Mesenchymal Stromal Cells Prevent Allostimulation In Vivo and Control Checkpoints of Th1 Priming: Migration of Human DC to Lymph Nodes and NK Cell Activation

Although the immunomodulatory potency of mesenchymal stromal cells (MSC) is well established, the mechanisms behind are still not clear. The crosstalk between myeloid dendritic cells (mDC) and natural killer (NK) cells and especially NK cell-derived interferon-gamma (IFN-γ) play a pivotal role in the development of type 1 helper (Th1) cell immune responses. While many studies explored the isolated impact of MSC on either in vitro generated DC, NK, or T cells, there are only few data available on the complex interplay between these cells. Here, we investigated the impact of MSC on the functionality of human mDC and the consequences for NK cell and Th1 priming in vitro and in vivo. In critical limb ischemia patients, who have been treated with allogeneic placenta-derived mesenchymal-like stromal cells (PLX-PAD), no in vivo priming of Th1 responses toward the major histocompatibility complex (MHC) mismatches could be detected. Further in vitro studies revealed that mDC reprogramming could play a central role for these effects. Following crosstalk with MSC, activated mDC acquired a tolerogenic phenotype characterized by reduced migration toward CCR7 ligand and impaired ability to stimulate NK cell-derived IFN-γ production. These effects, which were strongly related to an altered interleukin (IL)-12/IL-10 production by mDC, were accompanied by an effective prevention of Th1 priming in vivo. Our findings provide novel evidence for the regulation of Th1 priming by MSC via modulation of mDC and NK cell crosstalk and show that off-the-shelf produced MHC-mismatched PLX-PAD can be used in patients without any sign of immunogenicity.

Two cases of buttock claudication caused by isolated internal iliac artery stenosis

We present two cases of buttock claudication caused by severe stenosis of the internal iliac artery which disappeared totally after percutaneous transluminal angioplasty (PTA). Isolated stenoses of internal iliac arteries are rare. It is often difficult to distinguish between vascular buttock claudication and neurological or orthopaedic symptoms. Conventional or MR-angiography is necessary to secure the diagnosis. PTA of internal iliac artery stenosis is the adequate treatment.

Use of subcutaneous enoxaparin compared to intravenous heparin and oral phenprocoumon in the setting of cardioversion--the ACE study (Anticoagulation in Cardioversion using Enoxaparin)

The mode and duration of anticoagulation in the setting of cardioversion of atrial fibrillation-either with or without guidance by transesophageal echocardiography (TEE)-is still an unresolved issue. Oral anticoagulation with warfarin or phenprocoumon is frequently used but may be associated with an increased risk of bleeding complications or, conversely, episodes of undercoagulation. Moreover, it takes several days to reach full anticoagulation with oral compounds. This phase may be covered with intravenous heparin but this requires prolonged hospitalization. Low-molecular weight heparin is an attractive alternative as it not only provides a safe and predictable level of anticoagulation with few side effects but can also be administered safely on an outpatient basis. In addition, anticoagulation monitoring is usually unnecessary. The ACE study (Anticoagulation in Cardioversion using Enoxaparin) compared the safety and efficacy of subcutaneous enoxaparin with intravenous heparin/oral phenprocoumon before and after cardioversion (stratified to TEE guidance or no TEE guidance). This article summarizes the study rationale and design. The results will be published shortly.

Safety and Efficacy of Enoxaparin Compared With Unfractionated Heparin and Oral Anticoagulants for Prevention of Thromboembolic Complications in Cardioversion of Nonvalvular Atrial Fibrillation

Background— Anticoagulation in cardioversion of atrial fibrillation is currently performed with unfractionated heparin (UFH) and oral anticoagulants, with or without guidance by transesophageal echocardiography (TEE). Low-molecular-weight heparins may reduce the risk of bleeding, may obviate the need for intravenous access, and do not require frequent anticoagulation monitoring.

Methods and Results— In a randomized, prospective multicenter trial, we compared the safety and efficacy of enoxaparin administered subcutaneously with intravenous UFH followed by the oral anticoagulant phenprocoumon in 496 patients scheduled for cardioversion of atrial fibrillation of >48 hours’ and ≤1 year’s duration. Patients were stratified to cardioversion with (n=431) and without (n=65) guidance by TEE. The study aimed to demonstrate noninferiority of enoxaparin compared with UFH+phenprocoumon with regard to the incidence of embolic events, all-cause death, and major bleeding complications. Secondary end points included successful cardioversion, maintenance of sinus rhythm until study end, and minor bleeding complications. Of 496 randomized patients, 428 were analyzed per protocol. Enoxaparin was noninferior to UFH+phenprocoumon with regard to the incidence of the composite primary end point in a per-protocol analysis (7 of 216 patients versus 12 of 212 patients, respectively; P =0.016) and in an intention-to-treat analysis (7 of 248 patients versus 12 of 248 patients, respectively; P =0.013). There was no significant difference between the 2 groups in the number of patients reverted to sinus rhythm.

Conclusions— Enoxaparin is noninferior to UFH+phenprocoumon for prevention of ischemic and embolic events, bleeding complications, and death in TEE-guided cardioversion of atrial fibrillation. Its easier application and more stable anticoagulation may make it the preferred drug for initiation of anticoagulation in this setting.

Local vascular complications after use of the hemostatic puncture closure device Angio-Seal

BACKGROUND

As an alternative to manual pressure techniques new systems for achieving arterial hemostasis after cardiac catheterization were developed. Here we report about the diagnosis and therapy of femoral artery complications after use of the closure device Angio-Seal, consisting of an intraarterial anchor and extravascular collagen plug.

