Placental growth factor (PlGF) is linked to inflammation and metabolic disorders in mice with diet-induced obesity

Metabolic liability for weight gain in early adulthood

While weight gain is associated with a host of chronic illnesses, efforts in obesity have relied on single "snapshots" of body mass index (BMI) to guide genetic and molecular discovery. Here, we study >2,000 young adults with metabolomics and proteomics to identify a metabolic liability to weight gain in early adulthood. Using longitudinal regression and penalized regression, we identify a metabolic signature for weight liability, associated with a 2.6% (2.0%-3.2%, p = 7.5 × 10-19) gain in BMI over ≈20 years per SD higher score, after comprehensive adjustment. Identified molecules specified mechanisms of weight gain, including hunger and appetite regulation, energy expenditure, gut microbial metabolism, and host interaction with external exposure. Integration of longitudinal and concurrent measures in regression with Mendelian randomization highlights the complexity of metabolic regulation of weight gain, suggesting caution in interpretation of epidemiologic or genetic effect estimates traditionally used in metabolic research.

Excessive endometrial PlGF- Rac1 signalling underlies endometrial cell stiffness linked to pre-eclampsia

Cell stiffness is regulated by dynamic interaction between ras-related C3 botulinum toxin substrate 1 (Rac1) and p21 protein-activated kinase 1 (PAK1) proteins, besides other biochemical and molecular regulators. In this study, we investigated how the Placental Growth Factor (PlGF) changes endometrial mechanics by modifying the actin cytoskeleton at the maternal interface. We explored the global effects of PlGF in endometrial stromal cells (EnSCs) using the concerted approach of proteomics, atomic force microscopy (AFM), and electrical impedance spectroscopy (EIS). Proteomic analysis shows PlGF upregulated RhoGTPases activating proteins and extracellular matrix organization-associated proteins in EnSCs. Rac1 and PAK1 transcript levels, activity, and actin polymerization were significantly increased with PlGF treatment. AFM further revealed an increase in cell stiffness with PlGF treatment. The additive effect of PlGF on actin polymerization was suppressed with siRNA-mediated inhibition of Rac1, PAK1, and WAVE2. Interestingly, the increase in cell stiffness by PlGF treatment was pharmacologically reversed with pravastatin, resulting in improved trophoblast cell invasion. Taken together, aberrant PlGF levels in the endometrium can contribute to an altered pre-pregnancy maternal microenvironment and offer a unifying explanation for the pathological changes observed in conditions such as pre-eclampsia (PE).

A comparison of rat models that best mimic immune-driven preeclampsia in humans

Preeclampsia (PE), a hypertensive pregnancy disorder, can originate from varied etiology. Placenta malperfusion has long been considered the primary cause of PE. However, we and others have showed that this disorder can also result from heightened inflammation at the maternal-fetal interface. To advance our understanding of this understudied PE subtype, it is important to establish validated rodent models to study the pathophysiology and test therapies. We evaluated three previously described approaches to induce inflammation-mediated PE-like features in pregnant rats: 1) Tumor necrosis factor-α (TNF-α) infusion via osmotic pump from gestational day (GD) 14-19 at 50ng/day/animal; 2) Polyinosinic:polycytidylic acid (Poly I:C) intraperitoneal (IP) injections from GD 10-18 (alternate days) at 10mg/kg/day/animal; and, 3) Lipopolysaccharide (LPS) IP injections from GD 13-18 at 20ug-70ug/kg/day per animal. Maternal blood pressure was measured by tail-cuff. Upon sacrifice, fetal and placenta weights were recorded. Placenta histomorphology was assessed using H&E sections. Placenta inflammation was determined by quantifying TNF-α levels and inflammatory gene expression. Placenta metabolic and mitochondrial health were determined by measuring mitochondrial respiration rates and placenta NAD+/NADH content. Of the three rodent models tested, we found that Poly I:C and LPS decreased both fetal weight and survival; and correlated with a reduction in region specific placenta growth. As the least effective model characterized, TNF-α treatment resulted in a subtle decrease in fetal/placenta weight and placenta mitochondrial respiration. Only the LPS model was able to induce maternal hypertension and exhibited pronounced placenta metabolic and mitochondrial dysfunction, common features of PE. Thus, the rat LPS model was most effective for recapitulating features observed in cases of human inflammatory PE. Future mechanistic and/or therapeutic intervention studies focuses on this distinct PE patient population may benefit from the employment of this rodent model of PE.

