transition from cardiac hypertrophy to HF induced by sustained pressure overload, and suggest that modulating this pathway may provide a new therapeutic approach for hypertrophic heart diseases.

Macrophage polarization and inflammation are key factors for the onset and progression of atherosclerosis. The immunoproteasome complex consists of three inducible catalytic subunits (LMP2, LMP10, and LMP7) that play a critical role in the regulation of these risk factors. We recently demonstrated that the LMP7 subunit promotes diet-induced atherosclerosis via inhibition of MERTK-mediated efferocytosis. Here, we explored the role of another subunit of LMP10 in the disease process, using ApoE knockout (ko) mice fed on an atherogenic diet (ATD) containing 0.5% cholesterol and 20% fat for 8 weeks as an in vivo atherosclerosis model. We observed that ATD significantly upregulated LMP10 expression in aortic lesions, which were primarily co-localized with plaque macrophages. Conversely, deletion of LMP10 markedly attenuated atherosclerotic lesion area, CD68+ macrophage accumulation, and necrotic core expansion in the plaques, but did not change plasma metabolic parameters, lesional SM22α+ smooth muscle cells, or collagen content. Myeloid-specific deletion of LMP10 by bone marrow transplantation resulted in similar phenotypes. Furthermore, deletion of LMP10 remarkably reduced aortic macrophage infiltration and increased M2/M1 ratio, accompanied by decreased expression of pro-inflammatory M1 cytokines (MCP-1, IL-1, and IL-6) and increased expression of anti-inflammatory M2 cytokines (IL-4 and IL-10). In addition, we confirmed in cultured macrophages that LMP10 deletion blunted macrophage polarization and inflammation during ox-LDL-induced foam cell formation in vitro, which was associated with decreased IκBα degradation and NF-κB activation. Our results show that the immunoproteasome subunit LMP10 promoted diet-induced atherosclerosis in ApoE ko mice possibly through regulation of NF-κB-mediated macrophage polarization and inflammation. Targeting LMP10 may represent a new therapeutic approach for atherosclerosis.

Background/AimThe proliferation and migration of lymphatic endothelial cells (LECs) is essential for lymphatic vessel growth (also known as lymphangiogenesis), which plays a crucial role in regulating the tissue fluid balance and immune cell trafficking under physiological and pathological conditions. Several growth factors, such as VEGF-C, can stimulate lymphangiogenesis. However, the effects of angiotensin II (Ang II) on the proliferation and migration of mouse LECs and the underlying potential mechanisms remain unknown.MethodsWild-type mice were infused with Ang II (1,000 ng/kg/min) for 1–2 weeks. Murine LECs were stimulated with Ang II (500 nM) or saline for 12–48 h. Cell proliferation was determined with 5-bromo-2-deoxyuridine (BrdU) incorporation assays, while cell migration was assessed by scratch wound healing and transwell chamber assays. The gene expression profiles were obtained by time series microarray and real-time PCR analyses.ResultsAng II treatment significantly induced lymphangiogenesis in the hearts of mice and the proliferation and migration of cultured LECs in a time-dependent manner. This effect was completely blocked by losartan, an angiotensin II type 1 receptor (AT1R) antagonist. The microarray results identified 1,385 differentially expressed genes (DEGs) at one or more time points in the Ang II-treated cells compared with the control saline-treated cells. These DEGs were primarily involved in biological processes and pathways, including sensory perception of smell, the G protein coupled receptor signaling pathway, cell adhesion, olfactory transduction, Jak-STAT, alcoholism, RIG-I-like receptor and ECM-receptor interaction. Furthermore, these DEGs were classified into 16 clusters, 7 of which (Nos. 13, 2, 8, 15, 7, 3, and 12, containing 586 genes) were statistically significant. Importantly, the Ang II-induced alterations the expression of lymphangiogenesis-related genes were reversed by losartan.ConclusionThe results of the present indicate that Ang II can directly regulate the proliferation and migration of LECs through AT1R in vivo and in vitro, which may provide new potential treatments for Ang II-induced hypertension and cardiac remodeling.