PATIENTS AND METHODS

Angio-Seal was deployed in 350 patients undergoing cardiac catheterization. Vascular investigations after device application consisted of ankle/brachial-pressure-index measurement, duplex sonography, and angiography.

RESULTS

Vascular complications occurred in 10 of 350 patients. In two patients complete occlusions of the superficial femoral artery required immediate vascular surgery. Stenoses of the superficial (five patients) and the common (three patients) femoral arteries were diagnosed in 8 cases. Of these 10 patients eight were obese, in 2 cases there was a further catheterization with Angio-Seal device application via the same femoral approach. Until now six patients underwent successful surgery: in 4 cases the whole Angio-Seal device was located intraarterially, there was 1 case of intima-dissection, and 1 case remained unclear due to a diagnostic delay of 7 months. In three patients with stenoses of the common femoral arteries without hemodynamic relevance no therapy was required.

CONCLUSIONS

Occlusions or stenoses of femoral arteries after use of Angio-Seal can be diagnosed easily by duplex sonography. All hemodynamic relevant complications (n = 7 of 350 [2%]) concerned a puncture of superficial femoral arteries. In these patients vascular surgery seems to be an adequate therapy.

Low molecular weight heparin for prevention of thromboembolic complications in cardioversion--rationale and design of the ACE study (Anticoagulation in Cardioversion using Enoxaparin)

The modality and duration of anticoagulation before, during, and after cardioversion of atrial fibrillation--either with or without guidance by transesophageal echocardiography (TEE)--is still an unresolved issue. Intravenous infusion of unfractionated heparin until effective anticoagulation with phenprocoumon or warfarin is used as the standard therapy. However, this approach may be associated with several days of hospitalization because of the necessity for intravenous heparin administration. Moreover, there may be an increased risk of bleeding complications or, conversely, episodes of undercoagulation. Low-molecular weight heparin is an attractive alternative as it not only provide a safe and predictable level of anticoagulation with fewer side effects but can also be administered safely on an outpatient basis. In addition, no anticoagulation monitoring is needed. The ACE study (Anticoagulation in Cardioversion using Enoxaparin) is a randomized, prospective, open-label multicenter trial comparing the safety and efficacy of subcutaneous enoxaparin with intravenous heparin/oral phenprocoumon before and after cardioversion (stratified to TEE guidance or no TEE guidance). This article presents the rationale, design and status of the ACE study.

Incidence of cutaneous vasoactivity in patients with anemia and pulmonary hypoxia

BACKGROUND

In cutaneous laser Doppler flow (LDF)-recordings, various forms of flowmotion or vasoactivity can be observed. It is still a matter of dispute, whether flowmotion is a phenomenon of physiological or pathophysiological conditions. Therefore, we tested the hypothesis of increased vasoactivity being typical for patients with various degrees of acute and chronic anemia as well as with chronic obstructive pulmonary disease (COPD).

PATIENTS AND METHODS

We examined 12 healthy controls, 14 patients with COPD with a PO2 below 60 mmHg, 16 patients with chronic and 7 patients with acute anemia with an Hb below 12 g/dl. We used a simple LDF-technique on the dorsum of the forefoot. The regularity of blood flow frequencies was determined by calculation of the coefficient of variation.

RESULTS

Periods without vasoactivity (i.e. constant flow pattern) were 21% in normal controls, 7% in patients with COPD and 2% in patients with acute or chronic anemia. Mean frequencies in the four groups varied between 3.8 and 4.8 cpm, with significant changes only in the group with acute blood loss. However, vasoactivity was significantly more regular in the COPD- and anemia-groups as compared to normal controls, with coefficients of variation of 47.4% for controls, 31.8% for COPD- and 29.3% for chronic and 35.1% for acute anemia-patients.

CONCLUSIONS

The present paper shows that cutaneous vasoactivity is more regular in the three examined clinical entities of systemic tissue hypo-oxygenation, i.e. chronic and acute anemia and severe COPD as compared to healthy control subjects. Therefore, we hypothesize that increased vasoactivity constitutes a regulatory defense mechanism in cases of reduced oxygenation, by improving microcirculatory blood flow distribution.

Recombinant human GM-CSF in the treatment of poorly healing wounds

Although most wounds heal rapidly, impaired or delayed tissue repair represents a major clinical challenge. Current therapy is directed at providing a wound with the most favorable environment in which to heal, rather than aiming to increase the rate of healing pharmacologically. Recent studies have suggested that a number of drugs may act specifically to increase healing rates. In vivo studies have demonstrated that recombinant human granulocyte-macrophage colony-stimulating factor facilitates wound contraction, causes local recruitment of inflammatory cells, and induces keratinocyte proliferation. It also activates mononuclear phagocytes, promotes migration of epithelial cells, and further regulates cytokine production. In 2 recent placebo-controlled studies involving venous leg ulceration, subcutaneous perilesional injections of recombinant human granulocyte-macrophage colony-stimulating factor were found to be significantly better than placebo in the time to complete wound healing. In other studies, recombinant human granulocyte-macrophage colony-stimulating factor was administered topically to wounds. Several case reports have also demonstrated the use of recombinant human granulocyte-macrophage colony-stimulating factor for postsurgical wounds, chronic leg ulcers of sickle cell anemia patients, and refractory pyoderma gangrenosum. Despite proper attention to wound care, some wounds fail to heal in an appropriate fashion and may become chronic. Studies of wound physiology as well as experimental and clinical evidence suggest that recombinant human granulocyte-macrophage colony-stimulating factor may promote healing of these lesions.