Role of adventitia in vascular remodeling in hypertension: a trophobiological view

The vascular wall has the capacity to undergo remodeling in response to long-term changes or injuries. This is a process of structural rearrangement that involves cell growth, cell death, cell migration, cell modulation and secretion/degradation of extracellular matrix molecules. Vascular remodeling is an adaptive phenomenon, e.g. Glagov's compensatory enlargement in atherosclerosis, but it may grow into vascular diseases, such as hypertension, atherosclerosis, and coronary restenosis after angioplasty. Nowadays paradigms defining the cell biology of vascular diseases are the following: (i) the hypertensive vessel is characterized by hyperinnervation-associated medial thickening due to smooth muscle cell (SMC) hypertrophy/hyperplasia and increased extracellular matrix content, (ii) the atherosclerotic plaque is characterized by SMC/immune cells/increased extracellular matrix-containing intimal thickening, and (iii) the restenotic coronary artery is characterized by SMC/immune cells-containing neointimal thickening. The spontaneously hypertensive rats (SHR), the stroke-prone SHR (SHRSP), the genetically hypertensive (GH) rats, and other genetically hypertensive strains are widely used as a model of human essential hypertension. In this volume of Biomedical Reviews, Bell updates the knowledge about vascular wall neurotrophobiology in relation to the pathogenesis of hypertension in SHR and GH rats. Also, Kondo et al systematize the perivascular nerve-related SMC structural changes in the development of hypertension in SHR and SHRSP. The data presented in these reviews are evaluated mainly in terms of Levi-Montalcini's neurotrophic theory.Biomedical Reviews 1996; 6: 5-10

Leydig cell-immune cell interaction: an example of neuroendocrine-immune communication in testis

In her paper "Tilings will never be the same again" Dr Kathleen L. Wishner quoted Alvin Toffler's book Future Shock written in 1970. Toffler defined "future shock" as a time phenomenon, a product of the greatly accelerated change in society. The scientific research itself is a demonstration of this accelerated change. In particular, data systematized by Davidoff et al in this volume of Biomedical Reviews indicate the change in the understanding of the nature and origin of Leydig cells of the human testis.Biomedical Reviews 1996; 6: 1-4

Nerve-mast cell-nerve growth factor link: the mast cell as yin-yang modulator in inflammation and fibrosis

Inflammation and fibroproliferation are biological responses aiming at recovering from injury. Wound healing is considered a paradigm of such a homeostatic phenomenon. However, what begins as a protective response, in excess becomes a damaging process we call chronic inflammatory-fibroproliferative disease.Biomedical Reviews 1995; 4: 1-6

Neural-immune-effector (NIE) cross-talk in vascular trophobiology: proposal for new and not yet exploited purinergic regulatory mechanisms

In a state-of-the-art approach, Dr. Hasséssian presents purinoceptor-mediated vasoconstriction/vasodilation mechanisms of the pulmonary circulation. He focuses on P2 purinoceptors of smooth muscle cells, endothelial cells, platelets and mast cells, without addressing P1 (adenosine) purinoceptors. Recently, the Burnstock's purinoceptorology is "arborizing" into a variety of members of P1 and P2 purinoceptor families classified by the International Union of Pharmacology. Here we would like to add some possible, new and not yet exploited, purinergic regulatory mechanisms to the Hasséssian's work. Accordingly, we shall briefly focus on the involvement of connective tissue (adventitial) mast cells and their interactions with perivascular nerves and medial smooth muscle cells.Biomedical Reviews 1994; 3: 81-86

A suggestive neurotrophic potential of mast cells in heart and submandibular glands of the rat

According to the neurotrophic theory, the nerve growth factor (NGF) is widely distributed in the effector tissues of peripheral sympathetic and sensory neurons, suggesting that the density of innervation is controlled by effector derived NGF. Sympathetic neurons require access to NGF for survival throughout life, whereas sensory neurons are dependent on NGF only during restricted period of embryonic development. This development-related feature of sympathetic neurons suggests that they crucially depend on plasticity of NGF biology, including secretion, availability, and utilization, to maintain appropriate neuronal function in adult life, and even in old age. While most previous studies on the cellular source of NGF have focused on neuronal and nonneuronal effector cells, it was recently demonstrated that NGF secretion is not only restricted to cells receiving a direct innervation. Immune cells, including mast cells (MC), lymphocytes and macrophages, for example, produce and release NGF as well as NGF secretion-inducing cytokines. Likewise, since the first evidence that NGF treatment causes a significant increase in the number and size of MC has been published by Aloe and Levi-Montalcini in 1977, it has been repeatedly shown that these cells are also NGF-responsive cells, thus providing further evidence for a widely investigated MC-nerve interaction. Further on this trophobiological line, a positive correlation of the amount of NGF and expression of NGF mRNA with the density of sympathetic innervation was demonstrated in a variety of organs. In the rat heart, one such example, the atrium contains a higher amount of NGF corresponding to a denser sympathetic nerve supply compared to the ventricle. Such a correlation was also revealed in the submandibular glands (SMG) and iris. Likewise, the density of MC in the ankle joint capsule, which is heavily innervated, is greater than in the capsule of the knee, which is less densely innervated, and the MC number in the synovial joint of spontaneously hypertensive rats, which have increased sympathetic nerve supply, is significantly greater than in normotensive rats. A summing-up of the above mentioned data shows that (i) MC are NGF secreting/responsive cells and frequently colocalized with nerves, and (ii) a higher NGF amount correlates with a denser sympathetic innervation of a tissue . This, in our eyes, brings into question the sole contribution of the "classical" effector cells to neurotrophic support of sympathetic nerve-innervated tissues. Consequently, we suggest that MC, through their own and/or cytokine-induced NGF secretion, may also be implicated in the neurotrophic potential in these tissues.Biomedical Reviews 1998; 9: 143-145

Use veno-venous extra corporeal membrane oxygenation in elderly patients with post-cardiotomy hypoxia: the changing paradigm of respiratory support in adult respiratory distress syndrome

Abstract Background Veno-venous extracorporeal membrane oxygenation (VV-ECMO) support for ARDS treatment after cardiac surgery has progressed remarkably in the last 20 years. However, one of the limitations of a successful recover is age, being a powerful predictor of mortality. Case presentation In this case report we discuss a 78-year-old man who underwent aortic valve and aortic root replacement. The postoperative period was complicated by ARDS following aspiration pneumonia treated with VV-ECMO weaned after 6 days. At two-year follow up, the patient made an excellent recover, being the second oldest person to survive VV-ECMO following cardiac surgery in the world. Conclusion In the literature there is no consensus regarding a specific age limit and results, in the use of ECMO in the elderly are scarce and inconsistent. We do not think advanced age is a contraindication to the use of ECMO