Sustained cardiac hypertrophy is a major cause of heart failure (HF) and death. Recent studies have demonstrated that resveratrol (RES) exerts a protective role in hypertrophic diseases. However, the molecular mechanisms involved are not fully elucidated. In this study, cardiac hypertrophic remodeling in mice were established by pressure overload induced by transverse aortic constriction (TAC). Cardiac function was evaluated by echocardiography and invasive pressure-volume analysis. Cardiomyocyte size was detected by wheat germ agglutinin staining. The protein and gene expressions of signaling mediators and hypertrophic markers were examined. Our results showed that administration of RES significantly suppressed pressure overload-induced cardiac hypertrophy, fibrosis and apoptosis and improved in vivo heart function in mice. RES also reversed pre-established hypertrophy and restoring contractile dysfunction induced by chronic pressure overload. Moreover, RES treatment blocked TAC-induced increase of immunoproteasome activity and catalytic subunit expression (β1i, β2i and β5i), which inhibited PTEN degradation thereby leading to inactivation of AKT/mTOR and activation of AMPK signals. Further, blocking PTEN by the specific inhibitor VO-Ohpic significantly attenuated RES inhibitory effect on cardiomyocyte hypertrophy in vivo and in vitro. Taken together, our data suggest that RES is a novel inhibitor of immunoproteasome activity, and may represent a promising therapeutic agent for the treatment of hypertrophic diseases. Keywords: Resveratrol, Cardiac hypertrophy, Immunoproteasome, PTEN degradation, AKT/mTOR, AMPK

Background/Aims: Angiotensin II (Ang II)-mediated hypertension is a major risk factor for cardiovascular diseases. Ang II induces changes in vessel structure and function through the activation of genes related to signaling pathways. However, the changes in the gene expression profiles of blood vessels in response to Ang II remain unclear. Methods: Wild-type C57BL/6 mice were infused with Ang II (1500 ng/kg/min) using an osmotic pump for 1, 3, and 7 days. Vascular wall inflammation and remodeling were evaluated by pathological examination. Time-series microarray and quantitative PCR analyses were performed. Bioinformatics analyses were conducted to identify key genes, pathways, and biological processes. Results: After Ang II infusion, blood pressure and aortic remodeling were increased over time. Microarray analysis identified a totally of 3631 differentially expressed genes in aortas at days 1, 3, and 7 of Ang II infusion. These genes were involved in multiple biological processes, including cell adhesion, angiogenesis, cell migration, protein phosphorylation, immune system, and cell cycle, which may play important roles in regulating Ang II-induced arterial injury during hypertension. The genes were classified into 50 profiles by hierarchical cluster analysis, and finally, 14 significant profiles were identified. Among these genes, protein kinase cAMP-activated catalytic subunit alpha (Prkaca), a gene that directly regulated 137 neighboring genes, was located at the center of the gene network in Ang II-infused aortas. Further, Prkaca protein expression and cAMP level were downregulated in a time-dependent manner in Ang II-infused aortas. Conclusions: The combined use of DNA microarrays and cluster and gene network analyses identified Prkaca as a key Ang II-responsive gene that may mediate early vascular injury and hypertension.

Inflammation has been implicated in a variety of retinal diseases. The immunoproteasome plays a critical role in controlling inflammatory responses, but whether activation of immunoproteasome contributes to angiotensin II (Ang II)-induced retinopathy remains unclear. Hypertensive retinopathy (HR) was induced by infusion of Ang II (3000 ng/kg/min) in wild-type (WT) and immunoproteasome subunit LMP10 knockout (KO) mice for 3 weeks. Changes in retinal morphology, vascular permeability, superoxide production and inflammation were examined by pathological staining. Our results showed that immunoproteasome subunit LMP10 expression and its trypsin-like activity were significantly upregulated in the retinas and serum of Ang II-infused mice and in the serum from patients with hypertensive retinopathy. Moreover, Ang II-infused WT mice showed an increase in the central retinal thickness, vascular permeability, reactive oxygen species (ROS) production and inflammation compared with saline controls, and these effects were significantly attenuated in LMP10 KO mice, but were aggravated in mice intravitreally injected with rAAV2-LMP10. Interestingly, administration of IKKβ specific inhibitor IMD-0354 remarkably blocked an Ang II-induced increase in vascular permeability, oxidative stress and inflammation during retinopathy. Mechanistically, Ang II-induced upregulation of LMP10 promoted PTEN degradation and activation of AKT/IKK signaling, which induced IkBα phosphorylation and subsequent degradation ultimately leading to activation of NF-kB target genes in retinopathy. Therefore, this study provided novel evidence demonstrating that LMP10 is a positive regulator of NF-kB signaling, which contributes to Ang II-induced retinopathy. Strategies for inhibiting LMP10 or IKKβ activity in the eye could serve as a novel therapeutic target for treating hypertensive retinopathy. Keywords: Angiotensin II, Retinopathy, Immunoproteasome LMP10, Vascular permeability, Oxidative stress, Inflammation