Alzheimer's Amyloid β Peptide Induces Angiogenesis in an Alzheimer's Disease Model Mouse through Placental Growth Factor and Angiopoietin 2 Expressions

Increased angiogenesis, especially the pathological type, has been documented in Alzheimer's disease (AD) brains, and it is considered to be activated due to a vascular dysfunction-mediated hypoxic condition. To understand the role of the amyloid β (Aβ) peptide in angiogenesis, we analyzed its effects on the brains of young APP transgenic AD model mice. Immunostaining results revealed that Aβ was mainly localized intracellularly, with very few immunopositive vessels, and there was no extracellular deposition at this age. Solanum tuberosum lectin staining demonstrated that compared to their wild-type littermates, the vessel number was only increased in the cortex of J20 mice. CD105 staining also showed an increased number of new vessels in the cortex, some of which were partially positive for collagen4. Real-time PCR results demonstrated that placental growth factor (PlGF) and angiopoietin 2 (AngII) mRNA were increased in both the cortex and hippocampus of J20 mice compared to their wild-type littermates. However, vascular endothelial growth factor (VEGF) mRNA did not change. Immunofluorescence staining confirmed the increased expression of PlGF and AngII in the cortex of the J20 mice. Neuronal cells were positive for PlGF and AngII. Treatment of a neural stem cell line (NMW7) with synthetic Aβ_1-42 directly increased the expression of PlGF and AngII, at mRNA levels, and AngII at protein levels. Thus, these pilot data indicate that pathological angiogenesis exists in AD brains due to the direct effects of early Aβ accumulation, suggesting that the Aβ peptide regulates angiogenesis through PlGF and AngII expression.

The neutrophil elastase-upregulated placenta growth factor promotes the pathogenesis and progression of periodontal disease

BACKGROUND

Periodontal disease is a chronic inflammatory disease. Given its high prevalence, especially in aging population, the detailed mechanisms about pathogenesis of periodontal disease are important issues for study. Neutrophil firstly infiltrates to periodontal disease-associated pathogen loci and amplifies the inflammatory response for host defense. However, excessive neutrophil-secreted neutrophil elastase (NE) damages the affected gingival. In lung and esophageal epithelium, NE had been proved to upregulate several growth factors including placenta growth factor (PGF). PGF is an angiogenic factor with proinflammatory properties, which mediates the progression of inflammatory disease. Therefore, we hypothesize excessive NE upregulates PGF and participates in the pathogenesis and progression of periodontal disease.

METHODS

In gingival epithelial cells (GEC), growth factors array demonstrated NE-increased growth factors and further be corroborated by Western blot assay and ELISA. The GEC inflammation was evaluated by ELISA. In mice, the immunohistochemistry results demonstrated ligature implantation-induced neutrophil infiltration and growth factor upregulation. By multiplex assay, the ligature-induced proinflammatory cytokines level in gingival crevicular fluid (GCF) were evaluated. Finally, alveolar bone absorption was analyzed by micro-CT images and H & E staining.

RESULTS

NE upregulated PGF expression and secretion in GEC. PGF promoted GEC to secret IL-1β, IL-6, and TNF-α in GCF In periodontal disease animal model, ligature implantation triggered NE infiltration and PGF expression. Blockade of PGF attenuated the ligature implantation-induced IL-1β, IL-6, TNF-α and MIP-2 secretion and ameliorated the alveolar bone loss in mice.

CONCLUSION

In conclusion, the NE-induced PGF triggers gingival epithelium inflammation and promotes the pathogenesis and progression of periodontal disease.

Genetics of PlGF plasma levels highlights a role of its receptors and supports the link between angiogenesis and immunity

Placental growth factor (PlGF) is a member of the vascular endothelial growth factor family and is involved in bone marrow-derived cell activation, endothelial stimulation and pathological angiogenesis. High levels of PlGF have been observed in several pathological conditions especially in cancer, cardiovascular, autoimmune and inflammatory diseases. Little is known about the genetics of circulating PlGF levels. Indeed, although the heritability of circulating PlGF levels is around 40%, no studies have assessed the relation between PlGF plasma levels and genetic variants at a genome-wide level. In the current study, PlGF plasma levels were measured in a population-based sample of 2085 adult individuals from three isolated populations of South Italy. A GWAS was performed in a discovery cohort (N = 1600), followed by a de novo replication (N = 468) from the same populations. The meta-analysis of the discovery and replication samples revealed one signal significantly associated with PlGF circulating levels. This signal was mapped to the PlGF co-receptor coding gene NRP1, indicating its important role in modulating the PlGF plasma levels. Two additional signals, at the PlGF receptor coding gene FLT1 and RAPGEF5 gene, were identified at a suggestive level. Pathway and TWAS analyses highlighted genes known to be involved in angiogenesis and immune response, supporting the link between these processes and PlGF regulation. Overall, these data improve our understanding of the genetic variation underlying circulating PlGF levels. This in turn could lead to new preventive and therapeutic strategies for a wide variety of PlGF-related pathologies.

