Disorders of lymph flow

Case report of generalized lymphatic dysplasia with PIEZO1 mutation and review of the literature

Background

The newborn malformation of primary lymphatic dysplasia (PLD), developed primarily due to PIEZO1 gene autosomal recessive mutation, is known to hinder with the lymphatic system action, causing chyle or lymph effusion into the peritoneal cavity or pleura.

Case presentation

A 4-years-old male subject presented with a recurrent chylothorax and bilateral lower limb edema that started at age of 6 months. Lymphoscintigraphy showed lymphangiectasia with chylothorax. The whole exome sequence consisted of Pathogenic variants in PIEZO1 gene associated with lymphatic malformation type 6 (LMPHM6).

Conclusion

This is the first reported pediatric case of PIEZO1 gene mutation in Saudi Arabia. This case highlighted the wide differential diagnosis of recurrent chylothorax and lower limb edema, as well as the relative literature on the molecular foundation, clinical scale, pathophysiology, and lymphatic malformation treatment. patients can be improved via application of standardized chylothorax and lymphedema therapies. Overall, awareness of the diseases related to the thoracic lymphatic circulation should be observed as its prognosis may highly promote better approaches for its management.

Prolymphangiogenic Effects of 9-cis Retinoic Acid Are Enhanced at Sites of Lymphatic Injury and Dependent on Treatment Duration in Experimental Postsurgical Lymphedema

Background: Patients undergoing surgical treatment for solid tumors are at risk for development of secondary lymphedema due to intraoperative lymphatic vessel injury. The damaged lymphatic vessels fail to adequately regenerate and lymphatic obstruction leads to fluid and protein accumulation in the interstitial space and chronic lymphedema develops as a result. There are currently no effective pharmacological agents that reduce the risk of developing lymphedema or treat pre-existing lymphedema, and management is largely palliative. The present study investigated the efficacy of various 9-cis retinoic acid (9-cis RA) dosing strategies in reducing postsurgical lymphedema by utilizing a well-established mouse tail lymphedema model. Methods and Results: Short-duration treatment with 9-cis RA did not demonstrate a significant reduction in postoperative tail volume, nor an improvement in lymphatic clearance. However, long-term treatment with 9-cis RA resulted in decreased overall tail volume, dermal thickness, and epidermal thickness, with an associated increase in functional lymphatic clearance and lymphatic vessel density, assessed by LYVE-1 immunostaining, compared with control. These effects were seen at the site of lymphatic injury, with no significant changes observed in uninjured sites such as ear skin and the diaphragm. Conclusions: Given the reported results indicating that 9-cis RA is a potent promoter of lymphangiogenesis and improved lymphatic clearance at sites of lymphatic injury, investigation of postoperative 9-cis RA administration to patients at high risk of developing lymphedema may demonstrate positive efficacy and reduced rates of postsurgical lymphedema.

Lymphaticovenous Anastomosis for Lower Extremity Lymphedema: A Systematic Review

Background  Lymphedema is an accumulation of protein-rich fluid in the interstitial spaces resulting from impairment in the lymphatic circulation that can impair quality of life and cause considerable morbidity. Lower extremity lymphedema (LEL) has an overall incidence rate of 20%. Conservative therapies are the first step in treatment of LEL; however, they do not provide a cure because they fail to address the underlying physiologic dysfunction of the lymphatic system. Among several surgical alternatives, lymphaticovenous anastomosis (LVA) has gained popularity due to its improved outcomes and less invasive approach. This study aims to review the published literature on LVA for LEL treatment and to analyze the surgical outcomes.

Methods  PubMed database was used to perform a comprehensive literature review of all articles describing LVA for treatment of LEL from Novemeber 1985 to June 2019. Search terms included “lymphovenous” OR “lymphaticovenous” AND “bypass” OR “anastomosis” OR “shunt” AND “lower extremity lymphedema.”

Results  A total of 95 articles were identified in the initial query, out of which 58 individual articles were deemed eligible. The studies included in this review describe notable variations in surgical techniques, number of anastomoses, and supplementary interventions. All, except one study, reported positive outcomes based on limb circumference and volume changes or subjective clinical improvement. The largest reduction rate in limb circumference and volume was 63.8%.

Conclusion  LVA demonstrated a considerable reduction in limb volume and improvement in subjective findings of lymphedema in the majority of patients. The maintained effectiveness of this treatment modality in long-term follow-up suggests great efficacy of LVA in LEL treatment.

