Osteoblast Growth Inhibition by Unfractionated Heparin and by Low Molecular Weight Heparins: An in-vitro Investigation

2002 ◽  
Vol 8 (3) ◽  
pp. 251-255 ◽  
Author(s):  
H. J. Kock ◽  
A. E. Handschin
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Cell Cultures ◽  
Term Therapy ◽  
Low Molecular Weight ◽  
High Dose ◽  
Low Molecular Weight Heparins ◽  
In Vitro Investigation

Osteoporosis is a rare but potentially severe complication under high-dose, long-term unfractionated heparin therapy. Low-molecular-weight heparins (LMWHs) have gained increased importance in antithrombotic therapy over the past decade. Whether this heterogeneous group of drugs carries a comparable risk of osteoporosis in long-term application is unknown. In a standardized in vitro model, the effects of 4 different low-molecular-weight heparins (nadroparin, enoxaparin, dalteparin, certoparin) on osteoblast growth were studied at the same dose (50,μg/mL). As control, the effect of unfractionated heparin (Liquemin) was tested on human osteoblasts in vitro at an equal dose. Human osteoblast cell cultures were incubated with equal doses of the heparins, and cell concentrations were measured after 48 and 96 hours. In addition, a fluorescence assay was performed to detect potential cytotoxic effect of heparins on bone cells. In comparison to control groups of non-incubated cell cultures, LMWHs caused a significant inhibition of osteoblast growth (p<0.05). Therefore, the risk of osteoporosis under long-term therapy with high doses of LMWHs cannot be excluded and should be further evaluated in clinical trials.

Lack of In Vitro Cross-Reactivity Predicts Safety of Low-Molecular Weight Heparins in Heparin-Induced Thrombocytopenia

1997 ◽  
Vol 3 (1) ◽  
pp. 58-62 ◽  
Author(s):  
Sherif S. Farag ◽  
Heten Savoia ◽  
Cindy J. O'Malley ◽  
Katherine M. McGrath
Keyword(s):  
Molecular Weight ◽  
Platelet Count ◽  
Platelet Aggregation ◽  
Unfractionated Heparin ◽  
Cross Reactivity ◽  
Low Molecular Weight ◽  
Low Molecular Weight Heparins ◽  
Aggregation Assay ◽  
Heparin Induced Thrombocytopenia

Alternative anticoagulation in patients with heparin-induced thrombocytopenia (HIT) is often problematic. The relatively high cross-reactivity rate reported for the low-molecular-weight heparins (LMWH) has discouraged their use in this setting. This study has investigated the safety of using the LMWH Fragmin, based on a negative heparin-dependent platelet aggregation test using the latter, in patients with proven HIT. Fifty-three evaluable patients with clinical and laboratory evidence of HIT were evaluated for cross-reactivity with Fragmin using a Fragmin-dependent platelet aggregation test. In 20 of 38 patients who showed no in vitro cross-reactivity. Fragmin was substituted for unfractionated heparin. The outcome of these 20 patients was evaluated and compared to that of the remaining 33 patients, in whom anticoagulates were ceased or warfarin or Orgaran was used. Eighteen of 20 patients treated with Fragmin increased their platelet count by ≥50 x 109/l from a mean nadir of 57.9 ± 4.7 x 109/l within 2.8 ± 0.29 days following substitution of Fragmin for unfractionated heparin. Twenty-eight of the 33 remaining patients who did not receive Fragmin increased their platelet count by ≥50 x 109/l from a mean nadir of 53.0 ± 4.8 x 109/l within 3.0 ± 0.29 days. In seven patients (two treated with Fragmin), response could not be evaluated due to death within 36 h of cessation of heparin or discharge from hospital. The results indicate that in vitro cross-reactivity testing employing a heparin-dependent platelet aggregation assay can be safely used to select patients with HIT for further anticoagulation with LMWH. Key Words: Fragmin—Crossreactivity—Heparin-induced thrombocytopenia.