Evaluation of the Effects of Intravitreal Aflibercept and Ranibizumab on Systemic Inflammatory and Cardiovascular Biomarkers in Patients with Neovascular Age-related Macular Degeneration

Purpose: To investigate the effects of intravitreal ranibizumab (IVR) and intravitreal aflibercept (IVA) on systemic inflammatory and cardiovascular biomarkers in treatment-naive patients with neovascular age-related macular degeneration (nAMD)Methods: This study included 24 eyes of 24 patients treated with 0.5 mg ranibizumab (IVR group) and 25 eyes of 25 patients treated with 2.0 mg aflibercept (IVA group). Complete blood count, C-reactive protein (CRP), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), uric acid (UA), albumin, fibrinogen levels were measured in blood samples before and after the three-monthly loading dose treatment. Neutrophil/lymphocyte ratio (NLR), monocyte/HDL-c ratio (MHR), CRP/albumin ratio (CAR), monocyte/lymphocyte ratio (MLR), platelet/lymphocyte ratio (PLR) were also calculated.Results: A statistically significant decline was determined in post-treatment CRP (P = .002), LDL-c (P < .001) levels, white blood cell (WBC, P = .001), neutrophil (P < .001), monocyte (P = .019) counts and NLR (P = .020), MHR (P = .042), CAR (P = .010) ratios comparing with pre-treatment values in the IVA group. No statistically significant change was found in any of the parameters evaluated in the study in the IVR group. Also, there was no significant change in fibrinogen, lymphocyte count, MLR, HDL-c, UA, PLR, and platelet count values in both groups.Conclusion: Compared to IVR, IVA treatment had a small but significant effect on systemic inflammatory and cardiovascular biomarkers.

Capillary Rarefaction in Obesity and Metabolic Diseases-Organ-Specificity and Possible Mechanisms

Obesity and its comorbidities like diabetes, hypertension and other cardiovascular disorders are the leading causes of death and disability worldwide. Metabolic diseases cause vascular dysfunction and loss of capillaries termed capillary rarefaction. Interestingly, obesity seems to affect capillary beds in an organ-specific manner, causing morphological and functional changes in some tissues but not in others. Accordingly, treatment strategies targeting capillary rarefaction result in distinct outcomes depending on the organ. In recent years, organ-specific vasculature and endothelial heterogeneity have been in the spotlight in the field of vascular biology since specialized vascular systems have been shown to contribute to organ function by secreting varying autocrine and paracrine factors and by providing niches for stem cells. This review summarizes the recent literature covering studies on organ-specific capillary rarefaction observed in obesity and metabolic diseases and explores the underlying mechanisms, with multiple modes of action proposed. It also provides a glimpse of the reported therapeutic perspectives targeting capillary rarefaction. Further studies should address the reasons for such organ-specificity of capillary rarefaction, investigate strategies for its prevention and reversibility and examine potential signaling pathways that can be exploited to target it.

Neurodevelopmental Outcomes of Prenatal Preeclampsia Exposure

Preeclampsia is a dangerous hypertensive disorder of pregnancy with known links to negative child health outcomes. Here, we review epidemiological and basic neuroscience work from the past several decades linking prenatal preeclampsia to altered neurodevelopment. This work demonstrates increased rates of neuropsychiatric disorders [e.g., increased autism spectrum disorder, attention deficit hyperactivity disorder (ADHD)] in children of preeclamptic pregnancies, as well as increased rates of cognitive impairments [e.g., decreased intelligence quotient (IQ), academic performance] and neurological disease (e.g., stroke and epilepsy). We also review findings from multiple animal models of preeclampsia. Manipulation of key clinical preeclampsia processes in these models (e.g., placental hypoxia, immune dysfunction, angiogenesis, oxidative stress) causes various disruptions in offspring, including ones in white matter/glia, glucocorticoid receptors, neuroimmune outcomes, cerebrovascular structure, and cognition/behavior. This animal work implicates potentially high-yield targets that may be leveraged in the future for clinical application.

