Omental transposition in treatment of Alzheimer disease

Omentomyelopexy for the Treatment of a Persistent Lumbar Pseudomeningocele: A Case Report With Technical Note

BACKGROUND AND IMPORTANCE

Pseudomeningoceles are extradural accumulations of cerebrospinal fluid. In most cases, they appear as a complication of spinal operations. Omentomyelopexy is a surgery in which an autologous omentum flap is implanted over the dural opening. We describe a case of persistent pseudomeningocele treated with omentomyelopexy.

CLINICAL PRESENTATION

A 37-year-old man sustained a T12-L1 AO B3 fracture during a motorcycle accident. He underwent posterolateral fusion and then neurological rehabilitation. Two years later, however, his condition worsened, and he experienced progressive weakness-he was diagnosed with an intramedullary cyst, which was treated with laminectomy, arachnolysis and cystotomy. A pseudomeningocele developed afterward, and the patient underwent multiple reoperations in the following years, none of which were effective. Omentomyelopexy, a complex procedure aimed to facilitate cerebrospinal fluid absorption and subsequent formation of a permanent membrane, was offered to the patient as a "last resort." After undergoing omentomyelopexy, his pseudomeningocele resolved.

CONCLUSION

Although it should be reserved for exceptionally pertinent cases, omentomyelopexy is a viable option for managing persistent pseudomeningocele. However, further research is needed to better understand the effects and benefits of omentomyelopexy in this context.

Alzheimer's Disease: A Decreased Cerebral Blood Flow to Critical Intraneuronal Elements is the Cause

Normally, an adequate cerebral blood flow arrives at individual cerebral neurons in which the blood flow augments activity of intraneuronal mitochondria, which is the source of intraneuronal ATP, the energy source of cerebral neurons. With a decrease in cerebral blood flow that can occur as a function of normal aging phenomena, less blood results in decreased mitochondria, decreased ATP, and a decrease in neuronal activity, which can eventually lead to Alzheimer’s disease. It has been found that placement of the omentum directly on an Alzheimer’s disease brain can lead to improved cognitive function.

The proposed use of cervical spinal cord stimulation for the treatment and prevention of cognitive decline in dementias and neurodegenerative disorders

Cervical spinal cord stimulation is a well-established treatment for intractable neuropathic upper extremity pain. More than 20years ago it was demonstrated that cervical spinal cord stimulation could engender an increase in cerebral blood flow. Cerebral blood flow has been shown to be decreased in many patients with dementia and in various neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Furthermore, there is evidence that reduced cerebral blood flow worsens neurodegenerative disease and may also predict which patients progress from mild cognitive impairment to full blown Alzheimer's disease. Thus, the identification of decreased cerebral blood flow in patients with early cognitive problems may offer clinicians a window of opportunity to intervene and prevent further brain damage. Further evidence that supports augmenting cerebral blood flow as an effective strategy for preventing and treating cognitive brain dysfunction comes from experimental studies with omental transposition. The author proposes cervical spinal cord stimulation as a titratable, programmable extracranial neuromodulation technique to increase cerebral blood flow for the purposes of improving cognitive function and preventing cognitive deterioration in patients with dementias and neurodegenerative disorders.

Thymosin β4 mobilizes mesothelial cells for blood vessel repair

Mesothelium is the simple squamous epithelium covering all abdominal organs and the coeloms in which those organs reside. While the structural characteristics of this cell type were documented a century ago, its potential in development, disease, and wound healing is only now becoming apparent. In the embryo, mesothelia provide vasculogenic cells for the developing heart, lungs, and gut. Furthermore, adult mesothelial cells can be reactivated using thymosin β4 and mobilized to aid in tissue repair. Despite their positive role in development and repair, mesothelia are also susceptible to adhesion and tumor formation. With knowledge that the mesothelium is an important mediator of tissue repair as well as disease, it will be important to identify other factors like thymosin β4 that have the ability to potentiate these cells. Future use of chemical and genetic agents in conjunction with mesothelial cells will lead to enhanced therapeutic potential and mitigation of deleterious outcomes.

Omental grafting: a cell-based therapy for blood vessel repair

Clinicians regularly transplant omental pedicles to repair a wide variety of injured tissues, but the basic mechanism underlying this efficacious procedure is not understood. One possibility that has not been addressed is the ability of omentum to directly contribute regenerative cells to injured tissues. We hypothesized that if omental progenitor cells could be mobilized to incorporate into damaged tissue, the power of this therapy would be greatly expanded. Labelled omental grafts were transplanted into a murine carotid artery injury model. Selected grafts were treated with thymosin β4 (Tβ4) prior to transplantation to investigate the effects of chemical potentiation on healing. We found treatment of grafts with Tβ4-induced progenitor cells to fully integrate into the wall of injured vessels and differentiate into vascular smooth muscle. Myographic studies determined that arteries receiving Tβ4-stimulated grafts were functionally indistinguishable from uninjured controls. Concurrent in vitro analyses showed that Tβ4 promoted proliferation, migration and trans-differentiation of cells via AKT signalling. This study is the first to demonstrate that omentum can provide progenitor cells for repair, thus revealing a novel and naturally occurring source of vascular smooth muscle for use in cell-based therapies. Furthermore, our data show that this system can be optimized with inducing factors, highlighting a more powerful therapeutic potential than that of its current clinical application. This is a paradigm-setting concept that lays the foundation for the use of chemical genetics to enhance therapeutic outcomes in a myriad of fields.

Omentum-wrapped scaffold with longitudinally oriented micro-channels promotes axonal regeneration and motor functional recovery in rats

Background

Tissue-engineered nerve scaffolds hold great potential in bridging large peripheral nerve defects. However, insufficient vascularization of nerve scaffolds limited neural tissues survival and regeneration, which hampered the successful implantation and clinical application of nerve scaffolds. The omentum possesses a high vascularization capacity and enhances regeneration and maturation of tissues and constructs to which it is applied. However, combined application of nerve scaffolds and omentum on axonal regeneration and functional recovery in the treatment of large peripheral nerve defects has rarely been investigated thus far.

Methods

In the present study, an omentum-wrapped collagen-chitosan scaffold was used to bridge a 15-mm-long sciatic nerve defect in rats. Rats that received nerve autografts or scaffolds alone were served as positive control or negative control, respectively. The axonal regeneration and functional recovery were examined by a combination of walking track analysis, electrophysiological assessment, Fluoro-Gold (FG) retrograde tracing, as well as morphometric analyses to both regenerated nerves and target muscles.

Findings

The results demonstrated that axonal regeneration and functional recovery were in the similar range between the omentum-wrapping group and the autograft group, which were significantly better than those in the scaffold alone group. Further investigation showed that the protein levels of vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were significantly higher in the omentum-wrapping group than those in the scaffold alone group in the early weeks after surgery.

Conclusion

These findings indicate that the omentum-wrapped scaffold is capable of enhancing axonal regeneration and functional recovery, which might be served as a potent alternative to nerve autografts. The beneficial effect of omentum-wrapping on nerve regeneration might be related with the proteins produced by omentum.

The omentum: anatomical, metabolic, and surgical aspects

INTRODUCTION

The omentum is acknowledged to have diverse functions in the pathophysiology of intra-abdominal disease. Its angiogenic properties act as a natural defense mechanism in peritonitis and intra-abdominal sepsis. With advancing technology the omentum is revealing itself as a new player in the field of molecular surgery with special reference to cancer, obesity and tissue reconstruction.

MATERIALS AND METHODS

This article reviews the existing and potential surgical applications of the omentum.