A transplant patient with a swollen leg

A New Experimental Lymphedema Model: Reevaluating the Efficacy of Rat Models and Their Clinical Translation for Chronic Lymphedema Studies

BACKGROUND

Our aim was to create a new rodent hind limb lymphedema model lacking the fibrosis effect induced by radiotherapy and subjected to the inhibition of lymphangiogenesis via sirolimus (rapamycin) to maintain a chronic lymphedema model and investigate its reliability for human treatment modalities.

METHODS

Forty-two Sprague-Dawley rats were randomly assigned to 7 groups: (1) surgery control, (2) vehicle-surgery control, (3) vehicle control, (4) rapamycin control, (5) surgery with 1 mg/kg per day rapamycin, (6) surgery with 1.5 mg/kg per day rapamycin, and (7) surgery with 2 mg/kg per day rapamycin. All surgeries were performed on the right hind limbs, with the left hind limbs also considered as a control. The drug and its solvent were administered daily into the relevant groups intraperiteonally. The presence of lymphedema was investigated by weekly limb circumference measurements, microcomputed tomography, fluorescence lymphography using indocyanine green dye, and microscopic evaluation at the end of the sixth week to determine any histological changes in the hind limbs.

RESULTS

In group 1, lymphedema was observed for 2 weeks (P = 0.032), whereas in groups 5, 6, and 7, lymphedema lasted for 3 weeks (P < 0.05.) Fluorescence using indocyanine green revealed that the edema was totally resolved after 6 weeks of surgery by a well-developed superficial lymphatic organization instead of the normal distinct vessel structure. Histologically, groups 1, 5, 5, and 7 demonstrated a significant increase in both the number of macrophages (P < 0.001) and newly formed lymphatic vessels in the right side surgically treated hind limb (P < 0.05).

CONCLUSIONS

Despite the extreme surgical destruction and lymphangiogenesis inhibition in the rat model, the sustained lymphedema did not last >3 weeks. Because of the rapid neolymphangiogenesis in murines and a different wound healing mechanism, they should not be considered as an appropriate model for research on human lymphedema in first place.

Characteristics of Lymphedema in Patients Treated with Mammalian Target of Rapamycin Inhibitors

Purpose: To investigate the characteristics of lymphedema in patients treated with mammalian target of rapamycin (mTOR) inhibitors and delineate complex decongestive therapy (CDT) outcomes. Methods and Results: We retrospectively analyzed 24 patients with mTOR inhibitor-induced lymphedema and 7 lymphedema patients (control) not treated with mTOR inhibitors, who visited the lymphedema clinic of the department of rehabilitation medicine from March 2016 to December 2019. We comprehensively reviewed clinical features, medication history, associated diseases, lymphoscintigraphy, lower extremity computed tomography venography (LE CTV), and the effect of CDT. By using ImageJ program, we measured the cross-sectional area (CSA) of muscle and subcutaneous fat of mid-thigh image in LE CTV and compared them to a control group not treated with mTOR inhibitors. Seventeen patients on sirolimus and seven patients on everolimus were included, with an approximately equal distribution of stages 2 and 3 lymphedema, and most with pitting edema. Ten patients had breast or gynecological cancer and underwent lymph node dissection. Lymphedema developed after mTOR inhibitor initiation, not postoperatively. Lymphoscintigraphy revealed decreased lymph node uptake and dermal backflow. LE CTV revealed subcutaneous honeycomb-shaped trabecular areas in the affected limbs of seven patients. Patients treated with mTOR inhibitors had a larger mean subcutaneous fat CSA and a smaller mean muscular CSA than controls. Lymphedema improved or remained unchanged after initial CDT. Daily CDT adequately controlled 11 cases, but exacerbation occurred in 5 of 7 poorly compliant patients, and cellulitis occurred in 6 patients. Conclusion: Physicians should identify mTOR inhibitor-related lymphedema early and discuss medication alternatives and CDT with patients.

Skin disorders indicating peripheral arterial occlusive disease and chronic venous insufficiency in organ transplant recipients

BACKGROUND

Peripheral arterial occlusive disease (PAOD) and chronic venous insufficiency (CVI) in organ transplant recipients (OTR) can lead to harmful outcomes. We made an inventory of cutaneous manifestations of PAOD and CVI in OTR in relation with diabetes and other potential risk factors.

METHODS

A prospective study in a single center was performed. OTR (n = 112) were included at the outpatient clinic to investigate clinical signs of PAOD and CVI. The most commonly associated risk factors were determined.

RESULTS

PAOD had been diagnosed in 15.6% and CVI in 30.0% of the patients. Diabetes was the cause of organ failure in 9.8% of the patients. Type 1 diabetes had been diagnosed in 8.9% and type 2 diabetes in 21.4% (59.1% new-onset diabetes after transplantation). Type 1 diabetes showed an increased risk for PAOD and limb amputation with hazard ratios of 11.0 (95%CI 3.0-40.2) and 9.1 (95%CI 1.4-58.6). Type 2 diabetes showed no increased risk.

CONCLUSIONS

Patients with a history of type 1 diabetes were at high risk for PAOD even years after a simultaneous pancreas kidney transplantation and they should remain under close observation for PAOD even though they are supposedly "cured" from their diabetes to prevent a harmful outcome.