High Output Chylous Fistula Post First Rib Resection

We present a patient who developed high output chyle leak post left first-rib resection for neurogenic thoracic outlet syndrome. The persistent high output chylorrhea was refractory to 3 surgical reexplorations attempting to ligate leaking branches, bed rest, nonfat diet, parenteral nutrition, octreotide administration, and vacuum-assisted closure (VAC) therapy. In addition, she developed hypovolemia, hyponatremia, and hypoalbuminemia. Control of the chylous fistula was achieved by reattaching the sternocleidomastoid muscle laterally to protect the phrenic nerve and brachial plexus in order to redirect chyle to the medial portion of the neck incision site. This was supported by the application of fibrin sealants in combination with VAC therapy. The patient was discharged after a 27-day hospital stay with complete resolution of her chylous fistula prior to discharge.

Mechanisms of Connexin-Related Lymphedema

RATIONALE

Mutations in GJC2 and GJA1, encoding Cxs (connexins) 47 and 43, respectively, are linked to lymphedema, but the underlying mechanisms are unknown. Because efficient lymph transport relies on the coordinated contractions of lymphatic muscle cells (LMCs) and their electrical coupling through Cxs, Cx-related lymphedema is proposed to result from dyssynchronous contractions of lymphatic vessels.

OBJECTIVE

To determine which Cx isoforms in LMCs and lymphatic endothelial cells are required for the entrainment of lymphatic contraction waves and efficient lymph transport.

METHODS AND RESULTS

We developed novel methods to quantify the spatiotemporal entrainment of lymphatic contraction waves and used optogenetic techniques to analyze calcium signaling within and between the LMC and the lymphatic endothelial cell layers. Genetic deletion of the major lymphatic endothelial cell Cxs (Cx43, Cx47, or Cx37) revealed that none were necessary for the synchronization of the global calcium events that triggered propagating contraction waves. We identified Cx45 in human and mouse LMCs as the critical Cx mediating the conduction of pacemaking signals and entrained contractions. Smooth muscle-specific Cx45 deficiency resulted in 10- to 18-fold reduction in conduction speed, partial-to-severe loss of contractile coordination, and impaired lymph pump function ex vivo and in vivo. Cx45 deficiency resulted in profound inhibition of lymph transport in vivo, but only under an imposed gravitational load.

CONCLUSIONS

Our results (1) identify Cx45 as the Cx isoform mediating the entrainment of the contraction waves in LMCs; (2) show that major endothelial Cxs are dispensable for the entrainment of contractions; (3) reveal a lack of coupling between lymphatic endothelial cells and LMCs, in contrast to arterioles; (4) point to lymphatic valve defects, rather than contraction dyssynchrony, as the mechanism underlying GJC2- or GJA1-related lymphedema; and (5) show that a gravitational load exacerbates lymphatic contractile defects in the intact mouse hindlimb, which is likely critical for the development of lymphedema in the adult mouse.

Inflammation and Lymphedema Are Exacerbated and Prolonged by Neuropilin 2 Deficiency

The vasculature influences the progression and resolution of tissue inflammation. Capillaries express vascular endothelial growth factor (VEGF) receptors, including neuropilins (NRPs), which regulate interstitial fluid flow. NRP2, a receptor of VEGFA and semaphorin (SEMA) 3F ligands, is expressed in the vascular and lymphatic endothelia. Previous studies have demonstrated that blocking VEGF receptor 2 attenuates VEGFA-induced vascular permeability. The inhibition of NRP2 was hypothesized to decrease vascular permeability as well. Unexpectedly, massive tissue swelling and edema were observed in Nrp2^-/- mice compared with wild-type littermates after delayed-type hypersensitivity reactions. Vascular permeability was twofold greater in inflamed blood vessels in Nrp2-deficient mice compared to those in Nrp2-intact littermates. The addition of exogenous SEMA3F protein inhibited vascular permeability in Balb/cJ mice, suggesting that the loss of endogenous Sema3F activity in the Nrp2-deficient mice was responsible for the enhanced vessel leakage. Functional lymphatic capillaries are necessary for draining excess fluid after inflammation; however, Nrp2-mutant mice lacked superficial lymphatic capillaries, leading to 2.5-fold greater fluid retention and severe lymphedema after inflammation. In conclusion, Nrp2 deficiency increased blood vessel permeability and decreased lymphatic vessel drainage during inflammation, highlighting the importance of the NRP2/SEMA3F pathway in the modulation of tissue swelling and resolution of postinflammatory edema.