Inhibition of Human Osteoblast Growth by Unfractionated Heparin and by Low Molecular Weight Heparins in vitro

2002 ◽  
Vol 88 (08) ◽  
pp. 361-362 ◽  
Author(s):  
H. J. Kock ◽  
A. E. Handschin
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Low Molecular Weight ◽  
Human Osteoblast ◽  
Low Molecular Weight Heparins

Abbreviations: LMWHs: Low molecular weight heparins, UFH: Unfractionated heparin

Effects of Unfractionated and Low Molecular Weight Heparins on Platelet Thromboxane Biosynthesis “In Vivo”

1994 ◽  
Vol 72 (06) ◽  
pp. 942-946 ◽  
Author(s):  
Raffaele Landolfi ◽  
Erica De Candia ◽  
Bianca Rocca ◽  
Giovanni Ciabattoni ◽  
Armando Antinori ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Low Molecular Weight Heparin ◽  
Primary Source ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
Heparin Administration ◽  
To Receive

SummarySeveral “in vitro” and “in vivo” studies indicate that heparin administration may affect platelet function. In this study we investigated the effects of prophylactic heparin on thromboxane (Tx)A2 biosynthesis “in vivo”, as assessed by the urinary excretion of major enzymatic metabolites 11-dehydro-TxB2 and 2,3-dinor-TxB2. Twenty-four patients who were candidates for cholecystectomy because of uncomplicated lithiasis were randomly assigned to receive placebo, unfractionated heparin, low molecular weight heparin or unfractionaed heparin plus 100 mg aspirin. Measurements of daily excretion of Tx metabolites were performed before and during the treatment. In the groups assigned to placebo and to low molecular weight heparin there was no statistically significant modification of Tx metabolite excretion while patients receiving unfractionated heparin had a significant increase of both metabolites (11-dehydro-TxB2: 3844 ± 1388 vs 2092 ±777, p <0.05; 2,3-dinor-TxB2: 2737 ± 808 vs 1535 ± 771 pg/mg creatinine, p <0.05). In patients randomized to receive low-dose aspirin plus unfractionated heparin the excretion of the two metabolites was largely suppressed thus suggesting that platelets are the primary source of enhanced thromboxane biosynthesis associated with heparin administration. These data indicate that unfractionated heparin causes platelet activation “in vivo” and suggest that the use of low molecular weight heparin may avoid this complication.

Antithrombotic Therapy for DVT/PE

1997 ◽  
Vol 17 (03) ◽  
pp. 161-162
Author(s):  
Thomas Hyers
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Oral Anticoagulants ◽  
Cost Effective ◽  
Therapeutic Agents ◽  
Great Promise ◽  
Term Therapy ◽  
Low Molecular Weight ◽  
Long Term Therapy

SummaryProblems with unfractionated heparin as an antithrombotic have led to the development of new therapeutic agents. Of these, low molecular weight heparin shows great promise and has led to out-patient therapy of DVT/PE in selected patients. Oral anticoagulants remain the choice for long-term therapy. More cost-effective ways to give oral anticoagulants are needed.

Homozygous Protein C Deficiency: Description of a New Mutation and Successful Treatment with Low Molecular Weight Heparin

1998 ◽  
Vol 79 (04) ◽  
pp. 756-761 ◽  
Author(s):  
Paul Monagle ◽  
Maureen Andrew ◽  
Jacqueline Halton ◽  
Richard Marlar ◽  
Lawrence Jardine ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Bone Density ◽  
Skin Necrosis ◽  
Protein C ◽  
Low Molecular Weight Heparin ◽  
Whole Body ◽  
Term Therapy ◽  
Low Molecular Weight ◽  
New Mutation

SummaryWe present a kindred with a new mutation of the protein C gene, in which the proband had an unusual clinical presentation. The relationship between warfarin induced skin necrosis and level of anticoagulation was investigated. The pharmacokinetics of protein C concentrate was assessed to determine frequency of replacement therapy. The clinical and biochemical efficacy of therapy with low molecular weight heparin (LMWH) was assessed. The effect of long-term LMWH on bone density in the growing child was monitored using whole body densitometry.Warfarin therapy required an INR of greater than 3.5 to avoid skin necrosis. If protein C replacement was to be used, doses of 100 U/kg/day would have been required to maintain protein C levels consistently at or above 0.20 U/ml. While receiving prophylactic therapy with LMWH for almost 3 years, there were no episodes of recurrent thrombosis, no skin necrosis and no bleeding. Biochemical markers of in vivo thrombin generation were suppressed and within the normal range. Bone density continued to increase at the normal rate throughout the treatment period.LMWH is an effective form of long-term therapy for homozygous protein C deficient patients with measurable protein C levels.

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