Plasma Placental Growth Factor Concentrations Are Elevated Well in Advance of Type 2 Diabetes Mellitus Onset: Prospective Data From the WHS

Background

Pathologic angiogenesis is a hallmark of type 2 diabetes mellitus (T2DM) microvascular complications and may modulate adipogenesis and precede the onset of clinical diabetes mellitus; however, longitudinal data are unavailable. Placental growth factor is a potent proangiogenic factor that stimulates the formation of mature and durable vessels but is understudied in human diseases.

Methods and Results

We conducted a prospective case‐cohort study of baseline placental growth factor and incident T2DM within the WHS (Women's Health Study). A random sample of incident T2DM cases (n=491) occurring over a 15‐year follow‐up period was selected and compared with a reference subcohort (n=561). Case subjects were matched to the reference risk set on 5‐year age groups and race. All subjects in this analysis were required to have a hemoglobin A_1c <6.5% at WHS enrollment. Median baseline levels of placental growth factor were higher in case subjects compare to the reference subcohort (18.0 pg/mL versus 17.2 pg/mL) but were only weakly correlated with glycemic measures and not associated with obesity. The risk of diabetes mellitus increased across placental growth factor quartile in the base model (hazard ratios, 1.00, 1.14, 1.46, and 2.14; P‐trend<0.001) and in multivariable‐adjusted models accounting for clinical T2DM risk factors (hazard ratios, 1.00, 1.17, 1.45, and 2.61; P‐trend<0.001). These findings were not substantially altered by further adjustment for high‐sensitivity C‐reactive protein, hemoglobin A_1c, or fasting insulin and remained robust in sensitivity analyses excluding those diagnosed within 2 years of enrollment and those with baseline hemoglobin A_1c ≥6.0%.

Conclusions

Elevated placental growth factor levels are associated with future T2DM independent of traditional risk factors, measures of glycemia, insulin resistance, and high‐sensitivity C‐reactive protein. These prospective data suggest that pathologic angiogenesis may occur well before the clinical onset of T2DM and thus may have relevance to vascular complications of this disease.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000479.

Multifaceted Role of the Placental Growth Factor (PlGF) in the Antitumor Immune Response and Cancer Progression

The sharing of molecules function that affects both tumor growth and neoangiogenesis with cells of the immune system creates a mutual interplay that impairs the host’s immune response against tumor progression. Increasing evidence shows that tumors are able to create an immunosuppressive microenvironment by recruiting specific immune cells. Moreover, molecules produced by tumor and inflammatory cells in the tumor microenvironment create an immunosuppressive milieu able to inhibit the development of an efficient immune response against cancer cells and thus fostering tumor growth and progression. In addition, the immunoediting could select cancer cells that are less immunogenic or more resistant to lysis. In this review, we summarize recent findings regarding the immunomodulatory effects and cancer progression of the angiogenic growth factor namely placental growth factor (PlGF) and address the biological complex effects of this cytokine. Different pathways of the innate and adaptive immune response in which, directly or indirectly, PlGF is involved in promoting tumor immune escape and metastasis will be described. PlGF is important for building up vascular structures and functions. Although PlGF effects on vascular and tumor growth have been widely summarized, its functions in modulating the immune intra-tumoral microenvironment have been less highlighted. In agreement with PlGF functions, different antitumor strategies can be envisioned.

Is there an association between overweight/obesity and dental implant complications? A systematic review and meta-analysis

The aim of this systematic review was to test the following hypotheses: (1) that there is no difference in implant survival rate between individuals with overweight or obesity and those who are within the ideal weight range; (2) that there are no differences between these groups regarding indicators of peri-implant health. Two independent reviewers performed a literature search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published up to April 1, 2018. A meta-analysis was performed to determine the risk difference for implant failure and mean difference for marginal bone loss, probing depth, and bleeding on probing. Six studies were selected for review, involving a total of 746 patients with 986 implants: 609 in overweight or obese individuals and 377 in individuals within the ideal weight range. The findings of this systematic review indicate that the first hypothesis should be accepted, since no statistically significant difference in implant survival rate was found between individuals with overweight/obesity and those within the ideal weight range (P=0.64). The second hypothesis was rejected, as the review indicated a difference in marginal bone loss (P<0.00001), probing depth (P<0.00001), and bleeding around dental implants (P<0.00001).