Inflammation as Cause for Scar Cancers of the Lung

The molecular and cellular basis of inflammation has become a topic of great interest of late because of the association between mechanisms of inflammation and risk for cancer. Inflammatory-mediated events, such as the production of reactive oxygen species (ROS), the activation of growth factors (for wound repair), and the altering of signal-transduction processes to activate cell-proliferation (to replace necrotic/apoptotic tissue cells), events that also can occur independently of inflammation, are all considered to be components of risk for a variety of cancers. Using scar cancer of the lung as an example, mechanisms of inflammation associated with recurring infections with Mycobacterium tuberculosisare discussed in the context that they may, in fact, be the major or sole cause of a cancer. Production of ROS, prostaglandins, leukotrienes, and cytokines in pulmonary tissues is greatly enhanced due to a cell-mediated immune response against macrophages infected with M. tuberculosis. These responses lead to the extensive fibrosis associated with recurring infections, possibly leading to decreased clearance of lymph and lymph-associated particles from the infected region. They also will enhance rates of cell division by inhibiting synthesis of P21, leading to enhanced progression from G0 arrest to G1 phase, from G1 to Sphase, and from G2 to M phase of the cell cycle. By increasing rates of oxidative DNA damage and inhibiting apoptosis by enhancing synthesis of BCL-2, mutagenesis of progeny cells is enhanced, and these effects coupled with enhanced angiogenesis stimulated by COX-2 products lead to an environment that is highly conducive to tumorigenesis. Based on the evidence, it appears that but for an inflammatory response to recurring infections, some cases of scar cancer would not exist. By making appropriate lifestyle and dietary changes, a variety of anti-inflammatory effects can be produced, which should attenuate inflammation-induced risk for cancer.

Lymphaticovenular anastomosis to prevent cellulitis associated with lymphoedema

BACKGROUND

One of the complications of lymphoedema is recurrent cellulitis. The aim was to determine whether lymphaticovenous anastomosis (LVA) was effective at reducing cellulitis in patients with lymphoedema.

METHODS

This was a retrospective review of patients with arm/leg lymphoedema who underwent LVA. The frequency of cellulitis was compared before and after surgery. The diagnostic criteria for cellulitis were a fever of 38·5°C or higher, and warmth/redness in the affected limb(s).

RESULTS

A total of 95 patients were included. The mean number of episodes of cellulitis in the year preceding surgery was 1·46, compared with 0·18 in the year after surgery (P < 0·001).

CONCLUSION

LVA reduced the rate of cellulitis in these patients with lymphoedema.

Lymphatic pump treatment repeatedly enhances the lymphatic and immune systems

BACKGROUND

Osteopathic practitioners utilize manual therapies called lymphatic pump techniques (LPT) to treat edema and infectious diseases. While previous studies examined the effect of a single LPT treatment on the lymphatic system, the effect of repeated applications of LPT on lymphatic output and immunity has not been investigated. Therefore, the purpose of this study was to measure the effects of repeated LPT on lymphatic flow, lymph leukocyte numbers, and inflammatory mediator concentrations in thoracic duct lymph (TDL).

METHODS AND RESULTS

The thoracic ducts of five mongrel dogs were cannulated, and lymph samples were collected during pre-LPT, 4 min of LPT, and 2 hours post-LPT. A second LPT (LPT-2) was applied after a 2 hour rest period. TDL flow was measured, and TDL were analyzed for the concentration of leukocytes and inflammatory mediators. Both LPT treatments significantly increased TDL flow, leukocyte count, total leukocyte flux, and the flux of interleukin-8 (IL-8), keratinocyte-derived chemoattractant (KC), nitrite (NO2(-)), and superoxide dismutase (SOD). The concentration of IL-6 increased in lymph over time in all experimental groups; therefore, it was not LPT dependent.

CONCLUSION

Clinically, it can be inferred that LPT at a rate of 1 pump per sec for a total of 4 min can be applied every 2 h, thus providing scientific rationale for the use of LPT to repeatedly enhance the lymphatic and immune system.

Malpractice leading to secondary lymphedema after radical mastectomy: case report

BACKGROUND

With this case report we want to demonstrate the results of chemotherapy application to the mastectomized side in a patient who had undergone radical mastectomy.

CASE REPORT

A patient who was accidentally given chemotherapy on the mastectomized side (PCMS) and a control patient who received chemotherapy on the non-affected side (PCNS) were included in this study. Edema, pain, muscle strength, and shoulder mobility were evaluated. The results of the 2 patients were compared. After chemotherapy, PCMS experienced edema and pain in the affected arm compared to PCNS. Increased circumference measurement, and decreased shoulder mobility and muscle strength were observed in PCMS.

CONCLUSION

It was suggested that chemotherapy application on the mastectomized side triggered lymphedema. Our findings on the subject revealed that education of health care professionals and patients alike is very important.