Sirolimus and mTOR Inhibitors: A Review of Side Effects and Specific Management in Solid Organ Transplantation

Inhibitors of mechanistic target of rapamycin (mTOR inhibitors) are used as antiproliferative immunosuppressive drugs and have many clinical applications in various drug combinations. Experience in transplantation studies has been gained regarding the side effect profile of these drugs and the potential benefits and limitations compared with other immunosuppressive agents. This article reviews the adverse effects of mTOR inhibitors in solid organ transplantation, with special attention given to mechanisms hypothesized to cause adverse events and their management strategies.

Controlled arterial hypertension and adverse event free survival rate in heart recipients

Aim.To evaluate the prevalence of arterial hypertension (AH) in heart transplant recipients, and its influence on the risk of adverse events, as the efficacy and safety of antihypertension medications (AHM).

Material and methods.To the study, were consequently included all heart transplant recipients operated in the Shumakov Centre during the years 2013 to 2016 and survived 90 days after orthotopic heart transplantation.

Results.Totally, 353 recipients included, with AH or AHM intake in anamnesis in 62 (17,6%). Within 90 days post-surgery, AH that demanded  for medication therapy was found in 151 (42,8%) patients. In posttransplant AH patients there were the following specific parameters in preoperational period: higher body mass index — 25,7±4,1 vs 24,9±4,4 (р=0,026), blood creatinine concentration — 100,6±62,6 vs 68,8±4,8 (р<0,001), donor heart posterior wall thickness — 11,9±0,8 vs 11,3±0,7 (р=0,034), creatinine concentration in 3 month after operation  — 131,7±101,6 vs 94,1±46,5 (p<0,001). There was relation revealed, of AH development risk with anamnesis of AH and renal failure, as a necessity for renal replacement therapy within 30 days post surgery and episodes of acute antibody-mediated reaction on transplant. In the recipients taking angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (ACEi/ARB) before operation, the survival rate free from adverse events was better than in those taking calcium channel blockers (CCB) (plog-rank=0,042).

Conclusion.The results of the study point on high prevalence of AH in heart recipients. Presence of AH in anamnesis, renal failure, episodes of humoral, but not cellular, reaction to the transplant, and donor heart hypertrophy do significantly increase the probability of AH development after transplantation. Comparison revealed significant benefit of ACEi/ ARB versus CCB as antihypertension medications in either monotherapy or in combination with diuretics.

Lymphedema of the Transplanted Kidney and Abdominal Wall with Ipsilateral Pleural Effusion Following Kidney Biopsy in a Patient Treated with Sirolimus: A Case Report and Review of the Literature

BACKGROUND Sirolimus is a mammalian target of rapamycin (mTOR) inhibitor, which is used in immunosuppressive treatment regimens in organ transplant recipients. Although mTOR inhibitors are well tolerated, their adverse effects have been reported. Sirolimus treatment in transplant recipients has been reported to be associated with lymphedema of the skin and subcutaneous tissues, and with pleural effusion, but edema of internal organs and organomegaly have not been previously reported. A case is presented lymphedema of the transplanted kidney and abdominal wall with ipsilateral pleural effusion following kidney biopsy in a patient treated with sirolimus. CASE REPORT A 32-year-old woman with a history of end-stage renal disease of unknown etiology had undergone right renal transplantation from an unrelated living donor, eight years previously. She was referred to our hospital with dyspnea, localized abdominal pain, and swelling of the transplanted kidney. The symptoms appeared following a kidney biopsy and the replacement of cyclosporin with sirolimus four months previously. On examination, she had localized swelling of the abdominal wall overlying the transplanted kidney, and a right pleural effusion. Hydronephrosis and nephrotic syndrome were excluded as causes of kidney enlargement. Following the withdrawal of sirolimus therapy her symptoms resolved within three months. CONCLUSIONS A case is described of lymphedema of the transplanted kidney and abdominal wall with ipsilateral pleural effusion following kidney biopsy attributed to her change in anti-rejection therapy to sirolimus. This case report should raise awareness of this unusual complication of sirolimus anti-rejection therapy and its possible effects on the lymphatic system.

Lymphedema secondary to idiopathic occlusion of the subclavian and innominate veins after renal transplantation: A case report

RATIONALE

Among the causes of swelling in the extremities of renal transplantation patients, secondary lymphedema caused by complete idiopathic obstruction of large veins is rare and may be difficult to diagnose and treat.

PATIENT CONCERNS

A 64-year-old man presented with severe edema and pain that occurred suddenly in the right arm.

DIAGNOSES

The patient was diagnosed as stage-2 secondary lymphedema caused by idiopathic occlusion of the subclavian and innominate veins.

INTERVENTIONS

Lymphoscintigraphy and ascending venography of the right arm confirmed the diagnosis. Intensive complete decongestive therapy for lymphedema was performed.

OUTCOMES

Following 2 weeks of active rehabilitation, the pain level and edema status were significantly improved.

LESSONS

When idiopathic swelling of the extremities occurs in renal transplant patients, secondary lymphedema caused by venous occlusion may be the cause. When direct intervention for the venous occlusion proves to be difficult, a conservative approach may be helpful.