In the structure of the title complex, (C7H7N2S)2[Cd(C8H8O5)2]·6H2O, the CdII atom is located on an inversion center and is O,O′,O′′-chelated by two symmetry-related 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate ligands in a distorted octahedral geometry. The 2-aminobenzothiazolium cation links with the Cd complex anion via N—H...O hydrogen bonding. Extensive O—H...O and N—H...O hydrogen bonds involving lattice water molecules occur in the crystal structure.

In the title hydrated molecular salt, (C7H7N2S)2[Zn(C8H8O5)2]·6H2O, which is isotypic with its MnII, CoII and NiII analogues, the Zn2+ ion lies on a crystallographic inversion centre and a distorted ZnO6 octahedral coordination geometry arises from the two doubly deprotonated O,O′,O′′-tridentate ligands. In the crystal, the components are linked by N—H...Oa, N—H...Ow, Ow—H...Oa and Ow—H...Ow hydrogen bonds (w = water and a = anion).

The polymeric title complex, [Co(C8H8O5)(H2O)2]n was synthesized by reaction of cobalt acetate with 7-oxabicyclo[2,2,1]heptane-2,3-dicarboxylic anhydride. The CoII ion is six-coordinated in a distorted octahedral environment, binding to two water O atoms, to the ether O atom of the bicycloheptane unit, to two carboxylate O atoms from two different carboxylate groups of the same anion and to one carboxylate O atom from a symmetry-related anion. The bridging character of the dianion leads to the formation of ribbons along [001]. The ribbons are linked into a layered network parallel to (010) by several O—H...O hydrogen-bonding interactions involving the coordinating water molecules as donors and the carboxylate O atoms of neighbouring ribbons as acceptors. The crystal under investigation was an inversion twin.

In the title compound, C16H16N2O6, the dihedral angle between the two pyrrolidine rings is 79.38 (14)°.

The title compound, {[Cd(C8H8O5)(C10H8N2)]·H2O}n, was obtained by the reaction of cadmium acetate with 2,2′-bipyridine and 7-oxabicyclo(2.2.1)heptane-2,3-dicarboxylic anhydride. The CdII atom is seven-coordinated in a distorted pentagonal–bipyramidal configuration, defined by five O atoms from the carboxylate groups of three 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylato ligands and two N atoms from the 2,2′-bipyridine ligand. Two O atoms link two CdII atoms, forming a dinuclear center: the Cd—O—Cd bridging angle is 110.19 (6)°. The polymeric structure extends along [100] and is linked by intermolecular O—H...O hydrogen bonds involving the solvent water molecule. Extensive π–π stacking exists between 2,2-bypiridine ligands along [010] with centroid-centroid distance of 3.650 (2) Å

In the title compound, C16H15N3O3, the dihedral angle between the approximately planar benzimidazolyl group (r.m.s. deviation = 0.010 Å) and the pyrrolidine ring is 78.20 (6)°. The C—C—N bond angle of the bridging CH2 group is 112.14 (16)°. In the crystal, molecules are linked via N—H...N hydrogen bonds, forming infinite chains parallel to [101] and [10overline{1}].

The title complex, [Co(C8H8O5)(H2O)3]·H2O, was synthesized by reaction of cobalt acetate with 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride (norcantharidin) in aqueous solution. In the molecule, the CoII atom is six-coordinated in a distorted octahedral environment, binding to the bridging O atom of the bicycloheptane unit, to two O atoms from monodentate carboxylate groups and to three water O atoms. The crystal structure is stabilized by several O—H...O hydrogen-bonding interactions involving both the coordinated and uncoordinated water molecules as donors and the carboxylate O atoms of neighbouring molecules as acceptors.

In the crystal structure of the title complex, [Cd(C8H8O5)(C3H4N2S)3]·2H2O, the CdII atom exhibits a slightly distorted octahedral CdO3N3 coordination, defined by the bridging O atom of the bicycloheptane unit, two O atoms from the carboxylate groups and by three N atoms from three 2-aminothiazole ligands. Uncoordinated lattice water molecules are also present in the crystal structure. N—H...O and O—H...O hydrogen-bonding interactions link the components into a three-dimensional structure.