Lymphatic vessels in health and disease

The lymphatic vasculature plays vital roles in tissue fluid balance, immune defense, metabolism, and cancer metastasis. In adults, lymphatic vessel formation and remodeling occur primarily during inflammation, development of the corpus luteum, wound healing, and tumor growth. Unlike the blood circulation, where unidirectional flow is sustained by the pumping actions of the heart, pumping actions intrinsic to the lymphatic vessels themselves are important drivers of lymphatic flow. This review summarizes critical components that control lymphatic physiology.

Intestinal lymphatic transport for drug delivery

Intestinal lymphatic transport has been shown to be an absorptive pathway following oral administration of lipids and an increasing number of lipophilic drugs, which once absorbed, diffuse across the intestinal enterocyte and while in transit associate with secretable enterocyte lipoproteins. The chylomicron-associated drug is then secreted from the enterocyte into the lymphatic circulation, rather than the portal circulation, thus avoiding the metabolically-active liver, but still ultimately returning to the systemic circulation. Because of this parallel and potentially alternative absorptive pathway, first-pass metabolism can be reduced while increasing lymphatic drug exposure, which opens the potential for novel therapeutic modalities and allows the implementation of lipid-based drug delivery systems. This review discusses the physiological features of the lymphatics, enterocyte uptake and metabolism, links between drug transport and lipid digestion/re-acylation, experimental model (in vivo, in vitro, and in silico) of lymphatic transport, and the design of lipid- or prodrug-based drug delivery systems for enhancing lymphatic drug transport.

Positive pressure ventilation: what is the real cost?

Positive pressure ventilation is a radical departure from the physiology of breathing spontaneously. The immediate physiological consequences of positive pressure ventilation such as haemodynamic changes are recognized, studied, and understood. There are other significant physiological interactions which are less obvious, more insidious, and may only produce complications if ventilation is prolonged. The interaction of positive pressure with airway resistance and alveolar compliance affects distribution of gas flow within the lung. The result is a wide range of ventilation efficacy throughout different areas of the lung, but the pressure differentials between alveolus and interstitium also influence capillary perfusion. The hydrostatic forces across the capillaries associated with the effects of raised venous pressures compound these changes resulting in interstitial fluid sequestration. This is increased by impaired lymphatic drainage which is secondary to raised intrathoracic pressure but also influenced by raised central venous pressure. Ventilation and PEEP promulgate further physiological derangement. In theory, avoiding these physiological disturbances in a rested lung may be better for the lung and other organs. An alternative to positive pressure ventilation might be to investigate oxygen supplementation of a physiologically neutral and rested lung. Abandoning heroic ventilation would be a massive departure from current practice but might be a more rationale approach to future practice.

Thoracic lymphatic disorders

Thoracic complications of lymphatic disorders can culminate in respiratory failure and death and should be considered in any patient with a lymphatic disease and clinical or radiographic evidence of chest disease. Congenital lymphatic disorders are being increasingly recognized in the adult population. The spectrum of thoracic manifestations of lymphatic disorders ranges from incidental radiographic findings to diffuse lymphatic disease with respiratory failure. This article serves to review some recent advances that allow improved diagnosis and management of thoracic lymphatic disorders. Herein, we describe their anatomical and physiologic effects, the time course of their progression, and the therapies that are currently available. The management of malignant (cancerous) lymphatic disorders of the thorax is beyond the scope of this paper.

Proteomic technologies to study diseases of the lymphatic vascular system

Now that the human genome has been mapped, a new challenge has emerged: deciphering the various products of individual genes. Consequently, new proteomic technologies are being developed to monitor and identify protein function and interactions responsible for the total activities of the cell. The application of these new proteomic technologies to study cellular activities, will lead to a faster sample throughput and increased sensitivity for the detection of individual proteins, thus providing major opportunities for the discovery of new biomarkers for the early detection of protein alterations associated with the progression of the disease state.

Squamous cell carcinoma in chronic lymphedema: case report and review of the literature

BACKGROUND

Squamous cell carcinoma (SCC) arising in chronic lymphedema is rare; only nine cases have been reported.

OBJECTIVE

To present the evolution of SCC in chronic lymphedema.

METHODS

Case report and literature review.

RESULTS

The tumor was treated by wide excision and covered by a skin graft.

CONCLUSION

In most of the other reported SCC cases in lymphedema, there are additional factors for carcinogenesis. There is no additional carcinogenic factor except for chronic lymphedema in our case. This strongly supports that lymphedema itself is one of the carcinogenic factors for not only angiosarcoma but also SCC.