In the crystal structure of the title salt, (C7H7N2S)2[Mn(C8H8O5)2]·6H2O, the heterocyclic N atom of the 2-aminobenzothiazole molecule is protonated. The MnII atom (site symmetry overline{1}) has a slightly distorted octahedral MnO6 coordination defined by the bridging O atoms of the bicycloheptane unit and four carboxylate O atoms of two symmetry-related and fully deprotonated ligands. The crystal packing is stabilized by N—H...O hydrogen bonds between the cations and anions and by O—H...O hydrogen bonds including the crystal water molecules.

The title polymer, [Zn3(C8H8O5)2(C3H3N2)2(C3H4N2)2]n, was formed by the reaction of zinc acetate with imidazole and 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride (norcantharidine). One of the two crystallographically unique ZnII atoms is four-coordinated by three N atoms of three imidazole ligands, two of which are deprotonated, and by one carboxylate O atom of the demethylcantharate anion. The second ZnII atom is situated on an inversion centre and is six-coordinated by the bridging O atoms of two symmetry-related demethylcantharate anions and by four carboxylate O atoms of the corresponding carboxylate groups. The polymeric crystal structure is additionally stabilized by N—H...O hydrogen bonding between the imidazole ligands and carboxylate O atoms.

In the title polymer, [Mn(C8H8O5)(H2O)2]n, the MnII atom is in a distorted octahedral coordination mode, binding to the bridging O atom of the bicycloheptane unit, two O atoms from corresponding carboxylate groups, one carboxylate O atom from a symmetry-related bridging ligand and two water O atoms. This arrangement leads to the formation of polymeric chains propagating parallel to [001]. The crystal structure is stabilized by several O—H...O hydrogen-bonding interactions involving the coordinated water molecules as donors and the carboxylate O atoms as acceptors.

In the crystal structure of the title compound, [Co(C8H8O5)(C3H4N2)3]·3.35H2O, the central CoII ion is in a slightly distorted octahedral environment, coordinated by the bridging O atom from the bicyclo[2.2.1]heptane ligand, by two carboxylate O atoms from two different carboxylate groups and by three N atoms from imidazole ligands. Uncoordinated water molecules, some of them disordered, are present in the crystal structure. In the crystal structure, molecules are linked by O—H...O, N—H...O and O—H...N hydrogen-bonding interactions.

In the crystal structure of the title compound, [Ni(C8H8O5)(H2O)2]n, the NiII cation is in a Jahn–Teller-distorted octahedral coordination environment binding to two O atoms from water molecules, the bridging O atom of the bicycloheptane unit, two carboxylate O atoms from different carboxylate groups and one carboxylate O atom from a symmetry-related bridging ligand. The crystal structure is made up from layers propagating parallel to the bc plane.

The title compound, C8H10O5·C2H3N3S·H2O, was synthesized by the reaction of 2-amino-1,3,4-thiadiazole with norcantharidin. The crystal structure is stabilized by N—H...O, N—H...N, O—H...O and O—H...N hydrogen bonds. In addition, weak π–π interactions are observed between symmetry-related thiadiazole ring systems [centroid–centroid distance = 3.9110 (3) Å, interplanar spacing = 3.4845 Å].

In the crystal structure of the title compound {systematic name: diaquabis[1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylato]manganese(II) 2,2′-bipyridine solvate tetrahydrate}, [Mn(C17H17FN3O3)2(H2O)2]·C10H8N2·4H2O, the pyridone O and one carboxylate O atom of the two ciprofloxacin ligands are bound to the MnII ion and occupy the equatorial positions, while the two aqua O atoms lie in the apical positions resulting in a distorted octahedral geometry. The crystal packing is stabilized by N–H...O and O–H...O hydrogen bonding interactions.

The title compound, [Cd(C8H8O5)(C3H4N2)2]n, was synthesized by the reaction of 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride, cadmium acetate and imidazole. The CdII atom is seven-coordinated in a distorted pentagonal-bipyramidal configuration by five O atoms from carboxylate groups of three 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate ligands and two N atoms from two imidazole ligands. The crystal structure is stabilized by N—H...O and C—H...O hydrogen-bonding and C—H...π interactions.

The reaction of aniline with norcantharidin produced the imide title compound, C14H13NO3, which shows no significant hydrogen bonds in the crystal structure. The dihedral angle between the phenyl and pyrrolidine rings is 48.48 (6)°.